BRAIN
Computerized3-DimensionalSegmentedHumanAnatomyI.GeorgeZubal,Char
SKULL
nalphantomvolume.Thecentralvoxel'sfilteredvaluewascalculatedasth
heavailableUserInterfaceServices(UISroutines)forprogramcontrolof
mforECT.'J.Nucl.Med.,27,1577-85,(1986).[12]CEFloyd,RJJaszczak,KL
-123.'Radiology,164,279-81,(1987).[13]JWBeck,RJJaszczak,REColema
nNuclearScience,29,506-511,(1982).[14]DAcchiappati,NCerullo,RGuz
EdColchesterandHawkes,8-22,(1991).LEGENDSTOFIGURESTABLE1:Listofo
eousphantom.NM/MIRDPamphletNo.5.,(SocietyofNuclearMedicinePublic
1-407,(1992).[17]RMohan,GMageras,BBaldwin,LBrewster,GKutcher,SLe
lstothedisplayedtransverseimages.AseriallinehighresolutionSummag
orrespondingtotheorganindexvalue.Theassignmentofintegerstotheorg
redondiskwitharesolutionof512by512pixels.Membersofthemedicalstaf
therapy.'Med.Phys.,18,43-53,(1991).[19]IGZubal,CHHarell.'Voxelba
SPINE
'AScatterCorrectionMethodforT1201Images:AMonteCarloInvestigation
exsliceimagescanbereadintoa512by512by119voxel3-dimensionalarray,
ages.'Phys.Med.Bio.,30,239-49,(1985).[7]DRDance,GJDay:'Thecomput
inSPECT.'J.Nucl.Med.,26,403-8,(1985).[11]CEFloyd,RJJaszczak,KLGr
nformaltreatments.'Med.Phys.,19,933-944,(1992).[18]DNigg,PRandol
5).[6]HKanamori,NNakamori,KInone:'EffectsofScatteredx-raysonCTim
onalmatrices(eachcollapsedmatrix=128x246)byaddingallintegervalue
Brain20-Pancreas3-Spinalchord21-Adrenals4-Skull22-Fat5-Spine23-B
TWehavemanuallysegmented129x-rayCTtransverseslicesofalivingmaleh
onte-CarloSimulationTechniques.'EuropeanJournalofNuclearMedicine
-Lymphnodes10-Lungs28-Thyroid11-Heart29-Trachea12-Liver30-Diaphr
.[20]IGZubal,CRHarrell,PDEsser.'MonteCarlodeterminationofemergin
SPINAL CHORD
ferenceonInformationProcessinginMedicalImaging,,Springer-Verlag,
yYaleUniversitySchoolofMedicine,NewHaven,CT06510correspondingaut
n,CFStarmer,LWNolte.'AnalysisofSPECTIncludingScatterandAttenuati
ion,BenjaminM.Tsui,Ph.D.,Dept.ofRadiology,Univ.ofNorthCarolina.2
gr.,7,316-20,(1983).[9]CEFloyd,RSJaszczak,CCHarris,REColeman:'En
,15,683-686,(1989).[15]MSaxner,ATrepp,AAhnesjo:'Apencilbeammodel
toindexnumbers:4,5,6,7,and8).FIGURE2:Anteriorandlateralprojectio
jorinternalstructuresofthebody.Eachvoxelofthevolumecontainsanind
esolutionof1millimeterinthex,yplane.Thez-axisresolutionis1centim
uter-basedmodelingandsimulationcalculations.keywords:segmentatio
mscaneitherbedefinedbymathematical(analytical)functions,ordigita
frominternalorexternalsourcesofradioactivityandservedtocalculate
ADRENALS
herethestructuresadjacenttotheheartandtheheartitselfhavebeenmore
rticularlyforanalyzingscatterandattenuationproblemsinnuclearmedi
5-18].Thesenewtherapytechniquescanbemoreeffectivelyinvestigatedw
onsiderablenumberofpatientsareimagedfromheadtomid-thighinourhosp
ltlesionsofapproximately0.5,1.0,and2.0centimeterdiameterwerearbi
-dimensionalvoxelphantomofthehuman.SincetheoriginalCTimagesarest
rdisplay.DISCUSSIONWehavecreatedadigitalvoxel-basedphantomwhichc
hnotonlycloselyresembleclinicaldata,butincludeadditionalinformat
gthisveryrealistichumanmodelisthatsuchsimulationscandecreasethen
dRealisticHumanPhantomsandMonteCarloMethods',Phys.Med.Bio.,31,44
eer,REColeman:'InverseMonteCarloasaUnifiedReconstructionAlgorith
sedMonteCarloCalculationsofNuclearMedicineImagesandAppliedVarian
LYMPH NODES
rganindexnumbersandrespectiveorgansorstructuressegmentedinthehum
am13-Gallbladder31-Spleen14-Leftandrightkidney32-Urine15-Bladder
Inordertogainaccesstothephantomdata,pleasesendyourrequesttoDr.Ge
canthenbeindexedtoactivitydistributionsorotherphysicalcharacteri
4pixelrasterdisplayequippedwith8bitplanes.Onebitplaneisusedforov
sforPhotonSourcesUniformlyDistributedinVariousOrgansofaHeterogen
romtheCTarchivereeltoreelmagnetictape,decompressingtheimagesfrom
8x246matrixwheretheisotropiccubicvoxelresolutionis4millimeterson
orpublicaccessthroughourImagingScienceResearchLaboratory.2RESULT
salongrowsofvoxels.Thefinalmatriceswerenormalizedanddisplayedusi
ndtherapy.Wehopetoextendtheapplicationofthisphantomtotherapyrela
zardi:'AssessmentoftheScatterFractionEvaluationMethodologyusingM
THYROID
gooni,RNath:'Tissueinhomogeneitycorrectionforbrachytherapysource
ibel,CBurman,C.Long,ZFuks:'Clinicallyrelevantoptimizationof3-Dco
ett,HBBarber,JMWoolfenden.'SurgicalProbeDesignforacoincidenceIma
gingSystemWithoutaCollimator'Proceedingofthe12thInternationalCon
fDiagnosticRadiology,BML332333CedarStreetNewHaven,CT06510ABSTRAC
ansareshowninTable1.DataAccessandDisplayThe2-dimensionalorganind
dertomakethedatamoremanageableandtohaveconsistentvoxeldimensions
eachside.Thisvolumearrayiscreatedbycombiningpixelsinthex,yplanea
mantorso.Suchananthropomorphic3-dimensionalphantomhasseveralinte
ingthesegmenteddata.WeareindebtedtoCorneliusN.deGraafUtrecht,The
ObjectModelforMonteCarloSimulatedEmissionandTransmissionTomograp
MonteCarloinvestigation.'Phys.Med.Bio.,29,1217-30,(1984).[10]CEF
TRACHEA
onUsingSophisticatedMonteCarloModelingMethods.'IEEETransactionso
lsegmentedhumanphantom.Theskinandfat(indexnumber=1)arehighlighte
ngs(10),bladderandureters(15),andbone(34).FIGURE3:Anteriorandlat
ImagingScienceResearchLaboratoriesDepartmentofDiagnosticRadiolog
umanandcreatedacomputerized3-dimensionalvolumearraymodelingallma
fallowingveryfastcalculationoftheintersectionofraylineswiththean
alyticalsurfaceswhichdelineatetheorgans.Aversionofthismathematic
allyversions1ofthephantomwhichareusedfordedicatedcardiacstudiesw
runderstandtheimageformationprocessindiagnosticradiology[4-7],pa
cdistributionscannotbeadequatelyevaluatedbysuchsimplegeometries.
Inthefieldofoncology,internalandexternalradiotherapysourceshaveb
dx-raytomography(CT)suppliesustherequiredhighresolution3-dimensi
DIAPHRAM
italtostudydiffusediseases.Weselectedanadultmalewhosedimensionsw
of78sliceimageswereacquiredfromnecktomid-thighwitha1centimetersl
icethicknessusinga48centimeterfieldofview(pixelsize=1mm).Duringa
theresidentcolordisplayscreen.Thecolordisplaymonitorisa1024by102
amwasdevelopedtoreadthetransverseslicesfromdisk,displaythemonthe
sandcontoursweredrawnwith1millimeterresolutiontodefinethisfully3
linthedefinedstructures.Thescannerusedisaclinicalinstrument;thea
transversesliceinwhichtheHounsfieldnumbersarereplacedbyintegersc
inwhichthex,yresolutionis1millimeterperpixelandtheslicethickness
ctedanteriorandlateralviewsofselectedstructuresfromthe128x128x24
ntegervalueandsettingother(unselected)structuresto0.The3-dimensi
onalvolumewasthencollapsedparalleltothemajoraxesontotwo2-dimensi
RIB CAGE
hepatient'sbody;withinthisoutline,variousstructuresareselectedfo
ionnotdeterminableinpatientstudies.Suchdatasetscanhelptobetterun
canproveespeciallyinterestingintestingandimprovingtomographicrec
g'invivo'simulations.Thetumordetectioncapabilitiesofanovelcoinci
ansmissiondiagnosticradiology.'Med.Phys.,16,:490-5,(1986).[5]HPC
ph,FWheeler:'Demonstrationofthree-dimensionaldeterministicradiat
genergyspectrafordiagnosticallyrealisticradiopharmaceuticaldistr
ibutions.'NuclearInstrumentsandMethodsinPhysicsResearch,A299,544
anphantom.FIGURE1:Anteriorandlateralprojectionsofthe3-dimensiona
dtoshowtheoutlineofthepatientaswellasinternalbones(corresponding
alphantomhasbeenupdatedtoincludefemaleorgans[2].Thereareaddition
themanufacturer'slosslessstorageformat,andstoringtheminexpandedm
SKELETAL MUSCLE
129to119slicesisduetotheoverlapofinformationintheneckregion.Inor
nwithmillimeterresolutionineachof129transversesliceimagesofthehu
derstandtheimageformationprocessforclinicallyrealisticmodels,and
esandattenuatingmedia.Suchsimplegeometriesareusefulinstudyingmor
ntainedinthetransverseslices.Aregionofinterestcoloringroutinewas
onstructionalgorithms[21].Newimagingdevicescanbeinvestigatedusin
Greer,REColeman:'BrainPhantom:highresolutionimagingwithSPECTandI
33-Feces(coloncontents)16-Esophagus34-Testes17-Stomach35-Prostat
secondimagingsession,51slicesofthesamepatientwereacquiredofthehe
oourimageprocessinglabbyreadingthereconstructedtransverseslicesf
SInordertoappreciatethedetailoftheanthropomorphicphantom,weproje
orphicphantomswasdevelopedforestimatingdosestovarioushumanorgans
LUNGS
linders,orrectangularvolumes.Forinternaldosimetrypurposes,suchhu
ecomemoresophisticatedintheirdesignandapplications.Thecalculatio
nsinvolvedinclinicaltherapyplanninghavebecomemoresophisticated[1
stics(densityorelementalcomposition).Wehaveconstructedananatomic
adandneckregionwith5millimeterslicethicknessandafieldofviewof24c
erlaygraphicswhiletheremaining7bitsareusedformapping128colorleve
raphicsbitpadprovidedhighresolutioncursorcontrol.Anin-houseprogr
edforeachtransversesliceandcontainsthex,ycoordinatesofeachofthec
is10millimetersinthebodyand5millimeterinthehead.Thereductionfrom
ndbyduplicatingslicesalongthez-direction.Inordertoremovesomeofth
ontours=1Megabyte,organindexmatrices20Megabytes,andareavailablef
restingapplicationsintheradiologicalsciences.Wehaveroutinelyused
HEART
CES[l]WSnyder,MRFord,GWarner:EstimatesofSpecificAbsorbedFraction
ergyandspatialdistributionofmultipleorderComptonscatterinSPECT.A
ceReductionTechniques.'ImageandVisionComputing,10,342-348,(1992)
eralprojectionshighlightingtheskinandfat(indexnumber=1),andmyoca
9-452,(1986).[3]H.Wang,RJJaszczak,REColeman:'SolidGeometry-Based
hehumananatomyserveanimportantroleinseveralaspectsofdiagnostican
theS-factorsforinternaldosecalculationsinnuclearmedicine[1].This
mathematicalphantommodelsinternalstructuresaseitherellipsoids,cy
nshavesometimesbeenlimitedtosimplepoint,rod,andslabshapesofsourc
illavailable,theoriginalHounsfieldnumbersarealsoknownforeachvoxe
ceandcalibrationcarriedoutforqualityassurance.Thesegmentedimagei
6volume.Thiswasdonebyreplacingselectedindexnumberswithapositivei
ESOPHAGUS
erenderedwiththeskin/fatvoxelsselectedinordertoshowtheoutlineoft
estudiesareconductedinlivingmodels.Oneoftheadvantagesofdevelopin
'TheCalculationofDosefromExternalPhotonExposuresusingReferencean
realisticallymodeled[3].Computermodelshavealsobeenappliedtobette
cscalculations.Thesoftwarephantomsmodeledintheseimagingsimulatio
nswhereeachorgan(structure)issegmentedanditsinternalvolumeisrefe
loselyresemblesatypicalmaleanatomy.Organoutlinesweremanuallydraw
magingequipmentimproves,itisessentialtoenhanceourcomputermodels.
ccalculations,wemustbeabletodelineatethesurfacesandinternalvolum
patient'sheightwas5foot10inchesandweightwas155pounds.Hewasschedu
anoma.Thepatienthadnoadvancedsignsofdiseaseorobviouslesionsnorad
nformationisstoredintwoindependentfiles.Avariablesizefileiscreat
STOMACH
ontoursdrawnonthatslice.Theslicenumberisretainedinthenameofthefi
fixedsizeorganindeximage.Theorganindeximageisa512by512bytematrix
filledwithintegervalueswhichdelineatetheinternalstructures(organ
alongallthreeaxes,weroutinelytransformtheoriginaldataintoa128x12
ngagrayscalecolortableandareshowninFigures1through3.AllFiguresar
dencecountingprobesystemhasbeeninvestigatingusingtheanthropomorp
loyd,RJJaszczak,KLGreer,REColeman:'DeconvolutionofComptonscatter
sinaheterogeneousphantomwithcylindricalsymmetry.'Med.Phys.,19,40
-547,(1990).[21]GSHademenos,MAKing,MLjungberg,IGZubal,CRHarrell.
.Theoriginalx-rayCTimageswerereconstructedina512x512matrixwithar
dcanserveasavoxel-basedanthropomorphicphantomsuitableformanycomp
dtherapyrelatedimageprocessing.Computerizedanthropomorphicphanto
LIVER
Theintricateprotuberancesandconvolutionsofhumaninternalstructure
entimeters(pixelsize=0.5mm).Thebodyandheadslicesweretransferredt
atrixformatondisk.OrganDelineationThedataaccessandprocessingprog
sorcontrol.Thexandyintegerpositionsofalloftheorganoutlinesaresto
le.Thesecontoursserveastheinputtothefillingroutine,whichcreatesa
irection,weapplied3-dimensionalmodalfiltering.Inourapplicationof
emode(mostoftenoccurring)valuefromtheselected125sub-volume.Theto
talstoragecapacityofthefilesare:originalCTimages=29Megabyte,x,yc
20].Sinceweareabletomodelaknownsourcedistributionandknownattenua
tedsimulations.ACKNOWLEDGEMENTSWorkperformedunderContractNo.DEFG
Netherlands,forhisimplementationofthevolumetricsmoothing.REFEREN
hicImagingSystems.'IEEETransactionsonMedicalImaging,11,361-372,(
GALLBLADDER
iontransporttheorydosedistributionanalysisforboronneutroncapture
phantom18-Smallintestine1-Skin/bodyfat19-Colon/Largeintestines2-
ct.25-31,1992,OrlandoFL,Volume2,pp.1213-1216.[22]JRSaffer,HHBarr
lesR.Harrell,EileenO.Smith,ZacharyRattner,GeneGindi,PaulB.Hoffer
hor:I.GeorgeZubal,Ph.D.YaleUniversitySchoolofMedicineDepartmento
dualgammarayhistoriesbecomesofparamountimportanceforimagingphysi
ithhigherresolution,computerizedrealistichumanmodels.Inordertoma
onalhumananatomynecessarytoconstructthevolumesegmentedphantom.Ac
larlyprimates.Dosecalculationsforinternalandexternalradiationsou
1992).[4]GBarnea,CEDick:'MonteCarlostudiesofx-rayscatteringsintr
Thisvolumearrayrepresentsahighresolutionmodelofthehumananatomyan
manmodelapproximationsservequitesufficientlyandhavetheadvantageo
KIDNEYS
Eswhichdefinethevariousstructuresofthebody.Thesesegmentedvolumes
vancedsymptomsduringthetimeofthescans.Afterinformingthepatientof
thepotentialapplicationofhisscansforbiomedicalresearchpurposes,h
eagreedtoreleasehisscandataforresearchpurposes.Thestandardclinic
alimagingprotocolwascarriedout.UsingtheGE9800QuickScanner,atotal
foutlined35separateinternalorgans(seeTable1)andknownstructuresco
ccuracyoftheHounsfieldnumbersisassuredthroughtheroutinemaintenan
eblockyappearancecreatedinthetorsobyduplicatingvoxelsalongthez-d
thevoxelbasedphantominMonteCarlosimulationstoyielddiagnostically
ecessityofconductingexperimentalstudiesusinganimalmodels-particu
rcesusingthisphantomcangivenewinsightsinthefieldofhealthphysicsa
ation.,NewYork,1978).[2]GWilliams,MZankl,WAbmayr,RVeit,GDrexler:
BLADDER
han,KDoi:'Physicalcharacteristicsofscatteredradiationindiagnosti
.'1992IEEENuclearandScienceSymposiumandMedicalImagingConferenceO
loodpool(allvessels)6-Ribcageandsternum24-Gasvolume(bowel7-Pelvi
s25-Fluidvolume(bowel)8-Longbones26-Bonemarrow9-Skeletalmuscle27
exnumberdesignatingitasbelongingtoagivenorganorinternalstructure
eterfromnecktomid-thighand0.5centimeterfromnecktocrownofthehead.
n,humanmodel,anthropomorphicphanton,x-rayCTINTRODUCTIONModelsoft
l(voxel-based)volumearrays.Oneoftheearliestcomputerizedanthropom
cine[8-14].Sincemuchhigherstatisticsarenecessarytomodelimagingsi
efundamentalissuesofscatterandattenuation;but,clinicallyrealisti
sareimportantinevaluatingimagingtechniques;andastheresolutionofi
ke3-dimensionalanatomicaldatasuitableforuseinanyoftheseradiologi
PANCREAS
allycorrecthumangeometryforuseinthesetypesofradiologiccalculatio
rencedbyanindexnumber.METHODSAnatomicDataTransmissioncomputerize
eresimilarthedosimetrystandardmathematicalphantom[1].Ourselected
ramswerecreatedonaVAX3500workstationrunningVMSversion5.0-2usingt
colorworkstationmonitor,andpermitoutliningoforgansunderbitpadcur
usedtofilltheinsideofeachorganoutlinewithauniqueindexvalue.Defau
trarilydefinedatthreelocationsintheliver.Atotalofmorethanonethou
s)ofthebody.Theorganindeximageistherefore,ineffect,theoriginalCT
02-88ER60724withtheU.S.DepartmentofEnergy.WearethankfultoMindyLe
cradiology:MonteCarlosimulationstudies.'Med.Phys.,12,152-65,(198
ationofscatterinmammographybyMonteCarlomethods.'Phys.Med.Bio.,29
,237-47,(1984).[8]JLogan,HJBernstein:'AMonteCarlosimulationofCom
SPLEEN
ptonscatteringinpositronemissiontomography.'J.Comput.Assist.Tomo
mulations(comparedtodosimetrysimulations),speedofcomputingindivi
realisticimagesofinternaldistributionsofradiopharmaceuticals[19,
tordistribution,theMonteCarlosimulationsgiveusprojectiondatawhic
rdiumoftheheart(11).Table1OrganNumbersfortheTorso0-Voidoutsideof
e36-LiverlesionFigure1Figure2Figure3Footnotes1Personalcommunicat
ledforhead,thorax,abdomen,andpelvicscansfordiagnosisofdiffusemel
e,whosecomputerprogrammingskillswereessentialforoutliningandstor
nshighlightingtheskinandfat(indexnumber=1)aswellasthebrain(2),lu
modalfilteringasub-volumeof5by5by5voxelswasselectedoutoftheorigi
hicphantomdescribedhere[22].Earlydesignchangescanberealizedbefor
forphotondosecalculation.'Med.Phys.,19,p263-273,(1992).[16]ASMei
INTESTINES
orgeZubal.e-mail:Zubal@BioMed.Med.Yale.Edu...................PbN