2013
Dual-Tracer PET Using Generalized Factor Analysis of Dynamic Sequences
El Fakhri G, Trott C, Sitek A, Bonab A, Alpert N. Dual-Tracer PET Using Generalized Factor Analysis of Dynamic Sequences. Molecular Imaging And Biology 2013, 15: 666-674. PMID: 23636489, PMCID: PMC3812387, DOI: 10.1007/s11307-013-0631-1.Peer-Reviewed Original ResearchConceptsEmit gamma raysPositron emission tomographyNear-simultaneous imagingSingle-photon emissionBrain PET studiesGamma raysSingle-photon emission computed tomographyActivity distributionRaclopride studiesEmission computed tomographyPositron emission tomography radiopharmaceuticalsSimultaneous imagingD2 bindingFactor analysis of dynamic sequencesActivity estimationTime activity curvesRacloprideFDGRhesus monkeysEmission tomographyPET studiesActivation curveBrain metabolismEmissionSimulate human data
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
Improved activity estimation with MC‐JOSEM versus TEW‐JOSEM in SPECT
Ouyang J, Fakhri G, Moore S. Improved activity estimation with MC‐JOSEM versus TEW‐JOSEM in SPECT. Medical Physics 2008, 35: 2029-2040. PMID: 18561679, PMCID: PMC2673642, DOI: 10.1118/1.2907561.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsEquipment DesignImage Processing, Computer-AssistedIndium RadioisotopesLungModels, StatisticalMonte Carlo MethodPhantoms, ImagingRadiotherapy Planning, Computer-AssistedReproducibility of ResultsScattering, RadiationSoftwareTomography, Emission-Computed, Single-PhotonTomography, X-Ray ComputedConceptsMC-JOSEMWater-filled torso phantomMC scatter estimationTriple-energy-windowActivity estimationIterative reconstruction algorithmTorso phantomPhantom studyBackground compartmentScatter estimationActivity distributionAverage relative biasPhantomReconstruction algorithmActivity concentrationsSynthetic projectionsSphere locationScattering
2006
Monte Carlo-based compensation for patient scatter, detector scatter, and crosstalk contamination in In-111 SPECT imaging
Moore S, Ouyang J, Park M, Fakhri G. Monte Carlo-based compensation for patient scatter, detector scatter, and crosstalk contamination in In-111 SPECT imaging. Nuclear Instruments And Methods In Physics Research Section A Accelerators Spectrometers Detectors And Associated Equipment 2006, 569: 472-476. DOI: 10.1016/j.nima.2006.08.079.Peer-Reviewed Original ResearchScatter projectionsPatient scatterDetector scatterOrgan activity estimatesPhoton interaction pointIterative reconstruction algorithmDetector effectsEnergy binsReconstruction algorithmDelta scatteringTorso phantomPoint spread functionSegmented CT scanInteraction pointOSEM reconstructionNumerical phantomDetectorScatteringScattering mapSpherical tumorSpread functionImage noisePhantomActivity concentrationsActivity estimationFast Monte Carlo Simulation Based Joint Iterative Reconstruction for Simultaneous 99mTc/123I Brain SPECT Imaging
Ouyang J, Fakhri G, Moore S, Kijewski M. Fast Monte Carlo Simulation Based Joint Iterative Reconstruction for Simultaneous 99mTc/123I Brain SPECT Imaging. 2006, 4: 2251-2256. DOI: 10.1109/nssmic.2006.354362.Peer-Reviewed Original ResearchMC-JOSEMAW-OSEMMonte CarloFast Monte CarloIterative reconstructionOrdered-subset expectation maximizationStandard ordered subsetsIterative reconstruction algorithmScattered photonsPhoton transportSeptal penetrationAttenuation distributionPhysical effectsIdentical physiological conditionsPatient-specific activityReconstructed imagesReconstruction algorithmActivity estimationComptonRoot mean square errorPhotonsCorrection methodCollimatorBrain perfusionDetector
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
2001
A New Scatter Compensation Method for Ga-67 Imaging Using Artificial Neural Networks
Fakhri G, Moore S, Maksud P. A New Scatter Compensation Method for Ga-67 Imaging Using Artificial Neural Networks. IEEE Transactions On Nuclear Science 2001, 48: 799. DOI: 10.1109/23.940166.Peer-Reviewed Original ResearchK-shell X-raysEnergy window imagesAnthropomorphic torso phantomPoisson noise realizationsGa-67 studiesArtificial neural networkWindow imagesPhotoelectric absorptionPhoton interactionsTorso phantomCoherent scatteringMonte Carlo simulationsScatter correctionGa-67Neural networkReconstructed volumeCarlo simulationsCollimatorArtificial neural network learningError back propagationNoise realizationsScatteringGa-67 imagingActivity estimationOutput layer
2000
Absolute activity quantitation from projections using an analytical approach: comparison with iterative methods in brain SPECT
Fakhri G, Kijewski M, Moore S. Absolute activity quantitation from projections using an analytical approach: comparison with iterative methods in brain SPECT. 2011 IEEE Nuclear Science Symposium Conference Record 2000, 3: 18/7-1811 vol.3. DOI: 10.1109/nssmic.2000.949215.Peer-Reviewed Original ResearchVariable collimator responseI-123 studiesI-123Tc-99Attenuation correctionTc-99mBrain SPECTDigital brain phantomTc-99m studiesMonte Carlo simulated projectionsCollimator responseActivity quantitationActivity estimationBrain phantomOSEM algorithmBrain structuresActivity distributionAccurate quantitationPoor spatial resolutionSPECT activityFitting procedurePartial volume effectsCaudate nucleusCorpus callosumSpatial resolution