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A xC AA(A0Goo?o>0oyCݷ{yݶy/yoygy{i{8?~oo[o~o]sp]]Ϸ~]ϗv?׿z|o;o~O_<6pp?pwpwp?pwpw?w??w?w?w?w?w??????????????????????~???????????????~?{?{{{/\x????~??????~???~?~?~??~?~??~?~?~?~??~?~??~?~??~???~??~?~?~??~?~?~??~??~??~?~???~?~??~??~?~???~??~??~??~??~??~???~??~?߇{{{'\{{???~??~??~??~??~??~??~??~??~???~?~?~??~?~?~??~?~?~???????????????????????w??ݿ??ߟ?9߿99'\{{????????????????????e CCCCCN@Ch@CCA@Cv@CCQ@C|@CC>@CP@CCA@Cq@CCA@C`@CCA@C @C C A@C Ё@C C 9@C @@CTable_E ?DLP~=~SUMfromi{~}SUB{n}{CTDI}SUB{w}~cdot~T~cdot~N~cdot~C%%DLP%%%%{Inn.innn%%CTDInnw%%S%%T%%%% N%%%%\ CCCCCCC0@C@@CCCCCCCC CCC@`@C@C$@Cq= ףp?CT㥛 ?C?CMb?C RQ?CC`@C@C$@C(\?CS㥛?C(\?C+η?C Q?CC^@C@C$@CMb?C)\(?CQ?CX9v?C Q?C a@C@C @CS㥛?CCCˡE?C RQ?CCC^@Ch@C$@Cjt?C?C(\?CMb?C HzG?C@C^@Ch@C$@CPn?CMbX9?CQ?CMb?C ?C$@C^@C@C$@C&1?CM?Cffffff?CT㥛 ?C ףp= ?C C C ^@C @C $@C ?C {Gz?C ?C #~j?C = ףp=?C C ^@C @C $@C jt?C On?C ףp= ?C Q?C = ףp=?C C ^@C @C $@C &1?C ~jt?C ?C ˡE?C ?C C @@C @`@C @C $@C oʡ?C |?5^?C 333333?C 333333?C )\(?C C p@C @`@C p@C $@C !rh?C jt?C RQ?C ʡE?C p= ף?CTable_F DDLP~=~{SUM}from{i}{~}SUB{n}{CTDI}SUB{w}~cdot~T~cdot~A~cdot~t%%DLP%%%%{Inn.innn%%CTDInnw%%S%%T%%%% A%%%%P t / y'DKUS.,,,..         X  GXXXXG6 XGX <<8%"FACEANDSINUSES   ,yAZ Arial normal + y'DKUS.,,,..         X  IXXXXI6 XIX <%"PETROUSBONE   ,yAZ Arial normal % y'DKUS.,,,..         X  KXXXXK6 XKX B%"ORBITS   ,yAZ Arial normal 3 y'DKUS.,,,..         X  MXXXXM6 XMX 4%"SELLAANDHYPOPHYSIS   ,yAZ Arial normal J y'DKUS.,,,..         X  OXXXXO6 XOX   %"SALIVARYGLANDS(PAROTIDANDSUBMANDIBULAR)   ,yAZ Arial normal & y'DKUS.,,,..         X  QXXXXQ6 XQX A%"PHARYNX   ,yAZ Arial normal % y'DKUS.,,,..         X  SXXXXS6 XSX nnB%"LARYNX   ,yAZ Arial normal E y'DKUS.,,,..         X  UXXXXU6 XUX  "%"VERTEBRALANDPARAVERTEBRALSTRUCTURES   ,yAZ Arial normal > y'DKUS.,,,..         X  WXXXXW6 XWX oo)%"LUMBARSPINE,DISCALHERNIATION   ,yAZ Arial normal * y'DKUS.,,,..         X  YXXXXY6 XYX =%"SPINALCORD   ,yAZ Arial normal - y'DKUS.,,,..         X  [XXXX[6 X[X :%"CHEST,GENERAL   ,yAZ Arial normal 9 y'DKUS.,,,..         X  ]XXXX]6 X]X .%"CHEST,MEDIASTINALVESSELS   ,yAZ Arial normal ? y'DKUS.,,,..         X  _XXXX_6 X_X ,,(%"CHEST,HRCT(HIGHRESOLUTIONCT)   ,yAZ Arial normal / y'DKUS.,,,..         X  bXXXXb6 XbX 8%"ABDOMEN,GENERAL   :121, 2, 3,TalV  .V0 ,yAZ Arial normal ;CTDI~=~{1}OVER{T}~{INT}SUB{-INF}SUP{+INF}D(z)dzH$3_Equation Caption         X{P}SUB{H}~=~{({~}SUB{n}{CTDI}SUB{w}{)}SUB{H}}OVER{{~}SUB{n}{CTDI}SUB{air}}%%PnnH%%8%*%%(nnzn%%CTDInnSw%%)nnSHnnUn%%gCTDInn.air'dxd Level 1 Level 2 Level 3 Level 4 Level 5(#2Z4$ X!DKUS.,,,..        TRWP6&A43'6&A43'T X  ($    hijgA<< cWPCq-]q-]951313+',,dd0 D! ) j  r V)  ! D! 0 E EJ3JJzJ_E0 B B#6e6sN66B0 j -  o  H  0 yA*m0 !  !H ]- z  Qc]!0 G$,b$0 $  V  @  0 mQ6$Q$ $m0 [ !@$!]m@Q!][ !0 yy^y;00 <! i  N !    <l  iZ4#DKUS.,,,..         X  _H4J' u;N H (7) X{P}SUB{B}~=~{({~}SUB{n}{CTDI}SUB{w}{)}SUB{B}}OVER{{~}SUB{n}{CTDI}SUB{air}}%%PnnB%%0%*%% (nnzn%%CTDInnSw%%)nnSBnnUn%%gCTDInn.air Level 1 Level 2 Level 3 Level 4 Level 5($    (#2Z4$ X!DKUS.,,,..        TRWP6&A43'6&A43'T X  qsirgC<< c  iZ4#DKUS.,,,..         X  _H4J' u;N H (8)$359=AEIMQ4"""""""" E~=~{E}SUB{DLP}~cdot~~DLP Level 1 Level 2 Level 3 Level 4 Level 5($    zi{gM << deUU(O[|$0  2  a  .3  0` (#(#$%XXnEXXnXXnED4DLPXXnXX{nDLPa, b, c,Niveau 1Niveau 2Niveau 3Niveau 4Niveau 50#1..Lyna.   .0  iZ4#DKUS.,,,..         X  H4J' u;N Hu (HU)%%CTDI%%%%%:1%%>T%%SLnn.>nnt>nn.CnntC%%D%%=(%%zz%%)%% dz  y)DKUS.,,,..         X  XXXX@<<)a= XX  1  ?@?@@@?@@ @ @SKEMA A?@@?@@?@@@ @ @ @  @ "@$@&@(@SKEMA A?@??@@@@@ @  @ "@SKEMA A?@?@?@@@@ @ @  @ "@SKEMA A(EGMSY_ekqAutoList131.1.1.1.1.1.1.1.(EGMSY_ekqAutoList141.1.1.1.1.1.1.1. ?@@SKEMA C(EEGMSY_ekqAutoList231.1.1.1.1.1.1.1. 6 iZ4#DKUS.,,,..         X  _H4J' u;N H(_mSv_)󀀀(9) ?@@SKEMA B?@?@@?@@@ @ @ @  @ "@SKEMA A YMSAD~=~{1}OVER{}~{INT}SUB{-{I}OVER{2}}SUP{+{I}OVER{2}}{D}SUB{N,I}~(z)dz(%EGMSY_ekqAutoList151.1.1.1.1.1.1.1. MSAD~=~{T}OVER{I}~CTDI / iZ4#DKUS.,,,..         X  _H4J' u;N Hllu (_mGy_Ԁcm) iZ4#DKUS.,,,..         X  u (mSv)(5EGMSY_ekqAutoList161.1.1.1.1.1.1.1.(EEGMSY_ekqAutoList171.1.1.1.1.1.1.1. , iZ4#DKUS.,,,..         X  _H4J' u;N Hu (_mGy_) , iZ4#DKUS.,,,..         X  _H4J' u;N Hu (_mGy_) ;CTDI~=~{1}OVER{T}~{INT}SUB{-INF}SUP{+INF}D(z)dz d , iZ4#DKUS.,,,..         X  _H4J' u;N H (_mGy_) @{CTDI}SUB{w}~=~(1/3{CTDI}SUB{100,c}~+~2/3{CTDI}SUB{100,p})Table_ATable_B%%gCTDInn.w%%eg%%g(%%\g1%%g/%%g3%%QgCTDInn.100nn.,nn.c%%kg%%%g2%%g/%%g3%% gCTDInn .100nn .,nn .p%% g)%%CTDI%%%%%:1%%>T%%SLnn.>nnt>nn.CnntC%%D%%=(%%zz%%)%% dzTable_CTable_DTable_Edd [~~~{~}SUB{n}{CTDI}SUB{w}~=~{1}OVER{C}~(1/3{CTDI}SUB{100,c}~+~2/3{CTDI}SUB{100,p})Table_Fnn\n%%CTDInnDw%%]%%%:1%%>C%%(%%1%%O/%%3%%CTDInn100nnN ,nno c%% %% 2%% /%%I 3%% CTDInnQ 100nn,nn8p%%z) k iZ4#DKUS.,,,..         X  _H4J' u;N H & .(_mGy_)( {  3   )  iZ4#DKUS.,,,..         X  _H4J' u;N H& &XX  #XX &&# ( _mGy_(_mAs_)1)( {  2   ) \ iZ4#DKUS.,,,..         X  _H4J' u;N H & (_mGy_)( {  1   )iA  C%%MSAD%%o%5%%I:T%%h>I%%CTDI 2DLP~=~{SUM}from{i}{CTDI}SUB{w}~cdot~T~cdot~N%%DLP%%%%{Inn.i%%qCTDInnw%%%%>T%%%%zN%%#MSAD%%o#%5N%%I1%%`%%Lnn%nnInng2nn%nnInn.2%%2#DnnNnn ,nn,I%%#(%%#z%%(#)%%e#dzNiveau 1Niveau 2Niveau 3Niveau 4Niveau 5 & y'DKUS.,,,..         X  XXXX6 XX A%"KIDNEYS   ,yAZ Arial normal($$   1   -p~=~{T~N}OVER{I~(N-1)~+~T}~=~{T~N}OVER{L}%%!p%%%%%:T%%:N%%>I%%.>(%%k>N%%>%%X>1%%>)%%G>%%>T%%a%%%:T%%n:N%%>L&0 d d'dxdSKEMA BSKEMA CSKEMA ASKEMA ASKEMA ASKEMA A(;t$2  0  .3  0  (b$0  0` (#(#2   .3  0 ` (#` (#(xM$0  0` (#(#0 ` (#` (#2(  0  )3  0 (# (# CE~=~{SUM}from{T,R}{w}SUB{R}~cdot~{w}SUB{T}~cdot~{D}SUB{T}%%E%%%%Inn.Tnn.,nn.R%%wnnR%%%%6wnnT%%W%%DnnWT ' y'DKUS.,,,..         X  @XXXX@6 X@X @%"PANCREAS   ,yAZ Arial normal - y'DKUS.,,,..         X  BXXXXB6 XBX :%"ADRENALGLANDS   ,yAZ Arial normal . y'DKUS.,,,..         X  DXXXXD6 XDX 9%"PELVIS,GENERAL   ,yAZ Arial normal - y'DKUS.,,,..         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(# O~Z`@@@pf~[>` 0e~[0@ B `@0`\ 0O~[  @@ S\? |?Nr?  ?Nq? N~qO~q @P~q  0 `P~.A@ "Pp? O~p  P~pC ?P~q    P~q@  @Pp?a~t`b~p p?b~wAc~xpc~q@ ~p #0~K$@~K'~p`8~rlH~ppq~g~W~ sY ~ X!DKUS.,,,..        TRWP6&A43'6&A43'T X    XXXXUKDK,.ԛ@*&ë&XX  t&&ë EUROPEANGUIDELINES F ONQUALITYCRITERIAFORCOMPUTEDTOMOGRAPHY#&ë&t#kmWGCx< D`q-]@ HuuED`D J ##    ##@*@  &EUR16262  )%*   t&&ë EUROPEANGUIDELINES  ONQUALITYCRITERIÀFORCOMPUTEDTOMOGRAPHY  U  &ë&t  TheseGuidelinesresultfromthecooperativeeffortofthefollowingEuropeanStudyGroupofϜradiologistsandphysicistsinvolvedindiagnosticcomputedtomographyandconsultationwithexpertsinthefield:Radiologists:G.Bongartz(CH)S.J.Golding(UK)̜A.G.Jurik(DK)M.Leonardi(I)E.v.P.vanMeerten(NL)Physicists:J.Geleijns(NL)K.A.Jessen(DK)W.Panzer(D)P.C.Shrimpton(UK)G.Tosi(I)ThepresentReporthasbeensupportedandeditedintheframeworkoftheEuropeanϜCommission'sRadiationProtectionActionsby:H.G.MenzelH.SchibillaD.Teunen @*@vv$EUR16262EN  ,). М   Л@RR 6 &&ëQUALITYCRITERIAFORCOMPUTEDTOMOGRAPHY#&ë&6 v#    @"TableofContents  : p!p!F#Page̜ PREAMBLE ~"~"G#III $ s   ': ' 'CHAPTER1 0 : QualityCriteriaforComputedTomography""I#: #: #1    ]c  0 b 0: b#b#]c1 20' : #: #  Introduction   v  ;        O ~"~"H#' #' #20@' : #: #]c1 l ݌   Ќ  ]c  0 b 0: b#b#]cl 20' : #: #  Objectives~"~"H#' #' #2]cl ݌ p  Ќ  ݛ]c  0 b 0: b#b#]c> 20' : #: #  GeneralPrinciplesAssociatedwith""I#' #' #4]c> y ݌ A  Ќ  0 b 0: b#b#0' : #: #GoodImagingTechnique;Technical, ' #' # 0 b 0: b#b#0' : #: #ClinicalandPhysicalParameters ' #' # М]c  0 b 0: b#b#]c20' : #: #  GuidanceonImplementationM"M"H#' #' #11]c>݌  Ќ  ]c  0 b 0: b#b#]c20' : #: #  DescriptionofTermsusedintheListsM"M"H#' #' #12]c݌  Ќ  0 b 0: b#b#0' : #: #ofQualityCriteria ' #' # Л]c  0 b 0: b#b#]c020' : #: #  ݜListofQualityCriteriaforComputedM"M"H#' #' #15]c0k݌ 'v Ќ  0 b 0: b#b#0' : #: #Tomography ' #' # ]c  0 b 0: b#b#]ct20' : #: #  ListofReferencesM"M"H#' #' #62]ct݌  Ќ  ]c  0 b 0: b#b#]cO20' : #: #  AppendixI:GuidelinesonRadiationDoseM"M"H#' #' #64]cO݌  Ќ  0 b 0: b#b#0' : #: #tothePatient ' #' # ̜ CHAPTER2 0 : SummaryofResearchResultsandOngoingM"M"H#: #: #71  \ 0 b 0: b#b#ExperimentsRelatedtotheEstablishment : #: # 0 b 0: b#b#oftheQualityCriteriaforCTandReference : #: # 0 b 0: b#b#DoseValues : #: #  CHAPTER3 0 : QualityCriteriaImplementationandAuditGuidelinesM"M"H#: #: #87 &u   CHAPTER4 0 : GlossaryM"M"H#: #: #99 " М& &&&ëXX &&DKUK.,@)II#XXXX##&ë&XX+#UK.,DK,.Jԛ  1-7   Ӝ PREAMBLE   М֛ComputedTomography(CT)wasintroducedintoclinicalpracticein1972andrevolutionisedxrayimagingbyprovidinghighqualityimageswhichreproducedtransversecrosssectionsofthebody.Thetechniqueofferedinparticularimprovedlowcontrastresolutionforbettervisualizationofsofttissue,butwithrelativelyhighabsorbedradiationdose.Theinitialpotentialoftheimagingmodalityhasbeenrealisedbyrapidtechnologicaldevelopments,resultinginacontinuingexpansionofCTpractice. Asaresult,thenumbersofexaminationsareincreasingtotheextentthatCThas l  madeasubstantialimpactonnotonlypatientcarebutalsopatientandpopulationexposurefrommedicalxrays. 󛀀Todayitaccountsforupto40%oftheresultantcollectivedosefromdiagnostic  e  radiologyinsomecountriesoftheEuropeanUnion(EU)(1,2).SpecialmeasuresareconsequentlyrequiredtoensureoptimisationofperformanceinCT,andofpatientprotection.Incomparisonwithconventionalradiology,therelativecomplexity,rangeandflexibilityofscannersettingsinCTmayadverselyaffectthelevelsofimagequalityandpatientdoseachievedinpractice.Thereis,therefore,aneedtoestablishqualitycriteriaforCTwhichwillprovidetherequiredclinicalinformationinitsoptimalform,withminimumdosetothepatient.Thequalitycriteriaconcept,asdevelopedforconventionalxrayexaminationsofadultandpaediatricpatientsbytheEuropeanCommissions(EC)researchactions,hasprovedtobeaneffectivemethodforoptimisingtheuseofionisingradiationinmedicalimagingprocedures.ThepurposeofqualitycriteriaforCTwasthereforealsotoprovideanoperationalframeworkforradiationprotectioninitiativesforthismodality,inwhichtechnicalparametersrequiredforimagequalityareconsideredinrelationtopatientdose.CTcontinuestoevolveandtheresearchbaseforguidanceislimited.Thestudygroupon DevelopmentofQualityCriteriaforCThasdrawnextensivelyontheresultsoftheprojectscarriedoutintheECsResearchActiononOptimisationofRadiationProtectionofthePatient.IthasalsogainedinspirationfromtheguidelinesoftheGermanFederalChamberofPhysiciansonQualityAssuranceinComputedTomography(3).TheprimaryworkingdocumentofApril1997hasbeencommentedonbyexternalexpertsfromcountriesinEuropeandwaspresentedattheECworkshoponreferencedoseandqualityinmedicalimaging,October1997,Luxembourg(4).AreviseddocumentdatedMay1998waspostedontheInternet(http://www.drs.dk/CT/document/)andadvertisedtoallnationaldelegatesoftheEuropeanAssociationofRadiology(EAR)andtheEuropeanFederationofOrganisationsforMedicalPhysics(EFOMP),inadditiontotheEuropeanNationalBoardsofHealthandtheassociationsofradiographers.AnotificationwasalsogiventothesebodiesofaWorkshoponQualityCriteriaforComputedTomographythatwasheldinAarhus,Denmark,1314thNovember1998.Thedocumentwasopenfordiscussionattheworkshopandconsequentlyrevisedtothepresentfinalguidelines.Furthermore,thestudygroupperformedapilotstudyin19971998totesttheimagequalitycriteria,withsimultaneousregistrationoftheradiationdose,forfivetypesofexamination:1)faceandsinuses,2)vertebraltrauma,3)HRCTofthelung,4)liverandspleenand5)osseouspelvis(5).Theresultshavebeentakenintoaccountinthefinalguidelines,includingthespecificationofdiagnosticreferencedosevalues.TheseguidelinesonQualityCriteriaforComputedTomographyprovideguidanceonthedefinitionandintroductionofqualitycriteriafordiagnosticimagesandequipmentperformance,aswellasfordosetothepatient.Thereportcontainsfourchapters.ThefirstchapterpresentsgeneralprinciplesassociatedwithgoodimagingtechniqueandliststheQualityCriteriaforsixgroupsofCTexamination:cranium,faceandneck,spine,chest,abdomenandpelvis,andbonesandjoints.Eachgroupofexaminationsissubdividedintothemostcommonexaminationsofspecificorgansorpartsofthebody.ThechapterdefinesDiagnosticRequirementsbyspecifyinganatomicalimagecriteria;indicatesCriteriafortheRadiationDosetothePatient;andgivesExamplesofGoodImagingTechniquebywhichtheDiagnosticRequirementsandDoseCriteriacanbeachieved.ThesecondchaptersummarisesavailableresearchresultsaswellastheongoingexperimentswhichhavesupportedtheestablishmentoftheQualityCriterialistedinChapter1,andsuggestsdirections J2.9 forfutureresearch.ThethirdchapteroutlinesaprocedureforimplementingandauditingtheQualityCriteriaandamodelforimagequalityassessment.Thefourthchaptercontainsaglossaryoftermsusedintheguidelines.̜֛ThisinitiativeinCTwillcontinuewithintheframeworkofforthcomingresearchprogrammesandisreflectedbytheCouncilDirectiveonhealthprotectionofindividualsagainstdangersofionisingradiationinrelationtomedicalexposure(6).FortechniquessuchasCTthenewDirectiverequirestheestablishmentofqualityassurancemeasureswhichincludecriteriathatcanbeemployedandcheckedinacomparablewaysothattheradiationdosetothepatientcanbelinkedtotherequiredimagequalityandtotheperformanceofthechosentechnique.̛̜EmergingtechniquessuchasmultisliceCTandfluoroCThavenotbeenspecificallyaddressed.WiththecontinuingevolutionofCTtechnologytherewillbeaneedforregularupdatingoftheguidelines.̛ ItisthehopeoftheEuropeanCommissionsservicesthattheelaborationoftheQuality   CriteriaforCTwillstimulatetheprofessionalsconcernedtolookforimprovementsinthecriteriainsuchawaythatdaytodaypracticeachievesoptimaldiagnosticinformationandfulfilsatthesametimetherequirementsforoptimizationofradiationprotectioninthe1997CouncilDirective. ̜Mr.S.Kaiser0 : 0' : #: #0 ' #' #0 # #0v##0;v#v#Dr.H.Forsstrm];#;# DirectorateGeneral0 0 # #0v##0;v#v#DirectorateGeneral.};#;# Environment,NuclearSafetyand0  0v##0;v#v#Science,ResearchandDevelopmentN;#;# CivilProtection0 ' 0 ' #' #0 # #0v##0;v#v#NuclearFissionandRadiationProtection;#;# RadiationProtection1.0 b KaulA,BauerB,BernhardtJ,NoskeDandVeitR.Effectivedosestomembersofthepublic 4  fromthediagnosticapplicationofionizingradiationinGermany.EuropeanRadiology 7 ,1127 ! Є1132(1997) b#b# 2.0 b ShrimptonPCandEdyveanS.CTscannerdosimetry.BritishJournalofRadiology 71 ,13 -!|$ (1998) "Q%b#b#  3.0 b LeitlinienderBundesrztekammerzurQualittssicherunginderComputertomographie.Dt. #' rztebl. 89 :Heft49(1992)(Englishtranslation:GuidelinesoftheFederalChamberof u$ ( Physiciansonqualityassurrenceincomputedtomography.InternalDocumentCECXII/354/92-EN) b#b# 4.0 b BauerB,CorbettRH,MorresBH,SchibillaHandTeunenD(Eds).Proceedingsofa ' $, WorkshoponReferenceDosesandQualityinMedicalImaging,Luxembourg,October23251997.RadiationProtectionDosimetry 80 ,Nos13(1998)_)%.b#b# Л̜5.0 b JurikAG,PetersenJ,BongartzB,GoldingSJ,LeonardiM,vanMeertenPvE,GeleijnsJ, +T'0 JessenKA,PanzerW,ShrimptonP,TosiG.Clinicaluseofimagequalitycriteriaincomputedtomographyrelatedtoradiationdose.Apilotstudy.EuropeanRadiology(tobesubmitted) b#b# Л̜6.0 b CouncilDirective97/43/EURATOMof30June1997onhealthprotectionofindividuals /i+5 againstthedangersofionizingradiationinrelationtomedicalexposure.OfficialJournalL180,p.22,9.7.1997.(RepealingDirective84/466/EURATOM,O.J.no.L265,p.1,5.10.1984) 0 -7b#b# М%   %A# 6 &&ëChapter1#&ë&6 9#     Ӏ 6 &&ëQUALITYCRITERIAFORCOMPUTEDTOMOGRAPHY#&ë&6 :# :  TableofContents   E   p!p!F#Page INTRODUCTION ""I#2 ^  ̜ OBJECTIVES ""I#2   ̜ GENERALPRINCIPLESASSOCIATEDWITHGOODIMAGINGTECHNIQUE; ""I#4 [  М TECHNICAL,CLINICALANDPHYSICALPARAMETERS  0 ̜ GUIDANCEONIMPLEMENTATION M"M"H#11 % ̜ DESCRIPTIONOFTERMSUSEDINTHELISTSOFQUALITYCRITERIA M"M"H#12 | ̜ LISTOFQUALITYCRITERIAFORCOMPUTEDTOMOGRAPHY M"M"H#15 "q CraniumM"M"H#16  FaceandNeckM"M"H#20  SpineM"M"H#34 j ChestM"M"H#40 ; AbdomenandPelvisM"M"H#46  [ BonesandJointsM"M"H#58 , ̜ LISTOFREFERENCES M"M"H#62   ̜ APPENDIXI: 󛀜GuidelinesonRadiationDosetothePatientM"M"H#64 % t" _______TechnicaltermsaredefinedintheGlossary(Chapter4)andareprintedinitalicswhentheyareusedforthefirsttimeintheseguidelines.  %/")   Ӝ XX&&ëINTRODUCTION#&ë&XX>@#   ThetwobasicprinciplesofradiationprotectionformedicalexposuresasrecommendedbyICRParejustificationofpracticeandoptimisationofprotection,includingtheconsiderationofdiagnostic @ referencelevels(1,2,3).Theemphasisistokeepdosetothepatientaslowasreasonably ` achievable(_ALARA_),consistentwithclinicalrequirements.TheseprinciplesarelargelytranslatedintoalegalframeworkbytheCouncilDirective(4).Justificationisthefirststepinradiationprotectionandnodiagnosticexposureisjustifiablewithoutavalidclinicalindication.Everyexaminationmustresultinanetbenefitforthepatient.Thiswillbethecasewhenitcanbeanticipatedthattheexaminationwillinfluencetheefficacyofclinicaldecisionsmadewithrespecttothefollowing:C v $# &}'(PQRSC0 b 2"3  0: b#b#diagnosisj : #: # --0 b 2"3  0: b#b#patientmanagementandtherapy; : #: # 0 b 0: b#b# b 2"3  0: : #: #finaloutcomeforthepatient [ : #: # C v $$vCJustificationforcomputedtomography(CT)alsoimpliesthattherequiredresultcannotbeachievedbyothermethodswhichareassociatedwithlowerrisksforthepatient.UltrasoundandMRIofferalternativestoCTinmanyareasofapplication.ThemagnitudeoftheabsorbeddoseinCTmeansthatparticularcareisrequiredfortheexaminationofpregnantwomen,children,andparticularlysensitiveorgansortissues.Criteriaforapprovingclinicalrequestsinthesecircumstancesneedtobeparticularlystringent.Asacorollary,justificationrequiresthattheimagingprocedureisacceptablyreliable,i.e.itsresultsarereproducibleandhavesufficientpredictivevaluewithrespecttotheparticularclinicalquestion.Justificationalsonecessitatesthatasuitablyqualifiedperson(asrecognisedbythecompetentϜauthority),usuallyaradiologist,approvestheneedforCTandtakesoverallclinicalresponsibilityfortheexamination.Thispersonshouldworkinclosecontactwiththereferringphysicianinordertoestablishtheinvestigationproceduremostappropriatetopatientmanagement.Thepersonresponsiblemayauthorizeanappropriatelyqualifiedoperator(egradiographerormedicalradiationtechnologist)toperformtheexamination.Inrespectofradiologicalexaminations,ICRPdrawsattentiontotheuseofdiagnosticreferencelevelsasanaidtooptimisationofprotectioninmedicalexposure.Oncethediagnosticexaminationhasbeenclinicallyjustified,thesubsequentimagingprocessmustbeoptimised.Theoptimaluseofionisingradiationinvolvestheinterplayofthreeimportantaspectsoftheimagingprocess:3M : ' 3C v $$vC0 b 0Mb#b# b 2"3  0MM#M#diagnosticqualityoftheimageu$ (M#M# --0 b 0Mb#b# b 2"3  0MM#M#radiationdosetothepatientF%!)M#M# --0 b 0Mb#b# b 2"3  0MM#M#choiceofexaminationtechnique&f"*M#M# C v $$vCThisdocumentprovidesguidanceonallthreeoftheseaspectsforanumberofselectedCTexaminations,asanexampleofanachievablestandardofdaytodaypractice. TheQualityCriteria ($- presenteddefinealevelofperformanceconsiderednecessarytoproduceimagesofstandardqualityforaparticularanatomicalregion.  4*&/ Forcomparability,theaimhasbeentoestablishGuidelinesonQualityCriteriaforCTinaccordancewiththestructureoftheexisting"EuropeanGuidelinesforDiagnosticRadiographicImages"foradultandpaediatricpatientsinconventionalradiology(5,6).̜ XX&&ëOBJECTIVES /m+5  #&ë&XXR#ԛTheobjectivesoftheguidelinesaretoachieve:C v $$vC0 b 0Mb#b# b 2"3  0MM#M#adequateimagequality,comparablethroughoutEurope~2.9M#M# --0 b 0Mb#b# b 2"3  0MM#M#reasonablylowradiationdoseperexaminationM#M# C v $$vCTheguidelinesalsoprovideabasisforaccurateradiologicalinterpretationoftheimage.TheguidelinesaredirectedprimarilyatclinicalandtechnicalstaffwhoperformCTandreportonit.TheywillalsobeofinteresttothoseresponsibleforthedesignofCTequipmentandforthemaintenanceofitsfunction.Theywillbehelpfultothosewhohaveresponsibilityforequipmentspecificationandpurchase.Theguidelinesrepresentanachievablestandardofgoodpracticewhichmaybeusedasabasisforfurtherdevelopmentbytheradiologicalcommunity.Insupportoftheseobjectives,theguidelinesprovidestructuredadviceonthefollowingkeyareas: XX&&ëDiagnosticRequirements#&ë&XX[X# n   Thediagnosticrequirementsarepresentedasimagecriteria,whichinCTarebasicallyoftwodifferent  [  types:anatomicalandphysicalimagecriteria.Theanatomicalimagecriteriaincluderequirementswhichmustbefulfilledwhenspecificclinicalquestionsareposed.Thesecriteriamaybedefinedintermsof visualization or criticalreproduction ofanatomicalfeatures(seeDescriptionofTerms,  p.12).Evaluationofimagequalitybasedonanatomicalcriteriatakesintoaccountboththeanatomyoftheareaunderexaminationandthecontrastbetweendifferenttissueswhichisessentialforthedetectionofpathologicalchanges.Thephysicalimagecriteriaaremeasurablebyobjectivemeans.Theyincludenoise;lowcontrast  Мresolution;spatialresolution;linearity;uniformityandstabilityoftheCTnumbers;slicethicknessand i dose.ItismandatoryfordepartmentscarryingoutCTtoemployasuitablequalityassuranceprogrammetomaintainimagingperformanceatoptimallevels.Routinetestshavetospecifyphysicalimagecriteria. XX&&ëCriteriaforRadiationDosetothePatient#&ë&XXg]#  ~ ConsiderationofdoseconstrainthasparticularimportanceinCT,sincethisisrecognisedasarelativelyhighdosemodality.ICRP(1)hasrecommendedthedoseconstraintconceptformedicalexposure,thatistranslatedtodiagnosticreferencelevelsfordiagnosticradiography(3).TheapplicationofthisconceptisinlinewiththereferencedosevaluesforastandardsizedpatientindicatedinthepreviousEuropeanGuidelines(5,6).InthepresentguidelinestentativereferencedosevaluesforCThavebeenestablishedforselectedexaminationsinordertofacilitatecomparisonofexaminationprotocolsusedindifferentdepartmentsandwithdifferenttypesofequipment.ThereferencedosevaluesarebasedondosedescriptorsdefinedinAppendix1.Moredetaileddiscussion ""q% ofdosimetryisgiveninChapter2.̜ Diagnosticreferencedosevaluesprovidequantitativeguidancetohelpidentifyrelativelypoor $ ( orinadequateuseofthetechniqueratherthananindicationofsatisfactoryperformance.̛Furtherdosereductionbelowreferencevaluesmaybeachievablewithoutcompromisingthediagnosticvalueofanindividualexamination,andthisshouldalwaysbepursued.  '8$,  XX&&ëExamplesofGoodImagingTechnique#&ë&XXb# )%.  ImagequalityinCTdependsprimarilyontwotypesofscanparameter:doserelatedparametersand |*&/ thosewhicharerelatedtoprocessingandviewingoftheimage.Botharehardwarerelated.Doserelatedparametersaretheslicethickness,interslicedistance,pitchfactor,volumeofinvestigation, ,m(1 exposurefactorsandgantrytilt.Processingparametersarefieldofview,numberofmeasurements, ,>)2 reconstructionmatrixsize,reconstructionalgorithmandwindowsettingsforviewingtheimage.Impact -*3 oftheseparametersonimagequalityandpatientdosecanbeassessedquantitativelybymeasurementwithtestphantoms,whichprovideinformationessentialtothedefinitionofquality b/+5 criteriarelatedtotheclinicalobjective.̜  1S-7  XX&&ëGENERALPRINCIPLESASSOCIATEDWITHGOODIMAGINGTECHNIQUE:  TECHNICAL,CLINICALANDPHYSICALPARAMETERS #&ë&XXf#  ЛCTimagesaretheresultoftheinterplayofphysicalphenomenagivingrisetoattenuationbythe \ patientofathinfanbeamofxrays,andcomplextechnicalprocedures.EachimageconsistsofamatrixofpixelswhoseCTnumbers(measuredinHounsfieldUnits,HU)representattenuationvalues M forthevolumeelements(voxels)withintheslice.Thequalityoftheimagerelatestothefidelityofthe  CTnumbersandtotheaccuratereproductionofsmalldifferencesinattenuation(lowcontrastresolution)andfinedetail(spatialresolution).Goodimagingperformancedemandsthatimagequalityshouldbesufficienttomeettheclinicalrequirementfortheexamination,whilstmaintainingthedosetothepatientatthelowestlevelthatisreasonablypracticable.Inordertoachievethis,theremustbecarefulselectionoftechnicalparametersthatcontrolexposureofthepatientandthedisplayoftheimages,andalsoregularcheckingofscannerperformancewithmeasurementofphysicalimageparametersaspartofaprogrammeofqualityassurance.XX&&ë\>  \>alV1  .0 b   TechnicalParameters:DisplayandExposureParameterswithanInfluenceon (w  ImageQualityandDose \>allVیd b#b# Ќ  #&ë&XXBl#0 b   b  b#b# 1.10 b Nominalslicethickness"b#b# 0 b ThenominalslicethicknessinCTisdefinedasthefullwidthathalfmaximum(FWHM)of  thesensitivityprofile,inthecentreofthescanfield;itsvaluecanbeselectedbytheoperator u accordingtotheclinicalrequirementandgenerallyliesintherangebetween1mmand10mm.Ingeneral,thelargertheslicethickness,thegreaterthelowcontrastresolutionintheimage;thesmallertheslicethickness,thegreaterthespatialresolution.Iftheslicethicknessislarge,theimagescanbeaffectedbyartefact,duetopartialvolumeeffects;ifthe  slicethicknessissmall(e.g.12mm),theimagesmaybesignificantlyaffectedbynoise. b#b# 0 b   b  b#b# 1.20 b Interslicedistance/pitchfactor,{b#b# 0 b Interslicedistanceisdefinedasthecouchincrementminusnominalslicethickness.In L helicalCTthepitchfactoristheratioofthecouchincrementperrotationtothenominalslicethicknessattheaxisofrotation.Inclinicalpracticetheinterslicedistancegenerallyliesintherangebetween0and10mm,andthepitchfactorbetween1and2.TheinterslicedistancecanbenegativeforoverlappingscanswhichinhelicalCTmeansapitch<1.Ingeneral,foraconstantvolumeofinvestigation,thesmallertheinterslicedistanceorpitchfactor,thehigherboththelocaldoseandtheintegraldosetothepatient.Theincreaseinthelocaldoseisduetosuperimpositionofthedoseprofilesoftheadjacentslices.Theincrease  # intheintegraldoseisduetoanincreaseinthevolumeoftissueundergoingdirectirradiationasindicatedbyapackingfactor.V"%b#b# 0 b Inthosecaseswhere3Dreconstructionorreformattingoftheimagesincoronal,sagittalorobliqueplanesisrequired,itisnecessarytoreducetheinterslicedistancetozeroorperformahelicalscan.Inscreeningorexaminationsperformedwithregardtocontrolofdiseaseitcanbediagnosticallyjustifiabletohaveaninterslicedistancecorrespondingtohalftheslicethicknessorapitchfactorof1.52. b#b# 1.30 b Volumeofinvestigation(-%-b#b# 0 b Volumeofinvestigation,orimagingvolume,isthewholevolumeoftheregionunderexamination.Itisdefinedbytheoutermostmarginsofthefirstandlastexaminedslicesorhelicalexposure.Theextentofthevolumeofinvestigationdependsontheclinicalneeds;ingeneralthegreateritsvaluethehighertheintegraldosetothepatient,unlessanincreasedinterslicedistanceorpitchfactorisused. b#b# 1.40 b Exposurefactors.*4b#b# 0 b Exposurefactorsaredefinedasthesettingsofxraytubevoltage(kV),tubecurrent(mA)andexposuretime(s).Ingeneral,onetothreevaluesoftubevoltage(intherangebetween 70,6 80and140kV)canbeselected.AhightubevoltageisrecommendedforhighresolutionCT(HRCT)ofthelungsandmaybeusedforexaminationofosseousstructuressuchasthespine,pelvisandshoulder.Softtissuestructuresareusuallybestvisualisedusingthe 2.9 standardtubevoltageforthegivenequipment.Insomecasesofquantitativecomputed  tomography(QCT),thesamesliceisexaminedwithtwodifferentvaluesoftubevoltage,in  ordertosubtractcorrespondingimagesandderiveinformationaboutthecompositionofparticulartissues.Atgivenvaluesoftubevoltageandslicethickness,theimagequalitydependsontheproductofxraytubecurrent(mA)andexposuretime(s),expressedinmAs.AbsolutevaluesofmAsnecessaryforanimagingtaskwilldependonthetypeofscannerandthepatientsizeandcomposition.ForaparticularCTmodel,anincreaseinradiographic  exposuresetting(mAs)isaccompaniedbyaproportionalincreaseinthedosetothepatient. h  Relativelyhighvaluesofradiographicexposuresetting(mAs)shouldthereforebeselectedonlyinthosecaseswhereahighsignaltonoiseratioisindispensable. Y b#b# Л0 b Amethodforcorrelatingtheexposuresetting(foragiventubevoltage)withtheoverallimagequalityisbydrawingcontrastdetailcurvesforeachavailablesetting.ThesecurvesexpresstheminimumsizeofdetailwhichcanstillberecognisedintheCTimageforagivendifferenceincontrastbetweenthedetailandthesurroundingmedium. b#b# 1.50 b Fieldofview b#b# 0 b Fieldofview(FOV)isdefinedasthemaximumdiameterofthereconstructedimage.Itsvaluecanbeselectedbytheoperatorandgenerallyliesintherangebetween12and50cm.ThechoiceofasmallFOVallowsincreasedspatialresolutionintheimage,becausethewholereconstructionmatrixisusedforasmallerregionthanisthecasewithalargerFOV;thisresultsinreductionofthepixelsize.Inanycase,theselectionoftheFOVmusttakeintoaccountnotonlytheopportunityforincreasingthespatialresolutionbutalsotheneedforexaminingalltheareasofpossibledisease.IftheFOVistoosmall,relevantareasmaybeexcludedfromthevisibleimage.IfrawdataareavailabletheFOVcanbechangedbypost I processing. b#b# 1.60 b Gantrytilt b#b# 0 b Gantrytiltisdefinedastheanglebetweentheverticalplaneandtheplanecontainingthexraytube,thexraybeamandthedetectorarray.Itsvaluenormallyliesintherangebetween ^ Є25$and+25$.Thedegreeofgantrytiltischosenineachcaseaccordingtotheclinical /~ objective.Itmayalsobeusedtoreducetheradiationdosetosensitiveorgansortissuesand/ortoreduceoreliminateartefacts. b#b# 1.70 b Reconstructionmatrixs"b#b# 0 b Reconstructionmatrixisthearrayofrowsandcolumnsofpixelsinthereconstructedimage,typically512x512. b#b# 1.80 b Reconstructionalgorithm"&b#b# 0 b Reconstructionalgorithm(filter,orkernel)isdefinedasthemathematicalprocedureusedfor #' theconvolutionoftheattenuationprofilesandtheconsequentreconstructionoftheCT Y$ ( image.InmostCTscanners,severalreconstructionalgorithmsareavailable.TheappearanceandthecharacteristicsoftheCTimagedependstronglyonthealgorithmselected.MostCTscannershavespecialsofttissueorstandardalgorithmsforexaminationofthehead,abdomenetc.Dependingonclinicalrequirements,itmaybenecessarytoselectahighresolutionalgorithmwhichprovidesgreaterspatialresolution,fordetailedrepresentationofboneandotherregionsofhighnaturalcontrastsuchaspulmonaryparenchyma. b#b# 1.90 b Windowwidth+(1b#b# 0 b WindowwidthisdefinedastherangeofCTnumbersconvertedintogreylevelsanddisplayedontheimagemonitor.ItisexpressedinHU.Thewindowwidthcanbeselectedbytheoperatoraccordingtotheclinicalrequirements,inordertoproduceanimagefromwhichtheclinicalinformationmaybeeasilyextracted.Ingeneral,alargewindow(forinstance400HU)representsagoodchoiceforacceptablerepresentationofawiderangeoftissues.Narrowerwindowwidthsadjustedtodiagnosticrequirementsarenecessarytodisplaydetailsofspecifictissueswithacceptableaccuracy. b#b#  :2.9 1.100 b Windowlevelb#b# 0 b WindowlevelisexpressedinHUandisdefinedasthecentralvalueofthewindowusedforthedisplayofthereconstructedCTimage.Itshouldbeselectedbythevieweraccordingtotheattenuationcharacteristicsofthestructureunderexamination. b#b# XX&&ë\>  \>җV2  .0 b   ClinicalandAssociatedPerformanceParameters \>җVیb#b# Ќ  #&ë&XXx#0 b AseriesofclinicalfactorsplayaspecialpartintheoptimaluseofionisingradiationinCT.TheyaredescribedhereinordertoensurethatanappropriateCTexaminationiscarriedout,providingdiagnosticqualitywithareasonableradiationdoseforthepatient. b#b# Л0 b ACTexaminationshouldthereforeonlybecarriedoutonthebasisofajustifiable    clinicalindication,andexposureofthepatientshouldalwaysbelimitedtotheminimumnecessarytomeetclinicalobjectives. r b#b# 0 b Adequateclinicalinformation,includingtherecordsofpreviousimaginginvestigations,mustbeavailabletothepersonapprovingrequestsforCT. b#b# 0 b Incertainapplications,inordertopracticeCTeffectively,priorinvestigationofthepatientbyotherformsofimagingmightberequired. b#b# 2.10 b SupervisionMb#b# 0 b CTexaminationsshouldbeperformedundertheclinicalresponsibilityofaradiologist/practitioneraccordingtotheregulations(4)andstandardexaminationprotocols  shouldbeavailable. b#b# 0 b Effectivesupervisionmaysupportradiationprotectionofthepatientbyterminatingtheexaminationwhentheclinicalrequirementhasbeensatisfied,orwhenproblemsoccurringduringtheexamination(forexample,unexpecteduncooperationbythepatientortheϜdiscoveryofcontrastmediaresiduefrompreviousexaminations)cannotbeovercome. b#b# 0 b Problemsandpitfalls:theresponsibleradiologist/practitionershouldbeawareofclinicalortechnicalproblemswhichmayinterferewithimagequality.Manyoftheseareparticulartospecificorgansortissuesandmayleadtomodificationoftechnique.Theradiologist/practitionerandtheradiographermustbeawareofmanoeuvreswhichmaybeusedtoovercomesuchdiagnosticortechnicalproblemsinordertoprovideaclinicallyrelevantexamination. b#b# 2.20 b PatientPreparation".&b#b# 0 b ThefollowingpatientrelatedoperationalparametersplayanimportantroleforthequalityoftheCTexamination: b#b# VC v $$vCӜ0 b 2.2.10: b#b#Cooperation.Patientcooperationshouldbeensuredasfaraspossiblepriortothe #&r"* examination.Anexplanationoftheprocedureshouldbegiventoeachpatient.Goodcommunicationwithandcontrolofthepatientisequallynecessaryduringthewholeexamination. : #: # ̜0 b 2.2.20: b#b#ProtectiveShielding.Relevantprotectionforsensitiveorgansoutsidetheimagingfield 8*&/ isaleadpurseforthemalegonads,iftheedgeofthevolumeofinvestigationislessthan1015cmaway.Theprotectionoffemalegonadsbywraparoundleadhasnotyetbeendemonstrated(7,8).Appropriateprotectionmeasuresmustbeappliedtopersonswho,forclinicalreasonsortoensurecooperation,mayneedtoaccompanypatientsintheexaminationroomduringtheexamination. : #: # ̜0 b 2.2.30: b#b#Clothing.Theareaofexaminationshouldbefreeofexternalmetalorotherradio />,6 denseitemswherepossible.Specialattentionmustbegiventoeliminatinganyxraydensematerialinthepatientsclothesorhair. : #: #  b2.9 0 b 2.2.40: b#b#Fasting.Fastingpriortotheexaminationisnotessential.Restraintfromfood,butnot  fluid,isrecommendedifintravenouscontrastmediaaretobegiven. : #: # ̜0 b 2.2.50: b#b#Intravenouscontrastmedia.Theseareneededinsomeexaminationsandmustbe $s employedinamannerappropriatetotheclinicalindication,takingintoconsiderationtheriskfactors. : #: # ̜0 b 2.2.60: b#b# M 0: : #: #Oralorcavitatorycontrastmedia.Oralcontrastmediummayberequiredin h  abdominopelvicexaminationsandmustbeadministeredattimesandindosesappropriatetotheindication.Administrationofcontrastmediumperrectummayberequiredinsomeexaminationsofthepelvisandavaginaltamponshouldbeusedinsomeexaminationsforgynaecologicalapplications. : #: # ̜0 b 2.2.70: b#b#Positioningandmotion.MostCTexaminationsarecarriedoutwiththepatientsupine. N  Inthispositionthepatientismostcomfortablewiththekneesflexed.Alternatepositioningmayberequiredtoaidcomfortandcooperation,forappropriatedisplayofanatomy,toreduceabsorbedradiationtoparticularorgans,ortominimiseartefact.ϜMotionshouldbekepttoaminimumtoreduceartefacts;typicalsourcesofartefactsϜareinvoluntarypatientmovement,respiration,cardiovascularaction,peristalsisandswallowing. : #: # 2.30 b ExaminationTechnique%b#b# C w( X$vC0 b c  c."0Mb#b#  Scanprojectionradiograph.c.I݌xM#M# Ќ  0 b 0Mb#b#Ascanprojectionradiographpermitstheexaminationtobeplannedandcontrolled I accurately,andprovidesarecordofthelocationofimages.Itisrecommendedthatthisisperformedinallcases.IngeneralsuchimagingprovidesonlyasmallfractionofthetotalpatientdoseduringacompleteCTprocedure(9) M#M# C v $Xw(C0 b 2"3  0Mb#b#Clinicalaspectsofsettingtheappropriatetechnicalparameters.^M#M# М0 b 0Mb#b#Theseparametersmustbesetaccordingtotheareaofexaminationandclinicalindication,asfollows: M#M# М0 b 0Mb#b#*0: M#M#Nominalslicethicknessischosenaccordingtothesizeoftheanatomicalstructureor ! lesionthatneedstobevisualised.Staffshouldbeawareoftheimplicationsofchoiceofslicethicknessinrelationtotheimagequalityandradiationdosetothepatient. : #: # 0 b 0Mb#b#*0: M#M#&ë&&&ëInterslicedistanceischosenaccordingtotheareaunderexaminationandtheclinical !5% indication.StaffshouldbeawareoftheriskofoverlookinglesionswhichfallintheintersliceintervalduringserialCT. Ingeneral,theintervalshouldnotexceedone #' halfofthediameterofsuspectedlesions. Thisproblemisabsentinhelical ]$ ( Мscanning,whenanappropriatereconstructionindexisused.2%!): #: # --0 b 0Mb#b#*0: M#M##&ë&&&ë#Fieldofview(_FOV_).Selectionof_FOV_Ԁmustrespectimageresolutionandtheneedto &##+ examineallareasofpossibledisease.Ifthe_FOV_Ԁistoosmall,diseasemaybeexcludedfromthevisibleimage. : #: # 0 b 0Mb#b#*0: M#M#Exposurefactors:tubevoltage(kV),tubecurrent(mA)andexposuretime(s)affect *g&/ imagequalityandpatientdose.Increasingexposureincreaseslowcontrastresolutionbyreducingnoisebutalsoincreasespatientdose.Patientsizeisanimportantfactorindeterminingtheimagenoise.Imagequalityconsistentwiththeclinicalindicationsshouldbeachievedwiththelowestpossibledosetothepatient.Incertainexaminationsimagenoiseisacriticalissueandhigherdosesmightberequired. : #: # 0 b 0Mb#b#*0: M#M#Thevolumeofinvestigationistheimagingvolume,definedbythebeginningandend /,6 oftheregionimaged.Itshouldcoverallregionsofpossiblediseasefortheparticularindication. : #: #  B2.9 0 b 0Mb#b#*0: M#M#&ë&&&ëReconstructionalgorithm:thisissetaccordingtotheindicationandareaunder  examination.Formostexaminations,imagesaredisplayedutilisingalgorithmssuitableforsofttissues;otheralgorithmsavailableincludethoseprovidinggreaterspatialresolutionfordetaileddisplayofboneandotherareasofhighnaturalcontrast. : #: # C x( X$vC2.40 b HelicalorSpiralCTb#b# 0 b HelicalorspiralCTisobtainedbycontinuoustuberotationcoupledwithcontinuouspatienttransportthroughthegantry,resultinginvolumetricdataacquisition.DuetothehighspeedandeaseofimageperformancewiththistechniqueitshouldbeemphasizedthathelicalCTpresentsparticularchallengesinradiationprotectionanditshouldnotbeusedwithoutclinicaljustification.HelicalCTisinmostcasespreferabletoserialCTbecauseof advantages suchas:  b#b# C v $Xx(C0 b 2"3  0Mb#b#apossibilityofdosesaving:R M#M# 0 b 0Mb#b#*0: M#M#therepeatingofsinglescans,whichsometimesresultsfromlackofpatient C  cooperationinserialCT,isreducedinspiralCTbecauseoftheshorterexaminationtimesinvolved : #: # 0 b 0Mb#b#*0: M#M#forpitch>1thedosewillbereducedcomparedwithcontiguousserialscanning;there g arenodatamissingasmaybethecasewiththeuseofanintersliceintervalinserialϜCT : #: # 0 b 0Mb#b#*0: M#M#thepracticeofusingoverlappingscansorthinslicesinserialCTforhighquality3D ) displayor_multiplanar_Ԁreconstructionsisreplacedbythepossibilityofreconstructingoverlappingimagesfromonehelicalscanvolumedataset : #: # #&ë&&&ëW#&ë&&&ëԛ0 b 2"3  0Mb#b#extremelyshortenedexaminationtime:mM#M# 0 b 0Mb#b#*0: M#M#makesitpossibletoacquirecontinuouspatientdataduringasinglebreathhold;  problemswithinconsistentrespirationcantherebybeavoided : #: # 0 b 0Mb#b#*0: M#M#disturbancesduetoinvoluntarymovementssuchasperistalsisandcardiovascular b actionarereduced : #: # 0 b 0Mb#b# *0: M#M# mayoptimizescanningwiththeuseofintravenouscontrastmedia(10,11)S: #: # 0 b 0Mb#b# M#M# --0 b 2"3  0Mb#b#imagescanbereconstructedforanycouchpositioninthevolumeofinvestigation:!M#M# 0 b 0Mb#b#*0: M#M#anatomical_misregistration_ԀisavoidedL #: #: # 0 b 0Mb#b#*0: M#M#equivocallesionscanbefurtherevaluatedwithoutadditionalpatientexposure!l$: #: # 0 b 0Mb#b#*0: M#M#the_possibility_Ԁofdisplayingthedatavolumeintransverseslicesreconstructedat !=% intervalssmallerthanthexraybeamcollimationresultsinoverlappingsliceswhich, "& incombinationwithreducedoreliminatedmovementartefacts,makesitpossibletoperformhighqualitythreedimensional(3D)andmultiplanarreconstructionswithsmoothtissuecontours.Thisisusedespeciallyinskeletal(12)andvascularimaging(CTangiography)(10). : #: # --0 b HelicalCT,however,has drawbacks suchas:'#,b#b# 0 b 2"3  0Mb#b#easeofperformancemaytempttheoperatortoextendtheexaminationunjustifiably, K)%. eitherbyincreasingtheimagingvolume,orbyrepeatedexposureofaregion M#M# 0 b 2"3  0Mb#b#althoughmostimagequalityparametersareequivalentforcontiguousserialCTand + (1 helicalCTperformedwithapitch=1(13,14),theperformanceofhelicalCTwithapitchgreaterthan1.5mayimplylowerandpossiblyinsufficientdiagnosticimagequalityduetoreducedlowcontrastresolution(10,14) M#M# 0 b 2"3  0Mb#b#spatialresolutioninthezdirectionislowerthanindicatedbythenominalslicewidth /",6 М(13,15)unlessspecialinterpolationisperformed(15)0,7M#M#  b 2"3  0 M thetechniquehasinherent_ԀartefactF2.9M#M# Ї0 b WhenusinghelicalCTinconjunctionwithintravenousinjectionofcontrastmediatoprovideoptimallyenhancedimages,carefultimingofexposurerelativetointravenousinjectionisϜmandatory. b#b# ̜2.50 b ImageviewingconditionsDb#b# 0 b ItisrecommendedthatinitialreadingofCTimagesiscarriedoutfromtheTVmonitor.Displayofimagesandpostprocessingimagereconstructionshouldbeatadisplaymatrix  ofatleast512x512. b#b# 0 b Brightnessandcontrastcontrolontheviewingmonitorshouldbesettogiveauniformprogressionofthegreyscalefromblacktowhite.Acalibratedgreyscalewouldbepreferable. b#b# 0 b Settingsofwindowwidthandwindowleveldictatethevisiblecontrastbetweentissuesandshouldgenerallybechosentogiveoptimumcontrastbetweennormalstructuresandlesions. b#b# 2.60 b FilmProcessing b#b# 0 b Optimalprocessingofthefilmhasimportantimplicationsforthediagnosticqualityoftheimagestoredonfilm.Filmprocessorsshouldbemaintainedattheiroptimumoperatingconditionsasdeterminedbythemanufacturerandbyregularandfrequentqualitycontrolprocedures. b#b#  XX&&ë3.0 b PhysicalParameters:PhysicalMeasuresofScannerPerformance.#&ë&XXX# b#b# 0 b ThequalityoftheCTimagemaybeexpressedintermsofphysicalparameterssuchasuniformity,linearity,spatialresolution,lowcontrastresolutionandabsenceofartefactsϜaccordingtoIECrecommendations(16).ItdependsonthetechnologicalcharacteristicsoftheCTscanner,theexposurefactorsusedandimageviewingconditions.Qualitymaybeassessedbyquantitativemeasurementoftheparameterslistedabove,usingsuitabletestphantoms,andbytheappearanceofartefacts.Thesemeasurementsshouldbeconductedregularly,inordertoguaranteethemaintenanceofperformanceoftheCTscannerduringitswholeperiodofuse.Itisessentialthatsuchtechnicalqualitycontrolhasbeenperformedwhenusingthecriteriapresentedintheseguidelines. b#b# 3.10 b TestPhantoms"b#b# 0 b Testphantoms(phantomofastandardisedhumanshapeortestobjectsofaparticularshape,sizeandstructure)areusedforthepurposesofcalibrationandevaluationofthe 1!$ МperformanceofCTscanners.Performanceischeckedbyacceptancetestsafterinstallationandimportantrepairs,andbyperiodicqualitycontroltests,asestablishedinstandardisedprotocols.Anumberoftestphantomsarecommerciallyavailableandmostmanufacturersprovideoneormoretestobjects. b#b# 0 b Thetestphantomsshouldallowforthefollowingparameterstobechecked:meanCTϜnumber,uniformity,noise,spatialresolution,slicethickness,doseandpositioningofcouch(16). b#b# 3.20 b CTNumber[)%.b#b# 0 b TheaccuracyofCTnumberisverifiedbyscanningatestobjectutilisingtheusualoperatingparametersandreconstructionalgorithms.TheCTnumberisaffectedbythexraytubevoltage,beamfiltrationandobjectthickness.TheCTnumberofwaterisbydefinitionequalto0HUandthemeanCTnumbermeasuredoverthecentralregionofinterest(ROI)should ,(2 beintherange+/4HU#&ë&&&ë#&ë&&&ë.p-)3b#b# 0 b  b#b# 3.30 b Linearity/a+5b#b# 0 b LinearityconcernsthelinearrelationshipbetweenthecalculatedCTnumberandthelinear /2,6 attenuationcoefficientofeachelementoftheobject.Itisessentialforthecorrectevaluation 0-7 ofaCTimageand,inparticular,fortheaccuracyof_QCT_.Deviationsfromlinearityshouldnotexceed+/5HUoverspecificranges(softtissueorbone).V2.9b#b# 0 b  b#b# 3.40 b Uniformityb#b# 0 b UniformityrelatestotherequirementfortheCTnumberofeachpixelintheimageofahomogeneousobjecttobethesamewithinnarrowlimitsovervariousregionsoftheobjectsuchasacylindrical20cmdiameterphantomofwaterequivalentplastic.ThedifferenceinϜthemeanCTnumberbetweenaperipheralandacentralregionofahomogeneoustestobjectshouldbe8HU.Suchdifferencesarelargelyduetothephysicalphenomenonof  beamhardening.h b#b# 3.50 b Noise Y b#b# 0 b Pictureelement(pixel)orimagenoiseisthelocalstatisticalfluctuationintheCTnumbersofindividualpictureelementsofahomogeneousROI.Noiseisdependentontheradiationdose#&ë&&&ë#&ë&&&ëԛandhasamarkedeffectonlowcontrastresolution.Themagnitudeofthenoiseis }  indicatedbythestandarddeviationoftheCTnumbersoveraROIinahomogeneoussubstance.Itshouldbemeasuredoveranareaofabout10%ofthecrosssectionalareaofthetestobject.#&ë&&&ë#&ë&&&ëImagenoisediminisheswiththeuseofaslightlyflattenedconvolutionkernel, ?  withsimultaneousreductionofspatialresolutionandanincreaseinlowcontrastresolution.#&ë&&&ë#&ë&&&ëImagenoiseisinverselyproportionaltothesquarerootofthedoseandtotheslicethickness.   Forexample,ifthedoseishalvedthenthenoisewillonlyincreasebyabout40%.Conversely,areductioninslicethicknessrequiresaproportionateincreaseindoseinordertoavoidanincreaseinnoise.Themedicalproblemunderstudyandthecorrespondingimagequalityrequiredshoulddeterminewhatlevelofimagenoiseandwhatpatientdosearereasonablypracticable.#&ë&&&ë#&ë&&&ëԛb#b# 3.60 b SpatialResolutionIb#b# 0 b Spatialresolutionathighandlowcontrastareinterdependentandcriticaltoimagequalityandgoodimagingofdiagnosticallyimportantstructures. b#b# ̛0 b Thespatialresolutionathighcontrast(highcontrastresolution)determinestheminimumsize  ofdetailvisualisedintheplaneoftheslicewithacontrast10%.Itisaffectedbythe ^ _reconstruction_Ԁalgorithm,thedetectorwidth,theslicethickness,theobjecttodetector /~ distance,thexraytubefocalspotsize,andthematrixsize.Ob#b# Л0 b Thespatialresolutionatlowcontrast(lowcontrastresolution)determinesthesizeofdetailthatcanbevisiblyreproducedwhenthereisonlyasmalldifferenceindensityrelativetothesurroundingarea.Lowcontrastresolutionisconsiderablylimitedbynoise.Theperceptionthresholdinrelationtocontrastanddetailsizecanbedetermined,forexample,bymeansofacontrastdetailcurve.Insuchdeterminations,theeffectsofthereconstructionalgorithmandoftheotherscanningparametershavetobeknown.Doseandthecorrespondingimagenoisegreatlyaffectlowcontrastresolution. b#b# 0 b  b#b# 3.70 b SliceThickness*%y!)b#b# 0 b Theslicethicknessisdeterminedinthecentreofthefieldofviewasthedistancebetweenthetwopointsonthesensitivityprofilealongtheaxisofrotationatwhichresponsehasfallento50%.Certaindeviationsinthicknessshouldnotbeexceededbecauseoftheeffectofslicethicknessonimagedetail;forexample,withanominalslicethickness8mm,amaximum n($- deviationof#&ë&&&ëQ#&ë&&&ëԛ10%isacceptable;tolerabledeviationsforsmallerslicethicknessof28mm ?)%. and<2mmare25%and#&ë&&&ëC#&ë&&&ë#&ë&&&ë#Ԁ50%,respectively.*_&/b#b# 0 b Theuseofpostpatient_collimation_,whichisinherentinsomeCTequipmenttoreducetheϜslicesensitivityprofile,leadstosignificantincreasesinthepatientdoseforaseriesofcontiguousslices(9).0b#b#T-)3## 3.80 b StabilityofCTnumbers.E+5b#b# 0 b StabilityisdefinedasthemaintenanceovertimeofconstancyofCTnumberandofuniformity.Itcanbecheckedbymeansofasuitabletestobject,containingatleastthreespecimensofdifferentmaterials,e.g.water,_Polymethylmethacrylate_Ԁ(_PMMA_)andTeflon. i1-8 Deviationsshouldnotexceed+/5CTnumberswithrespecttoinitialmeanvalues.Asimilar :2.9 toleranceshouldbeappliedintheverificationofuniformity,asmeasuredinthree_ROI_s,eachcontainingapproximately100pixelsandplacedrespectivelyatthecentre,attheperiphery,andinapositionintermediatebetweenthecentreandtheperipheryofthereconstructedimage. b#b# 3.90 b Positioningofcouchb#b# 0 b Theaccuracyofpositioningofthepatientcouchisevaluatedbymovingtheloadedcouch  adefineddistancerelativetothegantryandsubsequentlymovingitbacktothestartposition(16).Positionalaccuracyincludesbothdeviationinlongitudinalpositioningandalsobacklash.Maximumtolerancesof2mmapplytobothcriteria.ThesealsoapplytomobileCTequipment. b#b# М XX&&ëGUIDANCEONIMPLEMENTATION#&ë&XX<#  }  QualityCriteriaarepresentedforanumberofselectedCTexaminations.Theyapplytoadultpatientsofstandardsize(~70kgmassand~170cmheight)undergoingusualapplicationofthetechniqueforthetypeofexaminationunderconsideration.TheseQualityCriteriaaretobeusedbyradiologists,operatorsandmedicalphysicistsasacheckontheroutineperformanceoftheentireimagingprocess.TheQualityCriteriaarehelpfulfortheimmediatecheckingofthequalityofimagingperformancewhilethepatientisstillinthescanner.However,theQualityCriteriacannotbeappliedtoallcases.Forcertainclinicalindicationsalowerlevelofimagequalitymaybeacceptablebutthisshouldalwaysbeassociatedwithalowerradiationdosetothepatient.ForeachselectedCTexaminationcertainpreparatorystepsarenecessarytoensurefulljustificationandaccuratecontroloftheexamination:Indications,Advisablepreliminaryinvestigations,PatientpreparationandScanprojectionradiograph.ThesewillbegivenatthetopoftheListofQualityCriteriaforeachtypeofexamination.TheQualityCriteriaaredividedintothefollowingthreepartsthataregenerallycharacteristicfortheCTprocedures,inadditiontoafourthpartwhichtakesintoaccountspecialclinicalconditions:\>  \>V1  .0 b   DIAGNOSTICREQUIREMENTS\>Vی< b#b# Ќ  0 b TheselistimagecriteriawhichspecifyimportantanatomicalstructuresthatshouldbevisibleϜintheimagetoaidaccuratediagnosis.AqualitativeguidetothenecessarydegreeofvisibilityoftheseessentialstructuresisprovidedinthefollowingDescriptionofTerms. b#b# 2.0 b CRITERIAFORRADIATIONDOSETOTHEPATIENT""&b#b# 0 b Referencedosevaluesareprovidedasfarasavailable,inrelationtotechniqueforastandardsizedpatientforeachtypeofCTexaminationconsidered.ThesequantitiesaredefinedinAppendix1toChapter1anddiscussedindetailinChapter2. b#b# V\>  \>ҘV3  .0 b   EXAMPLEOFGOODIMAGINGTECHNIQUE\>ҘVی'$,b#b# Ќ  0 b ThissectionprovidesexamplesofCTtechniqueparameterswhichfacilitategoodimagingperformancethatiscapableofmeetingalltheaboveQualityCriteria.IfradiologistsandoperatorsfindthatDiagnosticRequirementsorCriteriaforRadiationDosetothePatientarenotmet,thentheExampleofGoodImagingTechniquecanbeusedasaguidetohowtheirtechniquemightbeimproved. b#b# 4.0 b CLINICALCONDITIONSWITHIMPACTONIMAGINGPERFORMANCEA.*4b#b# 0 b Anumberofconditionsduetopatientbehaviourandtechnicalparticularitiesarelistedwhichrequirespecialawarenessandinterventionoftheoperator. b#b# ̜ V2.9  XX&&ëDESCRIPTIONOFTERMSUSEDINTHELISTSOFQUALITYCRITERIA#&ë&XX[#   V XX&&ë\>  \>/V1  .0 b   DIAGNOSTICREQUIREMENTS \>/JVیob#b# Ќ  #&ë&XX#0 b Thelisted imagecriteria refertocharacteristicfeaturesofimagedanatomicalstructuresthat -| aredefinedintheregionofexaminationwithaspecificdegreeofvisibility.Atthepresenttimetherearenointernationallyaccepteddefinitions.Forthepurposeoftheseguidelinesthedegreeofvisibilityisdefinedasfollows: b#b# 1.10 b Visualization 󛀄Theorgansandstructuresaredetectableinthevolumeofinvestigation.F  b#b# 1.20 b Criticalreproduction 󀄀Thestructuresparticulartothespecificindicationarediscriminated  ;  toalevelessentialfordiagnosis.Thiswillincludetheterms: b#b# 0 b 0Mb#b#reproduction 󀄀detailsofanatomicalstructuresarevisiblebutnotnecessarilyclearly c  Мdefined. M#M# 0 b 0Mb#b# visuallysharpreproduction 󀄀anatomicaldetailsareclearlydefined.)M#M#  XX&&ë\>  \>҉V2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT#&ë&XXj# \>҉Vیb#b# Ќ  0 b Diagnosticreferencedosevalues areindicatedfortwodosedescriptors򛀜weightedCTDI > (CTDIW)anddoselengthproduct(DLP)onthebasisofabsorbeddosetoair,inrelationto b techniqueforastandardsizedpatient. b#b# 2.10 b CTDIwistheapproximationofaveragedoseoverasinglesliceinthestandardheadorbody  CTdosimetryphantom,expressedintermsofabsorbeddosetoair(mGy).Wb#b# 2.20 b DLPcharacterisesexposureforacompleteexaminationinrelationtolinearintegrationofthe H dosetothestandardheadorbodyCTdosimetryphantomonthebasisofabsorbeddosetoair(mGycm). b#b# 2.30 b ComparisonofCTDIworDLPvaluesforaparticulartypeofprocedureprovidesauseful =  indicationofrelativeperformance.However,dataforexaminationsondifferentregionsofthebodycannotbecompareddirectlyinordertoassessrelativepatientrisk. b#b# 0 b Appendix1toChapter1givesfurtherinformationconcerningthedefinitionofthesequantities !$ andmethodstocheckcompliancewiththedosecriteria.ThederivationofthediagnosticreferencedosevaluesandadditionalbackgroundinformationisgiveninChapter2. b#b#  XX&&ë\>  \>Ҁ V3  .0 b   EXAMPLEOFGOODIMAGINGTECHNIQUE#&ë&XXa # \>Ҁ  Vی$!(b#b# Ќ  0 b ParametersarelistedthatcontributetothefulfilmentoftheDiagnosticRequirementsandtheCriteriaforRadiationDosetothePatient. b#b# ̜3.10 b Patientposition (E%-b#b# ̜3.2 0 b Volumeofinvestigation 󀄀anatomicallandmarksforbeginningandendofthescan.*&/b#b# ̜3.3 0 b NominalslicethicknessforserialorcollimationforhelicalCT 󀀄inmm.B,(1b#b# ̜3.4 0 b Interslicedistance/pitch 󀄀inmm/factor.-7*3b#b# М3.5 0 b FieldofView(FOV) 󀄀maximumdiameter(incm)ofthereconstructedimage./+5b#b# ̜3.6 0 b Gantrytilt 󀄀angle($)betweenverticalplaneandplanecontainingthexraytube,thexray 41-7 scanbeamandthedetectorarray. 2X.8b#b# Ї3.70 b Xraytubevoltage 󀄀inkV.Thisshould,ifpossible,beselectedsoastoachievethe  requiredimagequalityatlowestpracticabledose. b#b# ̜3.80 b Tubecurrentandexposuretimeproduct 󀄀in_mAs.S_electionoftubecurrent(mA)and (w exposuretime(s)todetermineradiographicexposure(mAs)isofcriticalimportance.AbsolutevaluesofmAscannotberecommendedinviewofsignificantdifferencesinoperatingcharacteristicsbetweentypesofscanner.Operatorsshouldbeawareofthecharacteristicsparticulartotheirscannerandunderstandtherangeofsettingsthatareconsistentwithmeetingrequiredimagequalityandreferencedosevalues. b#b# ̜3.9 0 b Reconstructionalgorithm 󀄀broadtypeofmathematicalfilterforthereconstructionofthe  2  CTimage. b#b# ̜3.10 0 b Windowwidth 󀄀inHU.RangeofCTnumbersconvertedintogreylevelsanddisplayedon Z  theimagemonitor. b#b# ̜3.11 0 b Windowlevel 󀄀inHU.Centralvalueofthewindowusedforthedisplayofthereconstructed   CTimage. b#b# ̜3.12 0 b Protectiveshielding 󀄀additionalprotectiondevicestoreduceexposureofsensitiveorgans H andtissues. b#b#  XX&&ë4.0 b CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE#&ë&XX # b#b# 0 b Motion 󀄀patientororganmovements.}b#b# 0 b Problemsandpitfalls 󀄀mostlysitespecificclinicalortechnicalproblemswhichimpede #r imagequality. b#b# 0 b Modificationoftechnique 󀄀inordertoprovideclinicallyrelevantexaminationincaseof  technicalordiagnosticproblems. b#b#   @ М6 &&ë   Л@qq LISTOFQUALITYCRITERIAFORCOMPUTEDTOMOGRAPHY  #&ë&6 # p!p!F#Page CRANIUM i  ]c  ]ct20 b   Brain,GeneralM"M"H#b#b#16]ct݌ ^ Ќ  ]c  ]c"20 b   SkullBaseM"M"H#b#b#18]c"=݌ / Ќ  FACEANDNECK    ]c  ]c20 b   FaceandSinusesM"M"H#b#b#20]c݌ ( w  Ќ  ]c  ]c20 b   PetrousBoneM"M"H#b#b#22]c݌  H  Ќ  ]c  ]cV20 b   OrbitsM"M"H#b#b#24]cVq݌    Ќ  ]c  ]c20 b   ݜSellaandHypophysisM"M"H#b#b#26]c݌   Ќ  ]c  ]c20 b   SalivaryGlands(ParotidandSubmandibular)M"M"H#b#b#28]c݌ l  Ќ  ]c  ]c20 b   PharynxM"M"H#b#b#30]c݌ =  Ќ  ]c  ]c* 20 b   LarynxM"M"H#b#b#32]c* E ݌ ]  Ќ  SPINE   ]c  ]c 20 b   VertebralandParavertebralStructuresM"M"H#b#b#34]c !݌ V Ќ  ]c  ]c!20 b   LumbarSpine,DiscalHerniationM"M"H#b#b#36]c!!݌ 'v Ќ  ]c  ]c"20 b   SpinalCordM"M"H#b#b#38]c""݌ G Ќ  CHEST   ]c  ]cM#20 b   Chest,GeneralM"M"H#b#b#40]cM#h#݌ @ Ќ  ]c  ]c#20 b   Chest,MediastinalVesselsM"M"H#b#b#42]c#$݌ ` Ќ  ]c  ]c$20 b   Chest,HRCT(HighResolutionComputedTomography)M"M"H#b#b#44]c$$݌ 1 Ќ  ABDOMENANDPELVIS   ]c  ]c%20 b   Abdomen,GeneralM"M"H#b#b#46]c%%݌ *y  Ќ  ]c  ]cm&20 b   LiverandSpleenM"M"H#b#b#48]cm&&݌ J! Ќ  ݜ]c  ]c!'20 b   KidneysM"M"H#b#b#50]c!'<'݌ " Ќ  ]c  ]c'20 b   PancreasM"M"H#b#b#52]c''݌  # Ќ  ]c  ]cs(20 b   AdrenalGlandsM"M"H#b#b#54]cs((݌ n!$ Ќ  ]c  ]c$)20 b   Pelvis,GeneralM"M"H#b#b#56]c$)?)݌ ?"% Ќ  BONESANDJOINTS #0 '  ]c  ]c*20 b   OsseousPelvisM"M"H#b#b#58]c**݌ %!) Ќ  ]c  ]c*20 b   OsseousShoulderM"M"H#b#b#60]c**݌ X&"* Ќ  ̜  )%. /   ? M ;M ?Preparatorysteps:   ̄0 b Indications:traumaticlesions,andsuspectedorknownfocalordiffusestructuraldisease [ ofthebrainwhenMRIiscontraindicatedornotavailable b#b# ̄0 b Advisablepreliminaryinvestigations:clinicalneurologicalexamination;MRIisoftenan   alternativeexaminationwithoutexposuretoionizingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is A  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:lateralfromskullbasetovertex;inpatientswithmultiple   injuriesfromcervicalvertebratovertex b#b#  1.0 b DIAGNOSTICREQUIREMENTS 'r b#b#  Imagecriteria:     1.10 b Visualizationof sb#b# 1.1.10 b WholecerebrumHb#b# 1.1.20 b Wholecerebellumdb#b# 1.1.30 b Wholeskullbase5b#b# 1.1.40 b Vesselsafterintravenouscontrastmediab#b#  1.20 b Criticalreproduction ]b#b# 1.2.10 b Visuallysharpreproductionoftheborderbetweenwhiteandgreymatter2}b#b# 1.2.20 b VisuallysharpreproductionofthebasalgangliaNb#b# 1.2.30 b Visuallysharpreproductionoftheventricularsystemb#b# 1.2.40 b Visuallysharpreproductionofthecerebrospinalfluidspacearoundthemesencephalonb#b# 1.2.50 b Visuallysharpreproductionofthecerebrospinalfluidspaceoverthebrainvb#b# 1.2.60 b Visuallysharpreproductionofthegreatvesselsandthechoroidplexusesafterintra G venouscontrastmedia b#b#  2.0 b CRITERIAFORRADIATIONDOSETOTHEPATIENT  !b#b# 2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#routinehead:60mGy`"### 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#routinehead:1050mGycm$M%##  3.0 b EXAMPLESOFGOODIMAGINGTECHNIQUE %'b#b# 3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supineJ'!)## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#fromforamenmagnumtotheskullvertex(7#+## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#2-5mminposteriorfossa;5-10mmin *$- hemispheres ## Ѐ3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0-L'0## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#headdimension(about24cm).(2## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#1012$abovetheorbito-meatal(OM)lineto E0*4 reduceexposureoftheeyelenses ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standard2-7## Ї3.80 b Tubecurrentand0b#b#0v##:0v#v#shouldbeaslowasconsistentwith## 0 b exposuretimeproduct(mAs)0vb#b#0v#v#requiredimagequality## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue(s## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#090HU(supratentorialbrain) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#140160HU(braininposteriorfossa) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#20003000HU(bones) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#4045HU(supratentorialbrain) Y ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#3040HU(braininposteriorfossa) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#200400HU(bones) ##  4.0 b CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE R b#b# 4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratesimagequality C  (preventedbyheadfixationorsedationofnon-cooperativepatients) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefultoidentifyvascularstructures,enhancing < lesionsandalterationsofblood-brainbarrier ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # # ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#calcificationsversuscontrastenhancement## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#interpetrousbeamhardeningartefacts## 4.40 b Modificationtotechnique0b#b#0v##0v#v#subtleirregularitycanbecheckedwithslicesin "m theareaofsuspectedpathology,beforeconsideringcontrastadministration ## '/( Preparatorysteps:   ̄0 b Indications:neurologicaldiseases(cranialnerves),trauma,malformations,metastasis [ andbonediseases b#b# ̄0 b Advisablepreliminaryinvestigations:x-rayexaminationoftheskullandbasemayonly   occasionallybenecessary;MRImaybeanalternativeexaminationwithoutexposuretoionisingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is  ]  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:lateralfromC2toskullvertex b#b# V\>  \>DJV1  .0 b   DIAGNOSTICREQUIREMENTS \>DJ_JVی'r b#b# Ќ  Imagecriteria:     1.10 b Visualizationof sb#b# 1.1.10 b EntireskullbasefromC1tothesuprasellarregionHb#b# 1.1.20 b Entirecerebellumdb#b# 1.1.30 b Basalpartofthefrontallobes5b#b# 1.1.40 b Vesselsafterintravenouscontrastmediab#b#  1.20 b Criticalreproduction ]b#b# 1.2.10 b Visuallysharpreproductionofthecorticalandtrabecularbonestructures2}b#b# 1.2.20 b VisuallysharpreproductionoftheairfilledcompartmentsNb#b# 1.2.30 b Visuallysharpreproductionofthesellaturcicab#b# 1.2.40 b Visuallysharpreproductionofthecerebellarcontoursb#b# 1.2.50 b Reproductionoftheborderbetweenthewhiteandgreymatter(cerebellum)vb#b# 1.2.60 b VisuallysharpreproductionofthecerebrospinalfluidspacearoundthebrainstemGb#b# 1.2.70 b Visuallysharpreproductionofthegreatvesselsandchoroidplexusesafterintravenous c contrastmedia b#b#  \>  \>nPV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>nPPVی!"b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for 1#|$ information:routinehead:60mGy) ## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for %' information:routinehead:1050mGycm) ##  \>  \>VSV3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>VSqSVی(b"*b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supine)$,## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#fromC1tothesuprasellarregion_+%.## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#2-5mm-L'0## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0.(2## 3.50 b _FOV_0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#headdimension(about24cm)E0*4## 3.50 b Gantrytilt0 b#b#0 # #0v##:0v#v#OMline12,6##  2-7 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standard## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithW## 0 b timeproduct(mAs)0b#b#0v##0v#v#requiredimagequality(s## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#highresolutionorsofttissue/standard ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#20003000HU(bones)l ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#7090HU(supratentorialbrain) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#100160HU(braininposteriorfossa) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#200400HU(bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#4045HU(supratentorialbrain) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#3040HU(braininposteriorfossa) ##  \>  \> _V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \> _&_Vی? b#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratesimagequality   (preventedbyheadfixationorsedationofnon-cooperativepatients) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefultoidentifyvascularstructures,enhancing ) lesionsandalterationsofblood-brainbarrier ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # # ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#calcificationsversuscontrastenhancementQ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#interpetrousbeamhardeningartefacts"m## 4.40 b Modificationtotechnique0b#b#0v##0v#v#subtleirregularitycanbecheckedwithslicesin  theareaofsuspectedpathology,beforeconsideringcontrastadministration ##  b  M 0 : 0' : #: #0 ' #' #0 # #0v##0v#v#highermAsmayberequiredifartefactsdegrade 7 theimagequalityintheposteriorfossa S## F'( Preparatorysteps:   ̄0 b Indications:trauma,malformations,malignanciesandinflammation[b#b# ̄0 b Advisablepreliminaryinvestigations:appropriatex-rayexaminationofthefaceexceptfor H isolatedevaluationofthesinuses;MRImaybeanalternativeexamination,especiallyinmalignancies b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is A  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:lateralfromjawtovertex b#b# V \>  \>+iV1  .0 b   DIAGNOSTICREQUIREMENTS \>+iFiVیV b#b# Ќ  Imagecriteria  G   1.10 b Visualizationof  b#b# 1.1.10 b Entirefacefrompalatetothetopofthefrontalsinuswb#b# 1.1.20 b VesselsafterintravenouscontrastmediaHb#b#  1.20 b Criticalreproduction5b#b#  1.2.10 b Visuallysharpreproductionofthecorticalandtrabecularbonestructures b#b# 1.2.20 b Visuallysharpreproductionofthefrontalsinusesb#b# 1.2.30 b Visuallysharpreproductionofthesphenoidsinusesab#b# 1.2.40 b Visuallysharpreproductionoftheorbitae2}b#b# 1.2.50 b Reproductionoftheglobe,opticnerveandorbitalmusclesNb#b# 1.2.60 b Visuallysharpreproductionoftheethmoidb#b# 1.2.70 b Visuallysharpreproductionofthemaxillaanditssinusesb#b# 1.2.80 b Visuallysharpreproductionofthenasalcavityvb#b# 1.2.90 b VisuallysharpreproductionoftherhinopharynxGb#b#  \>  \>oV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>ooVی4 b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#35mGy(pilotstudy(17))!"## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#360mGycm(pilotstudy)1#|$##  \>  \>hqV3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>hqqVی$&b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supineforaxialscans;supineorpronefor y& ( coronalscans ## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#frompalatetothetopofthefrontalsinus(7#+## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#3-5mm.HelicalCTispreferableforevaluation *$- oftheface ## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0;12mmorapitchup -L'0 to1.21.5maybeusedinscreeningexaminationsofthesinuses ## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#headdimension(about24cm)E0*4## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#0to10$fromOMforaxialscanningoftheface; 12,6 accordingtothepatientpositionforcoronal 2-7 scanning ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standardW## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithD## 0 b timeproduct(mAs)0b#b#0v##0v#v#requiredimagequality ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#highresolutionorstandardl ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#15003000HU(bones) Y ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#1401000HU(softtissue) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#200400HU(bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#30100HU(softtissue) ##  \>  \>Ҙ|V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>Ҙ||Vی? b#b# Ќ  4.10 b Motion '    0vb#b#0v#v#movementartefactdeterioratesimagequality   (preventedbyheadfixationorsedationofnon-cooperativepatients) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefultoidentifyvascularstructuresand ) enhancinglesions ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#artefactsfromteethordental_prothesis_/fillingsQ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#changeofgantryangulationorpatientpositionto > avoidartefact ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#examinationofthesinusesinapronepositionto  keepinflammatorysecretionawayfromtheosteomeatalcomplex ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#examinationofthesinusespreliminaryto S functionalendoscopicsinussurgeryisbestperformeddirectlyinthecoronalplane ##   #h$ HF( Preparatorysteps:   ̄0 b Indications:hearingdeficits,inflammation,vertigo,facialoracousticnervediseases, [ malformations,bonediseasesandtrauma b#b# ̄0 b Advisablepreliminaryinvestigations:examinationofacousticandlabyrinthfunction, b#b# 0 b evokedpotentials;appropriatex-rayexaminationofskull,baseandpetrousbonemayonlyoccasionallybenecessary;MRImaybeanalternativeexaminationwithoutexposuretoionisingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is  .  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:lateralfrommastoidtoaboveskullbaseV b#b# V \>  \>BV1  .0 b   DIAGNOSTICREQUIREMENTS \>B]VیC b#b# Ќ  Imagecriteria:     1.10 b Visualizationof Db#b# 1.1.10 b Entirepetrousbonedb#b# 1.1.20 b Vesselsafterintravenouscontrastmedia5b#b#  1.20 b Criticalreproduction b#b# 1.2.10 b Visuallysharpreproductionofthecorticalandtrabecularbonestructuresab#b# 1.2.20 b Visuallysharpreproductionofthebonestructuresofthetemporalbonesuchasthe 2} cochlea:ossicularchain,fenestraovale,facialcanalandlabyrinth b#b# 1.2.30 b Visuallysharpreproductionoftheairfilledcompartmentsb#b# 1.2.40 b Visuallysharpreproductionoftheadjacentcerebellumb#b# 1.2.50 b Visuallysharpreproductionoftheadjacentcerebrumvb#b# 1.2.60 b ReproductionofborderbetweenthewhiteandgreymatterGb#b# 1.2.70 b Visuallysharpreproductionofthegreatvesselsandchoroidplexusesafterintravenous c contrastmedia b#b#  \>  \>V2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>Vی!"b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for 1#|$ information:routinehead:60mGy) ## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for %' information:routinehead:1050mGycm) ##  \>  \>V3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>Vی(b"*b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supine,foraxialscans;supineorpronefor )$, coronalscans ## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#from0.5cmbelowto0.5cmabovethepetrous 0,{&/ bone ## &ë&&&ë3.30 b Nominalslicethickness0b#b#0v##:  1-3mm#&ë&&&ë^#&ë&&&ë.(2v#v# 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0E0*4## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # ##&ë&&&ë#0v##&ë&&&ë:0v#v#headdimension(about24cm);secondary 12,6 reductionofFOVisnecessaryforevaluationof 2-7 subtlepathology ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#OMlineortiltedaboveOMlineforaxial W scanning;accordingtothepatientpositionforcoronalscanning ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standard ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwith= ## 0 b timeproduct(mAs)0b#b#0v##0v#v#requiredimagequality Y ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#highresolutionorstandard ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#20003000HU(bones)R ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v###&ë&&&ëz#0v#v#&ë&&&ë140160HU(softtissue)#n ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v###&ë&&&ë#0v#v#&ë&&&ë15002500HU(middlesetting)? ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#200400HU(bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v###&ë&&&ë#0v#v#&ë&&&ë3040HU(softtissue)g## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v###&ë&&&ëȜ#0v#v#&ë&&&ë150250HU(middlesetting)8##  \>  \>4V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>4OVی%b#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratesimagequality  (preventedbyheadfixationorsedationofnon-cooperativepatients) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefultoidentifyvascularstructuresanden  hancinglesions ## 4.30 b Problemsandpitfalls#&ë&&&ëם#0b#b#&ë&&&ë0v##0v#v#calcificationsversuscontrastenhancement7## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # ##&ë&&&ë_#0v##&ë&&&ëԄ0v#v#interpetrousbonehardeningartefactsS## 4.40 b Modificationtotechnique0b#b##&ë&&&ë#&ë&&&ë0v##0v#v##&ë&&&ëp#subtleirregularitycanbecheckedwithslicesin  ! theareaofsuspectedpathology,beforeconsideringcontrastadministration ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#highermAsmayberequiredifartefactsdegrade #h$ theimagequalityintheposteriorfossa ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#coronalscansmaybeusedtoreduceartefacts$ &##  b  M  :  '    0 v 0v#v#_intrathecal_Ԁcontrastmaybeusefultodetectsmall %' accusticneuromas a& (## JH( Preparatorysteps:   ̄0 b Indications:structuraldiseasesoftheorbitsandorbitalcontent,trauma,foreignbody[b#b# ̄0 b Advisablepreliminaryinvestigations:evaluationofvisualfunction;evokedpotentials; H appropriatex-rayexaminationoftheorbitsmayoccasionallybenecessary;MRIandultrasonographymaybealternativeexaminationswithoutexposuretoionisingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is A  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:lateralfromjawtovertex b#b# V \>  \>۪V1  .0 b   DIAGNOSTICREQUIREMENTS \>۪VیV b#b# Ќ  Imagecriteria:  G   1.10 b Visualizationof  b#b# 1.1.10 b Entireorbitswb#b# 1.1.20 b OsseouswallsHb#b# 1.1.30 b Vesselsafterintravenouscontrastmediadb#b#  1.20 b Criticalreproduction b#b# 1.2.10 b Visuallysharpreproductionoftheosseouswallsb#b# 1.2.20 b Visuallysharpreproductionoftheopticnervecanalab#b# 1.2.30 b Visuallysharpreproductionoftheglobe2}b#b# 1.2.40 b VisuallysharpreproductionoftheopticnerveNb#b# 1.2.50 b Visuallysharpreproductionoftheorbitalmusclesb#b# 1.2.60 b Visuallysharpreproductionoftheretrobulbarfatb#b# 1.2.70 b Visuallysharpreproductionofthemainvesselsafterintravenouscontrastmediavb#b#  \>  \>V2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>Vیcb#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for  ! information:routinehead:60mGy) ## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for 1#|$ information:routinehead:1050mGycm) ##  \>  \>V3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>Vی%'b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supineforaxialscans;supineorpronefor J'!) coronalscans ## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#from0.5cmbelowto0.5cmabovetheorbital )$, cavity ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#2-5mm0,{&/## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0-(1## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#headdimension(about24cm);secondary t/)3 reductionofFOVisnecessaryforevaluationofsubtlepathology ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#6to10$fromOMorparalleltotheopticnerve 2-7 foraxialscanning;accordingtothepatientpositionforcoronalscanning ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standard(s## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwith ## 0 b timeproduct(mAs)0b#b#0v##0v#v#requiredimagequality ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#highresolutionorstandard= ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#140300HU(softtissue) * ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#20003000HU(bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#about4000HU(specialorbitwindow) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#3040HU(softtissue)#n ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#200400HU(bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#about0HU(specialorbitwindow) ##  \>  \>ҁV4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>ҁVیgb#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratesimagequality  X (preventedbyheadfixationorsedationofnon-cooperativepatients) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefultoidentifyvascularstructuresand Q enhancinglesions ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#calcificationsversuscontrastenhancement## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#foreignbodies(beamhardeningartefacts)## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#artefactsfromorbitalordental_prothesis_/fillingsf## 4.40 b Modificationtotechnique0b#b#0v##0v#v#changeofgantryangulationorpatientpositionto S avoidartefact $ ## LJ(  Preparatorysteps:   ̄0 b Indications:suspicionofsellarorhypophysealalterations(endocrinologicaldiseases, [ visualdefects,alterationsofocularmotility)whenMRIiscontraindicatedornotavailable.MRIistheexaminationofchoice b#b# ̄0 b Advisablepreliminaryinvestigations:evaluationofvisualfunction b#b# ̄0 b Patientpreparation:informationabouttheprocedure:restraintfromfood,butnotfluid,is A  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:lateralfromC2toaboveskullbase b#b# L LU($vL  &t   V&t.2U  1  .3  0 b   DIAGNOSTICREQUIREMENTS &t.u݌V b#b# Ќ  Imagecriteria:  G   1.10 b Visualizationof  b#b# 1.1.10 b Entirehypophysealregionincludingosseouswallswb#b# 1.1.20 b VesselsafterintravenouscontrastmediaHb#b#  1.20 b Criticalreproduction 5b#b# 1.2.10 b Visuallysharpreproductiontheosseouslimitofthesella b#b# 1.2.20 b Visuallysharpreproductionofthehypophysisanditsstalkb#b# 1.2.30 b Reproductionofintrahypophysealdensitydifferencesab#b# 1.2.40 b Visuallysharpreproductionofthechiasmandsuprasellarcisterns2}b#b# 1.2.50 b VisuallysharpreproductionofthecavernoussinusesandlateralsellarregionsNb#b# 1.2.60 b Visuallysharpreproductionofthemainvesselsafterintravenouscontrastmediab#b#  2.0 b CRITERIAFORRADIATIONDOSETOTHEPATIENT vb#b# 2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for g information:routinehead:60mGy) ## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for !" information:routinehead:1050mGycm) ##  3.0 b EXAMPLESOFGOODIMAGINGTECHNIQUE $M%b#b# 3.10 b Patientposition0 b#b#0 # # v :0##supineforaxialscans;supineorpronefor %' coronalscans ## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#from0.5cmbelowto0.5cmabovethe (f"* hypophysealregion ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#2-3mm*$-## 3.40 b Interslicedistance/pitch  0vb#b#:0v#v#contiguousorapitch=1.00,{&/## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#headdimension(about24cm);secondary -(1 reductionofFOVisnecessaryforevaluationofsubtlepathology ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#OMlineforaxialscanning;accordingtothe 1a+5 patientpositionforcoronalscanning ##  2-7 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standard## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequiredW## 0 b timeproduct(mAs)0b#b#0v##0v#v#imagequality(s## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissueorhighresolution ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#140300HU(softtissue)l ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#20003000HU(bones) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#3040HU(softtissue) * ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#200400HU(bones) ## L Mh (LL  &t   &tZ2h  4  .3  0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE &tZ݌R b#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratesimagequality C  (preventedbyheadfixationorsedationofnon-cooperativepatients) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefultoidentifyvascularstructures,enhancing < lesionsandalterationsofblood-brainbarrier ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#calcificationsversuscontrastenhancement## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#foreignbodies(beamhardeningartefacts)## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#artefactsfromdentalprothesis/fillingsQ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#changeofgantryangulationorpatientpositionto > avoidartefact ##    NL(  Preparatorysteps:   ̄0 b Indications:lateralfacialmass;recurrentparotidorsubmandibularswelling;T/Nstaging [ ofsalivaryglandneoplasms b#b# ̄0 b Advisablepreliminaryinvestigations:radiographyifcalculusissuspected;   ultrasonographyorMRImaybealternativeexaminationswithoutexposuretoionisingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is  ]  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalfromorbitalregiontoglottis b#b#  \>  \>V1  .0 b   DIAGNOSTICREQUIREMENTS \>Vی'r b#b# Ќ  Imagecriteria:     1.10 b Visualizationof sb#b# 1.1.10 b EntireparotidglandHb#b# 1.1.20 b Entiresubmandibularglanddb#b# 1.1.30 b Overlayingsubcutaneousfatandskin5b#b# 1.1.40 b Regionallymphnodeterritories(incasesofneoplasm)b#b# 1.1.50 b Vesselsafterintravenouscontrastmediab#b#  1.20 b Criticalreproduction .yb#b# 1.2.10 b VisuallysharpreproductionoftheglandulartissueNb#b# 1.2.20 b Visuallysharpreproductionofthemarginsofnormalglandsb#b# 1.2.30 b Visuallysharpreproductionoftheparaglandularfatspacesb#b# 1.2.4 b Visuallysharpreproductionofregionallymphnodeareas v 1.2.5 b Reproductionofthemandibleandassociatedmuscles G  2. b CRITERIAFORRADIATIONDOSETOTHEPATIENT  4  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for !" information:routinehead:60mGy) ## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for $M% information:routinehead:1050mGycm) ## V \>  \>RV3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>RmVیu& (b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supine(f"*## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#parotid:fromexternaleartoangleofjaw; )$, submandibulargland:fromdorsumoftonguetohyoidbone;fromexternaleartoglottisifdetectionoflymphadenopathyisrequired ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#35mm-(1## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguous,butforlargelesionsdistancesof t/)3 <35mmorapitchupto1.52.0maybeused ## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#adjustedtotheminimumrequiredto 12,6 demonstratecompletecrosssectionoftheface. 2-7 ReductionofFOVmaybenecessaryfortheevaluationofsubtlepathologies ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#none(s## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standard ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequiredl ## 0 b timeproduct(mAs)0b#b#0v##0v#v#imagequality= ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standardorifnecessaryhigh  *  resolution ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#250500HUR ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#030HU(unenhancedexamination)? ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#3060HU(enhancedexamination) ##  \>  \>V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>Vیgb#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimage  X quality(preventedbyquietrespiration;swallowingshouldbesuspendedduringexposurebutencouragedbetweenexposurestoavoidsalivarypooling) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#mayberequiredtodistinguishlymphadenopathy_ > andbloodvessels ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#forbetterdefinitionoflesions0##0O ##O #O # 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#fordemonstratinginvolvementofcraniumby f neoplasms ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#artefactfromdentalprothesis/fillings$ ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#movementartefactduetoswallowing !## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#submandibularlymphadenopathymaymimic {!" enlargedsubmandibularglands ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#extensionoftheexaminationtothecraniumto #9% demonstraterelationshipofdiseasetothebaseoftheskullandtheparapharyngealspace ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#changeofgantryangulationorpatientpositionto a& ( avoidartefact 2'}!)## PN(  Preparatorysteps:   ̄0 b Indications:diagnosisofparapharyngealmasses;T/Nstagingofpharyngealneoplasms[b#b# ̄0 b Advisablepreliminaryinvestigations:endoscopymaybeperformed;MRIand H ultrasonographymaybealternativeexaminationswithoutexposuretoionisingradiation,ultrasonographyespeciallywithregardtosurroundingstructures b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is A  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:lateralfromorbitalrooftorootofneck b#b#  1. b DIAGNOSTICREQUIREMENTS  V   Imagecriteria:  G   1.10 b Visualizationof  b#b# 1.1.10 b Entirepharynxwb#b# 1.1.20 b RegionallymphnodeareasandassociatedmusclesHb#b# 1.1.30 b Baseoftheskulldb#b# 1.1.40 b Oesophagopharyngealjunction5b#b# 1.1.50 b Vesselsafterintravenouscontrastmediab#b#  1.20 b Criticalreproduction ]b#b# 1.2.10 b Reproductionofthewallofpharynxthroughouttheareaofexamination2}b#b# 1.2.20 b VisuallysharpreproductionofthemucosalmarginNb#b# 1.2.30 b Visuallysharpreproductionoftheparapharyngealfatspacesb#b# 1.2.40 b Visuallysharpreproductionoftheparapharyngealmusclesb#b# 1.2.50 b Visuallysharpreproductionofregionallymphnodeareasvb#b# V \>  \>ҭV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>ҭVیcb#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for  ! information:routinehead:60mGy) ## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for 1#|$ information:routinehead:1050mGycm) ##  \>  \>ҕ V3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>ҕ  Vی%'b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supineJ'!)## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#nasopharynx:fromsphenoidbonetohyoidbone (7#+ andcontinuetorootoftheneckforN-stagingofneoplasms; ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#oropharynx/hypopharynx:frompalatetorootoftheneck ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#35mmserialorpreferablyhelical-(1## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguous,butforlargelesionsdistancesof t/)3 <35mmorapitchupto1.52maybeused ## 3.50 b FOV : 0' b#b#0 ' #' #0 # #0v##:0v#v#adjustedtotheminimumrequiredtodemon 12,6 stratecompletecrosssectionoftheface. 2-7 ReductionofFOVmaybenecessaryfortheevaluationofsubtlepathologies ## 3.60 b Gantrytilt0 b#b#  0v # #:0v#v#none(s## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standard ## 3.80 b Tubecurrentandexposure v :0b#b#shouldbeaslowasconsistentwithl ## 0 b timeproduct(mAs)0b#b#0v##0v#v#imagequality= ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standardorifnecessaryhigh  *  resolution ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#300500HUR ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#030HU(unenhancedexamination)? ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#3060HU(enhancedexamination) ##  \>  \>V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>Vیgb#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimagequal  X ity(swallowingshouldbesuspendedduringexposurebutencouragedbetweenexposurestoavoidsalivarypooling) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#mayberequiredtoimprovecontrastbetween "m normalandabnormaltissuesorcharacterizesomeparapharyngeallesions ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#routinelyrequiredifinvasionofthebaseofthe  skullissuspected ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#artefactfromdentalprothesis/fillingsS## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#appositionofthepharyngeal_mucosal_Ԁfoldsmay $  obscurepathology ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#poolingofsalivamaymimicpathology{!"## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#superficialmucosalextentofneoplasmsmaynot L"# beidentified ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#secretionfromoropharyngealneoplasms#9%## 4.40 b Modificationtotechnique0b#b#0v##0v#v#coronalsectionsfordemonstratingtherelation %' shipofdiseasetotheskullbase ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#exposurewithopenmouthorwithoralValsava 2'}!) toopennasopharyngealfolds ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#changeofgantryangulationorpatientpositionto (#+ avoidartefact )#,## RP(  Preparatorysteps:   ̄0 b Indications:T/Nstagingofneoplasm;evaluationofcongenitalorpost-traumatic [ abnormalitiesofairway b#b# ̄0 b Advisablepreliminaryinvestigations:MRIandultrasonographymaybealternative   examinationswithoutexposuretoionisingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is A  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:lateralfromfloorofmouthtothoracicinlet b#b#  1.0 b DIAGNOSTICREQUIREMENTS V b#b#  Imagecriteria:  G   1.10 b Visualizationof  b#b# 1.1.10 b Entirelarynxwb#b# 1.1.20 b Paralaryngealtissues,includingmuscles,bloodvesselsandthethyroidglandHb#b# 1.1.30 b Regionallymphnodeareasdb#b# 1.1.40 b Spineandparavertebralmuscles.5b#b# 1.1.50 b Vesselsafterintravenouscontrastmediab#b#  1.20 b Criticalreproduction ]b#b# 1.2.10 b Reproductionofthewallofthelarynxthroughouttheareaofexamination2}b#b# 1.2.20 b VisuallysharpreproductionofthemucosalfoldsNb#b# 1.2.30 b Visuallysharpreproductionoftheperimucosalfatspacesb#b# 1.2.40 b Visuallysharpreproductionoftheintrinsicpharyngealmusclesb#b# 1.2.50 b Visuallysharpreproductionoftheparalaryngealmusclesvb#b# 1.2.60 b VisuallysharpreproductionofregionallymphnodeareasGb#b#  2.0 b CRITERIAFORRADIATIONDOSETOTHEPATIENT 4 b#b# 2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for !" information:routinehead:60mGy) ## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for $M% information:routinehead:1050mGycm) ##  3.0 b EXAMPLESOFGOODIMAGINGTECHNIQUE u& (b#b# 3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supine(f"*## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#frombaseoftonguetorootofneck)$,## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#35mmserialorpreferablyhelicalCT, _+%. especiallyinpatientshavingdifficultieswithsalivarypooling ## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguous,butforlargelesionsdistancesof .(2 <35mmorapitchupto1.52.0maybeused ## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#adjustedtotheminimumrequiredto 1a+5 demonstratecompletecrosssectionoftheneck.ReductionofFOVmaybenecessaryforthe 2-7 evaluationofsubtlepathologies ## 3.50 b Gantrytilt0 b#b#0 # #0v##:0v#v#noneormodifiedparalleltothelineofvocal W foldsonscanprojectionradiograph ## 3.60 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standard ## 3.7 b Tubecurrentandexposure0 v :  shouldbeaslowasconsistentwithrequiredl v#v# 0 b timeproduct(mAs)   v 0b#b#imagequality= ## 3.80 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standardorifnecessaryhigh  *  resolution ## 3.90 b Windowwidth0 b#b#0 # #0v##:0v#v#250500HUR ## 3.100 b Windowlevel0 b#b#0 # #0v##:0v#v#030HU(unenhancedexamination)? ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#3060HU(enhancedexamination) ## V \>  \>^7V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>^7y7Vیgb#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimage  X quality(avoidedbyquietrespiration;swallowingshouldbesuspendedduringexposurebutencouragedbetweenexposurestoavoidsalivarypooling) ## 4.20 b Intravenouscontrastmedia v 0b#b#mayberequiredtodistinguishlymphadenopathy>## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#improvesdelineationofneoplasm## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#movementartefactduetorespirationf## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#stagingerrorsduetopoordiscrimination 7 betweennormalandabnormaltissues ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#salivarypoolingmaymimicpathology$ ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#displacementofvocalfoldbyadjacentmass  ! maymimicglottalinvolvement ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#reformattedimagesmayrequirethinserialslices #h$ ifhelicalCTisnotavailable ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#sectionsthroughglottismaybeobtainedduring $ & phonation ##   a& ( TR(  Preparatorysteps:   ̄0 b Indications:traumaticlesionsandasaguidetobiopsy;alsostructuraldiseasesofthe [ vertebrae,medullaandparavertebraltissues,ifMRIiscontraindicatedornotavailable.MRIistheexaminationofchoiceinnontraumaticdisorders b#b# ̄0 b Advisablepreliminaryinvestigations:radiographyofthevertebralcolumn,andinsome   patientsmyelography b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is  ]  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalorlateralofthesuspecteddiseasedregion b#b# V \>  \>:DV1  .0 b   DIAGNOSTICREQUIREMENTS \>:DUDVی'r b#b# Ќ  Imagecriteria:     1.10 b Visualizationof sb#b# 1.1.10 b TheentireregionofsuspectedpathologyHb#b# 1.1.20 b Vesselsafterintravenouscontrastmediadb#b# 1.1.30 b Spinalcordandnerverootsafterintrathecalinjectionofcontrastmedia(CTmyelography)5b#b#  1.20 b Criticalreproduction b#b# 1.2.10 b Visuallysharpreproductionofthecorticalandtrabecularboneeb#b# 1.2.20 b Visuallysharpreproductionoftheintervertebraljoints6b#b# 1.2.30 b VisuallysharpreproductionoftheintervertebraldiskprofilesRb#b# 1.2.40 b Visuallysharpreproductionoftheintervertebralradicularcanals#b#b# 1.2.50 b Reproductionofthethecalsacb#b# 1.2.60 b Visuallysharpreproductionofthespinalcordorcaudaequina(CTmyelography)zb#b# 1.2.70 b ReproductionoftheparavertebralligamentsKb#b# 1.2.80 b Visuallysharpreproductionoftheparavertebralmusclesgb#b# 1.2.90 b Reproductionofthemainvesselsandperithecalvenousplexusesafterintravenous 8  contrastmedium b#b#  \>  \>JV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>J KVی`"#b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#70mGyforvertebraltrauma(pilotstudy(17))$Q%## 2.20 b DLP : 0' b#b#0 ' #' #0 # #0v##:0v#v#460mGycmforvertebraltrauma(pilotstudy)%'##  \>  \>yMV3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>yMMVیJ'!)b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supine(;#+## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#from1cmaboveto1cmbelowtheregionof *$- suspectedpathology ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#2-5mm-P'0## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0.(2## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#dimensioncorrespondingtothespineand I0*4 surroundingparavertebralstructures ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#none(alloweasyproductionofreformatted 2-7 images)orparalleltotheintervertebraldisks ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standardorhighkVinlargepersonstoavoid W noise ## 3.80 b Tubecurrentandexposure v :0b#b#shouldbeaslowasconsistentwith ## 0 b timeproduct(mAs)0b#b#0v##0v#v#requiredimagequality ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissueorhighresolution Y ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#140350HU(softtissue) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#20003000HU(bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#300400HU(cervicalspine) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#3040HU(softtissue)? ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#200400HU(bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#2535HU(cervicalspine) ## 3.120 b Protectiveshielding0b#b#0v##:0v#v#leadpurseforthemalegonadsiftheedgeofthe 8 volumeofinvestigationislessthan1015cmaway ##  \>  \>ұZV4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>ұZZVی|b#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratesimagequality "m (preventedbysedationofnon-cooperativepatients) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefultoidentifyvascularstructuresand f enhancinglesions ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#foreignbodies(beamhardeningartefacts)$ ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#productionofreformattedimagesofadequate {!" qualitymayrequirethinserialslicesifhelicalCTisnotavailable #h$## VT( Preparatorysteps:   ̄0 b Indications:radiculopathy(sciatica),backpain,failureofconservativetreatmentand [ postoperativebackpain,especiallywhenMRIiscontraindicated b#b# ̄0 b Advisablepreliminaryinvestigations:radiographyofthespine;electromyography;MRIis   apreferablealternativeexaminationwithoutexposuretoionisingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is A  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:lateralofthesuspecteddiseaseddisks b#b# V \>  \>ubV1  .0 b   DIAGNOSTICREQUIREMENTS \>ubbVیV b#b# Ќ  Imagecriteria:  G   1.10 b Visualizationof b#b#  1.1.10 b Theentireregionofsuspectedpathologywb#b# 1.1.20 b VesselsafterintravenouscontrastmediaHb#b# 1.1.30 b Spinalcordandnerverootsafterintrathecalinjectionofcontrastmedia(CT-myelography)db#b#  1.20 b Criticalreproduction b#b# 1.2.10 b Visuallysharpreproductionoftheintervertebraldiskprofilesb#b# 1.2.20 b Visuallysharpreproductionofthethecalsacab#b# 1.2.30 b Visuallysharpreproductionoftheperithecalfat2}b#b# 1.2.40 b VisuallysharpreproductionoftheintervertebralradicularcanalsNb#b# 1.2.50 b Visuallysharpreproductionofthenerverootsb#b# 1.2.60 b Reproductionofthemainvesselsandperithecalvenousplexusesafterintravenous  contrastmedia b#b# 1.2.70 b ReproductionofthecorticalandtrabecularboneGb#b# 1.2.80 b Visuallysharpreproductionoftheintervertebraljointscb#b# 1.2.90 b Reproductionoftheparavertebralligaments4 b#b#  \>  \>iV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>iiVی!"b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for 1#|$ information:routineabdomen:35mGy) ## 2.20 b DLP0: b#b#0' : #: # 0' #' #0v##:0v#v#nospecificvalueasyetavailable(for %' information:routineabdomen:800mGycm) ##  \>  \>kV3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>klVی(b"*b#b# Ќ  3.10 b Patientposition0 b#b#  0v # #:0v#v#supine,legsinflexion)$,## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#frompedicletopediclewithtargetingofasliceat _+%. thecentreofthesuspecteddiseaseddisks ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#2-5mm-(1## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0t/)3## 3.50 b _FOV_0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#spinedimension1a+5## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#asparallelaspossibletotheintervertebraldisc 2-7 planes;adifferentgantrytiltmayberequiredforeachintervertebralspace ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standardorhighkVinlargepersonstoavoid (s noise ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwith ## 0 b timeproduct(mAs)0b#b#0v##0v#v#requiredimagequalityl ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standardorhighresolution Y ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#140400HU(softtissue) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#20003000HU(bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#250300HU(lumbarspine) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#3040HU(softtissue)? ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#200400HU(bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#2535HU(lumbarspine) ## 3.120 b Protectiveshielding0b#b#0v##:0v#v#leadpurseforthemalegonadsiftheedgeofthe 8 volumeofinvestigationislessthan1015cmaway ##  \>  \>QyV4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>QylyVی|b#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratesimagequality "m (preventedbysedationofnon-cooperativepatients) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefultoidentifyvascularstructuresand f enhancinglesions ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#foreignbodies(beamhardeningartefacts)$ ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#calcificationsversuscontrastenhancement !## 4.40 b Modificationtotechnique0b#b#0v##0v#v#intrathecalinjectionofcontrastmedium(CT- L"# myelography)todelineatethespinalcordandnerveroots #9%## XV( Preparatorysteps:   ̄0 b Indications:tetraparesis,paraparesis,otherneurologicaldeficitsandspinalcord [ compressionsyndromewhenMRIiscontraindicatedornotavailable.MRIistheexaminationofchoice b#b# ̄0 b Advisablepreliminaryinvestigations:radiographyofthespineand/ormyelography b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is A  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalorlateralofallthesuspectedvertebralsegments b#b# V \>  \>ҿV1  .0 b   DIAGNOSTICREQUIREMENTS \>ҿځVیV b#b# Ќ  Imagecriteria:  G   1.10 b Visualizationof  b#b# 1.1.10 b Theentireregionofsuspectedpathologywb#b# 1.1.20 b VesselsafterintravenouscontrastmediaHb#b# 1.1.30 b Spinalcordandnerverootsafterintrathecalinjectionofcontrastmedia(CT-myelography)db#b#  1.20 b Criticalreproduction b#b# 1.2.10 b Visuallysharpreproductionofspinalcordcontours(CT-myelography)b#b# 1.2.20 b Visuallysharpreproductionofthethecalsacab#b# 1.2.30 b Visuallysharpreproductionoftheperithecalfat2}b#b# 1.2.40 b VisuallysharpreproductionoftheintervertebraldiskprofilesNb#b# 1.2.50 b Reproductionofthemainvesselsandperithecalvenousplexusesafterintravenous  contrastmedia b#b# 1.2.60 b Visuallysharpreproductionoftheintervertebralradicularcanalsvb#b# 1.2.70 b VisuallysharpreproductionoftheintervertebraljointsGb#b# 1.2.80 b Reproductionoftheparavertebralligamentscb#b# 1.2.90 b Visuallysharpreproductionoftheparavertebralmuscles4 b#b#  \>  \>hV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>hVی!"b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for 1#|$ information:routinechestorabdomen:30/35mGy) ## 2.20 b DLP : 0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for %' information:routinechestorabdomen:650/800mGycm) ##  \>  \>gV3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>gVی(3#+b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supine,legsinflexion*$-## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#from1cmaboveto1cmbelowsuspected 0,{&/ pathology ## 3.30 b Nominalslicethickness0b#b#0v##:  2-5mm.(2v#v# 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0E0*4## 3.50 b _FOV_0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#spinedimension    12,6##  2-7 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#none(alloweasyproductionofreformatted  images) ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standardorhighkVinlargepersonstoavoid (s noise ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequired ## 0 b timeproduct(mAs)0b#b#0v##0v#v#imagequalityl ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standardorhighresolution Y ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#140400HU(softtissue) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#20003000HU(bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#250300HU(cervicalspine) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#30004000HU(CT-myelography) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#3040HU(softtissue) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#200400HU(bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#2535HU(cervicalspine) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#400600HU(CT-myelography) ## 3.120 b Protectiveshielding0b#b#0v##:0v#v#leadpurseforthemalegonadsiftheedgeofthe % volumeofinvestigationislessthan1015cmaway ##  \>  \>V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>6Vیib#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratesimagequality  (preventedbysedationofnon-cooperativepatients) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefultoidentifyvascularstructuresand S enhancinglesions ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#foreignbodies(beamhardeningartefacts){!"## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#calcificationsversuscontrastenhancementL"### 4.40 b Modificationtotechnique0b#b#0v##0v#v#intrathecalinjectionofcontrastmedium(CT- #9% myelography)todelineatethespinalcordandnerveroots ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#productionofreformattedimagesofadequate a& ( qualitymayrequirethinserialslicesifhelicalCTisnotavailable (N"*## ZX( Preparatorysteps:   ̄0 b Indications:suspectedorknownpulmonary,pleuralorlymphnodedisease,including [ metastaticneoplasms,infection,traumaticlesionsandfocaldiseases b#b# ̄0 b Advisablepreliminaryinvestigations:chestradiography b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is p  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalfromnecktoupperabdomen . b#b# V \>  \>oV1  .0 b   DIAGNOSTICREQUIREMENTS \>oVی b#b# Ќ  Imagecriteria:  +v   1.10 b Visualizationof  b#b# 1.1.10 b Entirethoracicwall b#b# 1.1.20 b Entirethoracicaortaandvenacavawb#b# 1.1.30 b EntireheartHb#b# 1.1.40 b Entirelungparenchymadb#b# 1.1.50 b Vesselsafterintravenouscontrastmedia5b#b#  1.20 b Criticalreproduction b#b# 1.2.10 b Visuallysharpreproductionofthethoracicaortaab#b# 1.2.20 b Visuallysharpreproductionoftheanteriormediastinalstructures,includingthymic 2} residue(ifpresent) b#b# 1.2.30 b Visuallysharpreproductionofthetracheaandmainbronchib#b# 1.2.40 b Visuallysharpreproductionoftheparatrachealtissueb#b# 1.2.50 b Visuallysharpreproductionofthecarinaandlymphnodeareavb#b# 1.2.60 b VisuallysharpreproductionoftheoesophagusGb#b# 1.2.70 b Visuallysharpreproductionofthepleuromediastinalbordercb#b# 1.2.80 b Visuallysharpreproductionoflargeandmediumsizedpulmonaryvessels4 b#b# 1.2.90 b Visuallysharpreproductionofsegmentalbronchi !b#b# 1.2.100 b Visuallysharpreproductionofthelungparenchyma!"b#b# 1.2.110 b Visuallysharpreproductionoftheborderbetweenthepleuraandthethoracicwall\"#b#b#  \>  \>AV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>A\Vی#I%b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#routinechest:30mGy%'## 2.20 b DLP0: b#b# ' 0 : #: #0 # #0v##:0v#v#routinechest:650mGycmF'!)##  \>  \>ҟV3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>ҟVی(3#+b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supine,armsabovethehead*$-## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#fromlungapextothebaseofthelungs0,{&/## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#710mmserialorpreferablyhelical-(1## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0;45mmorpitchup t/)3 to1.5maybeusedforlargelesionsordetectionoflymphadenopathyalone;evenlargerinterslicedistance/pitchmaybeappliedincriticallyillpatients2-7## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#adjustedtolargestthoracicdiameterwithinthe  volumeofinvestigation ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#none(s## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standard ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequiredl ## 0 b timeproduct(mAs)0b#b#0v##0v#v#imagequality= ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standard * ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#300600HU(softtissue) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#8001.600HU(lungparenchyma) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#030HU(softtissue,unenhancedexamination)? ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#3060HU(softtissue,enhancedexamination) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#500700HU(lungparenchyma) ##  \>  \>җV4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>җVی8b#b# Ќ  4.1 b Motion0 ' 0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimage ) quality.Thisispreventedbyastandardbreathholdtechnique;alternativelyifthisisnotpossiblescanduringquietrespiration ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#maybeusedtocharacteriselesionsorto > distinguishthemfromvessels ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#anatomicalmisregistrationduetovariationinthe f phaseofrespiration ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#focalatelectasismayobscurepathologyS## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#motionartefactduetocardiacpulsationor $  respiration ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#pronepositionmaybeusedtoelucidatepleural L"# lesionsorfocalspaces ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#theexaminationmaybeconfinedtoaspecific #9% areaofinterest ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#4mmslicesmaybeusedforspecific %' examinationofhilarpathologyandsubtlepulmonarylesions ##   (N"* \Z( Preparatorysteps:   ̄0 b Indications:suspectedorknownmajorvesselaneurysm,dissectionorcongenital [ anomaly b#b# ̄0 b Advisablepreliminaryinvestigations:chestradiography,includinglateralprojection;MRI   ortransoesophagealultrasonographymaybealternativeexaminationswithoutexposuretoionisingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is  ]  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalfromnecktoupperabdomen b#b# V \>  \>ґV1  .0 b   DIAGNOSTICREQUIREMENTS \>ґVی'r b#b# Ќ  Imagecriteria:     1.10 b Visualizationof sb#b# 1.1.10 b EntirethoracicaortaHb#b# 1.1.20 b Entirevenacavadb#b# 1.1.30 b Entireheart5b#b# 1.1.40 b Vesselsafterintravenouscontrastmediab#b#  1.20 b Criticalreproduction ]b#b# 1.2.10 b Visuallysharpreproductionofthecontourofthethoracicaorta2}b#b# 1.2.20 b VisuallysharpreproductionofthewallofthethoracicaortaNb#b# 1.2.30 b Visuallysharpreproductionofthesuperiorvenacavab#b# 1.2.40 b Visuallysharpreproductionofthemajoranteriormediastinalvesselsb#b# 1.2.50 b Visuallysharpreproductionoftheheartvb#b# 1.2.60 b VisuallysharpreproductionoftheinferiorvenacavaGb#b# 1.2.70 b Visuallysharpreproductionoflargeandmediumsizedpulmonaryvesselscb#b#  \>  \>,V2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>,GVی !b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for `"# information:routinechest:30mGy) ## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for $& information:routinechest:650mGycm) ##  \>  \>V3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>0VیF'!)b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supine,armsabovethehead(7#+## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#maybelimitedtoareaofradiographic *$- abnormalityorclinicallysuspectedlesion ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#45mmserialorpreferablyhelical-L'0## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0;24mmorapitch .(2 upto1.21.5forlargelesions ## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#limitedtoareaoftheheartandmajorvessels1a+5## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#none2-7## Ї3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standard## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequiredW## 0 b timeproduct(mAs)0b#b#0v##0v#v#imagequality(s## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standard ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#100400HU(softtissue,unenhanced l  examination) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#150500HU(softtissue,enhancedexamination) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#050HU(softtissue,unenhancedexamination) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#20150HU(softtissue,enhancedexamination,dependsondoseandmethodofcontrastadministration) ##  \>  \>1V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>1LVی b#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimage k quality.Thisispreventedbyastandardbreathholdtechnique;alternativelyifthisisnotpossiblescanduringquietrespiration ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#enhancementisrequiredformanyexaminations## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#artefactfromthecardiacoutlinemaycrossthe "m aortaandmimicdissectionflap ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#inhomogeneitiesinluminalopacificationdueto  inconstantbloodflow ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#inappropriateadministrationofcontrastmedia f maymimicthrombus ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#notusuallyrequired$ ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v## v#v#   L"# ^\( Preparatorysteps:   ̄0 b Indications:detectionandcharacterizationofdiffuseparenchymallungdiseaseincluding [ emphysemaorbronchiectasis b#b# ̄0 b Advisablepreliminaryinvestigations:chestradiographyandrespiratoryfunctiontests b#b# ̄0 b Patientpreparation:informationabouttheprocedurep b#b# ̄0 b Scanprojectionradiograph:frontalfromnecktoupperabdomen ] b#b# V \>  \>ҲV1  .0 b   DIAGNOSTICREQUIREMENTS \>ҲVی b#b# Ќ  Imagecriteria:  Z   1.10 b Visualizationof K b#b# 1.1.10 b Entirefieldoflungparenchyma b#b#  1.20 b Criticalreproduction wb#b# 1.2.10 b VisuallysharpreproductionofthelungparenchymaLb#b# 1.2.20 b Visuallysharpreproductionofpulmonaryfissureshb#b# 1.2.30 b Visuallysharpreproductionofsecondarypulmonarylobularstructuressuchas 9 interlobulararteries b#b# 1.2.40 b Visuallysharpreproductionoflargeandmediumsizedpulmonaryvesselsb#b# 1.2.50 b Visuallysharpreproductionofsmallpulmonaryvesselsab#b# 1.2.60 b Visuallysharpreproductionoflargeandmediumsizedbronchi2}b#b# 1.2.70 b VisuallysharpreproductionofsmallbronchiNb#b# 1.2.80 b Visuallysharpreproductionofthepleuromediastinalborderb#b# 1.2.90 b Visuallysharpreproductionoftheborderbetweenthepleuraandthethoracicwallb#b#  \>  \>ҋV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>ҋVیGb#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#35mGy(pilotstudy(17))8 ## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#280mGycm(pilotstudy)!"##  \>  \>V3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \> Vی1#|$b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supine,armsabovethehead$"&## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#fromlungapextothebaseofthelungs(survey) y& ( orcorrespondingtoradiographicallydefinedabnormality(localiseddisease) ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#12mm)$,## 3.40 b Interslicedistance0b#b#0v##:0v#v#1020mm_+%.## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#adjustedtotheminimumwhichwilldemonstrate -L'0 thewholelungfield ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#nonet/)3## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#highkVorstandard1a+5## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequired2-7## 0 b timeproduct(_mAs_)0b#b#0v##0v#v#imagequality## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#highresolutionW## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#10001600HUD## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#400700HU ##  \>  \>V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>Vی= b#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimage  .  qualityandbreathholdtechniqueismandatory ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#notrequiredV ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#motionartefactdueto_dyspnoea_C ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#_atelectasis_Ԁmayobscurepathology ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#pronepositionmaybeusedtoelucidate k dependentchanges,especiallysmallareasofatelectasis ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#examinationinsuspendedexpirationtodetectair ) trapping ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#sectionswithsmallerinterslicedistancefor  evaluationofverysmallareasofdisease0@ $"$" ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#sectionswithacraniocaudal25to30$gantry "m tiltfordetectionofbronchiectasies ## ̀   `^( Preparatorysteps:   ̄0 b Indications:inflammatorylesions,abscess,suspectedorknownstructuralalterationor [ spaceoccupyinglesionsoftheabdomenandretroperitoneum,lesionsofmajorvesselssuchasaneurysmsandtraumaticlesions,andasaguidetobiopsy b#b# ̄0 b Advisablepreliminaryinvestigations:ultrasonographyand/orradiographyofthe   abdomen.MRImaybeanalternativeexaminationwithregardtotheretroperitonealspace b#b# ̄0 b Patientpreparation:informationabouttheprocedure;excludehighdensitycontrastmedia  .  frompreviousinvestigations;oralapplicationofcontrastmediafortheintestine;restraintfromfood,butnotfluid,isrecommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalfromlowerchesttopelvis'r b#b# V \>  \>nV1  .0 b   DIAGNOSTICREQUIREMENTS \>nVی b#b# Ќ  Imagecriteria:  o  1.10 b Visualizationof `b#b# L 5( ML &t   &t251.1.  1  3  0 b   Diaphragm&tJ݌5b#b# Ќ  1.1.20 b Entireliverandspleenb#b# 1.1.30 b Retroperitonealparenchymalorgans(pancreas,kidneys)b#b# 1.1.40 b Abdominalaortaandtheproximalpartofthecommoniliacarteries]b#b# 1.1.50 b Abdominalwallincludingallherniations.yb#b# 1.1.60 b VesselsafterintravenouscontrastmediaJb#b#  1.20 b Criticalreproduction b#b# 1.2.10 b Visuallysharpreproductionoftheliverparenchymaand_intrahepatic_Ԁvesselsvb#b# 1.2.20 b VisuallysharpreproductionofthesplenicparenchymaGb#b# 1.2.30 b Visuallysharpreproductionoftheintestinecb#b# 1.2.40 b Visuallysharpreproductionoftheperivascularretroperitonealspace4 b#b# 1.2.50 b Visuallysharpreproductionofthepancreaticcontours !b#b# 1.2.60 b Visuallysharpreproductionoftheduodenum!"b#b# 1.2.70 b Visuallysharpreproductionofthekidneysandproximalureters\"#b#b# 1.2.80 b Visuallysharpreproductionoftheaorta-#x$b#b# 1.2.90 b Visuallysharpreproductionoftheaorticbifurcationandcommoniliacarteries#I%b#b# 1.2.100 b Reproductionoflymphnodessmallerthan15mmindiameter$&b#b# 1.2.110 b Reproductionofbranchesoftheabdominalaorta%'b#b# 1.2.120 b Visuallysharpreproductionofthevenacavaq& (b#b# 1.2.130 b ReproductionoftributariestothevenacavainparticulartherenalveinsB'!)b#b#  \>  \>Ҕ V2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>Ҕ  Vی(/#+b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#routineabdomen:35mGy*$-## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#routineabdomen:780mGycm,,w&/## Ѐ \>  \> V3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>  Vی-(1b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supinewitharmsatchestorheadlevelt/)3## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#fromdomeofthelivertotheaorticbifurcation1a+5## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#710mm;45mmfordedicatedindicationsonly 2-7 (suspectedsmalllesions),serialorpreferablyhelical ## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0;inscreening (s investigations,eg.fortraumaticlesions10mm D orapitchupto1.22.0 ## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#adjustedtothelargestabdominaldiameterl ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#none Y ## 3.70 b Xraytubevoltage(Kv)0b#b#0v##:0v#v#standard ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequired @! R ## 0 b timeproduct(mAs)0b#b#0v##0v#v#imagequality#n ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#standardorsofttissue ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#150-600HUg## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#2000-3000HU(bone,ifrequired) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#30-60HU(enhancedexamination)%## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#030HU(unenhancedexamination) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#400-600HU(bone,ifrequired) ## 3.120 b Protectiveshielding0b#b#0v##:0v#v#leadpurseforthemalegonadsiftheedgeofthe i volumeofinvestigationislessthan1015cmaway ##  \>  \>ҼV4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>ҼVیbb#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimage S quality.Thisispreventedbyastandardbreathholdtechnique;alternativelyifthisisnotpossiblescanduringquietrespiration ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefulfordifferentiatingvesselsandorgan #h$ tissuesfromadjacentstructuresandtodetectparenchymallesionsinsolidorgans ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#noncontrastedpartsoftheintestinemaymimic a& ( tumours ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#thedelineationoforgansandstructuresmaybe (N"* poorincachecticpatientswithreduced_intraabdominal_Ԁand_retroperitoneal_Ԁfat ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#helicalCTwhichisbeneficialforeliminationof G+%. motionartefactcanbeusedfordemonstratingvascularpathologies(CTangiography) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#maybecombinedwithexaminationofthepelvis-(1##   \/)3 $`( Preparatorysteps:   ̄0 b Indications:suspectedorknownfocalordiffusediseaseoftheliver,biliarytree, [ gallbladder,spleenoradjacentstructures b#b# ̄0 b Advisablepreliminaryinvestigations:ultrasonography;MRImaybeanalternative   examinationwithoutexposuretoionisingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;excludehighdensitycontrastmedia A  formpreviousinvestigations;oralcontrastmediaforbowelandstomachdemarcation;restraintfromfood,butnotfluid,isrecommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalfromlowerchesttopelvisV b#b# V \>  \>$V1  .0 b   DIAGNOSTICREQUIREMENTS \>$%VیC b#b# Ќ  Imagecriteria:    1.1 0 b Visualizationof Db#b# 1.1.10 b Entireliverdb#b# 1.1.20 b Entirespleen5b#b# 1.1.30 b Vesselsafterintravenouscontrastmediab#b#  1.20 b Criticalreproduction ]b#b# 1.2.10 b Visuallysharpreproductionoftheliverparenchymaandintrahepaticportalveins2}b#b# 1.2.20 b VisuallysharpreproductionoftheliverveinsNb#b# 1.2.30 b Visuallysharpreproductionofthestructuresoftheliverhilusb#b# 1.2.40 b Visuallysharpreproductionofthecommonhepaticductb#b# 1.2.50 b Reproductionoftheductuscholedochus(commonbileduct)inthepancreatic v parenchyma b#b# 1.2.60 b Reproductionofthegallbladderwallcb#b# 1.2.70 b Visuallysharpreproductionofthesplenicparenchyma4 b#b# 1.2.80 b Visuallysharpreproductionofthesplenicartery !b#b# 1.2.90 b Visuallysharpreproductionoftheextrahepaticportalveinsystemincludingv.lienalisand !" v.mesentericasup. b#b# 1.2.100 b Visuallysharpreproductionoftheaortaandinferiorvenacava-#x$b#b# 1.2.110 b Visuallysharpreproductionoftheoriginofthecoeliactrunk#I%b#b# 1.2.120 b Visuallysharpreproductionofthemesentericartery$&b#b#  \>  \>ң,V2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>ң,,Vیq& (b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#35mGy(pilotstudy(17))(b"*## 2.20 b DLP0: b#b# ' 0 : #: #0 # #0v##:0v#v#900mGycm(pilotstudy))$,##  3.0 b EXAMPLESOFGOODIMAGINGTECHNIQUE [+%.b#b# 3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supinewitharmsatchestorheadlevel-L'0## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#fromabovediaphragmto1cmbelowthecaudal t/)3 endoftheliverandspleen ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#710mm;45mmifsmalllesionsaresuspected, 12,6 serialorpreferablyhelical2-7## Ї3.40 b Interslicedistance0b#b#0v##:0v#v#contiguousorapitch=1.0;10mmorapitch  upto1.22.0inscreeninginvestigations ## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#adjustedtothelargestdiameteroftheabdomen (s withinthevolumeunderinvestigation ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#none ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standard= ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequired * ## 0 b timeproduct(mAs)0b#b#0v##0v#v#imagequality ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standardR ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#150-300HU? ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#40-80HU(enhancedexamination) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#030HU(unenhancedexamination) ## V \>  \>8V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>88Vی Tb#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimage  quality.Thisispreventedbystandardbreathholdtechnique;alternativelyifthisisnotpossiblescanduringquietrespiration ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#cardiacmotionmaycauseartefactsinleftliver > lobe ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefultodelineateorgantissueandvesselsand f detectfocallesionsinsolidorgans ## L l&}'(PQRS-h(L0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#multiphasedsectionexaminationmaybe S indicated ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#inconsistentbreathholdingbetweenslicesmay {!" obscuresubtlepathologyinserialCT ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#differentiationofsmallhepaticorspleniccysts #h$ fromtumourscanbedifficult ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#inhomogeneousattenuationduringinitial $ & contrastenhancementmaymimicfocalhepaticorsplenicdisease ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#non-calcifiedbilestonesmaynotbeidentifiable2'}!)## 4.40 b Modificationtotechnique0b#b#0v##0v#v#incaseofsuspectedhaemangioma,serialCTof (#+ thepathologyseveralminutesafterinjectionofcontrastmedia ##  b  M  :  '    0 v 0v#v#additionalthinnerslicesmaybeobtainedto G+%. delineatesubtlealterations ,c&/## $( Preparatorysteps:   ̄0 b Indications:suspectedorknownfocalordiffusestructuraldiseaseofthekidneys,and [ traumaticlesions ,wb#b# ̄0 b Advisablepreliminaryinvestigations:ultrasonography;blood-creatinine(especiallyprior   toadministrationofcontrastmedia).MRImaybeanalternativeexaminationwithoutexposuretoionisingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;excludehighdensitycontrastmedia  ]  frompreviousinvestigations;restraintfromfood,butnotfluid,isrecommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalfromliverdometoupperpelvisV b#b# V \>  \>ұGV1  .0 b   DIAGNOSTICREQUIREMENTS \>ұGGVیC b#b# Ќ  Imagecriteria:    1.10 b Visualizationof Db#b# 1.1.10 b Bothkidneysdb#b# 1.1.20 b Proximalpartoftheureters5b#b# 1.1.30 b Vesselsafterintravenouscontrastmediab#b#  1.20 b Criticalreproduction ]b#b# 1.2.10 b Visuallysharpreproductionoftherenalparenchyma2}b#b# 1.2.20 b Visuallysharpreproductionoftherenalpelvisandcalices/Nb#b# 1.2.30 b Visuallysharpreproductionoftheproximalpartoftheuretersb#b# 1.2.40 b Visuallysharpreproductionoftheperirenalspacesb#b# 1.2.50 b Visuallysharpreproductionoftheaortaandvenacavavb#b# 1.2.60 b VisuallysharpreproductionoftherenalarteriesGb#b# 1.2.70 b Visuallysharpreproductionoftherenalveinscb#b#  \>  \>LV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>LMVی !b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for `"# information:routineabdomen:35mGy) ## 2.20 b DLP0: b#b# ' 0 : #: #0 # #0v##:0v#v#nospecificvalueasyetavailable(for $& information:routineabdomen:800mGycm) ##  \>  \>OV3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>OOVیF'!)b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supinewitharmsatchestorheadlevel(7#+## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#1cmabovethemostcranialpoleofthekidneys *$- to1cmbelowthemostcaudalpole;dependingonthefindings(eg.tumour)extensionofthevolumemaybeneeded ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#4-5mmforunknownorsmallpathologies;7-10 .(2 mmforfollowupoflargerlesions ## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.01a+5##  2-7 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#adjustedtothelargestdiameteroftheabdomen  withinthevolumeunderinvestigation;secondarymagnificationbyreducingtheFOVmaybenecessaryforevaluationofsubtlepathology ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#none ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standardl ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequired Y ## 0 b timeproduct(mAs)0b#b#0v##0v#v#imagequality * ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standard ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#200-400HU#n ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#30-150HU(enhancedexamination) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#0-30HU(unenhancedexamination) ##  \>  \>҈ZV4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>҈ZZVی8b#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimage ) quality.Thisispreventedbyastandardbreathholdtechnique;alternativelyifthisisnotpossiblescanduringquietrespiration ## 4.20 b Intravenouscontrastmedia0vb#b#-0v#v#combinationofnativeandcontrastenhanced > studiesarenecessaryinmostpatientstocharacteriselesionsordistinguishthemfromvessels ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#multiphasedsectionexaminationmaybe 7 indicated.Anoptimalinjectionprotocolisthenimportant ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v## v#v# 4.30 b Problemsandpitfalls0b#b#0v##0v#v#inconsistentbreathholdingbetweenslicesmay {!" obscuresubtlepathologyinserialCT ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#differentiationofsmallcystsfromtumoursmay #h$ bedifficult ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#non-calcifiedstonesmaynotbeidentifiable$ &## ##J#4.40 b Modificationtotechnique  0vb#b#-0v#v#additionalthinnerslicesmaybeobtainedto a& ( delineateminoralterations ##   (N"* ?( Preparatorysteps:   ̄0 b Indications:suspectedorknownfocalordiffusediseaseofthepancreasorperipancreatic [ structures ,wb#b# ̄0 b Advisablepreliminaryinvestigations:ultrasonography;laboratoryinvestigations(amylase,   lipase).MRImaybeanalternativeexaminationwithoutexposuretoinonisingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;excludehighdensitycontrastmedia A  frompreviousinvestigations;oralcontrastmediadirectlypriortotheexamination(inrightlateralposition)todemarcatetheduodenum;restraintfromfood,butnotfluid,isrecommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalfromlowerchesttomiddleabdomenV b#b# V \>  \>QgV1  .0 b   DIAGNOSTICREQUIREMENTS \>QglgVیC b#b# Ќ  Imagecriteria:     1.10 b Visualizationof Db#b# 1.1.10 b Entirepancreas(head,body,tail,uncinateprocess)db#b# 1.1.20 b Entirediseasedperipancreatictissue5b#b# 1.1.30 b Adjacentpartsofliver,spleen,bowelsandstomachb#b# 1.1.40 b Vesselsafterintravenouscontrastmediab#b#  1.20 b Criticalreproduction .yb#b# 1.2.10 b VisuallysharpreproductionofthepancreaticcontoursNb#b# 1.2.20 b Visuallysharpreproductionofthepancreaticparenchymab#b# 1.2.30 b Reproductionofthepancreaticductb#b# 1.2.40 b Visuallysharpreproductionofthecommonbileductwithinthepancreaticheadvb#b# 1.2.50 b VisuallysharpreproductionofthemesentericarteryandveinGb#b# 1.2.60 b Visuallysharpreproductionofthesplenicarteryandveincb#b# 1.2.70 b Visuallysharpreproductionoftheportalvein4 b#b# 1.2.80 b Visuallysharpreproductionofthecoeliactrunk !b#b# 1.2.90 b Visuallysharpreproductionofdiaphragmaticcrura!"b#b# 1.2.100 b Visuallysharpreproductionoftheaorta\"#b#b# 1.2.110 b Visuallysharpreproductionofthevenacava-#x$b#b# 1.2.120 b Visuallysharpreproductionoftherenalvessels#I%b#b# 1.2.130 b Visuallysharpreproductionoftheduodenum$&b#b#  \>  \>doV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>dooVیq& (b#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for (b"* information:routineabdomen:35mGy) ## 2.20 b DLP0: b#b# ' 0 : #: #0 # #0v##:0v#v#nospecificvalueasyetavailable(for *$- information:routineabdomen:800mGycm) ##  \>  \>HrV3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>HrcrVی,H'0b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supinewitharmsatchestorheadlevel.(2## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#12cmabovethepancreatictailto12cmbelow E0*4 theuncinateprocess;largervolumemaybeneededtoincludeallperipancreaticlesionssuchaspseudocystsorexudates2-7## Ї3.30 b Nominalslicethickness0b#b#0v##:0v#v#3-5mm;7-10mminknownlargerlesions,  serialorpreferablyhelical ## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0;510mmorapitch (s upto1.22.0forexudatescaudaltothepancreas ## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#adjustedtothelargestdiameteroftheabdomen   withinthevolumeunderinvestigation;secondarymagnificationbyreducingtheFOVmaybenecessaryforevaluationofsubtlepathology ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#none ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standardR ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequired @! ? ## 0 b timeproduct(_mAs_)0b#b#0v##0v#v#imagequality ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissueg## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#150-400HU T## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#30-50HU(enhancedexamination)## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#030HU(unenhancedexamination) ##  \>  \>j}V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>j}}Vیib#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimage  quality.Thisispreventedbyastandardbreathholdtechnique;alternativelyifthisisnotpossiblescanduringquietrespiration ## Ѐ4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefulfordelineationoftumorousor $  inflammatorydisease ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#scanningearlyafterinjectionofintravenous {!" contrastmediaisusefulfordetectionofintrapancreatictumours ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#0;## ;#;# 4.30 b Problemsandpitfalls0b#b#0v##0v#v#inconsistentbreathholdingbetweenslicesmay $ & obscuresubtlepathologyinserialCT ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#insufficientdifferentiationofpancreaticheadand a& ( duodenumduetolackoforalcontrastmediainduodenum ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#insufficientpancreaticdelineationinpatientswith (#+ reducedretroperitonealfattytissue ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#bowelmotionmayrequirespasmolytictherapyG+%.## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#theexaminationmaybeextendedtoincludethe ,c&/ liverwithcontrastintheportovenousphaseinthecaseoftumoursuspicion ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#intraarterialcontrastmediamaybeusedfor .(2 detectionofendocrinepancreatictumours ##   -0x*4 A?( Preparatorysteps:   ̄0 b Indications:suspectedorknownfocalordiffusestructuraldiseaseoftheadrenalglands[b#b# ̄0 b Advisablepreliminaryinvestigations:ultrasonography;scintigraphy;laboratory H investigations.MRImaybeanalternativeexaminationwithoutexposuretoionisingradiation b#b# ̄0 b Patientpreparation:informationabouttheprocedure;excludehighdensitycontrastmedia A  frompreviousinvestigations;restraintfromfood,butnotfluid,isrecommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalfromlowerchesttomiddleabdomen b#b# V \>  \>V1  .0 b   DIAGNOSTICREQUIREMENTS \>!Vی'r b#b# Ќ  Imagecriteria:     1.10 b Visualizationof sb#b# 1.1.10 b BothadrenalglandsHb#b# 1.1.20 b Upperperirenalspacesdb#b# 1.1.30 b Vesselsafterintravenouscontrastmedia5b#b#  1.20 b Criticalreproduction b#b# 1.2.10 b Visuallysharpreproductionoftherightadrenalbodyab#b# 1.2.20 b Visuallysharpreproductionoftherightadrenalcrura2}b#b# 1.2.30 b VisuallysharpdifferentiationoftherightadrenalglandfromadjacentstructuresNb#b# 1.2.40 b Visuallysharpreproductionoftheleftadrenalbodyb#b# 1.2.50 b Visuallysharpreproductionoftheleftadrenalcrurab#b# 1.2.60 b Visuallysharpdifferentiationoftheleftadrenalglandfromadjacentstructuresvb#b# 1.2.70 b VisuallysharpreproductionofthediaphragmaticcruraGb#b# 1.2.80 b Visuallysharpreproductionoftheaortacb#b# 1.2.90 b Visuallysharpreproductionofthevenacava4 b#b#  \>  \>-V2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>-HVی!"b#b# Ќ  2.10 b _CTDIW_0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for 1#|$ information:routineabdomen:35_mGy_) ## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable(for %' information:routineabdomen:800mGycm) ## Ѐ \>  \>ZV3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>ZuVی(b"*b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supinewitharmsatchestorheadlevel)$,## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#12cmaboveto12cmbelowtheadrenal _+%. glands ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#25mm,serialorpreferablyhelical;canbe .(2 largerifpathologyisalreadyknown. ## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0;inthecaseofminor 1a+5 pathology,overlappingslicesbyserialCT ##  2-7 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#adjustedtothelargestdiameteroftheabdomen  withinthevolumeunderinvestigation;secondarymagnificationbyreducingtheFOVmaybenecessaryforevaluationofsubtlepathology ## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#none ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standardl ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequired @!  Y ## 0 b timeproduct(mAs)0b#b#0v##0v#v#imagequality * ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#150-400HU#n ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#30-50HU(enhancedexamination) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#030HU(unenhancedexamination) ##  \>  \>V4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>Vی8b#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimage ) quality.Thisispreventedbyastandardbreathholdtechnique;alternativelyifthisisnotpossiblescanduringquietrespiration ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefultoimprovedelineationoftheadrenals > fromadjacentorgansorstructures,andforcharacterizationoftumours ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#inconsistentbreathholdingbetweenslicesmay 7 obscuresubtlepathologyinserialCT ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#insufficientadrenaldelineationinpatientswith $  reducedretroperitonealfattytissue ## 4.40 b Modificationtotechnique0b#b#0v##-0v#v#administrationoforalcontrastmediato L"# improveddelineationfromadjacentorgansorstructures ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v# $ &## CA( Preparatorysteps:   ̄0 b Indications:&ë&&&ëdisordersoftheprostate,uterusorfemalegonadsand#&ë&&&ë8#suspectedorknown [ focalordiffusestructuraldiseaseofthepelviseg.lymphomas b#b# ̄0 b Advisablepreliminaryinvestigations:ultrasonographyandMRIarealternative   examinationswithoutexposuretoionisingradiation;endoscopy(forintraluminalpathology) b#b# ̄0 b Patientpreparation:informationabouttheprocedure;excludehighdensitycontrastmedia  ]  frompreviousinvestigations;administrationoforalorrectalcontrastmediaforboweldemarcation;vaginalcontrasttamponingynaecologicalindications.Urinarybladdershouldnotbeempty;restraintfromfood,butnotfluid,isrecommended,ifintravenous   contrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalfromiliaccresttoproximalfemurC b#b# V \>  \>sV1  .0 b   DIAGNOSTICREQUIREMENTS \>sVی b#b# Ќ  Imagecriteria:  @  1.10 b Visualizationof 1b#b# 1.1.10 b Entireiliacbonesb#b# 1.1.20 b Entireischialbonesb#b# 1.1.30 b Entirepubicsymphysis]b#b# 1.1.40 b Entireurinarybladder.yb#b# 1.1.50 b AllperipelvicmusclesJb#b# 1.1.60 b Vesselsafterintravenouscontrastmediab#b#  1.20 b Criticalreproduction rb#b# 1.2.10 b VisuallysharpreproductionofthebladderwallGb#b# 1.2.20 b Reproductionofthedistalportionoftheureterscb#b# 1.2.30 b Visuallysharpreproductionoftherectum4 b#b# 1.2.40 b Visuallysharpdifferentiationoftheperirectalspace !b#b# 1.2.50 b Visuallysharpreproductionoftheuterus!"b#b# 1.2.60 b Visuallysharpreproductionoftheparametricaltissuesorseminalvesicles\"#b#b# 1.2.70 b Visuallysharpreproductionoftheprostata-#x$b#b#  \>  \>iV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>iVی$&b#b# Ќ  2.10 b _CTDIW_0' b#b#0 ' #' #0 # #0v##:0v#v#routinepelvis:35mGyu& (## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#routinepelvis:570mGycm(b"*## Ѐ \>  \>V3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \> Vی)$,b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supinewitharmsatchestorheadlevel_+%.## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#fromiliaccresttopelvicfloor-L'0## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#7-10mm;4-5mmifsmalllesionsaresuspected, .(2 serialorpreferablyhelicalCT ## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0;45mmorapitch 1a+5 upto1.21.5maybeusedinscreeningexaminations2-7## Ї3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # # v :0##adjustedtothemaximumdiameterofthepelvis## 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#noneW## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standardD## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequired ## 0 b timeproduct(_mAs_)0b#b#0v##0v#v#imagequalityl ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standardorhighresolutionifbone  Y  evaluationisrequired ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#200-600HU(softtissues) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#2000-3000HU(bones) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#30-60HU(enhancedexamination)? ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#0-30HU(unenhancedexamination) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#400-600HU(bones) ## 3.120 b Protectiveshielding0b#b#0v##:0v#v#leadpurseforthemalegonads8##  \>  \>aV4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>a|Vی%b#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratestheimage  quality ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefulfordelineationofneoplasticor > inflammatorydiseasesanddistinguishinglesionsfromvessels ## Ѐ4.30 b Problemsandpitfalls0b#b#0v##-0v#v#delineationoforgansandstructuresmaybe 7 difficultincachecticpatientswithreduced_intraabdominal_Ԁand_retroperitoneal_Ԁfattytissue ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#foldsofthebowelwallorstoolmaymimic  ! tumour ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#emptyurinarybladderL"### 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#contrastmedia"jets"fromtheuretersintothe #h$ urinarybladder ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#additionalthinnerslicestodelineatesmall %' alterations ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#additionalenteralcontrastmediamaybeneeded 2'}!) tovisualisethebowel ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#additionali.v.contrastmediawithregardtothe (#+ urinarybladder ##  b  M  :  '    0 v 0v#v#fillingoftheurinarybladderbyoralwaterintakev*$-##   G+%. EC( Preparatorysteps:   ̄0 b Indications:evaluationorverificationofpelvicringandacetabularfractures,hip [ dislocation,bonetumours,degenerative,infectious,arthriticandosteonecroticchanges b#b# ̄0 b Advisablepreliminaryinvestigations:alwaysconventionalradiography;MRIorultrasono   graphymaybealternativeexaminationswithoutexposuretoionisingradiationinnontraumaticdisorders b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is  ]  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalfromiliaccresttoischialtuberosity b#b# V \>  \>fV1  .0 b   DIAGNOSTICREQUIREMENTS \>fVی'r b#b# Ќ  Imagecriteria:     1.10 b Visualizationof sb#b# 1.1.10 b WholepelvicringHb#b# 1.1.20 b Hip(s)includingthetrochanterregiondb#b# 1.1.30 b Sacroiliacjoints5b#b# 1.1.40 b Pubicsymphysisb#b#  1.20 b Criticalreproduction ]b#b# 1.2.10 b Visuallysharpreproductionofthepelvicbones2}b#b# 1.2.20 b Visuallysharpreproductionofthehipjoint(s)Nb#b# 1.2.30 b Visuallysharpreproductionofthesacroiliacjointsb#b# 1.2.40 b Visuallysharpreproductionofthepubicsymphysisb#b# 1.2.50 b Visuallysharpreproductionofthepelvicmusculaturevb#b#  \>  \>V2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>Vیcb#b# Ќ  2.10 b _CTDIW_0' b#b#0 ' #' #0 # #0v##:0v#v#25_mGy(pilotstudy(17)_) !## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#520mGycm(pilotstudy)`"###  \>  \>ҢV3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>ҢVی$M%b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supine&ë&&&ëԀwitharmsatchestorheadlevel#&ë&&&ë#&ë&&&ë%'## #&ë&&&ë\#3.20 b Volumeofinvestigation0b#b#0v##:0v#v#tumour/fracture:from1cmaboveto1cmbelow J'!) thediseasedarea; ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#jointdisorders:1cmaboveto1cmbelowthejointregion ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#35mminthehipregion;310mmoutsidethe _+%. hip,serialorpreferablyhelical ## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorpitch=1.0inthehipregion,<5 -(1 mmorapitchupto1.21.5outsidethehipregion ## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#pelvis,hiporsacroiliacjointdimension(usually 1a+5 1540cm) ##  2-7 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#usuallynone,butcranialtiltingshouldbeused  forexaminationofthesacroiliacjointstoreduceradiationtothefemalegonads ## 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standardorhighkVinlargepersonstoavoid D noise ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithl ## 0 b timeproduct(_mAs_)0b#b#0v##0v#v#requiredimagequality= ## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standardorhighresolution * ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#10001500HU(joints/bones) ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#200600HU(softtissue) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#150200HU(joints/bones)? ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#3050HU(softtissue) ## 3.120 b Protectiveshielding0b#b#0v##:0v#v#leadpurseforthemalegonadsg##  \>  \>қV4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>қVی Tb#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratesimagequality  andthevalueofreconstructions ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefulfordelineatingmalignantand "m inflammatorylesionsextendingintothesofttissue,andfordetectingtraumaticlesionofpelvicorgans ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#artefactduetometallicobjectssuchasprothesis7## 4.40 b Modificationtotechnique0b#b#0v##0v#v#intracavitarycontrastmediatodelineate $  traumaticlesionofpelvicorgans  !## 4E( Preparatorysteps:   ̄0 b Indications:evaluationorverificationoffracture/dislocation,bonetumours,degenerative, I infectious,arthriticandosteonecroticchanges b#b# ̄0 b Advisablepreliminaryinvestigations:alwaysconventionalradiography;MRIor  ultrasonographymaybealternativeexaminationswithoutexposuretoionisingradiationinnontraumaticdisorders b#b# ̄0 b Patientpreparation:informationabouttheprocedure;restraintfromfood,butnotfluid,is  ]  recommended,ifintravenouscontrastmediaaretobegiven b#b# ̄0 b Scanprojectionradiograph:frontalfromtopofacromionextending1225cmcaudally, s  dependingonsuspectedpathology b#b# V \>  \>V1  .0 b   DIAGNOSTICREQUIREMENTS \>VیC b#b# Ќ  Imagecriteria:     1.10 b Visualizationof 2b#b# 1.1.10 b Shoulderjointdb#b# 1.1.20 b Wholescapula5b#b# 1.1.30 b Proximal8cmormoreofthehumerusb#b#  1.20 b Criticalreproduction Kb#b# 1.2.10 b Visuallysharpreproductionofthebones(humerus,scapula,lateralendoftheclavicle) }b#b# 1.2.20 b VisuallysharpreproductionoftheshoulderjointNb#b# 1.2.30 b Visuallysharpreproductionofthemusculatureandothersofttissuestructuresb#b#  \>  \>ҖV2  .0 b   CRITERIAFORRADIATIONDOSETOTHEPATIENT \>ҖVیdb#b# Ќ  2.10 b CTDIW0' b#b#0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable g## 2.20 b DLP0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#nospecificvalueasyetavailable !##  \>  \>V3  .0 b   EXAMPLESOFGOODIMAGINGTECHNIQUE \>-VیN!#b#b# Ќ  3.10 b Patientposition0 b#b#0 # #0v##:0v#v#supine;ifnecessaryslightlyoblique;diseased "Q% shoulderasneargantrycentreaspossiblewithdiseasedarmalongthebody,theotherarmabovethehead ## 3.20 b Volumeofinvestigation0b#b#0v##:0v#v#humeralandscapularfracture/tumour:the  'f"* fracture/tumourarea; ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#jointdisorders:topofacromionto1cmbelowtheglenohumeraljoint ## 3.30 b Nominalslicethickness0b#b#0v##:0v#v#35mm,serialorpreferablyhelical+{&/## 3.40 b Interslicedistance/pitch0b#b#0v##:0v#v#contiguousorapitch=1.0inthejointregion;25 ,(1 mmorapitchupto1.21.5outsidethejointregion ## 3.50 b FOV0: b#b#0' : #: #0 ' #' #0 # #0v##:0v#v#shoulderdimension(usually1520cm)0a+5##   02,6 3.60 b Gantrytilt0 b#b#0 # #0v##:0v#v#none1-7##  {2-8 3.70 b Xraytubevoltage(kV)0b#b#0v##:0v#v#standardorhighkVinlargepersonstoavoid  noise ## 3.80 b Tubecurrentandexposure0vb#b#:0v#v#shouldbeaslowasconsistentwithrequireds## 0 b timeproduct(mAs)0b#b#0v##0v#v#imagequalityD## 3.90 b Reconstructionalgorithm0b#b#0v##:0v#v#softtissue/standardorhighresolution ## 3.100 b Windowwidth0 b#b#0 # #0v##:0v#v#10001500HU(joints/bones)+ ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#200600HU(softtissue) ## 3.110 b Windowlevel0 b#b#0 # #0v##:0v#v#150200HU(joints/bones)  ## 0 b 0Mb#b#0: M#M#0' : #: #0 ' #' #0 # #0v##0v#v#3050HU(softtissue) ##  \>  \>ҍV4  .0 b   CLINICALCONDITIONSWITHIMPACTONGOODIMAGINGPERFORMANCE \>ҍVیn b#b# Ќ  4.10 b Motion0' b#b#0 ' #' #0 # #0v##0v#v#movementartefactdeterioratesimagequality   andthevalueofreconstructions(cansometimesbepreventedbysuspendedinspiration) ## 4.20 b Intravenouscontrastmedia0vb#b#0v#v#usefulfordelineatingmalignantand X inflammatorylesionsextendingintothesofttissue ## 4.30 b Problemsandpitfalls0b#b#0v##0v#v#immobilitypreventingcorrectpositioningand ? causingartefact ## 4.40 b Modificationtotechnique0b#b#0v##0v#v#intraarticularcontrastmediaforoutliningintra  articularstructures ##   T 4  Ӛ 6 &&ëLISTOFREFERENCESFORCHAPTER1#&ë&6 w#   1.0 b ICRPPublication60,1990RecommendationsoftheInternationalCommissionon  RadiologicalProtection,AnnalsoftheICRPVol. 21 Nos.13(PergamonPress,Oxford) U (1991) b#b# 2.0 b ICRPPublication34,ProtectionofthePatientinDiagnosticRadiology,AnnalsoftheICRP  / Vol. 9 Nos.23(PergamonPress,Oxford)(1982) b#b# 3.0 b ICRPPublication73,RadiologicalProtectionandSafetyinMedicine,AnnalsoftheICRPVol. C    26 No.2(PergamonPress,Oxford)(1996) w b#b# 4.0 b CouncilDirective97/43/EURATOMof30June1997onhealthprotectionofindividuals   againstthedangersofionizingradiationinrelationtomedicalexposure.O.J.No.L180,p.22,9.7.1997.(RepealingDirective84/466/EURATOM,O.J.L265,p.1,5.10.1984) b#b# 5.0 b EuropeanGuidelinesonQualityCriteriaforDiagnosticRadiographicImages,ReportEUR a  16260(1996) b#b# 6.0 b EuropeanGuidelinesonQualityCriteriaforDiagnosticRadiographicImagesinPaediatrics, q ReportEUR16261(1996) b#b# 7.0 b HidajatN,SchrderRJ,VoglT,SchedelHandHelixR.EffektivittderBleiabdeckungzur G DosisreduktionbeimPatienteninderComputertomographie.FortschritteRntgenstrahlen,   165 ,462465(1996)b#b# 8.0 b BeaconsfieldT,NicholsonR,TorntonAandAlKutoubiA.Wouldthyroidandbreastshielding , bebeneficialinCTofthehead?EuropeanRadiology, 8, 664667(1998)`b#b# 9.0 b ShrimptonPC,JonesDG,HillierMC,WallBF,LeHeronJCandFaulknerK.SurveyofCT  practiceintheUK.Part2:Dosimetricaspects.Chilton,NRPBR249(London,TSO)(1991) b#b# 10.0 b BrinkJA,McFarlandEGandHeikenJP.Helical/spiralcomputedbodytomography.Clinical y  Radiology, 52 (7),489-503(1997)J!b#b# 11.0 b CostelloP,DupuyDE,EckerCPandTelloR.SpiralCTofthethoraxwithreducedvolume !# ofcontrastmaterial:acomparativestudy.Radiology, 183 (3),663-666(1992)^"$b#b# 12.0 b JurikAGandAlbrechtsenJ.SpiralCTwiththreedimensionalandmultiplanarreconstruction $g& inthediagnosisofanteriorchestwalldisorders.ActaRadiologica, 35 ,468472(1994)$8 'b#b# 13.0 b KalenderWA.TechnicalfoundationsofspiralCT.SeminarsinUltrasound,CTandMRI, 15  {&!) (2),8189(1994) b#b# 14.0 b VerdunFR,MeuliRA,BochudFO,ImsandC,RaimondiS,SchnyderPandVallyJF.Image (U$, qualityanddoseinspiralcomputedtomography.EuropeanRadiology, 6 ,485488(1996))&%-b#b# 15.0 b ReynoldsMD,HeuscherDJandVembarM.EvaluationofspiralCTonafourthgeneration i+&/ system.EuropeanRadiology, 5 ,102109(1995):,'0b#b# 16.0 b InternationalElectrotechnicalCommission:Evaluationandroutinetestinginmedicalimaging -C)2 departments.Part26:Constancytestsxrayequipmentforcomputedtomography,1994:IEC122326(Geneva,IEC) b#b# 17.0 b JurikAG,PetersenJ,Bongartz,GoldingSJ,LeonardiM,vanMeertenPvE,GeleijnsJ, $1,6 JessenKA,PanzerW,ShrimptonP,TosiG.Clinicaluseofimagequalitycriteriaincomputedtomographyrelatedtoradiationdose.Apilotstudy.EuropeanRadiology(tobe 2).8 submitted) b#b#  A#6 &&ëChapter1    @#APPENDIXI   #&ë&6 # @UU6 &&ëGUIDELINESONRADIATIONDOSETOTHEPATIENT#&ë&6 W#    OBJECTIVE    TheconditionsofexposureduringCTexaminationsarequitedifferentfromthoseinconventionalxrayproceduresandspecifictechniquesarenecessaryinordertoallowdetailedassessmentofpatientdosefromCT.NationalsurveysofCTpracticeusingsuchmethodsofdosimetryhaveestablishedtheincreasingimportanceofCTasasignificantsourceofmedicalxraysforpopulationsindevelopedcountries(1).EvidencefromdosesurveyshasalsoindicatedpotentialscopeforimprovementintheoptimisationofprotectionforpatientsundergoingCTandtheneedformorewidespreadassessmentoftypicallevelsofpatientdoseaspartofroutinequalityassurance(2,3).InherentdifferencesinthedesignofCTequipmentleadtovariationsbetweenscannermodelsbyuptoafactorofthreeinthecalculatedvaluesofeffectivedoseforstandardexaminationsunderconditionsofsimilarimagequality A  (4).However,largervariationsindoseareapparentinclinicalpractice,withtheminimumandmaximumvaluesoftypicaldoseforagiventypeofprocedurevaryingbyfactors,forexample,of1040intheUK(4)and820inNorway(5);thisislargelyasaresultofdifferencesinthelocalscanningtechniquetypicallyemployedforaparticulartypeofexamination,asdeterminedbythenumberandthicknessofslicesimaged,thecouchincrementbetweenslices,theuseofcontrastmediumforadditionalscansandtheexposuresettingsselected.TheExamplesofGoodImagingTechniquegivenintheListsofQualityCriteriaareintendedtohelpavoidunnecessaryexposuresinCT.TheCriteriaforRadiationDosetothePatientindicatediagnosticreferencedosevaluesforgeneraltypesofexaminationasapracticalmeansofpromotingstrategiesforoptimisationofpatientprotection.Thepurposeofareferencedosequantityforadiagnosticmedicalexposureistoprovidequantificationofperformanceandallowcomparisonofexaminationtechniquesatdifferenthospitals. Diagnosticreferencedosevaluesshouldnotbeappliedlocally { onanindividualpatientbasis,butrathertothemean dosesobservedforrepresentative P groupsofpatients. Referencedosevaluesareintendedtoactasthresholdstotriggerinternal % investigationsbydepartmentswheretypicalpracticeislikelytobewellawayfromtheoptimumandwhereimprovementsindosereductionareprobablymosturgentlyrequired. Typicallevelsofdose . inexcessofareferencedosevalueshouldeitherbethoroughlyjustifiedorreduced. Ingeneral,   patientdosesshouldalwaysbereducedtothelowestlevelsthatarereasonablypracticableandconsistentwiththeclinicalpurposeoftheexamination.ThederivationofthediagnosticreferencedosevaluesisdescribedinChapter2.Referencedosequantitiesandmethodsfortheirassessmentarediscussedbelow. COMPUTEDTOMOGRAPHYDOSEINDEX(_CTDI_) [% '  TheprincipaldosimetricquantityusedinCTisthecomputedtomographydoseindex(_CTDI_).Thisis 0&!( defined(6)astheintegralalongalineparalleltotheaxisofrotation(z)ofthedoseprofile(D(z))forasingleslice,dividedbythenominalslicethicknessT:|cTD@zx F: p% @ Hdd22@Eh)t6& )<LInpractice,aconvenientassessmentof_CTDI_Ԁcanbemadeusingapencilionisationchamberwithanactivelengthof100mmsoastoprovideameasurementofCTDI100expressedintermsof ,(0 absorbeddosetoair(_mGy_).Suchmeasurementsmaybecarriedoutfreeinaironorparallelwiththeaxisofrotationofthescanner(CTDI100,air),oratthecentre(CTDI100,c)and10mmbelowthesurface Z.)2 (CTDI100,p)ofstandardCTdosimetryphantoms.Thesubscript`n'(_nCTDI_)isusedtodenotewhen +/*3 thesemeasurementshavebeennormalisedtounitradiographicexposure(_mAs_).Furtherdiscussionofthequantity_CTDI_ԀisgiveninChapter2.Suchmeasurementsof_CTDI_ԀinthestandardheadorbodyCTdosimetryphantommaybeusedto o2-7 provideanindicationoftheaveragedoseoverasinglesliceforeachsettingofnominalslicethickness.Ontheassumptionthatdoseinaparticularphantomdecreaseslinearlywithradialpositionfromthesurfacetothecentre,thenthenormalisedaveragedosetotheslice(7)isapproximatedbythe(normalised)weighted_CTDI_Ԁ(_CTDIw_): s __|TD@zxG p% @ Hdd22@E("JLwhereCistheradiographicexposure(_mAs_)andCTDI100,prepresentsanaverageofmeasurements T  atfourdifferentlocationsaroundtheperipheryofthephantom.Valuesof_nCTDIw_canvarywith %  nominalslicethickness,particularlyforthenarrowestsettings. REFERENCEDOSEQUANTITIES     TworeferencedosequantitiesareproposedforCTinordertopromotetheuseofgoodtechnique: m  (a) b Weighted_CTDI_ԀinthestandardheadorbodyCTdosimetryphantomforasingleslicein r  serialscanningorperrotationinhelicalscanning:_|;TD@zx W p% @ Hdd22@EKt6& <y_where_nCTDIw_isthenormalisedweighted_CTDI_Ԁintheheadorbodyphantomforthesettingsof S nominalslicethicknessandappliedpotentialusedforanexamination(Equation2)andCistheradiographicexposure(_mAs_)forasinglesliceinserialscanningorperrotationinhelicalscanning.Monitoringof_CTDIw_fortheheadorbodyCTdosimetryphantom,asappropriatetothetypeof  examination,providescontrolontheselectionofexposuresettings,suchas_mAs_.(b)0 b Doselengthproductforacompleteexamination: mb#b# 0 b _|AB9TD@zx S p% @ Hdd22@Et  6U& ^<_ b#b# where_i_ԀrepresentseachserialscansequenceformingpartofanexaminationandNisthenumberofslices,eachofthicknessT(cm)andradiographicexposureC(_mAs_),inaparticularsequence.Anyvariationsinappliedpotentialsettingduringtheexaminationwillrequirecorrespondingchangesinthevalueof_nCTDIw_used. $  Inthecaseofhelical(spiral)scanning:_|DE:TD@zx$ p% @ Hdd22@E! $U!_where,foreachof_i_Ԁhelicalsequencesformingpartofanexamination,Tisthenominalirradiatedslicethickness(cm),Aisthetubecurrent(mA)andtisthetotalacquisitiontime(s)forthesequence._nCTDIw_isdeterminedforasinglesliceasinserialscanning. I% ( MonitoringofDLPprovidescontrolonthevolumeofirradiationandoverallexposureforanexamination.Proceduresforestimating_CTDIw_andDLParegivenbelow. ^)$-  METHODSOFDOSEASSESSMENTTOCHECKCOMPLIANCEWITHTHECRITERIA +c&/  Comparisonofperformanceagainstthecriteriaforeachparticulartypeofexaminationrequires +8'0 assessmentofthevaluesofthereferencedosequantitiesassociatedwiththeparametersoftechniquetypicallyusedwhenscanningastandardsizedadultpatient. Intheabsenceofawell w-(2 definedscanningprotocol,typicaldosimetricpracticeshouldbedeterminedonthebasisofthemeanresultsderivedforasampleofatleast10patientsforeachprocedure.  !/*4 _CTDIw_maybeassesseddirectlyfromEquations(2)and(3)usingtheresultsofmeasurementsof 0*,6 CTDI100,porcfortheheadorbodyCTdosimetryphantomcarriedoutduringroutineperformance 1,7 testing.Suchmeasurementsmaybeaccomplishedusing_thermoluminescent_Ԁ_dosemeters_Ԁ(_TLDs_)or i2-8 moreconvenientlyusinganappropriatelycalibrated100mmlongpencilshapedionisationchamber(8).IthasbeenrecommendedbytheInternational_Electrotechnical_ԀCommissionthatvaluesof_CTDIw_ n shouldbedisplayedontheoperatorsconsoleoftheCTscanner,reflectingtheconditionsofoperationselected,althoughanappropriatecorrectionshouldbeincludedifthenominalslicethicknessisnotequaltothecouchincrementpertuberotation(9).Typicalvaluesof_nCTDIw_forawiderangeof D scannermodelshavebeencollatedintoareferencedatabaseonCTdosimetrythathasbeenpublishedontheInternet(10).Somestandarddosedataforaselectionofscannersisgiven,forillustrativepurposes,inAppendixItoChapter2.Estimatesof_CTDIw_mayalsobemadeusingthetypicaldosedatacommonlyprovidedby  Y  manufacturersinfulfilmentoftherequirementsoftheFoodandDrugAdministration(FDA)intheUSA.Accordingly,manufacturersofCTscannersareobligedtoreportvaluesof_CTDI_ԀmeasurementsinthestandardheadandbodyCTdosimetryphantomsusingaspecificprotocol(11)forwhichthereareimportantdifferencesfromtheapproachadvocatedinthisreport;suchvaluesof_CTDIFDA_referto :  anintegrationlengthequivalentto14nominalslicethicknesses(ratherthan100mm)andareexpressedintermsofabsorbeddoseto_PMMA_Ԁ(ratherthanair).SimilarmeasurementshavepreviouslybeenrecommendedbytheInternational_Electrotechnical_ԀCommission(_IEC_)aspartofconstancytestinginCT(12).However,valuesof_CTDIFDA_determinedinthephantomswillbeonly ~  slightlylessthanCTDI100forthelargestsettingsofslicethickness,butmoresignificantlysoforsmaller O slicethicknesses.Table1givesbroadfactors(13)toallowtheestimationof_CTDIw_fromsuch   manufacturersdata(_CTDIFDA_). T Asapracticalalternative,estimatesof_CTDIw_fortheheadorbodyCTdosimetryphantommaybe  derivedfromsimplermeasurementsof_CTDI_Ԁmadefreeinair(_CTDIair_)undersimilarconditionsof d exposure(H=head,B=body):d      d Ethe      @c_CTDIw_=_CTDIair_PHorB:)"& &&&ëXX &&DKUK.,(mGycm)#XXXXF##&ë&XX6F#UK.,DK,.UF__Ԁ(6) : wherethefactorPHorBisgivenby:  |efnTD@zx @ p% @ Hdd22@E=:: y Tand|opuTD@zx C? p% @ Hdd22@E : : | TMeasurementsof_CTDIair_areeasilyaccomplishedwitheitherthe100mmpencilshapedionisation #& chamberorashorterlengthof_TLDs_Ԁsincethetailsonthedoseprofilesinairarelesssignificantthaninaphantominviewoftheloweramountofscatteredradiation.Sometypicalvaluesofthe ]% ( factorPforselectedscannermodelsaregiveninAppendixItoChapter2.FurtherdataforawiderrangeofmodelsareavailableinthereferencedatabaseonCTdosimetry(10).SubsequentestimatesofDLPforanexaminationmaybederivedusingEquations(4)and(5),withknowledgeofappropriatevaluesof_nCTDIw_forthescanneranddetailsoftheparticularscanning r)$- protocolused.Inthecaseofexaminationsinvolvingseparatescanningsequencesinwhichdifferenttechniqueparametersareapplied(suchasslicethicknessorradiographicexposure,forexample),thetotalDLPshouldbedeterminedfortheentireprocedureasthesumofthecontributionsfromeachserialorhelicalsequence. ASSESSMENTOFEFFECTIVEDOSE X.)3  Inadditiontocomparisonofperformanceagainstreferencedosevalues,thereissometimesa -/*4 needtoassesseffectivedose(14)forCTproceduressoas,forexample,toallowcomparisonwithothertypesofradiologicalexamination.Theeffectivedoseforaparticularscanningprotocolmaybeestimatedfromameasurementof_CTDIair_utilisingscannerspecificnormalisedorgandosedata 1-7 determinedforamathematicalanthropomorphicphantomusingMonteCarlotechniques(15,16). q2-8 Fortypesofscannernotincludedamongstthesecalculations,appropriatedatasetsmaybeselectedfromthoseavailableonthebasisofsimilarityofvaluesofP(Equations(7)and(8))(17,18).Alternatively,broadestimatesofeffectivedose(E)maybederivedfromvaluesofDLPforanexaminationusingappropriatelynormalisedcoefficients:|y~TD@zxw pX @ Hdd22@E },\,!` EwhereDLP(_mGy_Ԁcm)isthedoselengthproductasdefinedinEquations(4)or(5)and_EDLP_isthe  Y  regionspecificnormalisedeffectivedose(_mSv_Ԁ_mGy_1cm1).  *  Generalvaluesof_EDLP_appropriatetodifferentanatomicalregionsofthepatient(head,neck,chest, i  abdomenorpelvis)aregiveninTable2.Suchanestimateofeffectivedosemayalsobederivedfromameasurementof_CTDIair_onthe ?  basisofEquation(6)andEquations(4)or(5)todetermineDLP. XX&&ëLISTOFREFERENCESFORAPPENDIX1TOCHAPTER1#&ë&XXxT#    1.0 b ShrimptonPCandWallBF.Theincreasingimportanceofxraycomputedtomography A asasourceofmedicalexposure.RadiationProtectionDosimetry, 57 (14),413415  (1995) b)"b)" 2.0 b _NRPB_.Protectionofthepatientinxraycomputedtomography.Documentsofthe_NRPB_, &  3 ,No.4,(1992)Zb)"b)" 3.0 b ShrimptonPC,JessenKA,GeleijnsJ,PanzerWandTosiG.Referencedosesin  computedtomography.RadiationProtectionDosimetry, 80 (13),5559(1998)nb)"b)" 4.0 b ShrimptonPC,JonesDG,HillierMC,WallBF,LeHeron_JC_ԀandFaulknerK.Surveyof w CTpracticeintheUK.Part2:Dosimetricaspects._Chilton_,_NRPB_ԄR249(London,_TSO_)(1991) b)"b)" 5.0 b _Olerud_ԀHM.AnalysisoffactorsinfluencingpatientdosesfromCTinNorway.Radiation X!# ProtectionDosimetry, 71 (2),123133(1997))"$b)"b)" 6.0 b _Shope_ԀTB,_Gagne_ԀRMandJohnsonGC.Amethodfordescribingthedosesdeliveredby #2& transmissionxraycomputedtomography.MedicalPhysics, 8 (4),488495(1981)$ 'b)"b)" 7.0 b _Leitz_ԀW,_Axelsson_ԀBand_Szendr_ԀG.Computedtomographydoseassessmenta F&!) practicalapproach.RadiationProtectionDosimetry, 57 (14),377380(1995)'z"*b)"b)" 8.0 b SuzukiAandSuzukiMN.Useofapencilshapedionizationchamberformeasurement ( $, ofexposureresultingfromacomputedtomographyscan.MedicalPhysics, 5 (6),536539 )$- (1978) b)"b)" 9.0 b InternationalstandardofIEC60601244:MedicalelectricalequipmentPart244: ,h'0 Particularrequirementsforthesafetyofxrayequipmentforcomputedtomography(1999) b)"b)" _10.0 b InternetaddressoftheReferenceDatabaseonCTDosimetry:http://www.efomp.orgI/*4b)"b)" 11.0 b DepartmentofHealthandHumanServices,FoodandDrugAdministration.21_CFR_ԀPart 0N,6 1020:Diagnosticxraysystemsandtheirmajorcomponents;amendmentstoperformancestandard;Finalrule.FederalRegister, 49 ,171(1984)2-8b)"b)" Ї12.0 b International_Electrotechnical_ԀCommission._IEC_Ԁ122326:Evaluationandroutinetesting  inmedicalimagingdepartments.Part26:ConstancytestsXrayequipmentforcomputedtomography.(Geneva,_IEC_)(1994) b)"b)" 13.0 b _Edyvean_ԀS,LewisMA,_Britten_Ԁ_AJ_,_Carden_Ԁ_JF_,HowardGAand_Sassi_ԀSA.Typetestingof D CTscanners:methodsandmethodologyforassessingimagingperformanceanddosimetry.MDAEvaluationReportMDA/98/25.London,MedicalDevicesAgency(1998) b)"b)" 14.0 b ICRPPublication60,1990RecommendationsoftheInternationalCommissionon %  RadiologicalProtection,AnnalsoftheICRPVol. 21 Nos.13(PergamonPress,Oxford)  Y  (1991) b)"b)" 15.0 b JonesDGandShrimptonPC.Normalisedorgandosesforxraycomputedtomography m  calculatedusingMonteCarlotechniques._Chilton_,_NRPB_ԄSR250(1993) b)"b)" 16.0 b _Zankl_ԀM,PanzerWand_Drexler_ԀG.Thecalculationofdosefromexternalphoton C  exposuresusingreferencehumanphantomsandMonteCarlomethods.PartVI:Organdosesfromcomputed_tomographic_Ԁexaminations._GSF_Ԅ_Bericht_Ԁ30/91(_Neuherberg_,_Gesellschaft_Ԁ_fr_Ԁ_Strahlen_Ԅund_Umweltforschung_)(1991) b)"b)" V 17.0 b ShrimptonPC.Unpublisheddata(1995)Xb)"b)" 18.0 b GeleijnsJ.Patientdosimetryindiagnosticradiology.Thesis,LeidenUniversity(1995)b)"b)"   h  Table1 0 b BroadfactorstoallowestimationofCTDI100frommeasurementsof_CTDIFDA_instandard  CTdosimetryphantomsbymanufacturers b)"b)"  G*q ddd Xdd Xdd X)")"q,-td@,(td@,0td@,tt@+  1" N C1Phantom 9*^C C9Sliceϐthickness(mm) A. cC CARationCTDI100/_nCTDIFDA_ qG O@(^C"   CO 9* D C C9 9* D C C9Centreofphantom =* D C" C=1cmdepth L=% D C"   CLHead 9* % C C910 9* %CU C91.0 =* %CU C=1.1 L=% %CU   CL 9* C C95 9* CU C91.3 =* CU C=1.2 L=% CU   CL 9* C C93 9* CU C91.6 =* CU C=1.3 L=% CU   CL 9*e C C92 9*e CU C92.0 =*e CU C=1.5 L=%e CU   CLBody 9*F C C910 9*F CU C91.0 =*F CU C=1.1 L=%F CU   CL 9*' !C C95 9*' "CU C91.4 =*' #CU C=1.2 L=%' $CU   CL 9*k %C C93 9*k &CU C91.9 =*k 'CU C=1.3 N=%k (CU   CN ;*L )C C;2 ;*L *CU C;2.6 =*L +CU C=1.5 *q5+)L ,CU   5 * Table20 b Normalisedvaluesofeffectivedoseperdoselengthproduct(DLP)overvariousbody =/ regions b)"b)"  G* d d-td@(td@0td@tt@)")", td@, tt@+  1" Q2 C1Regionofbody qG =*a3C C=Normalisedeffectivedose,EDLP a4 (mSvmGy1cm1) L=%25C   CLHead aN6C HPsb?0,0023CHPsb?a0 O 0:OJOJ0.0023 zkS7:J:JC HPsb?0,0023  HPsb? CzNeck aN8C _vOv?0,0054C_vOv?a0 O 0:OJOJ0.0054 zkS9:J:JC _vOv?0,0054  _vOv? CzChest `Mr:C  rh?0,017C rh?`0 O 0:OJOJ0.017 yjRr;:J:JC  rh?0,017   rh? CyAbdomen `MS<C Q?0,015CQ?`0 O 0:OJOJ0.015 {jRS=:J:JC Q?0,015  Q? C{Pelvis `M4>C ~jt?0,019C~jt?`0 O 0:OJOJ0.019 *qbXV4?:J:JC ~jt?0,019   ~jt? b *  *!D 6 &&ë6n    ?)"Chapter2  #&ë&6 }#cz)&&ëSUMMARYOFRESEARCHRESULTSANDONGOINGEXPERIMENTS@@MMb , RELATEDTOTHEESTABLISHMENTOFQUALITYCRITERIA@@B B bFORCT@@  `ANDREFERENCEDOSEVALUES#&ë&)cz~#U~)+&&ë#&ë&+)#@ll!cTableofContents  e   D)"Page ESTABLISHMENTOFQUALITYCRITERIAe!e!F)" 72  O   Introductione!e!F)"72 X  ConventionalRadiographye!e!F)"72 ) ComputedTomographye!e!F)"72   ESTABLISHMENTOFREFERENCEDOSEVALUES e!e!F)"73  m SelectionofReferenceDoseQuantitiese!e!F)"73  DerivationofReferenceDoseValuese!e!F)"75   LISTOFREFERENCES e!e!F)"76 W  APPENDIX1 e!e!F)"84    o ?)"6 &&ë Chapter2   #&ë&6 j# 6 &&ëESTABLISHMENTOFQUALITYCRITERIA#&ë&6 Ճ#    INTRODUCTION k  TheconceptofqualitycriteriafordiagnosticxrayexaminationswasintroducedbytheCECasEuropeanGuidelinesonQualityCriteriaforDiagnosticRadiographicImages(1).Theseprovideguidanceondiagnosticrequirements,theradiationdosetothepatientandthechoiceofradiographictechnique.Theconceptwassubsequentlyappliedtopaediatricradiology(2)and,inthisreport,isnowbeingextendedtoCT.InthemeantimeevaluationsoftheapplicationofqualitycriteriahavebeenperformedforconventionalradiographyimagesandCT,assummarisedbelow. CONVENTIONALRADIOGRAPHY +   QualitycriteriaforconventionaldiagnosticradiographicimagesinadultradiologyhavebeendevelopedoveraperiodofabouttenyearsduringwhichtwoEuropeanwidetrialshavebeenconductedinordertoassessrelevance,acceptabilityandeaseofusefortechnicalandclinicalstaffindiagnosticxraydepartments.Thefindingsofthetrialsprovideasupplementaryscientificbackgroundtotheapplicationofsuchqualitycriteria(3,4).ThefirstEuropeantrial(3)wasconductedin1987/88andinvolvedinformationfrom24xraydepartmentsin10Europeancountries.ItconcernedradiographictechniqueandcompliancewiththeimagecriteriagiveninthepreliminaryQualityCriteriaWorkingDocument.Theresultsconfirmedthevalidityoftheapplicationofqualitycriteriaasatoolfortheoptimisationofradiationprotection.Inparticulartheypermittedtheidentificationofsuitabletechnicalmodalitiesforachievingthebestpossiblecompromisebetweentheessentialmedicalinformationinaradiographicimageandthepatientdose.However,thetrialclearlyhighlightedtheneedforestablishingqualityassuranceprogrammesandqualitycontrolprotocolsindiagnosticradiology,sincelargevariationsindosewerefoundforthesametypeofxrayexamination.InordertoassessthevalidityofarevisedQualityCriteriaWorkingDocumentandtoovercomesomeofthelimitationsofthefirsttrial,asecondtrialwascarriedoutin1991(4).Originalfilmsofchest,lumbarspineandbreastradiographsweresenttoanindependentpanelofradiologistsforassessmentagainsttheimagecriteria.Aquestionnairewasemployedtocollectentrancesurfacedosesanddetailsoftheradiographicequipmentandtechniquefactorsinuse.Theresultsofthe1991trialhighlightedanumberofimportantfeaturesofradiographicpracticeinEurope.Informationconcerningthetechnicalparametersofradiographicequipmentwasstillinmanycasesnotsufficientlyknownbystaffinxraydepartments.ThetrialdemonstratedthatinconventionalradiologytheentrancesurfacedoseprovidesausefulmeasureofthepatientdoseanditconfirmedthatthereexistedwidevariationsinperformancethroughoutEurope.Furthermoretheresultsshowedthatradiologistsfinditdifficulttointerpretunequivocallycriteriawhichinvolvesomeformofassessmentofsymmetry,fieldcoverageandfulfilmentoftechnicalrequirements.Itwasconcludedthatacompartmentalisationofimagecriteriawasrequiredinordertolink,moreconsistently,theimagequality,patientdoseandradiographictechnique.BesidessuchEuropeanwidetrials,reportsarealsobecomingavailableconcerningtheexperiencesofclinicalapplicationofthequalitycriteriaforconventionalradiographyatanationallevel.Forexample,Vaoandcolleagues(5,6)haveconfirmedtheclinicalapplicabilityofthequalitycriteriaconceptandillustratedthepotentialfordosereductioninSpain. COMPUTEDTOMOGRAPHY  .5*3 Todatenoresultsofresearchstudiesareavailabletoindicatetowhatextentradiationdosemaybereducedwhileretainingclinicaleffectivenessoftheexamination.Thebasisforthecurrentguidelinesisthesuppositionthatthequalitycriteriaconcept,whichwasdevelopedforconventional 2}-7 radiography,canalsobeusedforadvancingoptimisationofCTexaminations.NeverthelesssomefundamentalmodificationshavehadtobemadeowingtotheparticularcharacteristicsofCT,forexample,patientdoseduringCTshouldnotbeexpressedasentrancesurfacedosebutintermsofquantitiesthathavebeenspecificallydevelopedforCT,suchastheweightedcomputedtomographydoseindex(CTDI,-,J&ëW#&ë&-,,#)forasliceandthedoselengthproduct(DLP)foracomplete D examination.FortheestablishmentofthequalitycriteriaforCTextensivedatawerecurrentlyavailableonpatientdosimetryandpatientdoseinrelationtoCTexaminations(713).Inaddition,someinformationhasbeenpublishedconcerningtherelationshipbetweendoseandCTimagequality(1416).Morecomprehensiveapproachestopatientdose,diagnosticimagequalityandtechnicalparametershavealsobeendescribedforCT(1719).TheelaborationoftheimagecriteriainCThasbeendifficultduetothecomplexityofCTanatomyandtechnique.TheimagecriteriathathavebeenelaboratedbytheGermanFederalChamberofPhysicians(20)provedtobeavaluablesourceofinformation.TheyweretestedinapilotstudyattheUniversityHospitalofAarhusforCTofthemediastinum(23examinations)andCToftheretroperitonealspace(30examinations)(17).Theanalysisshowedthatitisnecessarytodifferentiatethedegreeofvisualizationoftheanatomicalstructuresbyincludingthetermvisuallysharpreproductioninsteadofjustvisualizationofcriticalanatomicalstructures.Consequentlyasetofmodifiedcriteriawastestedinthesameinstitution(190examinations)(17)andanewlistofcriteriawaselaboratedforthemediastinumandtheretroperitonealspace.Theresultsshowedthatnearlyallofthenewcriteriawereusefulformeasuringthediagnosticimagequalityastheywerefulfilledinanacceptableamountofexaminationsbutnotalways(18).ThesecriteriawereincludedinthefirstworkingdocumentonCTqualitycriteriathatwaspublishedApril1997.Itwassentoutforcommentstoprofessionalgroups,suchasradiologists,radiographers,andmedicalphysicistsaswellastomanufacturersandhealthcareauthoritiesinthememberstatesoftheEuropeanUnion.Thisrequestyieldedsome50responses.ThequalitycriteriaandreferencedosesforCTwerepresentedatseveralcongressesandsymposia,e.g.atECR97andattheECWorkshoponReferenceDosesandQualityinMedicalImaging,heldOctober1997inLuxembourg.AtthisWorkshoptheUniversityofAarhuspresentedresultsandguidelinesonimagecriteriaforCTbrain,basedon119examinations(21).Alsothefirstexperienceswiththeclinicalimplementationofqualitycriteriafor102CTbrainexaminationswerepresentedbyCalzadoetal.andfoundtobeuseful(22).ThecommentsonthefirstworkingdocumentwereincorporatedintheMay1998versionwhichwasdiscussedattheECworkshoponqualitycriteriaforcomputedtomography,heldNovember1998inAarhus,Denmark.Theworkshopaimedatderivingconsensusonthe1998workingdocumentbeforepublication.Ofthe49participants,46camefrom12Europeancountries,2fromBraziland1fromtheUSA.Theyrepresentedhospitals,governments,professionalbodiesandmanufacturersofCTscanners.AttheworkshopandatECR'99resultsofapilottrailwerepresented,whichevaluatedthequalitycriteriaforexaminationofthefaceandsinuses,thespine,thechest(HRCT),liverandspleen,andosseouspelvisinhospitalsoffourcountries(Denmark,TheNetherlands,SwitzerlandandtheUnitedKingdom).Thistrailshowedthathighradiationdosestothepatientdidnotalwaysimplyoptimaldiagnosticquality.Dosereduction,especiallyregardingexaminationsofthefaceandsinusesandosseouspelvis,seemedtobeachievablewithoutlossofdiagnosticimagequality.ItwasconcludedthatthequalitycriteriacanbeusedtooptimisetheseCTprocedures.Asaresultofthisstudysomechangesofthecriteriafortheliverandspleenandforosseouspelviswereincludedinthepresentguidelines. 6 &&ëESTABLISHMENTOFREFERENCEDOSEVALUES  /t*4 #&ë&6 # SELECTIONOFREFERENCEDOSEQUANTITIES 0[,6  Referencedosesareintendedtoallowcomparisonofperformance.Inordertoachievethis 2.8 objectiveforCT,referencedoseshadtobeexpressedintermsofquantitieswhichfulfilthefollowingcriteria:(a) b provideameaningfulindicationofpatientexposure,takingintoaccountthedetailsof s scanningtechniqueusedbyindividualcentresforparticularexaminations;(b) b welldefinedandsimpletomeasureoreasytodetermineinordertoencourage   widespreaduseatCTcentresofallsizesandlevelsofsophistication;(c) b applicabletoallcurrentandnewtypesofscannerandtoallcommontechniques,including  Y  helicalscanning;(d) b consistencyofapproachwithotherreferencedosesanddosedescriptorsalreadyin i  widespreaduse.ThereareanumberofdosimetricquantitiesthatareemployedroutinelyundervariouscircumstancestocharacteriseexposurefromCTscanners.Oneofthemostpracticalmeasurementsconcernsthecomputedtomographydoseindex(CTDI)(23).Thisquantityissimpleandcaneasilybedeterminedfreeinairontheaxisofrotationofthescannerforasinglescan(CTDIair).Thisapproachhasformedthebasisfornationalsurveysinseveralcountries.Byitself,   CTDIairisonlyacoarseindicatorofpatientexposureforanexamination,forexample,the T relationshipbetweenCTDIairandeffectivedoseforastandardexaminationvariesbyuptoafactor % threebetweenmodelsofscannerasaresultofinherentdifferencesindesign,andinparticulartheuseofshapedbeamfiltration(24).CTDIairthereforeisnotwellsuitedforuseasareferencedose d quantitysincethesettingofasinglelevelforagivenprocedurewouldnotequitablydictatepracticeforalltypesofscanner.CTDIaircan,however,stillbeanimportantelementintheimplementation i ofpatientdosimetry.Effectivedose(25)iscertainlyausefulindicatorofpatientexposure,althoughitisalsonotparticularlysuitableasareferencedosequantitysinceitcannotbemeasureddirectlyanditsdefinitionmaybesubjecttofurtherchanges.Measurementswithphantomsoffertheadvantageoftakingintoaccountdifferencesindosedistributionarisingfromscannerdesign,particularlyifmeasurementsarenotconfinedtothephantomsurface.However,anysuchdosimetricapproachshouldutilisewelldefinedandcommonlyavailablephantomsinordertogainwideacceptance.Foraseriesofmultiplescanswithconstantseparation,themultiplescanaveragedose(MSAD)(23)isanindicationofthemagnitude "d$ ofthedosealongthelengthofthescannedvolumeataparticularradialdepthinaphantom.ThisquantityhasbeenrecommendedbytheAmericanAssociationofPhysicistsinMedicine(AAPM)inrelationtothespecificationandacceptancetestingofCTscanners(26)andhasbeenreportedinsurveysofCTpracticeintheUSA(27).MSADisequaltoCTDIwhenthedistancebetweenscansisequaltotheslicethickness(23).AnotherquantityinwidespreaduseistheparticulardefinitionofCTDIgivenbytheFoodandDrugAdministration(FDA),i.e.CTDIFDA(28),inrelationtomeasurementsinaphantomforthepurposes (#, ofcompliancetestingofCTsystemsintheUSA.ItinvolvestheintegrationofD(z)overadistanceof14timestheslicethickness,whereD(z)isthedoseatapointzonanylineparalleltothez(rotational)axisforasinglesliceofnominalthicknessT.UnderrequirementsofFDAintheUSA,manufacturersofCTscannersareobligedtoreportvaluesofCTDIFDAforallmodesofoperation.ValuesofsuchmeasurementsinstandardCTdosimetry ,(1 phantomsarequotedintermsofabsorbeddoseinPMMA.ForagiventypeofscannerandCTdosimetryphantom(headorbody),valuesofCTDIFDA /t*4 measuredsimultaneouslyatthesurfaceandthecentreofthephantommayvarybyuptoafactorofthree.Variationsinthisratiobetweenscannersreflectdifferencesinequipmentdesign,andinparticulartheshapeofthebeamfiltration.AlthoughmeasurementsofCTDIFDArepresentanestablishedbodyofdata,thisquantityisnotideal, U2-8 however,fromthepointofviewofpracticaldosimetry.NotonlyisitexpressedintermsofdosetoPMMA,whichrequirestheintroductionofanadditionalcalibrationfactortogetherwithitsassociateduncertainty,butalsothelengthofintegration(14slicethicknesses)variesinabsolutetermsbetweensettingsandisdifficulttorealiseexperimentally.Inpractice,itismoreconvenienttomeasureCTDIoverafixedlengthofintegrationusingapencilionisationchamberwithanactivelengthof100mm.ThisprovidesameasurementofCTDI100,   expressedintermsofabsorbeddosetoair(mGy).Whenmeasuredinphantoms,suchvaluesarelargerthancorrespondingvaluesofCTDIFDAundersimilarconditionsofexposure,withthis %  differencebeingmostsignificantatsmallslicethicknesses(Table1,AppendixItoChapter1).AlthoughtheratioofabsorbeddosesinairandPMMAisapproximately1.1fortheradiationqualitiescommonlyfoundinCT,thisdifferenceislower(29)formeasurementswithslicethicknessesinexcessof7mmbytherelativelyshorterlengthsofintegrationforCTDI100in i  comparisonwithCTDIFDA;conversely,thedifferenceisexacerbatedatsmallerslicethicknesses :  bytherelativelylongerlengthsofintegrationforCTDI100.ThedefinitionofCTDI,-,&&ë100#&ë&-,,s#Ԁinthisguidelines  n  isconsistentwiththeIECstandardoncomputedtomography(30).Comparingthepropertiesofthevariousdosequantities,ithasbeendecidedtotaketheCTDI100atthesurfaceandcentreofthe   headorbodyCTdosimetryphantomsasanadequatebasisforspecifyingreferencedosesforCT.FromthesemeasurementsaweightedCTDI(CTDIw),representingtheaveragedosetoasingle O slice,andanassociateddoselengthproduct(DLP)foracompleteexamination,canbederived.MoredetailsaboutthedefinitionofthesequantitiesaregiveninAppendixItoChapter1. DERIVATIONOFREFERENCEDOSESVALUES  d Inconcept,referencedosevaluesfordiagnosticmedicalexposuresareessentiallyinvestigationlevelswhichrelatetotypicalpracticeratherthantoindividualpatients.Suchdosesarenotintendedtoinhibitthedevelopmentofsoundclinicalpractice.Referencedosevaluesshouldbeexaminationspecificandbesettoprovideanindicationofpotentiallyunacceptablepractice.Theymay,forexample,bebasedontheresultsoflargescalesurveyswhichtakeintoaccountthevariationinperformancebetweencentres(31).ThisapproachhasbeensuccessfullyappliedtocommonconventionalxrayexaminationsintheUK,wherebyexaminationspecificreferencedosevaluesweresetpragmaticallyatthethirdquartilevaluesofthedistributionsofmeandosesobservedforrepresentativesamplesofpatientsateachcentreinanationalsurvey(32).Accordingly,thetopdosequartileshavebeentakentorepresenttheboundsofpotentiallyunacceptablepractice;centreswithdosesabovethislevelofthedistributionsareencouragedtocarryouturgentinvestigationswithaviewtocorrectactionorprovideathoroughclinicaljustificationfortheuseofexceptionallyhighdoses.LevelsofdosefromCTexaminationsdependonthegeneraltechniqueandequipmentinuse,andalsotheclinicalandphysicalcharacteristicsofthepatient.WidescalesurveydatarelatingtoCTpracticemayalsoprovideaconvenientmeansforderivinginitialvaluesofreferencedosequantitiesforCT.Dosedataforsomeroutineexaminations(head,chest,abdomenandpelvis)areavailablefromanationalsurveyintheUKatthebeginningofthe1990's(8).DistributionsareshowninFigures1and2illustratingthevariationsintypicalvaluesofCTDIwpersinglesliceand (#, DLPpercompleteexamination,respectively,observedbetweenCTcentresforroutineheadexaminations(8).Forcompleteness,thevaluesofCTDIairunderlyingthesedataareshownin /*%. Figure3inordertodemonstratethatthisquantityismoredependentonscannerdesignandhenceshowsgreatervariationthanCTDIw.ThisiswhyasinglevalueofCTDIairisimpracticalasa +4'0 universalreferencedosequantity,asdiscussedabove.Morerecentinformationconcerningsomespecificexaminations(faceandsinuses,vertebraltrauma,HRCTofthelung,liverandspleen,andosseouspelvis)havebeenprovidedbyapilotstudyofthequalitycriteria(33).MoredetailedanalysesofthesurveydatadescribedabovearegiveninTables1and2,includingquartilevaluesforthedistributionsofCTDIwandDLP,respectively.Accordingly,initialreferencedosevaluesfor /I+5 CT,proposedonthebasisofthethirdquartilevaluesfromthesedistributions,aregiveninTable3.Effectivedosecanbecalculatedfromtheoperationaldosevalues(CTDIairorDLP)thusenabling 1,7 thedifferentexaminationstobecomparedmeaningfullytakingintoaccounttherelative Y2-8 radiosensitivitiesofthebodyregionsinvolved.ThesuitabilityoftheinitialreferencedosevaluesproposedinTable3shouldbecheckedbymeansofawidescaletrial.Consequentlythesettingandreviewofreferencedosevaluesshouldbeseenasacontinuingprocessinordertopromotecontinousimprovementovertime. XX&&ëLISTOFREFERENCESFORCHAPTER2#&ë&XX#  T  1.0 b EuropeanGuidelinesonQualityCriteriaforDiagnosticRadiographicImages.ReportEUR  u  16260(1996) b)"b)" 2.0 b EuropeanGuidelinesforQualityCriteriaforDiagnosticRadiographicImagesin   Paediatrics.EUR16261(1996) b)"b)" 3.0 b MacciaC,WallBF,PadovaniR,ShrimptonPC,andHussonB.Resultsofatrialsetup [  byastudygroupoftheradiationprotectionprogrammeoftheCEC.In:Optimisationofimagequalityandpatientexposureindiagnosticradiology.BritishInstituteofRadiologyReport20,EditedbyMooresBM,WallBF,EriskatH,andSchibillaH,pp242246(London,BIR)(1989) b)"b)" 4.0 b MacciaC,MooresBM,andWallBF.The1991trialonqualitycriteriafordiagnostic A radiogarphicimages,detailedresultsandfindings,ReportEUR16635(1997) b)"b)" 5.0 b VaoE,OlieteS,GonzlezL,GuibelaldeE,VelascoA,andFernndezJM.Imagequality Q anddoseinlumbarspineexaminations:resultsofa5yearqualitycontrolprogrammefollowingtheEuropeanqualitycriteriatrial.BritishJournalofRadiology, 68 ,13321335 V (1995) b)"b)" 6.0 b VaoE,GuibelaldeE,MorilloA,AlvarezPedrosaCS,andFernndezJM.Evaluationof j theEuropeanimagequalitycriteriaforchestexaminations.BritishJournalofRadiology, ;  68 ,13491355(1995) ob)"b)" 7.0 b PanzerW,ScheurerC,andZanklM.Dosetopatientsincomputedtomographic ! examinations:resultsandconsequencesfromafieldstudyintheFederalRepublicofGermany.In:Optimisationofimagequalityandpatientexposureindiagnosticradiology.BritishInstituteofRadiologyReport20,EditedbyMooresBM,WallBF,EriskatH,andSchibillaH,pp185187(London,BIR)(1989) b)"b)" 8.0 b ShrimptonPC,JonesDG,HillierMC,WallBF,LeHeronJC,andFaulknerK.Surveyof $' CTpracticeintheUK.Part2:Dosimetricaspects.Chilton,NRPBR249(London,HMSO)(1991) b)"b)" Ѐ9.0 b JonesDGandShrimptonPC.SurveyofCTpracticeintheUK.Part3:Normalisedorgan '?#+ dosescalculatedusingMonteCarlotechniques.Chilton,NRPBR250(1991) b)"b)" 10.0 b ZanklM,PanzerWandDrexlerG.Thecalculationofdosefromexternalphoton O*%. exposuresusingreferencehumanphantomsandMonteCarlomethods.PartVI:Organdosesfromcomputedtomographicexaminations.GSFBericht30/91(Neuherberg,GesellschaftfrStrahlenundUmweltforschung)(1991) b)"b)" 11.0 b ShrimptonPCandWallBF.Theincreasingimportanceofxraycomputedtomography d.)3 asasourceofmedicalexposure.RadiationProtectionDosimetry, 57 (14),413415 5/*4 (1995) b)"b)" 12.0 b UnnikJGvan,BroerseJJ,GeleijnsJ,JansenJThM,ZoeteliefJ,ZweersD.SurveyofCT 0>,6 techniquesandabsorbeddoseinvariousDutchhospitals.BritishJournalofRadiology, 1-7  70 ,367371(1997)}2-8b)"b)" Ї13.0 b OlerudHM.AnalysisoffactorsinfluencingpatientdosesfromCTinNorway.Radiation  ProtectionDosimetry, 71 ,123133(1997)nb)"b)" 14.0 b DallaPalmaLandPozziMucelliRS.Imagequalitycriteriaforcomputedtomography.In: w Optimisationofimagequalityandpatientexposureindiagnosticradiology.BritishInstituteofRadiologyReport20,EditedbyMooresBM,WallBF,EriskatHandSchibillaH,pp7278(London,BIR)(1989) b)"b)" 15.0 b CarvalhoAF,OliveiraAD,AlvesJG,CarreiroJV,JensenLCandJessenKA.Quality )  controlincomputedtomographyperformedinPortugalandDenmark.RadiationProtectionDosimetry, 57 (14),333337(1995) . b)"b)" 16.0 b OlerudHM,OlsenJBandSkrettingA.Ananthropomorphicphantomforreceiver q  operatingcharacteristicstudiesinCTimagingofliverlesions.BritishJournalofRadiology, 72 ,3543(1999)v b)"b)" V 17.0 b AlbrechtsenJ,HansenJ,JensenLC,JessenKAandJurikAG.Qualitycontrolandimage   qualitycriteriaincomputedtomography.RadiationProtectionDosimetry, 57 (14),125   127(1995) b)"b)" V18.0 b JurikAG,JessenKAandHansenJ.Imagequalityanddoseincomputedtomography. d EuropeanRadiology, 7 ,7781(1997)5b)"b)" 19.0 b JurikAG,FiirgaardB,JensenJH,JessenKAandHansenJ.Imagequalitycriteriaand x patientdoseinCTofthebrain.BritishJournalofRadiology(tobepublished) b)"b)" 20.0 b LeitlinienderBundesrztekammerzurQualittssicherunginderComputertomographie. N Dt.rztebl. 89 :Heft49(1992)(Englishtranslation:GuidelinesoftheFederalChamber  ofPhysiciansonqualityassurrenceincomputedtomography.InternalDocumentCECXII/354/92-EN) b)"b)" 21.0 b JurikAG,BongartzB,GoldingSJ,LeonardiM.Thequalitycriteriaforcomputed g tomography.RadiationProtectionDosimetry, 80 ,4953(1998)8 b)"b)" 22.0 b CalzadoA,RodrguezRandMuozA.Qualitycriteriaimplementationforbraincomputed { " tomographyexaminations.RadiationProtectionDosimetry, 80 ,6568(1998)L!#b)"b)" 23.0 b ShopeTB,GagneRMandJohnsonGC.Amethodfordescribingthedosesdeliveredby "U% transmissionxraycomputedtomography.MedicalPhysics, 8 (4),488495(1981)#&&b)"b)" 24.0 b ShrimptonPCandEdyveanS.CTscannerdosimetry.BritishJournalofRadiology 71 ,1 i% ( 3(1998) b)"b)" 25.0 b ICRPPublication60,1990RecommendationsoftheInternationalCommissionon 'C#+ RadiologicalProtection,AnnalsoftheICRPVol. 21 Nos.13(PergamonPress,Oxford) ($, (1991) b)"b)" 26.0 b AAPM.Specificationandacceptancetestingofcomputedtomographyscanners.Report (+&/ No39(NewYork,AAPM)(1993) b)"b)" 27.0 b ConwayBJ,McCrohanJL,AntonsenRG,RueterFG,SlaytonRJandSuleimanOH. -(2 AverageradiationdoseinstandardCTexaminationsofthehead:resultsofthe1990NEXTsurvey.Radiology, 184 ,135140(1992)=/*4b)"b)" 28.0 b DepartmentofHealthandHumanServices,FoodandDrugAdministration.21_CFR_ԀPart 0F,6 1020:Diagnosticxraysystemsandtheirmajorcomponents;amendmentstoperformancestandard;Finalrule.FederalRegister, 49 ,171(1984)2-8b)"b)" Ї29.0 b EdyveanS,LewisMA,BrittenAJ,CardenJF,HowardGAandSassiSA.Typetestingof  CTscanners:methodsandmethodologyforassessingimagingperformanceanddosimetry.MDAEvaluationReportMDA/98/25.London,MedicalDevicesAgency(1998) b)"b)" 30.0 b InternationalstandardofIEC60601244:MedicalelectricalequipmentPart244: D Particularrequirementsforthesafetyofxrayequipmentforcomputedtomography(1999) b)"b)" 31.0 b IAEA.InternationalBasicSafetyStandardsforProtectionagainstIonizingRadiationand %  fortheSafetyofRadiationSources.InternationalAtomicEnergyAgencySafetySeriesNo115Vienna,IAEA(1996) b)"b)" 32.0 b NRPB.Medicalexposure:Guidanceonthe1990RecommendationsofICRP.Documents i  oftheNRPB, 4 ,No2,4374(1993): b)"b)" 33.0 b JurikAG,PetersenJ,Bongartz,GoldingSJ,LeonardiM,vanMeertenPvE,GeleijnsJ, C  JessenKA,PanzerW,ShrimptonP,TosiG.Clinicaluseofimagequalitycriteriaincomputedtomographyrelatedtoradiationdose.Apilotstudy.EuropeanRadiology(tobesubmitted) Sb)"b)"  Table10 b 0Mb)"b)"AnalysisofestimatedvaluesofCTDIwfromsurveysofCTpractice,expressedinterms s ofabsorbeddosetoair M)"M)"  G*` dd td@ tt@)")"`,GG@,GG@,RGG@,GG@,fGG@,GG@,GG@,fGG@,GG@+  1"  $ C1Examinationtype A. 4C CACTDIw(mGy) qG O@( 4C"   CO 9*  C C9Samplesize 9*  C" C9Mean 9*  C" C9SD 9*  C" C9Min 9* C" C925% 9* C" C9Median 9* C" C975% =* C" C=Max L=% C"   CLHeada ZKd C Y@102CY@Z102 |m@d C" Y@102 Y@ I@50,0CI@|50.0 }nAd C" I@50,0 I@ 333333-@14,6C333333-@}14.6 }nAd C" 333333-@14,6 333333-@ 5@21,0C5@}21.0 }nAd C" 5@21,0 5@ 33333D@41,9C33333D@}41.9 }nAd C" 33333D@41,9 33333D@ H@49,6CH@}49.6 }nAd C" H@49,6 H@ fffffL@57,8CfffffL@}57.8 mAd C" fffffL@57,8 fffffL@ @`@130C@`@130 hYFd C" @`@130  @`@ ChFaceandsinusesb YJE C  4@20C4@Y20 {l?E C"  4@20 4@ 33333?@31,7C33333?@{31.7 }nAE C" 33333?@31,7 33333?@ /@15,9C/@}15.9 [LAE C" /@15,9 /@ C[Є [LE  C" fffff3@19,9Cfffff3@[19.9 }nAE !C" fffff3@19,9 fffff3@ <@28,0C<@}28.0 }nAE "C" <@28,0 <@ A@35,2CA@}35.2 _LAE #C" A@35,2 A@ C_Є G8%E $C"   CGVertebraltraumab YJ& %C  4@20C4@Y20 {l?& &C"  4@20 4@  F@44,1C F@{44.1 }nA& 'C"  F@44,1  F@ 5@21,5C5@}21.5 [LA& (C" 5@21,5 5@ C[Є [L& )C" ffffff=@29,4Cffffff=@[29.4 }nA& *C" ffffff=@29,4 ffffff=@ C@39,7CC@}39.7 }nA& +C" C@39,7 C@ 33333Q@68,3C33333Q@}68.3 _LA& ,C" 33333Q@68,3 33333Q@ C_Є L=%& -C"   CLChesta YJj .C  V@88CV@Y88 {l?j /C"  V@88 V@ L4@20,3CL4@{20.3 |mAj 0C" L4@20,3 L4@ ffffff@7,6Cffffff@|7.6 {l@j 1C" ffffff@7,6 ffffff@ @4,0C@{4.0 |m@j 2C" @4,0 @ ffffff.@15,2Cffffff.@|15.2 }nAj 3C" ffffff.@15,2 ffffff.@ 2@18,6C2@}18.6 }nAj 4C" 2@18,6 2@ :@26,8C:@}26.8 nAj 5C" :@26,8 :@ 333333G@46,4C333333G@46.4 iZGj 6C" 333333G@46,4  333333G@ CiHRCToflungb YJK 7C  4@20C4@Y20 {l?K 8C"  4@20 4@ 33333?@31,7C33333?@{31.7 }nAK 9C" 33333?@31,7 33333?@ -@14,9C-@}14.9 [LAK :C" -@14,9 -@ C[Є [LK ;C" ffffff3@19,4Cffffff3@[19.4 }nAK <C" ffffff3@19,4 ffffff3@ ?@31,0C?@}31.0 }nAK =C" ?@31,0 ?@ A@35,0CA@}35.0 _LAK >C" A@35,0 A@ C_Є L=%K ?C"   CLAbdomena YJ, @C  V@91CV@Y91 {l?, AC"  V@91 V@ 9@25,6C9@{25.6 |mA, BC" 9@25,6 9@  @8,4C @|8.4 {l@, CC"  @8,4  @ 333333@6,8C333333@{6.8 |m@, DC" 333333@6,8 333333@ 2@18,8C2@|18.8 }nA, EC" 2@18,8 2@ 8@24,8C8@}24.8 }nA, FC" 8@24,8 8@ ffffff@@32,8Cffffff@@}32.8 nA, GC" ffffff@@32,8 ffffff@@ 333333G@46,4C333333G@46.4 iZG, HC" 333333G@46,4  333333G@ CiLiverandspleenb YJ IC  .@15C.@Y15 {l? JC"  .@15 .@ :@26,1C:@{26.1 }nA KC" :@26,1 :@ &@11,3C&@}11.3 [LA LC" &@11,3 &@ C[Є [L MC" .@15,4C.@[15.4 }nA NC" .@15,4 .@ 9@25,0C9@}25.0 }nA OC" 9@25,0 9@ A@34,0CA@}34.0 _LA PC" A@34,0 A@ C_Є L=% QC"   CLPelvisa YJ RC  T@82CT@Y82 {l? SC"  T@82 T@ ffffff:@26,4Cffffff:@{26.4 |mA TC" ffffff:@26,4 ffffff:@ 333333#@9,6C333333#@|9.6 {l@ UC" 333333#@9,6 333333#@ 333333@6,8C333333@{6.8 |m@ VC" 333333@6,8 333333@ 2@18,5C2@|18.5 }nA WC" 2@18,5 2@ :@26,0C:@}26.0 }nA XC" :@26,0 :@ ̌@@33,1Č@@}33.1 nA YC" ̌@@33,1 ̌@@ K@55,2CK@55.2 *q kZG ZC" K@55,2  K@ CkOsseouspelvisb [J[C  0@16C0@[16 }l?\C"  0@16 0@ 333338@24,7C333338@}24.7 nA]C" 333338@24,7 333338@ 1@17,8C1@17.8 ]LA^C" 1@17,8 1@ C]Є ]L_C" -@14,8C-@]14.8 nA`C" -@14,8 -@ 4@20,0C4@20.0 nAaC" 4@20,0 4@ 8@24,6C8@24.6 _LAbC" 8@24,6 8@ C_Є5+)cC"   5 *Notes:a. b EstimatedvaluesfromUKsurveydata(8) re b. b DosedatafromPilotStudy(33) Cf  Table2 0 b 0Mb)"b)"AnalysisofestimatedvaluesofDLPfromsurveysofCTpracticeonthebasisof )l absorbeddosetoair(mGycm) M)"M)"  G* d dGG@GG@RGG@GG@fGG@GG@GG@fGG@GG@)")",GG@,GGB,RGGB,GGB,fGGB,GGB,GGB,fGGB,kGGB+  1" wo C1Examinationtype A.pC CADLP(mGycm) qG O@(qC"   CO 9*hrC C9Samplesize 9*9 tC" C9Mean 9*huC" C9SD 9*hvC" C9Min 9*hwC" C925% 9*hxC" C9Median 9*hyC" C975% =*hzC" C=Max L=%h{C"   CLHeada ZK!}|C Y@102CY@Z102 {l@!}}C3 Y@102 Y@ @882C@{882 {l@!}~C3 @882 @ t@332Ct@{332 {l@!}C3 t@332 t@ l@231Cl@{231 {l@!}C3 l@231 l@ @673C@{673 {l@!}C3 @673 @ ؈@795C؈@{795 |m@!}C3 ؈@795 ؈@ T@1045CT@|1045 nA!}C3 T@1045 T@ N@2087CN@2087 iZG!}C3 N@2087  N@ CiFaceandsinusesb YJ!^C  4@20C4@Y20 zk?!^C3  4@20 4@ 0p@259C0p@z259 {l@!^C3 0p@259 0p@ ]@118C]@{118 {l@!^C3 ]@118 ]@ c@158Cc@{158 {l@!^C3 c@158 c@ f@180Cf@{180 {l@!^C3 f@180 f@ i@204Ci@{204 {l@!^C3 i@204 i@ v@353Cv@{353 l@!^C3 v@353 v@ @506C@506 hYF!^C3 @506  @ ChVertebraltraumab YJ"?C  4@20C4@Y20 zk?"?C3  4@20 4@ x@392Cx@z392 {l@"?C3 x@392 x@ j@214Cj@{214 zk@"?C3 j@214 j@  D@40CD@z40 zk?"?C3  D@40 D@ o@254Co@z254 {l@"?C3 o@254 o@ v@353Cv@{353 {l@"?C3 v@353 v@ p|@455Cp|@{455 l@"?C3 p|@455 p|@ @914C@914 m^F"?C3 @914  @ CmChesta YJ# C  V@88CV@Y88 zk?# C3  V@88 V@ (@517C(@z517 {l@# C3 (@517 (@ `n@243C`n@{243 zk@# C3 `n@243 `n@  R@72CR@z72 zk?# C3  R@72 R@ u@349Cu@z349 {l@# C3 u@349 u@ ~@490C~@{490 {l@# C3 ~@490 ~@ H@649CH@{649 m@# C3 H@649 H@ `@1304C`@1304 iZG# C3 `@1304  `@ CiHRCToflungb YJ$ C  4@20C4@Y20 zk?$ C3  4@20 4@ i@200Ci@z200 zk@$ C3 i@200 i@  Q@71CQ@z71 zk?$ C3  Q@71 Q@ Y@100CY@z100 {l@$ C3 Y@100 Y@ a@136Ca@{136 {l@$ C3 a@136 a@ h@199Ch@{199 {l@$ C3 h@199 h@ `q@278C`q@{278 l@$ C3 `q@278 `q@ s@312Cs@312 m^F$ C3 s@312  s@ CmAbdomena YJ% C  V@91CV@Y91 zk?% C3  V@91 V@ @597C@z597 {l@% C3 @597 @ q@281Cq@{281 {l@% C3 q@281 q@ \@115C\@{115 {l@% C3 \@115 \@ y@415Cy@{415 {l@% C3 y@415 y@ h@525Ch@{525 {l@% C3 h@525 h@ 0@774C0@{774 m@% C3 0@774 0@ H@1874CH@1874 iZG% C3 H@1874  H@ CiLiverandspleenb YJ`&!C  4@20C4@Y20 zk?`&!C3  4@20 4@ @658C@z658 {l@`&!C3 @658 @ Pr@293CPr@{293 {l@`&!C3 Pr@293 Pr@ b@151Cb@{151 {l@`&!C3 b@151 b@ P~@485CP~@{485 {l@`&!C3 P~@485 P~@ X@651CX@{651 {l@`&!C3 X@651 X@ @894C@{894 m@`&!C3 @894 @ t@1181Ct@1181 n_G`&!C3 t@1181  t@ CnPelvisa YJQ'"C  T@82CT@Y82 zk?Q'"C3  T@82 T@ {@443C{@z443 {l@Q'"C3 {@443 {@  m@233C m@{233 zk@Q'"C3  m@233  m@  Q@68CQ@z68 zk?Q'"C3  Q@68 Q@ p@266Cp@z266 {l@Q'"C3 p@266 p@ z@416Cz@{416 {l@Q'"C3 z@416 z@ @566C@{566 m@Q'"C3 @566 @ @1324C@1324 *q kZGQ'"C3 @1324  @ CkOsseouspelvisb [JB(#C  0@16C0@[16 |k?B(#C3  0@16 0@ @514C@|514 }l@B(#C3 @514 @ z@426Cz@}426 |k@B(#C3 z@426 z@  E@43CE@|43 |k?B(#C3  E@43 E@  l@225C l@|225 }l@B(#C3  l@225  l@ }@465C}@}465 }l@B(#C3 }@465 }@ 0@518C0@}518 m@B(#C3 0@518 0@ x@1758Cx@1758WMKB(#C3 x@1758  x@ W *Notes:a. b EstimatedvaluesfromUKsurveydata(8) *(& b. b DosedatafromPilotStudy(33) +&   g,' 6nW  Table3 0 b 0Mb)"b)"ProposedreferencedosevaluesforroutineCTexaminationsonthebasisofabsorbed { dosetoair M)"M)"  G* d dGG@GGBRGGBGGBfGGBGGBGGBfGGBkGGB)")",td@,Std@,tt@+  1"  , C1Examination A. <C CAReferencedosevalue qG O@( <C"   CO 9*  C C9CTDIw(mGy) =*  C C=DLP(mGycm) L=%  C   CLRoutineheada YJ  C  N@60CN@Y60 l?  C"  N@60 N@ h@1050Ch@1050 iZG C" h@1050  h@ CiFaceandsinusesa YJ| C  A@35CA@Y35 ~k?| C"  A@35 A@ v@360Cv@~360 hYF| C" v@360  v@ ChVertebraltraumab YJ] C  Q@70CQ@Y70 ~k?] C"  Q@70 Q@ |@460C|@~460 m^F] C" |@460  |@ CmRoutine_chestb_ YJ> C  >@30C>@Y30 ~k?> C"  >@30 >@ P@650CP@~650 hYF> C" P@650  P@ ChHRCToflungb YJ C  A@35CA@Y35 ~k? C"  A@35 A@ q@280Cq@~280 m^F C" q@280  q@ CmRoutine_abdomenb_ YJc C  A@35CA@Y35 ~k?c C"  A@35 A@ `@780C`@~780 hYFc C" `@780  `@ ChLiverandspleenb YJD C  A@35CA@Y35 ~k?D C"  A@35 A@  @900C @~900 m^FD C"  @900   @ CmRoutinepelvisb YJ5 !C  A@35CA@Y35 ~k?5 "C"  A@35 A@ Ё@570CЁ@~570 *q jYF5 #C" Ё@570  Ё@ CjOsseouspelvisb [J&$C  9@25C9@[25 ~k?&%C"  9@25 9@ @@520C@@~520VLJ&&C" @@520  @@ V *Notes:1.  1.EXa  .0 b   Datarelatetoheadphantom(PMMA,16cmdiameter)1.EX`XیF(b)"b)" Ќ  b.0 b Datarelatetobodyphantom(PMMA,32cmdiameter)z)b)"b)"   ,  Figure1 0 M HistogramofCTDIwdataforroutineheadexaminationsintheUK,onthebasisof ? absorbeddosetoair M)"M)" p< ,(`~0| < ` E<<| p ||)")" |||| > ||  Figure2 0 M HistogramofDLPdataforroutineheadexaminationsintheUK,onthebasisof  absorbeddosetoair M)"M)"  )")"            p< ,(`~04 ` / EE44qP p            Figure3 0 M HistogramofCTDIairdataforroutineheadexaminationsintheUK,expressedinterms  ofabsorbeddosetoair M)"M)" p< ,(`~0s ` E Z UV p )")"           ?)"6 &&ëChapter2   >)" APPENDIXI    @4 4 cCTSCANNERDOSIMETRYDATA  P #&ë&6 `#DataaretabulatedbelowforaselectionofscannermodelsrelatingtotypicalvaluesofthenormaliseddosequantitiesnCTDIairandnCTDIw,andthefactorPHorB,asdescribedinAppendixI   toChapter1.TheseillustrativedatamaybeusedintheabsenceofmeasureddatatoprovidebroadestimatesofthereferencedosequantitiesforCT.FurtherdatarelatingtoamorecomprehensiverangeofscannersareavailableinthereferencedatabaseonCTdosimetrythathasbeenpublishedontheInternet(http://www.efomp.org).    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W * b Note: '   0 b a: M Fullfield(Filter0used)b72b72  b ForfurtherinformationseeReferenceDatabaseonCTdosimetry:#&ë&XX#http://www.efomp.org n  L7272k72  W LBTRWP6&A4_&6A4 Liggende6&A4&6A4 Liggende\\T   ?)"6 &&ëChapter3  @>>cQUALITYCRITERIAIMPLEMENTATIONANDAUDITGUIDELINES #&ë&6 #Ԉ , @ll!c TableofContents     QUALITYCRITERIAIMPLEMENTATIONANDAUDITGUIDELINES e!e!F)"88  ,   APPENDIXI: 0 : 0' : )": )"SampleQuestionnaireforRecordingDataonEquipment,@ ' )"' )" 0 b 0Mb)"b)"0: M)"M)"0' : )": )"RadiographicTechniqueandDosee!e!F)"' )"' )"90 x   APPENDIXII :0 : 0' : )": )"ExamplesofImageQualityAssessmentFormse!e!F)"' )"' )"9%3%%2%   0 b 0Mb)"b)"0: M)"M)"0' : )": )"Faceandsinusese!e!F)"' )"' )"94 ] 0 b 0Mb)"b)"0: M)"M)"0' : )": )"Spinee!e!F)"' )"' )"95 . 0 b 0Mb)"b)"0: M)"M)"0' : )": )"Chest,HRCTe!e!F)"' )"' )"96 b 0 b 0Mb)"b)"0: M)"M)"0' : )": )"Liverandspleene!e!F)"' )"' )"97 3 0 b 0Mb)"b)"0: M)"M)"0' : )": )"Osseouspelvise!e!F)"' )"' )"98    C  QUALITYCRITERIAIMPLEMENTIONANDAUDITGUIDELINES   Thequalitycriteriaaredesignedtobeeasilyappliedinpracticeinanyxraydepartmentwithouttheneedforspecialequipmentapartfromthatneededformeasuringorestimatingthedosetothepatient.Theyareintendedtoprovideademonstrablyachievablestandardofgoodpracticebothintermsofasatisfactorylevelofimagequalityandanacceptablylowradiationdosetothepatient.However,thequalitycriteriawillonlybeofrealbenefittoanxraydepartmentiftheyallowinadequatelevelsofperformancetobereadilyidentifiedandcorrected.Theimpactofapplyingthequalitycriteriainaparticularxraydepartmentintermsofthelevelofimprovementinperformanceachieved,canonlybeproperlyassessedthroughacorrectlystructuredprocessofmedicalaudit.Theessentialcomponentsofthemedicalauditprocesscanbesummarisedas:0 b 0Mb)"b)"Setstandards M)"M)" 0 b 0Mb)"b)"Checkcompliance M)"M)" 0 b 0Mb)"b)"Correctbadpractice M)"M)" 0 b 0Mb)"b)"Setnewstandards M)"M)" 0 b 0Mb)"b)"Repeat M)"M)" Thequalitycriteriaessentiallyprovidetheinitial"standards"forimagequalityandpatientdoseaudit:aspecialcaseof"medical"audit.Moredetailedstepsintheauditprocessspecifictothisspecialcaseare:1.0 b ChoosetypeofCTexaminationandCTequipmenttoaudit.>b)"b)" 2.0 b Takerandomsampleofatleast10standardsizedpatients(6080kg).}b)"b)" 3.0 b PerformchosentypeofCTexaminationoneachpatientusingtheestablishedtechniques.b)"b)" 4.0 b Recordallthetechniqueandequipmentparametersforeachexamination.(Seeexample $  ofaquestionnaireinAppendixItothischapterforrelevantdetailstoberecorded). b)"b)" 5.0 b RecordtheCTDIWandDLPforeachexaminationusingthemethodsdescribedin 4!# AppendixIofChapter1.Comparethemeanvalueforthesampleofatleast10standardsizedpatientswiththecorrespondingreferencedoselistedinthequalitycriteria. b)"b)" 6.0 b AtleasttwoobserverscheckcomplianceofeachCTexaminationwiththeimagecriteria x$' independently.AppendixIItothischaptercontainsexamplesofimagecriteriaassessmentformsforthe5typesofexaminationevaluatedinapilottrialofqualitycriteria.Aswellasprovidingasystemforscoringcompliancewiththeimagecriteriaandthevisibilityofimportantimagedetails,theseformsalsoincludeasystemforscoringmoregeneralaspectsoftheimage,suchasnoise,spatialresolutionanddiagnosticacceptability.Similarformscanbeelaboratedforothertypesofexaminationsforwhichqualitycriteriaareprovidedintheguidelines. b)"b)" 0 b Tohelpinjudgingtheseimagefeatures,bothduringthisauditprocessandmoregenerallyatanytime,xraydepartmentsshouldconsiderhavingavailableasetof"ideal"hardcopiesofexaminationsinwhichallqualityaspectsareoptimisedandagainstwhichanyotherexamination,canbedirectlyvisuallycompared.Itisessential,ofcourse,thatthe"ideal"examinationscanbeproducedwithadosetothepatientbelowthecorrespondingdiagnosticreferencevalue. b)"b)" 7.0 b Identifywherethestandard(imagequalityordosecriteria)arebeingnotmet.1,7b)"b)"  Y2-8 8.0 b Investigatethecause(s)ofanypersistentnoncompliancewiththecriteria.The  "ExamplesofGoodRadiographicTechnique"maybeusefultohelpidentifythoseaspectsoftheestablishedtechniqueorequipmentwhichareresponsiblefornoncompliance. b)"b)" 9.0 b Takecorrectiveactionbychangingtechniquesorequipmentinamannerlikelytoremedy D theoccurrenceofnoncompliance. b)"b)" 10.0 b Afterashortperiodofusingtherevisedtechniquesorequipment,repeatsteps27.T b)"b)" 11.0 b Ifnoimprovement,repeatsteps810. Y b)"b)" 12.0 b Ifinitialstandards(qualitycriteria)arenowbeingmetinfull,considerimproving    standards,forexample,bysettinglowerreferencedosesinlinewiththeoptimisationprincipleALARA(AsLowasReasonablyAchievable). b)"b)" Tohelpestablishamoreuniformandmorewidespreadlevelofperformanceindiagnosticradiology,itwouldbedesirabletoextendtheauditprocesstoincludeindependentobservers,externaltothexraydepartmentbeingaudited,andprogressivelytoapplytheprocesstolargergroupingsthanindividualxraydepartments.    6 &&ë ?)"Chapter3 #&ë&6 #Ԉ   >)"6 &&ëAPPENDIXI#&ë&6 ~#   XX&&ë #&ë&XX#6 &&ë  @@bSAMPLEQUESTIONNAIREFOR@@bRECORDINGDATAON  Y EQUIPMENT,RADIOGRAPHICTECHNIQUEANDDOSE   o #&ë&6 -#L  k  tI 95||   p EttE   @cc)c XX&&ëA)RADIOGRAPHICTECHNIQUE[tobefilledinbytheradiographer/radiologist #&ë&XX# "   A.1.0 b CTscanner  pb)"b)" 0 b Manufacturer/Type:............................../.............................. Eb)"b)" 0 b Yearofmanufacture:............................  b)"b)"  A.2.0 b Patientposition U b)"b)" 0 b Supine...............................................................................................................l!l!G)"b)"b)"g-H @E+cM5 g߈ *  0 b Prone.................................................................................................................l!l!G)"b)"b)"g-H @E4M5g߈ ^  0 b Otherposition,describe:..................................................................................../ b)"b)"  A.3.0 b Gantrytilt n b)"b)" 0 b None..................................................................................................................l!l!G)"b)"b)"g-H @ED|M5g߈ C 0 b Cranial,degree................................................................................................... G)"b)"b)"g-H z@EzM 5g߈ w 0 b Caudal,degree................................................................................................... G)"b)"b)"g-H z@Ez 5g߈ H 0 b  b)"b)"  A.4.0 b Hardcopyfacilities b)"b)" 0 b Lasercamera0 b)"b)"  Manufacturer/Type:................................/............................\ )" )" 0 b 0Mb)"b)"0: M)"M)" ' 0 : )": )"0 )" )"Inusesince(date):............................................................. )")" 0 b Film '  0b)"b)"Manufacturer/Type:................................/............................a)")" 0 b FilmProcessor0b)"b)"Manufacturer/Type:................................/............................2)")" 0 b 0Mb)"b)"0: M)"M)"0' : )": )"0 ' )"' )"0 )" )"ProcessingTime:......................................................77B)")")"sec.U#@ zEzM 5U߈  0 b 0Mb)"b)"0: M)"M)"0' : )": )"0 ' )"' )"0 )" )"DeveloperTemperature:...........................................D)")")"$CU#@ zErz 5U߈ q  XX&&ëB)PATIENTRELATEDDATA[tobefilledinbytheradiographer/radiologist #&ë&XX<# G  B.1.0 b Age ........................................................................................................A)"b)"b)"yearsg-H z@E z 5g߈  2  B.2.0 b Sex ........................................................................................................?)"b)"b)"Fg-H @E=v"u!M5g߀Mg-H @EVv"!M5g߈ u"  B.3.0 b Height ......................................................................................................D)"b)"b)"cmg-H z@E $zX# 5g߈ $!  B.4.0 b Weight .....................................................................................................C)"b)"b)"kgg-H z@E%z% 5g߈ %,!#   &"$ N% bM ; M ;NC)0  IMAGEVIEWINGDATA[tobefilledinbytheradiographer/radiologist r## *&*d dtd@dtd@td@td@`td@ td@td@td@td@tt@##,dd ,dd ,dd ,dd +   E  Settings .!  . Sequence1 7* " 7 Sequence2 =* " = Sequence3 9* " 9C1)Reconstructionalgorithm +! u +   u     u   0! u  0C2)Fieldofview +!{   +  {     {   0!{  0C3)Windowwidth +! G +   G    G  6% G ^6C4)Windowlevel 2!M  2 )M  ) +M  +," M  d^   , D)0  DOSERELATEDDATA& ## D.I)0  DOSERELATEDDATA[tobefilledinbytheradiographer/radiologist 3 ## *dddd dd dd dd &*##,c ,dd ,dd ,dd +     Detailsoftechnique .!j . Sequence1 7*j" 7 Sequence2 =*j " = Sequence3 3$j!" 3 Exposurefactors %p" % %p# % .p$ . 'p% '].x = !!X bM ;]0  Tubevoltage(kV) ," <& ,  <'   <(  *<) *0  Tubecurrentxexposuretime(mAs/slice)(1) ," >* ,  >+   >,  *>- *0  Tubecurrentxtotalacquisitiontime(mAstotal)(2) ," . ,  /   0  '1 ' Slicethickness(mm) "k2 "  k3   k4  0!k5 0Couchincrement(tablefeed)(mm) +!q6 +  q7   q8  )q9 ) Numberofslices )=: ) )=; ) +=< +&==   &]% bM ;x = !!X]0  (1)Forserialscanningb>##   (2)Forhelicalscanning 3 ?  T% FbM ; bM ;TD.II) 0 F DOSERELATEDDATA[tobefilledinbythephysicist!8AF#F#  *ddc dd dd dd ##,dd ,dd ,dd ,dd +   #C  Quantity .!$sD . Sequence1 7*$sE" 7 Sequence2 =*$sF" = Sequence3 0!$sG" 0Tubefiltrationsetting(3) "y% H "  y% I  +y% J + 'y% K 'nCTDIw(4)(mGy/mAs) "&A"L "  &A"M  +&A"N + '&A"O '_CTDIw_(_mGy_)(5) "C(#P "  C(#Q  +C(#R + -C(#S ^-Doselengthproduct(mGyxcm) )) %T ) )) %U ) +) %V + 3") %W d^  ^3Totaldoselengthproduct(mGyxcm)(6) +;+&X + %;+&Y % %;+&Z  %," ;+&[ d^    ,*+,dddd dd dd dd ##,A dd ,dd +   j,'[ Phantomdiameter(cm) +,1(\ +&,1(]  &0 F (3)0bF#F#ListifthiscanbevariedR.)^b#b# 0 F (4)0bF#F#ThenormalizedweightedCTdoseindexnCTDIwhastobedeterminedfortheradiationquality #/*_ (tubevoltage,filtration)andbeamgeometry(focustoaxisdistance,FOV,beamshaping)asusedintherespectivesequence b#b# 0 F (5)0bF#F#Persliceforserialscanningandperrotationforhelicalscanning1,bb#b# 0 F (6)0bF#F#Sumofallsequences g2-cb#b# 6 &&ë C#Chapter3    A##&ë&6 #6 &&ëAPPENDIXII#&ë&6 {#   @??M 6 &&ëEXAMPLESOFIMAGEQUALITYASSESSMENTFORMS#&ë&6 #  <  @yy#M 6 &&ëFaceandsinuses  W @)MSpine@&MChest,HRCT@#MLiverandspleen@$MOsseouspelvis   #&ë&6 #   =l<# 6 &&ëFACEANDSINUSES#&ë&6 #Ԉ   Nameofradiologist/radiographer:__________________________________Patientnumber:_____________0  0v##Hospitalcode:______________Nv#v# 0 F  F#F# *fddA dd dd +,##f, dd ,dd ,dd ,dd ,dd ,dd ,dd +   +  Imagequalitycriteria C6'% ` C Sequence1 >1"T " > Sequence2 D1"T " D Totalexamination 2("T " 2 ! Y   !Yes '  " 'No '  " 'Yes ' " 'No ' " 'Yes 0 " 0No 0! " 0 Visualizationof  " ] ].Fx = !!X FbM ;]1.0 F Entirefacefrompalatetothetop  2  ofthefrontalsinus ,"   F$F$ ,  " ]   " ]   " ]   " ]   " ]  '" ] '2.0 F Vesselsafterintravenouscontrast -h  media ," 9 F$F$ ,  -h    -h    -h    -h    -h !  '-h " ' Criticalreproduction  c # 1.0 F Visuallysharpreproductionofthe 8s$ corticalandtrabecularbonestructures ," &F$F$ ,  c '   c (   c )   c *   c +  'c , '2.0 F Visuallysharpreproductionofthe ?z- frontalsinuses ," K.F$F$ ,  ?z/   ?z0   ?z1   ?z2   ?z3  '?z4 '3.0 F Visuallysharpreproductionofthe u5 sphenoidsinuses ," F6F$F$ ,  u7   u8   u9   u:   u;  'u< '4.0 F Visuallysharpreproductionofthe = orbitae ," |>F$F$ ,  ?   @   A   B   C  'D '5.0 F Reproductionoftheglobe,optic E nerveandorbitalmuscles ," FF$F$ ,  G   H   I   J   K  'L '6.0 F Visuallysharpreproductionofthe RM ethmoid ," #NF$F$ ,  RO   RP   RQ   RR   RS  'RT '7.0 F Visuallysharpreproductionofthe MU maxillaanditssinuses ,"  YVF$F$ ,  MW   MX   MY   MZ   M[  'M\ '8.0 F Visuallysharpreproductionofthe !] nasalcavity ," T"^F$F$ ,  !_   !`   !a   !b   !c  -!d ^-9.0 F Visuallysharpreproductionofthe # e rhinopharynx 3" $!fF$F$ 3 )# g ) )# h ) )# i ) )# j ) +# k +," # l d^  ,Itisimportantforeverycriteriontoevaluateifitisfulfilledornot. Ifacriterioncannotbeevaluatedit %"l shouldbeclearlymarkedbyNAintheyesbox.  &#m  Generalassessment: 4(o%o   Acceptablenoise ...............................................................................................................""I#*g-H @E )LB(M5g   )D&p   Acceptablespatialresolution ..........................................................................................""I#*g-H @E)L)M5g  )'q   Diagnosticacceptability ...................................................................................................""I##g-H @E*+)M5g߈ *'r *0  +optimum;toomuch;toolittleY,)t## #0  1:fullyacceptable;2:probablyacceptable;3:onlyacceptableunderlimitedconditions;4: *-e*u unacceptable(givereasons) ##  Comments ____________________________________________________________________  /,x =lf>&ë&&&ë  '# >6 &>&ëVERTEBRAANDPARAVERTEBRALSTRUCTURES  #>&ë&>6 S# Nameofradiologist/radiographer:__________________________________Patientnumber:_____________0  0}##Hospitalcode:______________N}#}# *d d dd dd dd dd dd dd dd ##, dd ,dd ,dd ,dd ,dd ,dd ,dd +  # + G# Imagequalitycriteria C6' CU C Sequence1 >1"7r " > Sequence2 D1"7r " D Totalexamination <2(7r " G0  G< ! < w  !Yes '  " 'No '  " 'Yes ' " 'No ' " 'Yes 0 " 0No :+% " G0  G: Visualizationof    1.0 F Theentireregionofsuspected   pathology ," q F$F$ ,                     1"  G0  G12.0 F Vesselsafterintravenouscontrast   media ,"  F$F$ ,                   !  1" " G0  G13.0 F Spinalcordandnerverootsafter  # intrathecalinjectionofcontrastmedia(CT_myelography_) ," t%F$F$ ,   &    '    (    )    *  1" + G0  G1 Criticalreproduction  , 1.0 F Visuallysharpreproductionofthe - corticalandtrabecularvertebralbone ," 3n/F$F$ ,  0   1   2   3   4  1"5 G0  G12.0 F Visuallysharpreproductionofthe {6 intervertebraljoints ," L7F$F$ ,  {8   {9   {:   {;   {<  1"{= G0  G13.0 F Visuallysharpreproductionofthe > intervertebraldiskprofiles ," e?F$F$ ,  @   A   B   C   D  1"E G0  G14.0 F Visuallysharpreproductionofthe F intervertebral_radicular_Ԁcanals0F$F$ ," ~G$$ ,  H   I   J   K   L  1"M G0  G15.0 F Reproductionofthecalsac ," NF$F$ ,  O   P   Q   R   S  1"T G0  G16.0 F Visuallysharpreproductionofthe IU spinalcordorcandaequina(CTmyelography) ," WF$F$ ,  IX   IY   IZ   I[   I\  1"I] G0  G17.0 F Reproductionoftheparavertebral  3^ ligaments ," !_F$F$ ,   3`    3a    3b    3c    3d  1" 3e G0  G18.0 F Visuallysharpreproductionofthe #L f paravertebralmuscles ," #!gF$F$ ,  #L h   #L i   #L j   #L k   #L l  7&#L m G0  G^79.0 F Reproductionofthemainvessels *%e"n andperithecalvenousplexusesafterintravenouscontrastmedia 3" &$pF$F$ 3 )*%e"q ) )*%e"r ) )*%e"s ) )*%e"t ) +*%e"u +," *%e"v G^  ,Itisimportantforeverycriteriontoevaluateifitisfulfilledornot. Ifacriterioncannotbeevaluatedit '6%v shouldbeclearlymarkedbyNAintheyesbox.  ( &w  Generalassessment:  v*'y  Acceptablenoise ...............................................................................................................""I#*g-H @EL+L*M5g  K+(z   Acceptablespatialresolution ..........................................................................................""I#*g-H @E!,LY+M5g   ,[){   Diagnosticacceptability ...................................................................................................""I##g-H @E,+.,M5g߈ ,0*| *0  +optimum;toomuch;toolittle.+~## #0  1:fullyacceptable;2:probablyacceptable;3:onlyacceptableunderlimitedconditions;4: l/, unacceptable(givereasons) ##  Comments ___________________________________________________________________ 1/   2/ A#>6 &>&ëCHEST,HRCT#>&ë&>6 7#Ԉ   Nameofradiologist/radiographer:__________________________________Patientnumber:_____________0  0}##Hospitalcode:______________ N}#}#  0   ## *dd dd dd dd dd dd dd dd ##, dd ,dd ,dd ,dd ,dd ,dd ,dd +   +  Imagequalitycriteria C6'% `;b C Sequence1 >1"T " > Sequence2 D1"T " D Totalexamination 2("T " 2 ! Y   !Yes '  " 'No '  " 'Yes ' " 'No ' " 'Yes 0 " 0No 0! " 0 Visualizationof  " ] 1.0 F Entirefieldoflungparenchyma ,"  2 FF ,  " ]   " ]   " ]   " ]   " ]  '" ] ' Criticalreproduction  \  1.0 F Visuallysharpreproductionofthe 1l  lungparenchyma ," = FF ,  \    \    \    \    \ !  '\ " '2.0 F Visuallysharpreproductionof g # pulmonaryfissures ," 8s$FF ,  g %   g &   g '   g (   g )  +g * ^+3.0 F Visuallysharpreproductionof + secondarypulmonarylobularstructuressuchasinterlobulararteries ," K.FF ,  /   0   1   2   3  1"4 d^  ^14.0 F Visuallysharpreproductionoflarge 5 andmediumsizedpulmonaryvessels ," E7FF ,  8   9   :   ;   <  1"= d^  ^15.0 F Visuallysharpreproductionofsmall > pulmonaryvessels ," ?FF ,  @   A   B   C   D  1"E d^  ^16.0 F Visuallysharpreproductionoflarge <wF andmediumsizedbronchi ,"  HGFF ,  <wH   <wI   <wJ   <wK   <wL  1"<wM d^  ^17.0 F Visuallysharpreproductionofsmall N bronchi ," qOFF ,  P   Q   R   S   T  1"U d^  ^18.0 F Visuallysharpreproductionofthe !?V pleuromediastinalborder ," !WFF ,  !?X   !?Y   !?Z   !?[   !?\  3"!?] d^  ^39.0 F Visuallysharpreproductionofthe h# ^ borderbetweenthepleuraandthethoracicwall 3"  %E"`FF 3 )h# a ) )h# b ) )h# c ) )h# d ) +h# e +," h# f d^  ,&ë&&>&ëԀItisimportantforeverycriteriontoevaluateifitisfulfilledornot. Ifacriterioncannotbeevaluatedit 9&t#f shouldbeclearlymarkedbyNAintheyesbox.  'I$g #>&ë&&&ëI# Generalassessment: (%i   Acceptablenoise .............................................................................................................""I#*g-H @E)L(M5g  )&j   Acceptablespatialresolution ........................................................................................""I#*g-H @E_*L)M5 g  ^*'k   Diagnosticacceptability .................................................................................................""I##g-H @E4++l*M5!g߈ 3+n(l *0  +optimum;toomuch;toolittle,*n## #0  1:fullyacceptable;2:probablyacceptable;3:onlyacceptableunderlimitedconditions;4: -*o unacceptable(givereasons) ##  Comments ___________________________________________________________________ 0X-r   0-.s >6 &>&ë11<#LIVERANDSPLEEN#>&ë&>6 O#Ԉ   Nameofradiologist/radiographer:__________________________________  Patientnumber:_____________0  0}##Hospitalcode:______________}}#}# *d d dd dd dd dd dd dd dd ##, dd ,O// ,O// ,O// ,O// ,O// ,O// ,O// ,K// +  ' Z &' Imagequalitycriteria C6'Qp C Sequence1 >1"E" > Sequence2 D1"E " D Sequence3 D1"E " D Total E  examination @6(U " &  &@ !  B  !Yes '- h " 'No '- h" 'Yes '- h" 'No '- h" 'Yes '- h" 'No '- h" 'Yes 0- h" 0No >/%- h" &  &> Visualizationof  < w 1.0 F Entireliver ,"  LF$F$ ,  < w   < w   < w   < w   < w   < w   < w  5&< w &  &52.0 F Entirespleen ,"  [ F$F$ ,   [     [ !    [ "    [ #    [ $    [ %    [ &  5& [ ' &  &53.0 F Vesselsafterintravenouscontrast / j ( media ," ; )F$F$ ,  / j *   / j +   / j ,   / j -   / j .   / j /   / j 0  5&/ j 1 &  &5 Criticalreproduction  J 2 1.0 F Visuallysharpreproductionofthe  3 liverparenchymaandintrahepaticportalveins ," 5F$F$ ,  J 6   J 7   J 8   J 9   J :   J ;   J <  5&J = &  &52.0 F Visuallysharpreproductionofthe > liverveins ," f?F$F$ ,  @   A   B   C   D   E   F  5&G &  &53.0 F Visuallysharpreproductionofthe uH structuresoftheliverhilus ," FIF$F$ ,  uJ   uK   uL   uM   uN   uO   uP  5&uQ &  &54.0 F Visuallysharpreproductionofthe UR commonhepaticduct ," &aSF$F$ ,  UT   UU   UV   UW   UX   UY   UZ  5&U[ &  &55.0 F Reproductionoftheductus 5p\ choledochus(commonbileduct)inthepancreaticparenchyma ," ^F$F$ ,  5p_   5p`   5pa   5pb   5pc   5pd   5pe  5&5pf &  &56.0 F Reproductionofthegallbladder !g wall ," hF$F$ ,  !i   !j   !k   !l   !m   !n   !o  5&!p &  &57.0 F Visuallysharpreproductionofthe q splenicparenchyma ," rF$F$ ,  s   t   u   v   w   x   y  5&z &  &58.0 F Visuallysharpreproductionofthe { splenicartery ," w|F$F$ ,  }   ~                 5& &  &59.0 F Visuallysharpreproductionofthe   extrahepaticportalveinsystemincludingv.lienalisandv.ϐmesentericasup. ," "4 F$F$ ,                             5&  &  &510.0 F Visuallysharpreproductionofthe $C! aortaandinferiorvenacava ," $"F$F$ ,  $C!   $C!   $C!   $C!   $C!   $C!   $C!  5&$C! &  &511.0 F Visuallysharpreproductionofthe %## originofthecoeliactrunk ," &#F$F$ ,  %##   %##   %##   %##   %##   %##   %##  7&%## &  &712.0 F Visuallysharpreproductionofthe '% mesentericartery 3" (%F$F$ 3 )'% ) )'% ) )'% ) )'% ) )'% ) )'% ) +'% +," '% &   ,fӀItisimportantforeverycriteriontoevaluateifitisfulfilledornot. Ifacriterioncannotbeevaluatedit )& shouldbeclearlymarkedbyNAintheyesbox.  A*|'  Generalassessment:  +(  Acceptablenoise ...............................................................................................................""I#*g-H @E|,L+M5"g  {,)   Acceptablespatialresolution ..........................................................................................""I#*g-H @E;-Ls,M5#g  :-u*   Diagnosticacceptability ...................................................................................................""I##g-H @E-+2-M5$g߈ -4+ *0  +optimum;toomuch;toolittlet/,## #0  1:fullyacceptable;2:probablyacceptable;3:onlyacceptableunderlimitedconditions;4: 00k- unacceptable(givereasons) ## fj Comments ____________________________________________________________________  }2/ >#>6 &>&ëOSSEOUSPELVIS#>&ë&>6 q#Ԉ   Nameofradiologist/radiographer:__________________________________Patientnumber:_____________0  0}##Hospitalcode:______________ N}#}#  0   ## *d d dd O// O// O// O// O// O// O// K// ##, dd ,dd ,dd ,dd ,dd ,dd ,dd +   +  Imagequalitycriteria C6'% `| C Sequence1 >1"T " > Sequence2 D1"T " D Totalexamination 2("T " 2 ! Y   !Yes '  " 'No '  " 'Yes ' " 'No ' " 'Yes 0 " 0No 0! " 0 Visualizationof  " ] 1.0 F Wholepelvicring ,"  2 F$F$ ,  " ]   " ]   " ]   " ]   " ]  '" ] '2.0 F Hip(s)includingthetrochanter \  region ," -h F$F$ ,  \    \    \    \    \   '\ ! '3.0 F Sacroiliacjoints ,"  "F$F$ ,   #    $    %    &    '  ' ( '4.0 F Pubicsymphysis ," 2)F$F$ ,  2*   2+   2,   2-   2.  '2/ ' Criticalreproduction  \0 1.0 F Visuallysharpreproductionofthe 1l1 pelvicbones ," =2F$F$ ,  \3   \4   \5   \6   \7  '\8 '2.0 F Visuallysharpreproductionofthe g9 hipjoint(s) ," 8s:F$F$ ,  g;   g<   g=   g>   g?  'g@ '3.0 F Visuallysharpreproductionofthe A sacroiliacjoints ," nBF$F$ ,  C   D   E   F   G  'H '4.0 F Visuallysharpreproductionofthe I pubicsymphysis ," JF$F$ ,  K   L   M   N   O  )P )5.0 F Visuallysharpreproductionofthe  DQ pelvicmusculature 3" RF$F$ 3 ) DS ) ) DT ) ) DU ) ) DV ) + DW +& DX  &Itisimportantforeverycriteriontoevaluateifitisfulfilledornot. Ifacriterioncannotbeevaluatedit X shouldbeclearlymarkedbyNAintheyesbox.  Y  Generalassessment: V [   Acceptablenoise .............................................................................................................""I#*g-H @E,!Ld M5%g  +!f\   Acceptablespatialresolution ..........................................................................................""I#*g-H @E"L9!M5&g  ";]   Diagnosticacceptability ..................................................................................................""I##g-H @E"+"M5'g߈ " ^ *0  +optimum;toomuch;toolittle{$!`## #0  1:fullyacceptable;2:probablyacceptable;3:onlyacceptableunderlimitedconditions;4: L%"a unacceptable(givereasons) ##  Comments _________________________________________________________________  '$d C# >6 &>&ëChapter4   @'M GLOSSARY#>&ë&>6 m#  ( ThisglossarycontainsdescriptionsofcommonlyusedtechnicaltermsinCTasanaidtounderstandingtheGuidelines.Theboldfacedtypedwordsintheexplanatorytextindicatesthattheyoccurelsewhereintheglossary. artefact(structurednoise): TheappearanceintheCTimageofdetailsnotpresentinthescanned  S object.Themaincomponentsofstructurednoiseareduetoaformof partialvolumeeffect andto beam  (  hardening .Botheffectsusuallyresultinstreakingartefacts,whichareobservedinregionsofhigh    contrastwhenthereisasharpdiscontinuityinobjectdensity,suchasatairtissue,airboneandmetaltissueboundaries.Streakingwillalsoarisefrommechanicalmisalignmentwithinthescannerand,inclinicalpractice,frompatientmotionandtheuseofhighdensitycontrastmedia. attenuation: Reductionoftheradiation intensity ,uponpassagethroughmatter,resultingfromalltypes   ofinteraction. backprojection: MathematicalprocedureforthereconstructionoftheCTimage,basedonthesmearing * oftheindividual rays withinaview(projection)backalongthedirectioninwhichtheyweremeasured. b Spatialfiltration( convolution )ofthe rawdata isnecessarybeforebackprojectioninordertoreduce 7  artefacts .    beamhardening: Theprocessoffiltrationofapolychromaticbeambythepreferentialabsorptionof S lowerenergyphotonsintissue,withasubsequentincreaseineffectiveenergy.Theassociatedartefactsareofparticularsignificancein quantitativecomputedtomography(QCT) . \  calibrationofaCTscanner: Correctionproceduresusedtotakeaccountofvariationsinbeamintensity  or detector efficiencyinordertoachievehomogeneitywithinthefieldofviewandaccuracyof CT t number .Calibrationproceduresincludescanningairoranappropriate testphantom . I  collimation: Geometricallimitationoftheextentoftheradiationbeaminthezdirection. R  computedtomographydoseindex(CTDI): Integralalongalineparalleltotheaxisofrotation(z)of  ! the doseprofile (D(z)),measuredfreeinairorina CTdosimetryphantom forasingleslice,divided n!" bythe nominalslicethickness (T): C"# |T(D@zx : p% @ Hdd22@E2#`u .#( 4(Inpractice,itisconvenienttouseapencilionisationchamberwithanactivelengthof100mmsoastoprovideameasurementofCTDI100(mGytoair). \&!(  computedtomographynumber(CTnumber): Numberusedtorepresentthemeanx-rayattenuation 'a#* associatedwitheachelementalareaoftheCTimage.Numbersarenormallyexpressedintermsof Hounsfieldunits(HU) .Measuredvaluesof attenuation aretransformedinto CTnumbers usingthe )%, internationalHounsfieldscale:|8<T)D@zx  pX @ Hdd22@Ek+`g gu +( )whereistheeffective linearattenuationcoefficient forthexraybeam. .)2 TheCTnumberscaleisdefinedsothatwaterhasavalueof0HUandairavalueof-1000HU. contrast: Inrelationtotheradiationemergingfromanirradiatedobject,ifthephotonfluenceatsome 1h,5 referencepointis,0,andatanadjacentpointis,1,thecontrastcanbedefinedas(,1󀄀,0)/,0,or 1=-6 ,/,0.Contrastcanalsobeexpressedintermsofenergyfluenceorexposure. 2.7  contrastenhancement: Administrationofintraveneousorintraarterialcontrastincreasethevisibilityof  lowcontraststructuresduetoincreaseddensityofvesselsandorgans/tissuecontainingcontrastmedia.  r  contrastresolution: See lowcontrastresolution .   convolution: Themathematicalprocessbywhich rawdata undergospatialfiltrationpriorto back ) projection .    couchincrement: Distancebywhichpositionofpatientcouch(table)ischangedbetweenindividual A  slicesinserialscanningorthedistancethecouchpositionischangedduringone360orotationofthetube  y  duringhelicalscanning. CTdosimetryphantoms: Cylindersof polymethylmethacrylate ( PMMA )usedforstandard   measurementsofdoseinCT,havingadiameterof16cm(headphantom)or32cm(bodyphantom)andalengthofatleast14cm.Thephantomsareconstructedwithremovableinsertsparalleltotheaxistoallowthepositioningofadosemeteratthecentreand1cmfromtheoutersurface(periphery). CTnumber: Abbreviationfor computedtomographynumber .   CTDI: Abbreviationfor computedtomographydoseindex . H  CTDIair: Valueof CTDI determinedfreeinair. U  CTDIw: See weightedCTDI .   detector: Asingleelementofa detectorarray ,whichproducesanelectricalorlightsignalinresponse > tostimulationbyxrays. detectorarray: Theentireassemblyof detectors ,includingtheirinterspacematerial,arrangedalong  anarcorcircumference(dependingonscannertechnology)ofacirclecentredontheaxisofrotation. detectorefficiency: foreach detector containedina detectorarray ,theratiobetweenthenumberof , pulsesrecordedandthenumberofxrayphotonsincidentonthedetector.  d  detectorwidth: Ina detectorarray ,thedistancebetweenthetwooppositefacesofanysingle detector .  "  diagnosticreferencelevel: Advisorydoselevelssetbyprofessionalbodiestopromptlocalreviewsof M"$ practiceifconsistentlyexceeded.  "#% displaymatrix: Thearrayofrowsandcolumnsof pixels inthedisplayedimage,typicallybetween512 $+ ' x512and1024x1024.Itmaybeequaltoorlargerthanthesizeofthe reconstructionmatrix dueto %!(  interpolation procedures. r&!)  dosedescriptor: measurableparameter,suchas CTDIair , CTDIw or DLP ,fromwhichthe effectivedose  (#+ ortheorgandosedeliveredtoapatientinaCTexaminationcanbeestimated,ortheperformancesofdifferentCTscannerscanbecompared. dose-lengthproduct(DLP): Dosedescriptorusedasanindicatorofoverallexposureforacomplete d+&/ CTexaminationinordertoallowcomparisonofperformanceagainstareferencedosevaluesetforthepurposeofpromotingoptimisationofpatientprotection.|T*D@zx ) p% @ Hdd22@E.``Uu bh.( *whereirepresentseachscansequenceformingpartofanexamination,andCTDIwisthe weightedCTDI  N0+5 foreachoftheNslicesofthicknessT(cm)inthesequence. doseprofile: Representationofthedoseasafunctionofpositionalongalineperpendiculartothe 1W-7 tomographicplane. dosimetryphantom: See CTdosimetryphantom . ?  dynamicscanning: AmethodofobtainingCTscansinrapidsequencesoas,forexample,tofollowthe L passageofcontrastmaterialthroughvesselsortissue,ortodecreaseexaminationtime. effectivedose: Riskrelatedquantityusedasindicatorofoverallpatientdose.Itisdefinedbythe `  InternationalCommissiononRadiologicalProtection(ICRP)inPublication60(1991)asthesumoftheweightedabsorbeddosesinalltissuesandorgansofthebody:|,.T+D@zx ^ p% @ Hdd22@E5 `Uu H ( +&ë&&>&ëwhereDTistheabsorbeddose(mGy)intissueTduetoradiationR,wRistheweightingfactorfor J  radiationRandwTistheweightingfactorfortissueT.Forxrays,wRisequaltounity.#>&ë&&&ë3# ~   exposurefactors: Thesettingsofx-raytubevoltage(kV),tubecurrent(mA)and exposuretime (s).    exposuretime: Durationofemissionofradiationbythex-raytube(seconds)foranindividualslicein c axialscanningortotalacquisitiontimeforhelicalscanning. fieldofview(FOV): Themaximumdiameterofthereconstructedimage. =  filter: Mathematicalprocedureusedforthe convolution oftheattenuationprofilesandtheconsequent  reconstructionoftheCTimage. focalspot: Theeffectiveareaonthexraytubeanodefromwhichxraysareemitted.Thesizeofthe Z focal spothasinfluenceon spatialresolution . /  fullwidthathalfmaximum(FWHM): Intervalparalleltotheabscissabetweenthepointsonacurve r withthevalueofonehalfofthemaximumofthe%%%symmetrical%curve. gantry: Scannerstructurecontainingthex-raytube,collimatorsandthe detectorarray . L   gantryaperture: Diameterofthephysicalopeningofthe gantry throughwhichthepatientismoved  " fortheexamination. gantrytilt: Theanglebetweentheverticalplane,andtheplanecontainingthex-rayfanbeamandthe  #m%  detectorarray . #B&  helicalCT: Aparticulartechniqueofscanninginwhichthereiscontinuousrotationofthex-raytube % ( coupledwithcontinuouslineartranslationofthepatientthroughthe gantryaperture inordertoachieve Z&!) volumetricdataacquisition.Alsoknownas spiral or volumeCT . /'"*  highcontrastresolution: See spatialresolution . (8$,  HU(hounsfieldunits): See CTnumber . {*%.  imagingvolume: See volumeofinvestigation . !,'0  intensity: Thequantityofradiationenergyflowingthroughunitareainunittime. -*)2  interpolation: Amathematicalmethodofaveragingorsmoothingimagesthatarebeingdisplayedon m/*4 alargernumberof pixels thanthatforwhichtheywereoriginallyreconstructed. B0+5  interslicedistance: Thedistancebetweentheadjacentnominalmarginsofconsecutiveslicesinserial 1K-7 CTscanning.Itisdependentuponthecouchincrementbetweenslices. 2 .8 Ї linearity: InCT,theextenttowhichthe CTnumber ofagivenmaterialisexactlyproportionaltoits  density(inHUunit). linearattenuationcoefficient: Thefractionalreductioninintensityperunitthicknessofmaterialasan w xraybeampassesthroughanabsorber.Forapolychromaticbeam,theeffectivelinearattenuationcoefficientdependsontheeffectiveenergyofthebeam,andthedensityandatomicnumber(composition)ofthematerial. kernel: See filter . -   lowcontrastresolution: Ameasureoftheabilitytodiscriminatebetweenstructureswithslightly  6  differingattenuationproperties( CTnumber ).Itdependsonthestochastic noise andisusually   expressedastheminimumdetectablesizeofdetaildiscernableintheimage,forafixedpercentagedifferenceincontrastrelativetotheadjacentbackground. MonteCarloTechnique: Atechniqueforobtaininganapproximatesolutiontocertainmathematicaland S  physicalproblems,characteristicallyinvolvingthereplacementofaprobabilitydistributionbysamplevalues,usuallyperformedusingacomputer. multiplescanaveragedose(MSAD): TheMSADistheaveragedoseacrossthecentralslicefroma 8 seriesofNslices(eachofthicknessT)whenthereisaconstantincrementIbetweensuccessiveslices:|T,D@zx =p p% @ Hdd22@E`U)u 0( ,whereDN,I(z)isthemultiplescandoseprofilealongalineparalleltotheaxisofrotation(z). " Forasufficientnumberofslicessuchthatthefirstandthelastintheseriesdonotcontributeanysignificantdoseoverthewidthofthecentralslice:|M-=9zd p% @ Hdd22@E`u 9( L- noise: Noiseisthepointtopointvariationinimagedensitythatdoesnotcontainusefulinformation.The  o magnitudeofnoiseisindicatedbythepercentagestandarddeviationofthe CTnumbers withina region D  ofinterest intheimageofauniformsubstance(generallywater),relativetothedifferenceinCT ! numbersbetweenwaterandair. nominal(tomographic)slicethickness: The slicethickness selectedandindicatedatthecontrol -"$ paneloftheCTscanner. numberofmeasurements: Thetotalnumberofattenuationvaluesmeasuredduringtheacquisitionof $ ' the rawdata forasingleslice. y% (  packingfactor: InrelationtodosimetryforserialCT,thepackingfactor(p)isusedtospreadthe #'"* radiationdensityevenlyoverthe volumeofinvestigation whentheslicesarenotcontiguous.Fora '[#+ seriesofNslices,eachofthicknessT,andwitha couchincrement Isuchthatthetotalscanlengthis (0$, L:|Z3JFzx <> p% c@ Hdd22@Ew*` w}*( L.p=1forcontiguousslicesp>1foroverlappingslicesp<1forgapsbetweenslices. partialvolumeeffect: Theinaccuracyin CTnumber causedbythepresenceofastructurewithinonly *0+5 partofa slice .Sucheffectsbecomelessimportantasthe slicethickness isreduced. 0b,6  pitchfactor: InrelationtohelicalCT,ratioofthepatientcouchtravelinhorizontaldirectionperrotation 2.8 ofthexray tubedividedbytheproductofthenumberoftomographicsectionsproducedbyasingle  rotationofthexray tubeNtimesthe nominaltomographicslicethickness T: r r|23:/*&bt  `%@E`P dG /r ##     ##where:d0  isthepatientcouchtravelinhorizontaldirection a ## N0  isthenumberoftomographicsectionsproducedbyasinglerotationofthexray tube 2 ## T0  isthe nominaltomographicslicethickness .  ##  pixel: Individualsquarepictureelementofadigitalimagedisplay,beingthetwo-dimensional N  representationin HU ofa voxel withinthescannedslice.Pixelsizeisdeterminedbythediameterofthe #   fieldofview andthenumberofelementsinthe displaymatrix . [   polymethylmethacrylate(PMMA): Polymethylmethacrylate,apolymerplastic%%%commercially%%%ava%i%l%i%able  forexampleasPerspexorLucite.  s profileofCTnumbers: Representationofthe CTnumbers ofthe pixels alongaspecifieddirection | inaCTimage. quantitativecomputedtomography(QCT): TheuseofCTimagesandthecorresponding CT  numbers forquantitativecharacterizationoforgansortissues.QCTismostwidelyusedinrelationto e thedeterminationofbonemineralcontentandtreatmentplanninginradiotherapy. radiographicexposure: Productoftubecurrentandexposuretime. ?  rawdata: Thevaluesofxray detector responsefromallviewsand rays withinascan.Thesedataare  convolvedwiththe convolution filterandundergo backprojection toproduceaCTimage. W  ray: Thenarrowbeamofxraysfromthetube focalspot toasingle detector withina detectorarray , `  givingrisetoadetectorreading.Eachvieworprojectioniscomposedofnumerousrays. reconstructionalgorithm: Mathematical%procedure%%equation%usedtoconvert rawdata intoanimage.Different t!# algorithmsareusedtoemphasize,enhance,orimprovecertainaspectsofthedata. reconstructionmatrix: Thearrayofrowsandcolumnsof pixels inthereconstructedimage. #N&  regionofinterest(ROI): Localisedpartofanimagedefinedbytheoperatorwhichisofparticular % ( interestatagiventime. ringartefacts: Circular artefacts ,usuallyfoundinthirdgenerationscanners,causedbyfaultycalibration (k#+ oradefectindetectorfunction. scanning: Theprocessofrecordingxrayattenuationdatathroughasliceofanobject,fromwhich *%. imagesarereconstructed. scanprojectionradiograph(SPR): Genericnameforthedigitalimageobtainedbylinearlytranslating ,Y(1 thepatientthroughthe gantryaperture duringanxrayexposurewhilethexraytuberemainsstationary. -.)2 TheSPRhasasimilarappearancetoaplainradiographandisusedprimarilyforlocalizingtherequiredregionofscanning.Synonymoustermsincluderadiographicmodeandlocalizerimage,togetherwiththeproprietarynamesPilotscan,Scanogram,Scanoscope,Scoutview,SurviewandTopogram. scantime: Thetimeintervalbetweenthebeginningandtheendoftheacquisitionof attenuation data 1G-7 forasingleexposure.ForsomeCTscanners,thismaybelongerthanthe exposuretime duetothe 2.8 pulsingofxrayemission. scatteredradiation: Secondaryradiationbelongingtothesameradiationtypeastheoriginalradiation, ? producedintheinteractionoftheoriginalradiationwithamaterialmedium.Theinteractioncanbecharacterizedbyareductioninradiationenergyand/orbyachangeinthedirectionoftheradiation. sensitivityprofile: RelativeresponseofasystemforCTasafunctionofpositionalongaline   perpendiculartothetomographicplane. signaltonoiseratio: Theratioofthestrengthofthesignalforinformationcontentintheimagetothe  a  noiselevel(thestandarddeviationofthesignal). slice: Tomographicsection(definedbypositionandthickness)ofa testphantom orpatientunder u  investigationduringasingleCTexposureinserialscanning. slicethickness: Effectivethicknessofthetomographicsection,asmeasuredbythe fullwidthathalf O  maximum ofthe sensitivityprofile inthecentreofthescanfield. $   spatialresolution(orhighcontrastresolution): Theabilitytoresolvedifferentobjectsinthedisplayed g CTimage,whenthedifferencein attenuation betweentheobjectsandthebackgroundislarge < comparedto noise ;normallyadifferencecorrespondingtoatleastonehundred HU isconsidered t adequate. spiralCT: See helicalCT .   stability: Themaintainanceovertimeofconstancyof CTnumbers and uniformity . 2  standardexamination: Outlineofscanningprocedureforaparticularclinicalindicationthatisgenerally ; acceptedasbeingabletoprovideadequateclinicalinformationinmostofthepatientsexamined. testphantom: Objectofparticularshape,sizeandstructure(includingstandardisedrepresentations S ofhumanform),usedforthepurposesofcalibrationandevaluationofperformanceofCTscanners. uniformity: Consistencyofthe CTnumbers intheimageofahomogeneousmaterialacrossthescan -! field. volumeCT: See helicalCT . A"$  volumeofinvestigation(imagingvolume): Entirevolumeoftheregionunderinvestigationby #J& scanning.̀ voxel: Elementaryvolumeelement(expressedinunitsofmm3)withinthescannedsliceoftheobject, ^&!) withwhich CTnumbers areassociated. 3'"*  weightedCTDI(CTDIw): Anestimateoftheaveragedoseoverasinglesliceina CTdosimetry (<$, phantom thatisusedtoallowcomparisonofperformanceagainstareferencedosevaluesetforthe )%- purposeofpromotingoptimisationofpatientprotection.|N0>:xx S p% @ Hdd22E^,L< +Oy0 ##   ##whereCTDI100,corprefertomeasurementsofCTDI100atthecentre(c)orperiphery(p)oftheheadorbody i/*4 phantomforthesettingsusedinclinicalpractice. windowlevel: Thecentralvalueofthewindow(in HU )usedforthedisplayofthereconstructedimage 1?-7 ontheimagemonitoroftheCTscanner. 2.8 Ї windowsetting: Thesettingofthe windowlevel andthe windowwidth ,selectedforoptimizationof  thegreyscalelevelsinthedisplayedCTimage. windowwidth: Therangeof CTnumbers withinwhichtheentiregreyscaleisdisplayedontheimage w monitoroftheCTscanner.