Joint Dual Photopeak Image Reconstruction in Lu-177 SPECT · 2019-12-17 · Energy Spectrum of...
Transcript of Joint Dual Photopeak Image Reconstruction in Lu-177 SPECT · 2019-12-17 · Energy Spectrum of...
JointDualPhotopeak ImageReconstructioninLu-177SPECT
2018EANM
HongkiLim,JeffreyFessler,YuniDewarajaUniversityofMichigan,AnnArbor
EANMDisclosure Statement
1) I or one of my co-authors hold a position as an employee, consultant, assessor or advisor for a pharmaceutical, deviceor biotechnology company. If yes, please specify name/position/company:Nothing to disclose
2) I or one of my co-authors receive support from a pharmaceutical, device or biotechnology company. If yes, pleasespecify name/position/company/which project and whether support is in kind or monetary:Yuni Dewaraja is paid consultants forMIM Software Inc., Cleveland, USA
3) I or one of my co-authors hold property rights/patents for (radio)pharmaceuticals, medical devices or medicalconsulting firms. If yes, please specify name/position/company:Nothing to disclose
4)Ioroneofmyco-authorshavewrittenarticlesfor(radio)pharmaceutical,medicaldevice,biotechnologyorconsultingcompaniesduringthelast5years.Ifyes,pleasespecifyname/position/company/article/journalandco-authors:Nothing to disclose
2/21JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
EnergySpectrumof177Lu
3/21JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
1. Ljungberg et al. "MIRD pamphlet no. 26" J Nucl Med 57.1 (2016): 151-62.
q Generalrecommendation1
• MEcollimator+208keV
q Anotheroption
• MEcollimator+113&208keV
0 300Re
lativeCo
unts
Energy(keV)
Simulationwithpointsourceinwaterphantom&MEcollimator
Totalevents PrimaryEvents Total- Primary
EnergySpectrumofLu-177
3/21
q Generalrecommendation
• MEcollimator+208keVàClinicallyadoptedoption
q Anotheroption
• MEcollimator+113&208keV
0 300Re
lativeCo
unts
Energy(keV)
Simulationwithpointsourceinwaterphantom&MEcollimator
Totalevents PrimaryEvents Total- Primary
208
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
EnergySpectrumofLu-177
3/21
q Generalrecommendation
• MEcollimator+208keV
q Anotheroption
• MEcollimator+113&208keVàGoodtousewhen#ofcountsis
insufficient(imagingatlatertimepointorpretherapydiagnosticimaging)
0 300Re
lativeCo
unts
Energy(keV)
Simulationwithpointsourceinwaterphantom&MEcollimator
Totalevents PrimaryEvents Total- Primary
113 208
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
EnergySpectrumofLu-177
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q Comparedto208-keV,113-keV has
! ~60%ofYield! ~70%PrimaryCounts(cps/MBq)forMEcollimator
0 300Re
lativeCo
unts
Energy(keV)
Simulationwithpointsourceinwaterphantom&MEcollimator
Totalevents PrimaryEvents Total- Primary
113 208
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Optionsforusingbothphotopeaks- 113&208keV
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q Twooptions1) Reconstructtwoimagesseparately andmakesum
𝑦#~Poisson 𝐴#𝑥# + 𝑠# ,𝑥/# = argmin𝑥#𝑓(𝑥#; 𝑦#, 𝑠#)𝑦8~Poisson 𝐴8𝑥8 + 𝑠8 ,𝑥/8 = argmin𝑥8𝑓(𝑥8; 𝑦8, 𝑠8)𝑥/ = 𝑥/#+𝑥/8
2)Reconstructoneimagejointly
𝑦 =𝑦#𝑦8 ~Poisson( 𝐴#𝐴8
𝑥 +𝑠#𝑠8 )
𝑥/ = argmin𝑥𝑓(𝑥; 𝑦, 𝑠)
• 𝒚#(𝒚8) ismainenergywindowand𝒔#(𝒔8) isscatterenergywindowacquisitionaround208(113)-keV• 𝑓(𝑥)denotesnegativePoisson likelihood function• Forscatterestimation,weusedtriple-energy-window(TEW)technique
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Optionsforusingbothphotopeaks- 113&208keV
5/21
àMorealignedwithactualPoissonnatureofmulti-windowacquisition
• 𝒚#(𝒚8) ismainenergywindowand𝒔#(𝒔8) isscatterenergywindowacquisitionaround208(113)-keV• 𝑓(𝑥)denotesnegativePoisson likelihood function• Forscatterestimation,weusedtriple-energy-window(TEW)technique
q Twooptions1) Reconstructtwoimagesseparately andmakesum
𝑦#~Poisson 𝐴#𝑥# + 𝑠# ,𝑥/# = argmin𝑥#𝑓(𝑥#; 𝑦#, 𝑠#)𝑦8~Poisson 𝐴8𝑥8 + 𝑠8 ,𝑥/8 = argmin𝑥8𝑓(𝑥8; 𝑦8, 𝑠8)𝑥/ = 𝑥/#+𝑥/8
2)Reconstructoneimagejointly
𝑦 =𝑦#𝑦8 ~Poisson( 𝐴#𝐴8
𝑥 +𝑠#𝑠8 )
𝑥/ = argmin𝑥𝑓(𝑥; 𝑦, 𝑠)
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Whatfactorsneedtobeconsideredforjointreconstruction?
6/21
q SystemModel𝑦#𝑦8 ~Poisson(
𝐴#𝐴8
𝑥 +𝑠#𝑠8 ),
where𝑎EFG = 𝛼G𝑝EFG𝑔EFG
𝑎EFG: elementofsystemmodel(𝐴G) at𝑖-th rowand𝑗-th column in𝑘-th energywindow
𝛼G:Relativecameradetection efficiency × branchingratio𝑝EFG :depth-dependentandenergy-dependenteffectofattenuation𝑔EFG:depth-dependentandenergy-dependent3D-collimator detectorresponse
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Experimentalsetting
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q 2measurements+1simulation+1patientscan
I. Spherephantommeasurement(4scans)
II. Liver-torsophantommeasurement(4scanswithhigh/low-counts)
III. XCATphantomsimulation (10realizationswithhigh/low-counts)
IV. Patientscan
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Physicalphantommeasurement1
8/21
q Spherephantommeasurement(4scanstoassessnoise)- Sphere-to-backgroundratiowas6:1 ,30minutesacquisition- Mainwindowwidth:20%,scatterwindowwidth:10%
208-keVmainwindow 208-keVscatterwindow
113-keVmainwindow 113-keVscatterwindow
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Physicalphantommeasurement2
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q Liver-torsophantommeasurement- 4scanstoassessnoise:
4scanof35 min(mimickingDay3post177Lu-DOTATATE)4scansof3 min(mimickingDay3pre-therapydiagnosticimaging)
- Lesion-to-liverratiowas4:1
35 minutesscan
208-keVmainwindow
113-keVmainwindow
208-keVmainwindow
113-keVmainwindow
3 minutesscanJointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
XCATsimulation
10/21
q XCATcoupledwithSIMIND2 simulation(10realizationstoassessnoise)- Realisticactivitydistributionfor177Lu-DOTATATE
2. Ljungberg M. Monte Carlo Calculation in Nuclear Medicine: Application in Diagnostic Imaging, 2nd edn, 2012.
OrganRelativeactivity
concentration
Lesioninliver 1.00
Spleen 0.59
Kidney 0.48
Liver 0.16
Gallbladder 0.02
Renalpelvis 0.02
Post-therapyDay1count-level Pre-therapyDay1count-level
208-keVmain 208-keVscatter
113-keVmain 113-keVscatter
208-keVmain 208-keVscatter
113-keVmain 113-keVscatter
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
177Lu-DOTATATEPatientscan
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q Day5 acquisition- 1clinicalscanwith208-keV (Scannedfor25minutes)- 3researchscanswithboth photopeaks (Scannedfor2 minutestomimicpre-therapy)
25minutesscanatDay5
2minutesscanatDay5
208-keVmainwindow 208-keVscatterwindow
113-keVmainwindow 113-keVscatterwindow
208-keVmainwindow 208-keVscatterwindow
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
ReconstructionandEvaluationmethods
12/21
I. Activity-recovery
II. Contrast-recovery
III. Image-ensemble-noise(variabilityacrossmultipleacquisitions)
q Reconstructiondetails(forbothsingleandjoint)• AppliedGaussiansmoothingtoTEWscatterestimate• EMalgorithm+50iteration(1subset)
q Evaluationmetrics
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Calibrationfactorforabsolutequantification
13/21
1. NISTrecommendation3 (0.9%uncertainty)• 3mL177Luina10mLSchottvial:CRC-15Rdialsetting449x10
2. TransferringCalibrationtoanewgeometry(10mLsyringe)• Activity insyringe=activityinvial- residual
3. Withthesyringe inthedosecalibratoradjustsetting• Settingtogetcorrectreadingfor3mLinsyringe:480x10
Syringe tapedtoSourceholder
q Imagingforcalibrationfactor• planar with20%mainwindow&10%TEWSC
q 208keV(head1):12.9cps/MBq(head2):13.4cps/MBq
à (within1%ofmanuf.specifiedvalue for5/8”xtal)q 113keV(head1): 9.2cps/Mbq (70%ofabove)
(head2):9.3cps/MBq
‘NISTgeometry’fordosecalibrator
Transfertosyringeforfillingphantomandcamerasensitivity
3. Bergeron DE, Cessna JT. Nucl Med Commun. 2018 Jun;39(6):500-504
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Result:Spherephantommeasurement
14/21
Single208-keV Single113-keV Joint
Single208-keV Single113-keV Joint
0 200 400 600x-axis
0
5
10
Activ
ity (B
q/m
l)
104
TRUESIR 208SIR 113JIR
Profileacrosscoldspot
Profile
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Result:Spherephantommeasurement
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0
2
4
6
8
10
12
14
0 50 100 150
ContrastRecoverytoNoiseRatio
SphereSize(ml)
SinglePhotopeakRecon@208-keV
SinglePhotopeakRecon@113-keV
JointPhotopeakRecon
0
20
40
60
80
100
0 20 40 60 80 100 120
ContrastRecovery
SphereSize(ml)
SinglePhotopeakRecon@208-keV
SinglePhotopeakRecon@113-keV
JointPhotopeakRecon
0
20
40
60
80
100
120
0 20 40 60 80 100 120
ActivityRecovery
SphereSize(ml)
SinglePhotopeakRecon@208-keV
SinglePhotopeakRecon@113-keV
JointPhotopeakRecon
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Result:Liver-torsophantommeasurement(axialview)
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Single208-keV Single113-keV Joint
Single208-keV Single113-keV Joint
HighCountsà
LowCountsà
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Result:Liver-torsophantommeasurement
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Noise ContrastRecovery CRNR29mlovoid 16mlsphere 29mlovoid 16mlsphere
208-keV 11.4 75.3 70.4 6.6 6.2113-keV 16.4 72.4 66.6 4.4 4.1Joint 9.5 74.4 69.1 7.8 7.2
Noise ContrastRecovery CRNR29mlovoid 16mlsphere 29mlovoid 16mlsphere
208-keV 36.4 65.2 63.7 1.8 1.8113-keV 48.5 58.7 51.8 1.2 1.1Joint 29.3 62.1 58.1 2.1 2.0
35 minutesscan
3 minutesscan
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Result:XCATphantomsimulation
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Noise ContrastRecovery CRNR29mlovoid 16mlsphere 29mlovoid 16mlsphere
208keV 10.1 76.3 92.9 7.5 9.2113keV 12.9 73.3 90.4 5.7 7.0Joint 8.0 75.0 91.8 9.4 11.5
Noise ContrastRecovery CRNR29mlovoid 16mlsphere 29mlovoid 16mlsphere
208keV 65.2 75.8 91.7 1.2 1.4113keV 85.5 68.7 91.5 0.8 1.1Joint 52.2 72.8 91.6 1.4 1.8
Post-therapyDay1count-level
Pre-therapycount-level
208-keV 113-keV Joint
208-keV 113-keV Joint
Liver
Kidneys
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Result:Patientscan
19/21
25minutes scan,208-keVSPECT/CT
Single208-keVShortScan
Single113-keVShortScan
JointShortScan
Recon(unit:Bq/ml) RMSD* Noise*208-keV 1.47e4 332.9113-keV 1.90e4 278.6Joint 1.45e4 260.4*RMSDrelativetolongscan*Imageensemblenoisebetween3repeatshortscans
Spleen
Liver
Tumor
Single208-keVLongScan
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Summary
20/21
q Jointreconstructionw/E-dependentsystemmodel&TEWSCiseasytoimplementq Comparedtosinglephotopeak(208-keV)reconstruction,jointreconstruction- Gavecomparableactivity/contrastrecovery- Improvednoisesignificantlyevenforhigh-countsdataà Importantforvoxel-leveldosimetry- Improvedcontrastrecoverytonoiseratio: 16.7-27.3%
q Jointreconstructioncanbebeneficialforreducingscantime
ExperimentsSpherephantom Liverphantom XCAT
Count-level High Low High Low
Improvement(%) 20.9-23.2 16.7-17.5 17.3-21.5 25.4-25.8 24.7-27.3
Improvement(%)ofContrastRecoverytoNoiseRatiooversingle208-keV
JointdualphotopeakimagereconstructioninLu-177SPECT
HongkiLim(Universityof Michigan)
Thank You
Weacknowledge• UofMichiganRadiologySeedGrant• JeremyNiedbala,Gerrid Rosebushforallhelpinmeasurementsandcalibration
Contact:[email protected]