2021
A layered single-side readout depth of interaction time-of-flight-PET detector
Bläckberg L, Sajedi S, Fakhri G, Sabet H. A layered single-side readout depth of interaction time-of-flight-PET detector. Physics In Medicine And Biology 2021, 66: 045025. PMID: 33570050, PMCID: PMC8130834, DOI: 10.1088/1361-6560/abd592.Peer-Reviewed Original ResearchConceptsDepth of interactionMulti-pixel photon counterDepth-of-interaction determinationDepth-of-interaction informationTime resolutionTime resolution valuesReduced crystal thicknessNon-DOI detectorsOptical photonsScintillator arrayPET detectorsPhoton counterCrystal pixelsReadout schemeCrystal arrayCrystal thicknessTransport simulationsDetectorPhotodetector arrayReadoutPixel sizePhotodetectorsResolution valuesFirst layerSignal amplitude
2020
Motion correction for PET data using subspace-based real-time MR imaging in simultaneous PET/MR
Marin T, Djebra Y, Han P, Chemli Y, Bloch I, Fakhri G, Ouyang J, Petibon Y, Ma C. Motion correction for PET data using subspace-based real-time MR imaging in simultaneous PET/MR. Physics In Medicine And Biology 2020, 65: 235022. PMID: 33263317, PMCID: PMC7985095, DOI: 10.1088/1361-6560/abb31d.Peer-Reviewed Original ResearchConceptsPositron emission tomography reconstructionMotion-corrected PET reconstructionsPET reconstructionMotion-corrected PET imagesIrregular respiratory motionMotion fieldMotion correction methodMotion correction approachIrregular motion patternsUndersampled k-space dataImage quality of positron emission tomographyQuality of positron emission tomographyMotion patternsLow-rank characteristicsRespiratory motionContrast-to-noise ratioEstimated motion fieldSurrogate signalsMotion correctionK-space dataImage qualityReal-time MR imagingSimultaneous PET/MRMotion artifact reductionPET/MR scannersHigh-performance rapid MR parameter mapping using model-based deep adversarial learning
Liu F, Kijowski R, Feng L, El Fakhri G. High-performance rapid MR parameter mapping using model-based deep adversarial learning. Magnetic Resonance Imaging 2020, 74: 152-160. PMID: 32980503, PMCID: PMC7669737, DOI: 10.1016/j.mri.2020.09.021.Peer-Reviewed Original ResearchMeSH KeywordsBrainDeep LearningHumansImage Processing, Computer-AssistedKneeMagnetic Resonance ImagingTime FactorsConceptsConvolutional neural networkMR parameter mappingAdversarial learningState-of-the-art reconstruction methodsEnd-to-end convolutional neural networkUndersampled k-space dataConvolutional neural network approachAdversarial learning approachState-of-the-artStructural similarity indexImage reconstruction frameworkEnd-to-endImage sharpnessData consistencyConventional reconstruction approachesReconstruction approachK-space dataImprove image sharpnessImage reconstruction approachEstimated parameter mapsImage sparsityTexture restorationNetwork trainingImage datasetsReconstruction performance
2019
Time of flight PET reconstruction using nonuniform update for regional recovery uniformity
Kim K, Kim D, Yang J, Fakhri G, Seo Y, Fessler J, Li Q. Time of flight PET reconstruction using nonuniform update for regional recovery uniformity. Medical Physics 2019, 46: 649-664. PMID: 30508255, PMCID: PMC6501218, DOI: 10.1002/mp.13321.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsHumansImage Processing, Computer-AssistedPancreasPositron-Emission TomographyTime FactorsConceptsSignal-to-noise ratio regionVariant step sizeSignal-to-noise ratioNesterov momentumOS-SQSUniform recoveryOS-EMStep sizeNon-TOF PETOrdered subsetsQuad-core CPUEarly stopping criterionGraphics processing unitsTime-of-flight PET reconstructionReconstruction methodPET reconstruction methodsNesterov's momentum methodImage qualityPET reconstructionTOF-PETOverall signal-to-noise ratioActive regionLow activity regionsComputer simulationsRecovery ratio
2015
Accelerated acquisition of tagged MRI for cardiac motion correction in simultaneous PET‐MR: Phantom and patient studies
Huang C, Petibon Y, Ouyang J, Reese T, Ahlman M, Bluemke D, El Fakhri G. Accelerated acquisition of tagged MRI for cardiac motion correction in simultaneous PET‐MR: Phantom and patient studies. Medical Physics 2015, 42: 1087-1097. PMID: 25652521, PMCID: PMC4312342, DOI: 10.1118/1.4906247.Peer-Reviewed Original ResearchConceptsPET motion correctionMotion correctionSimultaneous PET-MRTMR dataPET list-mode dataPET-MRList-mode dataCardiac motion correctionPET-MR scannersImage qualityParallel imagingAcquisition timePET imagingRespiratory motionCompressive sensingMotion fieldAttenuation correctionDefect contrastModerate acceleration factorsDegradation of image qualityTagged MRCardiac phantomLong acquisition timesPhantomAccurate motion field
2014
MR‐based motion correction for PET imaging using wired active MR microcoils in simultaneous PET‐MR: Phantom study
Huang C, Ackerman J, Petibon Y, Brady T, Fakhri G, Ouyang J. MR‐based motion correction for PET imaging using wired active MR microcoils in simultaneous PET‐MR: Phantom study. Medical Physics 2014, 41: 041910. PMID: 24694141, PMCID: PMC3978416, DOI: 10.1118/1.4868457.Peer-Reviewed Original ResearchConceptsMotion correctionMR-based motion correctionStatic phantom dataPET quantitative accuracyPET-MRPET-MR scannersSimultaneous PET-MRHoffman phantomList-modePositron emission tomography imagingPET reconstructionBrain positron emission tomographyIterative PET reconstructionPhantom dataPhantomQuantitative accuracyIndependent noise realizationsImage contrastNoise realizationsHead motionPET dataPositron emission tomographyStatic referenceBrain PET scansMotion artifacts
2013
Simultaneous 99mTc‐MDP/123I‐MIBG tumor imaging using SPECT‐CT: Phantom and constructed patient studies
Rakvongthai Y, Fakhri G, Lim R, Bonab A, Ouyang J. Simultaneous 99mTc‐MDP/123I‐MIBG tumor imaging using SPECT‐CT: Phantom and constructed patient studies. Medical Physics 2013, 40: 102506. PMID: 24089927, PMCID: PMC3785531, DOI: 10.1118/1.4820977.Peer-Reviewed Original ResearchConceptsScatter correctionDual-radionuclideContrast recoveryPhantom studyAnthropomorphic torso phantomPatient studiesTumor uptakeTumor imagingSPECT projectionsTorso phantomMonte-CarloPhantom dataPhantomIterative reconstructionOSEMProjection dataDR dataIncrease patient throughputNoise realizationsSPECT-CTImage reconstructionClinical studiesTumorTumor projectionPoisson noiseCardiac motion compensation and resolution modeling in simultaneous PET-MR: a cardiac lesion detection study
Petibon Y, Ouyang J, Zhu X, Huang C, Reese T, Chun S, Li Q, Fakhri G. Cardiac motion compensation and resolution modeling in simultaneous PET-MR: a cardiac lesion detection study. Physics In Medicine And Biology 2013, 58: 2085-2102. PMID: 23470288, PMCID: PMC3657754, DOI: 10.1088/0031-9155/58/7/2085.Peer-Reviewed Original ResearchConceptsContrast recoveryDetector point spread functionPartial volume effectsK-spaceMotion compensationB-spline registrationLesion-detection studiesCardiac motion compensationPET-MR scannersSimultaneous PET-MRPET contrastIterative reconstruction frameworkPoint spread functionMotion correctionPET countsNon-rigid B-spline registrationCardiac phantomPSF modelPET-MRMotion deblurringReconstruction frameworkSystem matrixCardiac PETSpread functionDefect detectionClinical impact of time-of-flight and point response modeling in PET reconstructions: a lesion detection study
Schaefferkoetter J, Casey M, Townsend D, Fakhri G. Clinical impact of time-of-flight and point response modeling in PET reconstructions: a lesion detection study. Physics In Medicine And Biology 2013, 58: 1465-1478. PMID: 23403399, PMCID: PMC3616316, DOI: 10.1088/0031-9155/58/5/1465.Peer-Reviewed Original ResearchConceptsPoint spread functionTime-of-flightBenefit of TOFPET reconstructionNumerical modelOptimal reconstruction parametersLocalization receiver operating characteristicsLesion-detection studiesObserved SNRReconstruction schemeSpread functionReconstruction parametersPerformanceNumerical observationsPatient imagesClinical Application of In-Room Positron Emission Tomography for In Vivo Treatment Monitoring in Proton Radiation Therapy
Min C, Zhu X, Winey B, Grogg K, Testa M, Fakhri G, Bortfeld T, Paganetti H, Shih H. Clinical Application of In-Room Positron Emission Tomography for In Vivo Treatment Monitoring in Proton Radiation Therapy. International Journal Of Radiation Oncology • Biology • Physics 2013, 86: 183-189. PMID: 23391817, PMCID: PMC3640852, DOI: 10.1016/j.ijrobp.2012.12.010.Peer-Reviewed Original ResearchConceptsIn-room positron emission tomographyProton therapyIn-roomPositron emission tomography scanIn-room PET scannerPassive scattering proton therapyShapes of target volumesPositron emission tomographyMC predictionBeam range uncertaintiesMeasured PET imagesMonte CarloProton radiation therapyLocal elemental compositionBiological washoutScan timeTreatment headTreatment verificationRange uncertaintiesTarget volumePET scan timePET scannerPET systemComputed tomographyMC results
2012
MRI-Based Nonrigid Motion Correction in Simultaneous PET/MRI
Chun Y, Reese T, Ouyang J, Guerin B, Catana C, Zhu X, Alpert N, Fakhri G. MRI-Based Nonrigid Motion Correction in Simultaneous PET/MRI. Journal Of Nuclear Medicine 2012, 53: 1284-1291. PMID: 22743250, PMCID: PMC4077320, DOI: 10.2967/jnumed.111.092353.Peer-Reviewed Original ResearchConceptsChannelized Hotelling observerMotion correctionDetection signal-to-noise ratioSignal-to-noise ratioMRI-based motion correctionRespiratory motion correctionMotion-corrected reconstructionOrdered-subsets expectation maximization algorithmNonrigid motion correctionChannelized Hotelling observer studyPET image qualityNonrigid image registration methodCoincidence dataDeformable phantomRespiratory gatingReduce radiation doseDynamic phantomImage registration methodReduced signal-to-noise ratioSimultaneous PET/MRICost of increased noiseHotelling observerPhantomAttenuation measurementsRabbit studies
2011
Nonrigid PET motion compensation in the lower abdomen using simultaneous tagged‐MRI and PET imaging
Guérin B, Cho S, Chun S, Zhu X, Alpert N, Fakhri G, Reese T, Catana C. Nonrigid PET motion compensation in the lower abdomen using simultaneous tagged‐MRI and PET imaging. Medical Physics 2011, 38: 3025-3038. PMID: 21815376, PMCID: PMC3125080, DOI: 10.1118/1.3589136.Peer-Reviewed Original ResearchConceptsPET-MRI acquisitionsMotion correctionPET motion compensationPET motion correctionRespiratory motion correctionMotion-corrected reconstructionMotion correction strategiesWhole-body PET studiesSignal-to-noise ratioPET reconstruction algorithmDeformable phantomNCAT phantomEffects of motionAttenuation mapDetected coincidencesPET-MRIGated framesBrain scannerSimulations of tumorsSignal-to-noisePhantomSusceptibility artifactsReconstruction algorithmPhase domainsNonrigid deformationImpact of Time-of-Flight PET on Whole-Body Oncologic Studies: A Human Observer Lesion Detection and Localization Study
Surti S, Scheuermann J, Fakhri G, Daube-Witherspoon M, Lim R, Abi-Hatem N, Moussallem E, Benard F, Mankoff D, Karp J. Impact of Time-of-Flight PET on Whole-Body Oncologic Studies: A Human Observer Lesion Detection and Localization Study. Journal Of Nuclear Medicine 2011, 52: 712-719. PMID: 21498523, PMCID: PMC3104282, DOI: 10.2967/jnumed.110.086678.Peer-Reviewed Original ResearchConceptsLocalization receiver operating characteristicsTime-of-flight PETLong scan timesArea under the LROC curveScan timeFunction of scan timePatient sizeTime-of-flight (TOFLROC curveLow-uptake lesionsTOF imagesTOF kernelLesion detection taskTOF-PETWhole-body oncologyLesion detection performanceScanner fieldPhantom studyPatient body mass indexProbability of correct localizationLesion detectionSphere dataBody mass indexLarger patientsReceiver operating characteristic
2009
Quantitative simultaneous cardiac SPECT using MC‐JOSEM
Ouyang J, Zhu X, Trott C, Fakhri G. Quantitative simultaneous cardiac SPECT using MC‐JOSEM. Medical Physics 2009, 36: 602-611. PMID: 19292000, PMCID: PMC2673670, DOI: 10.1118/1.3063544.Peer-Reviewed Original ResearchConceptsMC-JOSEMEnergy windowWater-filled torso phantomScatter correctionPhotopeak energy windowStandard OSEMCardiac SPECT imagingActivity concentration ratioIterative reconstruction algorithmReconstruction algorithmMyocardium wallTorso phantomActivity estimationDetector responseEmission energyBackground compartmentPhantom dataCardiac SPECTActivity distributionRest/stress imagingScatteringCases of patientsOSEMChest painCardiac protocols
2008
Sequential and simultaneous dual‐isotope brain SPECT: Comparison with PET for estimation and discrimination tasks in early Parkinson disease
Trott C, Fakhri G. Sequential and simultaneous dual‐isotope brain SPECT: Comparison with PET for estimation and discrimination tasks in early Parkinson disease. Medical Physics 2008, 35: 3343-3353. PMID: 18697558, PMCID: PMC2673561, DOI: 10.1118/1.2940605.Peer-Reviewed Original ResearchConceptsEnergy resolutionTime-of-flight PET scannerRealistic Monte Carlo simulationsAcquisition energy windowSequential SPECTSystem energy resolutionGamma cameraEnergy windowThree-head cameraPET scannerEmission energyMonte Carlo simulationsDual-isotope SPECTSimultaneous SPECTBrain PETTwo-headed cameraCarlo simulationsProdromal disease stagesIdentical physiological conditionsSpatial resolutionDiscrimination taskStriatal sizeActivity concentrationsEarly identification of PDCamera head