（核医学课件）08甲状腺显像

ThyroidImaging DuanDong DepartmentofNuclearMedicineTheFirstAffiliatedHospitalofChongqingMedicalUniversity ClassificationandprincipleofthyroidimagingImagingagentsandtheirfeatures imagingmethodsNormalandabnormalimagingClinicalapplicationofthyroidimaging Contents Thefirstpart Classificationandprincipleofthyroidimaging TheClassificationofthyroidimaging Thyroidstaticimaging Thyroiddynamicimaging Principleofstaticthyroidimaging Administratinganagent 131I NaIor99mTcO4 whichcanbetrappedandaccumulatedselectivelybythyroidwhenenteringthebodyofpatients Certaintimeafteradministration Detectingther rayemittedbyradionuclidesinthethyroidwithcertainnucleardevice thenwecanobtaintheimageofthyroid site morphology size function Trappedbythyroid 131Ior99mTc r r r r Principleofdynamicthyroidimaging ivadministrationimgingagent 99mTcO4 flowwithbloodinveintohearttoarterysystemtothyroidalarterytothyroidDetectingther rayemittedbyradionuclidesandacquiretheimagescontinuallywithcertainnucleardevice Bytheseimageswecanobtaintheinformationofthyroid sblood flow speedandamount reflectingthefunctionofthyroid Thesecondpart Imagingagentsandtheirfutrers imagingmethods Imagingagentsandtheircharacteristics Iodine 131 131I Longphysicalhalf life 8 04d raysoccupy90 r raysonlyoccupy10 ofitsemissionTheenergyofprincipalr rayishigh 364Kev Arelativelyhighirradiationdosetothethyroidandwhole bodyEasilyobtainedandwithlowercostMainlybeusedfordetectingectopicthyroidtissueandmetastasisofthyroidcarcinomaThescanningmustbeperformedatleast24hafteroral131I Iodine 123 123I Itdecaysbyelectroncapturewithar photon energyis159Kev whichisverysuitableforimaging Physicalhalf lifeis13 27hHighcost producedbycyclotron Technetium 99m 99mTc Itdecaysbypurer rays energyis140Kev ShortPhysicalhalf life 6 02h EasilyobtainedandlowercostLowerirradiationdosetothethyroidandwhole bodyDisadvantageisitsnon specificity Methodsofimaging 1 Askingthediseasehistoryandpalpatingthethyroidofpatientsbeforetheexamination 2 Administrationofradiopharmaceuticals orimagingagents Table1Comparisionoftwoagents Staticimagingisbeginatcertaintime 30minor24h afteradministrationofimagingagents Fromtheseimages mainlyobtainingtheinformationsuchassite morphology sizeandfunctionofthyroid fig1 Fig1 Staticimagingofthyroid 3 Theacquisitionofimages SometimestomographicimagingorSPET CTimagesfusionisnecessarytoidentifysuspiciousfocusshowninplanarimaging 3 Theacquisitionofimages Dynamicthyroidimagingisbeginatthesametimewithintravenousadministration andacquiretheimagescontinually 2sperframe sumto20frames Fig 2 Fig2 Dynamicimagingofthyroid Supine neckextended anddetectinginanterior sometimesinleftorrightanteriorobliqueposture 4 Thepostureofimaging Fig3 postureofimaging Thethirdpart Normalandabnormalimagingpresent 1 Thenormalsiteofthyroidimageisinthemiddleofneck 1 Normalstaticimaging Fig5 2 It sshapelikeabutterfly havetwolobes whichusuallywerejoinedbytheisthmus andsometimesthepyramidallobecanbefoundinsomenormalpeople 3 Thenormalsize themeanheightis4 5cm widthis2 5cmoftwolobes 4 Thedistributionofimagingagentsshouldbeuniform 5 Ifimagingagentis99mTc theimagesofsalivaryglandandmucosaofmouth nasopharynx usuallycanbeseen 2 AbnormalStaticimages 1 abnormalofmorphology irregularorincomplete couldbeseeninmultinodulargoiterandcongenitalabsenceofonelobe Fig6 2 Theabnormalofsize usuallyenlarge beseeninhyperthyroidandmultinodulargoiter Fig7 3 Theabnormalofsite seeninectopicthyroid theimageofthyroidmayoccurinthebaseoftongue orsublingual orsubsternal eveninthepelvis Fig8 4 TheabnormalofdistributionTheradioactivitywasdiffuseincreasedinthewholethyroid seeninhyperthyroid Fig9 Theradioactivitywasdiffusedecreasedinthewholethyroid seeninhypothyroidorthyroiditis Fig10 Theradioactivitywasfocallyincreasedordecreasedinthethyroid seeninthyroidnodules wedefineitbytherelativeamountofradioactivitypresentasfollows Hotnodule higherthannormaltissue Fig11 coolorcoldnodule lowerthannormaltissueorno Fig12 warmnodule equaltonormaltissue Fig13 3 Normaldynamicimaging Fig4 8 12safterintravenousadministration theimagesofbilateralcarotidarterycanbeseen then2 6safterthistheimageofthyroidisshown andlater whichgraduallystrengthenandcanbeseenclearly Themeanpasstimefromcarotidarterytothyroidis2 5 7 5s Thedistributionofagentsinthyroidisuniform Fig4 Normaldynamicimagingofthyroid Theimageofthyroidisshownearlyandtheradioactivityisincreased whichindicatethattheblood floworthefunctionofthyroidisincreased usuallyseeninGD Fig14 Ifthepasstimefromcarotidarterytothyroidisprolongedandtheradioactivityisdecreased whichindicatetheblood floworthefunctionofthyroidisdecreased usuallyseeninhypothyroid Figi5 Toanoduleinthyroid ifitsradioactivityishigheroritsimageisshownearlierthanthenormalpart itindicatesthatthenodulemaybeautonomoushyperfunctionadenomaormalignantdisease Andonconversely maybebenigndisease Fig16 17 18 4 Abnormaldynamicimaging Thefouthpart Clinicalapplicationofthyrodimaging Clinicalapplication 1 Evaluationthefunctionofthyroid Fig19 20 Table2 Comparisionoftwodiseasedynamicstaticpasstimeisshortendiffuseincreasedhyperthyroid theblood flowisofactivityincreased hypothyroidpasstimeisprolongeddiffusedecreased theblood flowisofactivitydecreased 2 Diagnosingofectopicthyroid with131I Ectopicthyroidwhichisacongenitalabnormality maybefoundinthebaseoftongue sublingual substernal eveninthepelvis Ifthereisnoimageofthyroidinthenormalsite andatissuewhichcanuptake131Iwasfoundinothersite wecandiagnose Fig21 Fig21 Ectopicthyroid A Sublingualthyroid B Substernalthyroidgoiter A B 3 Identificationofthefunctionandpropertyofthethyroidnodule hotnodulewarmnodulecoolandcoldnodule Appearance theradioactivitywasfocallyincreasedcomparingwiththesurroundingthyroidtissue Clinicalsignificance almostallhotnodulesaretowardbenigndisease suchasautonomoushyperfunctioningadenomal focalthincken onelobecompensatory theincidenceofmalignantislessthan1 1 Hotnodule 2 WarmnoduleAppearance Therelativeamountofradioactivityinnoduleisequaltosurroundingthyroidtissue Clinicalsignificance maybe thyroidtumorswithfunctionsnormal Nodulargoiter ThyroiditisTheincidenceofmalignantisabout4 5 3 CoolorcoldnoduleAppearance Therelativeamountofradioactivityinnoduleislessornocomparedwiththenormalthyroidtissue Clinicalsignificance Theincidenceofmalignantisabout10 20 especiallysolitarynodule Otherpossibilityarebenigndiseases cyst hemorrhage etc Tab2 Identificationofthefunctionandpropertyofthethyroidnodule 4 Identifyingthepropertyofthyroidcoolorcoldnodule 1 Applyingtumor locatingimagingagents suchas67Ga 201Tl 99mTc MIBI 99mTc DMSA 2 Staticimagingcombiningwithdynamicimaging Case1 A imagingwith99mTc B imagingwith99mTc MIBI A B C D Case2 C imagingwith201Tl D imagingwith99mTc 5 IdentifyingthecervicalmassIfthemasscanuptakeagentsorthemorphologyofthyroidisincomplete orthedistributionofagentsinthyroidisnotuniform itindicatesthemassmaycomefromorbecorrelatedwiththyroid A Onconversely themassisnotcorrelatedwiththyroid B A B 6 EvaluationtheweightofthyroidItisnecessarytoevaluatetheweightofthyroidinpatientspreparingtoaccept131Itherapy Usuallycalculatetheweightofthethyroidasthefollowformula W S H KW g weightofthyroid