2021
Investigation of a Model-Based Time-Over-Threshold Technique for Phoswich Crystal Discrimination
Bouziri H, Pepin C, Koua K, Benhouria M, Paulin C, Ouyang J, Normandin M, Pratte J, Fakhri G, Lecomte R, Fontaine R. Investigation of a Model-Based Time-Over-Threshold Technique for Phoswich Crystal Discrimination. IEEE Transactions On Radiation And Plasma Medical Sciences 2021, 6: 393-403. PMID: 35372739, PMCID: PMC8974315, DOI: 10.1109/trpms.2021.3077412.Peer-Reviewed Original ResearchPulse shape discriminationCrystal identificationPhoswich detectorEnergy windowTime-over-threshold techniqueBroad energy windowCR-RC shaperCharge sensitive preamplifierFree running analogPhoswich assembliesLYSO scintillatorSensitive preamplifierCrystal discriminationAPD arraysShape discriminationEvent energyElectronic readoutTime of occurenceDecay timeLGSODetectorIncreasing pixelizationLYSODetection front endCrystal
2016
Scintillator-Based Photon Counting Detector: Is it Feasible?
Bläckberg L, Moebius M, Moghadam N, Uzun-Ozsahin D, Mazur E, Fakhri G, Sabet H. Scintillator-Based Photon Counting Detector: Is it Feasible? 2016, 1-5. DOI: 10.1109/nssmic.2016.8069382.Peer-Reviewed Original ResearchLaser induced optical barriersPhoton counting detectorsScintillator arrayOptical barrierBarrier refractive indexRefractive indexApplication Specific Integrated CircuitFast decay timeHigh light outputBuilt-in photodiodeScintillation lightLYSO crystalsCounting detectorsScintillator pixelsEnergy windowAtomic numberScintillationDecay timeLight outputLaserDetectorTransparent crystalsCrystalIntegrated circuitsLaser cutting technique
2009
Monte Carlo modeling of cascade gamma rays in 86Y PET imaging: preliminary results
Zhu X, Fakhri G. Monte Carlo modeling of cascade gamma rays in 86Y PET imaging: preliminary results. Physics In Medicine And Biology 2009, 54: 4181-4193. PMID: 19521011, PMCID: PMC3111055, DOI: 10.1088/0031-9155/54/13/014.Peer-Reviewed Original ResearchConceptsCascade gamma raysScatter fractionGamma raysPhoton energy distributionLow count ratesHigh-energy photonsMonte Carlo programScatter correction methodGATE simulation packageMonte Carlo modelDevelopment of correction methodsSpatial resolutionGamma photonsEnergy windowCount rateScattering eventsRandom coincidencesEnergy distributionPhantom acquisitionsPersonal dosimetryPET imagingVariance reduction techniquesPhotonsCorrection methodSimSETQuantitative 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
2007
Fast Monte Carlo based joint iterative reconstruction for simultaneous SPECT imaging
Ouyang J, Fakhri G, Moore S. Fast Monte Carlo based joint iterative reconstruction for simultaneous SPECT imaging. Medical Physics 2007, 34: 3263-3272. PMID: 17879789, DOI: 10.1118/1.2756601.Peer-Reviewed Original ResearchConceptsMC-JOSEMEnergy windowFast Monte CarloSignal-to-noise ratioScatter correction methodOrdered-subsets expectation-maximizationMonte CarloOrdered-subsets expectation-maximization algorithmIterative reconstruction algorithmPrimary photonsReconstruction algorithmPhoton transportSeptal penetrationDetector responseMC simulationsIterative reconstructionAttenuation distributionStandard OSEMPhotonsProjection dataPatient-specific activityDetectorReconstructed imagesScatteringEstimation of scattering
2005
Collimator Optimization for Detection and Quantitation Tasks: Application to Gallium-67 Imaging
Moore S, Kijewski M, Fakhri G. Collimator Optimization for Detection and Quantitation Tasks: Application to Gallium-67 Imaging. IEEE Transactions On Medical Imaging 2005, 24: 1347-1356. PMID: 16229420, DOI: 10.1109/tmi.2005.857211.Peer-Reviewed Original ResearchMeSH KeywordsCitratesComputer SimulationComputer-Aided DesignEquipment DesignEquipment Failure AnalysisGalliumHumansImage EnhancementImage Interpretation, Computer-AssistedModels, BiologicalNeoplasmsPhantoms, ImagingPositron-Emission TomographyRadiopharmaceuticalsReproducibility of ResultsSensitivity and SpecificityConceptsMedium-energy low-penetration collimatorCollimator optimizationGeometric spatial resolutionPhotopeak energy windowSimulation of photon transportLead X-raysClinical imaging tasksActivity estimation taskSignal-to-noise ratioGallium-67 imagingContaminating photonsEnergy windowGeometric efficiencyCollimator designFixed energyPhoton transportOptimal collimatorCollimatorHotelling observerFWHMSpatial resolutionNuclear medicineDetectorResolution valuesImaging tasksFast Monte Carlo Estimation of Patient and Detector Scatter and Crosstalk Contamination in SPECT Imaging
Ouyang J, Moore S, Park M, Fakhri G. Fast Monte Carlo Estimation of Patient and Detector Scatter and Crosstalk Contamination in SPECT Imaging. 2005, 3: 1560-1562. DOI: 10.1109/nssmic.2005.1596616.Peer-Reviewed Original ResearchDetector effectsEnergy windowTriple-energy window methodConvolution-based forced detectionPhoton interaction pointSimulate photon interactionsLower energy windowScattering mapCompton scatteringPhoton contributionEnergy binsPhoton interactionsMultiple photonsDetector scatterImaging isotopesCoherent scatteringAttenuation phantomMonte Carlo methodPhotoelectric effectInteraction pointPhantom experimentsDetectorCrosstalk contaminationScatteringCarlo method
2003
The Effects of Compensation for Scatter, Lead X-Rays, and High-Energy Contamination on Tumor Detectability and Activity Estimation in Ga-67 Imaging
Fakhri G, Kijewski M, Maksud P, Moore S. The Effects of Compensation for Scatter, Lead X-Rays, and High-Energy Contamination on Tumor Detectability and Activity Estimation in Ga-67 Imaging. IEEE Transactions On Nuclear Science 2003, 50: 439. DOI: 10.1109/tns.2003.812446.Peer-Reviewed Original ResearchLead X-raysHigh-energy contaminationPresence of scatteringOptimal energy windowSignal-to-noise ratioAnthropomorphic torso phantomHigh-energy photonsMonte Carlo programGa-67 imagingSpherical tumorCompton scatteringPhoton interactionsEnergy windowScattered photonsEnergy photonsPhotopeak windowTorso phantomActivity estimationHigh energyFactors affecting image qualityX-rayScatter correctionPhotopeakGa-67Photons
2002
Quantitative Simultaneous 99MTc/123I Spect: Design Study and Validation With Monte Carlo Simulations and Physical Acquisitions
Fakhri G, Maksud P, Kijewski M, Zimmerman R, Moore S. Quantitative Simultaneous 99MTc/123I Spect: Design Study and Validation With Monte Carlo Simulations and Physical Acquisitions. IEEE Transactions On Nuclear Science 2002, 49: 2315. DOI: 10.1109/tns.2002.803819.Peer-Reviewed Original ResearchMonte Carlo simulationsBrain phantomCarlo simulationsSimultaneous dual-isotope imagingIterative ordered subsetsDigital brain phantomDual-isotope SPECT studyVariable collimator responseArtificial neural networkPhysical acquisitionEnergy windowNonuniform attenuationCollimator responseDual-isotope imagingPhantom acquisitionsScatter correctionClinical cameraNeural networkMontePhantomIsotope imagingCorrected projectionsSPECT studiesProjector/backprojectorClinical applicationOptimization of Ga‐67 imaging for detection and estimation tasks: Dependence of imaging performance on spectral acquisition parameters
Fakhri G, Moore S, Kijewski M. Optimization of Ga‐67 imaging for detection and estimation tasks: Dependence of imaging performance on spectral acquisition parameters. Medical Physics 2002, 29: 1859-1866. PMID: 12201433, DOI: 10.1118/1.1493214.Peer-Reviewed Original ResearchConceptsIdeal signal-to-noise ratioEnergy windowSignal-to-noise ratioMonte Carlo programDetection of spheresTorso phantomPhantom acquisitionsSphere of radiusEstimation taskPhantom dataLower-energyGa-67 imagingPhantomAcquisition parametersActivity concentrationsSpectral acquisition parametersGa-67Sphere sizeEnergyPhotopeakTumor imagingOptimal windowTaskClinicMonteOptimal Parallel-Hole Collimation for Lesion Detection and Activity Estimation in Ga-67 Imaging
Moore S, Kijewski M, Fakhri G. Optimal Parallel-Hole Collimation for Lesion Detection and Activity Estimation in Ga-67 Imaging. 2002, 3: 1390-1392. DOI: 10.1109/nssmic.2002.1239580.Peer-Reviewed Original ResearchCollimator designMedium-energy (MESimulation of photon transportSignal-to-noise ratioParallel-hole collimatorDesign of collimatorsClinical imaging tasksGa-67Contaminating photonsField of nuclear medicineEnergy windowFixed energyPhoton transportOptimal collimatorCollimatorCommercial collimatorsStaging of lymphoma patientsHotelling observerGa-67 imagingNuclear medicine clinicsLesion detectionNuclear medicineDetectorActivity concentrationsResolution values
2001
Realistic Monte Carlo Simulation of Ga-67 SPECT Imaging
Moore S, El Fakhri G. Realistic Monte Carlo Simulation of Ga-67 SPECT Imaging. IEEE Transactions On Nuclear Science 2001, 48: 720. DOI: 10.1109/23.940153.Peer-Reviewed Original ResearchRealistic Monte Carlo simulationsNumerical torso phantomLead X-raysMonte Carlo programPhoton emission energyPoisson noise realizationsGa-67 SPECT imagingCollimator penetrationDetector resolutionEnergy windowRSD phantomPhoton propagationPhoton scatteringTorso phantomHeart/thorax phantomAttenuation mapEnergy distributionEmission energyImproved variance reductionSPECT imagesPhantomGa-67 studiesNoise realizationsScatteringAxillary lymph nodesAbsolute Quantitation in Simultaneous 99mTc/123I Brain SPECT Using ANN: Design Optimization and Validation
Fakhri G, Maksud P, Moore S, Zimmerman R, Kijewski M. Absolute Quantitation in Simultaneous 99mTc/123I Brain SPECT Using ANN: Design Optimization and Validation. 2001, 3: 1429-1431. DOI: 10.1109/nssmic.2001.1008605.Peer-Reviewed Original ResearchMonte Carlo simulationsBrain phantomSimultaneous dual-isotope imagingDigital brain phantomDual-isotope SPECT studyVariable collimator responseCarlo simulationsNon-uniform attenuationI-123 imagingEnergy windowCollimator responseDual-isotope imagingPhantom acquisitionsOSEM algorithmArtificial neural networkPhysical acquisitionScatter correctionClinical cameraBrain structuresPhantomIsotope imagingMonteSPECT studiesActivity concentrationsTc-99Comparative Assessment of Energy-Based Methods of Compensating for Scatter and Lead X-Rays in Ga-67 SPECT Imaging
Moore S, Fakhri G, Maksud P. Comparative Assessment of Energy-Based Methods of Compensating for Scatter and Lead X-Rays in Ga-67 SPECT Imaging. 2001, 4: 2197-2198. DOI: 10.1109/nssmic.2001.1009260.Peer-Reviewed Original ResearchLead X-raysGa-67Energy windowArtificial neural networkGa-67 SPECT imagingSPECT imagesHigh-energy contaminationGa-67 SPECTPoisson noise realizationsActivity estimation taskTumor activity concentrationAnthropomorphic phantomEvaluable tumorsGS methodTumorMean square errorData setsOrgan uptakeProjection imagesLymphoma studiesNeural networkPixel valuesX-raySpherical tumorNoise realizationsOptimization of Ga-67 Imaging for Detection and Estimation Tasks: Dependence of Imaging Performance on Choice of Energy Windows
Fakhri G, Moore S, Kijewski M. Optimization of Ga-67 Imaging for Detection and Estimation Tasks: Dependence of Imaging Performance on Choice of Energy Windows. 2001, 3: 1355-1357. DOI: 10.1109/nssmic.2001.1008588.Peer-Reviewed Original ResearchEnergy windowSignal-to-noise ratioMonte Carlo programDetection of spheresIdeal signal-to-noise ratioTorso phantomEstimation taskDetection signal-to-noise ratioPhantom acquisitionsSphere of radiusPhantom dataLower-energyPhotopeakImaging performancePhantomGa-67Detection metricsGa-67 imagingSphere sizeOptimal window widthWindow widthEnergyTaskQuantitative tasksOptimal window
2000
Realistic Monte Carlo simulation of Ga-67 imaging for optimization and evaluation of correction methods
Moore S, Fakhri G. Realistic Monte Carlo simulation of Ga-67 imaging for optimization and evaluation of correction methods. 2011 IEEE Nuclear Science Symposium Conference Record 2000, 3: 20/35-20/38 vol.3. DOI: 10.1109/nssmic.2000.949312.Peer-Reviewed Original ResearchRealistic Monte Carlo simulationsNumerical torso phantomMonte Carlo programLead X-raysPhoton emission energyPoisson noise realizationsMaximum rectangular regionCollimator penetrationDetector resolutionEnergy windowRSD phantomPhoton scatteringPhoton propagationTorso phantomHeart/thorax phantomAttenuation mapEnergy distributionEmission energyImproved variance reductionPhantomNoise-free imageGa-67 studiesGa-67Noise realizationsScattering