Omnidirectional 3D Gamma-ray Imaging with a Free-moving ...
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Omnidirectional3DGamma-rayImagingwithaFree-movingSphericalActiveCodedAperture
D.Hellfeld Omnidirectional3DSphericalCodedAperture 10.24.171
D.Hellfeld1,P.Barton2,A.Haefner2,D.Gunter2,L.Mihailescu2,andK.Vetter1,2
1UniversityofCalifornia,BerkeleyDepartmentofNuclearEngineering
2LawrenceBerkeleyNationalLaboratoryAppliedNuclearPhysics– NuclearScienceDivision
IEEENuclearScienceSymposiumandMedicalImagingConferenceAtlanta,Georgia
21-28October2017
Outline
• Introduction• Activesphericalcodedaperture– PRISM• 2Dimaging
• 3Dimaging
• Experimentalresults
• GPUacceleration• Conclusionsandfuturework
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Introduction
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MotivationDetect,locate,andidentifyweakradioactivesourcesincomplexenvironmentsandefficientlymapradiationfields.Applicationsinastrophysics,nuclearsecurityandsafeguards,nuclearcontaminationremediation,medicalimaging
NeedPortable(hand-held)2D/3Dimagingsystemwithhighefficiency,widefield-of-view,highenergyresolution,andbroadenergysensitivity
ApproachMultipleroom-temperatureoperatedcm3CdZnTe (CZT)coplanargird(CPG)detectorsarrangedtofacilitatecodedaperture(40– 400keV)andComptonimaging(300keV– 2MeV)modalities
CrabnebulawithNCT
Bandstra etal,TheAstrophysicalJournal,738(1),2011
137CscontaminationinFukushimahome
CourtesyofA.Haefner,LBNL,2016
ActivePlanarArrangement- HEMI
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HighEfficiencyMulti-modalImager(HEMI)• 96CZTCPGdetectors(1cm3,<2%FWHMat662keV)• 32inactivecodedfrontplane,64infullypopulatedbackplane• Codedaperture(50keVto350keV)andComptonimaging
(300keVto3MeV)• 10° resolutionat662keV(Compton)and186keV(CA)• <10lbs
137Cs8μCi
22Na10μCi
88Y20μCi
50cm
88Y22Na
137Cs
Comptonmode
-80° 80°
0°180°
Φ
θ
1 2 3
2
3
1
Codedaperturemode
-30°
30°
-30° -30° -30°30° 30° 30°
133Ba(81keV)
θ
Φ Φ Φ
M.Galloway,Ph.D.Thesis,UCBerkeley,2014
ActiveSphericalCodedAperture
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• PlanararrangementofHEMIsuffersfromalimitedandanisotropicfield-of-viewinthecodedaperturemodality
• Mask-detectorgeometryhaspartialcodingexcepton-axis
FC-FOV
15cm
7.5cm
• Arrangedetectorsintoasphericalactivecodedconfigurationtofacilitateomnidirectionalimaging
HEMI
4𝝅 CodedApertureFieldofView
Spherical
15cm
PRISM
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PortableRadiationImagingSpectroscopyandMapping(PRISM)• Hand-held,free-moving,CZTCPG-based,spherical
activecodedaperture• 1cm3 crystalsinmodularLexancasings• 6modular(identical)faces• 192totalavailabledetectorlocations• <2%FWHMat662keV• <10° resolutionat186(CAI)and662keV(Compton)• <10lbs,<10Wpower
èHardwarespecifictalkintheNSS/RTSDjointsession(next)inCentennialIIbyPaulBarton
2DFar-fieldCodedApertureImagingin4𝜋
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• 93/192detectorspopulatedo Pseudo-random(notoptimized†)o 74/93detectorsfunctional
• 10-mindwell,20𝜇Ci241Am(60keV)
†Foroptimization,see D.Hellfeldetal,IEEETNS,2017.DOI: 10.1109/TNS.2017.2755982
𝟐𝟎∘1
3
4
𝟓𝟎∘
2
1 2
3 4
MLEMreconstruction(50iterations)
2Dto3DImaging
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• 2Dimagingprovidesaccuratereconstructionsofthesourcedirectioninspace,thoughpositionalongdirectionisambiguous
Static2Dimagewith3Doverlay Multi-location3Dreconstruction
Barnowski,Ph.D.Thesis,UCBerkeley,2016
• Datafromdifferentperspectivescanbecombinedtocreate3Dimages
Free-movingTrackingandSceneDataFusion
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• Auxiliarycontextualsensors(visualcamera,LiDAR,IMU)usedwithSimultaneouslyLocalizationandMapping(SLAM)algorithmstotrackthepositionandorientationofthesystemasitmovesfreelythroughanenvironment
• 3Dscenedatafusedwith3Dradiationimagetoprovidevisualcontext,increaseimageaccuracy,reducenoise,and decreasereconstructioncomputationaltime
Systempath
Topdownview
Free-moving3DComptonImagingwithHEMI
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• Equippedwithauxiliarycontextualsensors(visualcamera,LiDAR,andIMU)
• Demonstrated137CsmappinginFukushimawithComptonimagingo Hand-heldandUAVoperation
HEMI
LiDAR
Camera,IMU
<5min
27min
PRISMSystemSetup
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LiDARandIMU PRISM
Backpackcontainsbatteriesandlaptopforcontextualdataprocessing
Hand-heldtabletforgamma-rayreconstructionandvisualization
ExperimentalMeasurementSetup
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20𝜇Ci241Am(60keV)
Results
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Measurementtime:120sTotalcounts(60keVROI):7982Occupiedvoxels:33340 (14%oftotal)Voxelsize:10cmPoses:927Operatingdetectors:74
MLEM(20iterations)Topdownview
20𝜇Ci241Am(60keV)
ZoomedIsometricview
10 0.25 0.5 0.75
Head-onboxes
GPUAcceleration
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• Asthevoxelized spacegrowslarger,imagereconstructioncanbecomeverycomputationallyexpensive
• SignificantspeedupswhencomputationparallelizedonGPUvs.CPUusingOpenCL
Hardware Sensitivity(s)
MLEM iteration(s)
Total(20iterations)(s)
2.7GHz Intelquad-corei7-6820HQ 6.1 29.0 586 -
IntelHDGraphics530(integrated) 4.4 9.5 173 3.4x
AMDRadeonPro455(dedicated) 2.6 4.3 89 6.6x
• Furtherworkisnecessarytoimproveefficiencyandovercomememorymanagementissues
• However,resultsarepromisingtowardsareal-timeon-boardimagereconstruction
Conclusions
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• Developingasphericalactivecodedaperturegamma-rayimagingsystemtoovercomethelimitedandanisotropicfield-of-viewissuesintraditionalplanarsystems
• Firstexperimentaldemonstrationofsphericalcodedapertureomnidirectional2Dimaging
• Firstsuccessfulfree-moving3Dcodedapertureimagereconstruction
• SignificantspeedupsobservedinreconstructiontimewithGPUparallelization
Futurework• Continueexploringthe3Dcodedapertureimagingcapabilities/limitationsofPRISM• Real-timeimaging• 3Dimagingimprovementswithdepth-of-interactionreadout• Near-field3Dimaging
AcknowledgementsandDisclaimer
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NuclearScienceDivision,LBNLLucianMihailescu,PaulBarton,AndyHaefner,DonGunter,RossBarnowski,MarcosTurqueti,VictorNegut,RyanPavlovsky
Dept.ofNuclearEngineering,UCBerkeleyKaiVetter
EngineeringDivision,LBNLPaulLuke,MarkAmman,JulieLee
DefenseThreatReductionAgency,DODHankZhu,MarcBlack
This material is based on work supported in part by the Department of Energy National Nuclear Security Administration through the Nuclear Scienceand Security Consortium under Award Number DE-NA-0003180 and the Defense Threat Reduction Agency under Contract Number DTRA10027-19346.
This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government norany agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for theaccuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringeprivately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwisedoes not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Theviews and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.