2016
Development and characterization of a compact hand-held gamma probe system, SURGEOGUIDE, based on NEMA NU3-2004 standards
Kaviani S, Zeraatkar N, Sajedi S, Gorjizadeh N, Farahani M, Ghafarian P, Fakhri G, Sabet H, Ay M. Development and characterization of a compact hand-held gamma probe system, SURGEOGUIDE, based on NEMA NU3-2004 standards. Journal Of Instrumentation 2016, 11: t12004-t12004. DOI: 10.1088/1748-0221/11/12/t12004.Peer-Reviewed Original ResearchScattering mediumAngular resolutionCsI(Tl) scintillatorMeasured system sensitivitySingle-hole collimatorSpatial resolutionSilicon photomultipliersGamma probeDetector unitClinically node-negative patientsSentinel lymph node localizationTc-99mCollimatorNode-negative patientsSite of regional metastasisScatteringLymph node localizationIntra-operative gamma probePeritumoral injectionRegional metastasesNodal sitesPathological analysisProbe systemI-131NEMA
2010
Novel Scatter Compensation of List-Mode PET Data Using Spatial and Energy Dependent Corrections
Guérin B, Fakhri G. Novel Scatter Compensation of List-Mode PET Data Using Spatial and Energy Dependent Corrections. IEEE Transactions On Medical Imaging 2010, 30: 759-773. PMID: 21118770, PMCID: PMC3120772, DOI: 10.1109/tmi.2010.2095025.Peer-Reviewed Original ResearchConceptsScattered coincidencesEnergy resolutionE-pdfNCAT phantomDependent correctionsEnergy of individual photonsScatter correctionEnergy dependent correctionsEnergy probability density functionScatter correction schemeTotal energy spectrumList-mode acquisitionEnergy informationPositron emission tomography dataActivity distribution estimationScatter sinogramIndividual photonsEnergy spectrumCylindrical phantomEnergy distributionMonte Carlo simulationsScattering approachPhotonsScatteringScattering component
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
2007
Impact of Acquisition Geometry, Image Processing, and Patient Size on Lesion Detection in Whole-Body 18F-FDG PET
Fakhri G, Santos P, Badawi R, Holdsworth C, Van Den Abbeele A, Kijewski M. Impact of Acquisition Geometry, Image Processing, and Patient Size on Lesion Detection in Whole-Body 18F-FDG PET. Journal Of Nuclear Medicine 2007, 48: 1951-1960. PMID: 18006613, DOI: 10.2967/jnumed.108.007369.Peer-Reviewed Original ResearchConceptsAttenuation-weighted OSEMOrdered-subset expectation maximizationNoise equivalent countPhantom sizeBed positionCho SNRPatient sizeFourier rebinningAttenuation mapPET scannerLesion detectionMarginal detectionTransmission scanWhole-body (18)F-FDG PETAttenuation correctionWhole-body 18F-FDG PETHotelling observerScaling 2DSinogramReconstructed volumeDetection SNRPhantomSystematic improvementFBPScatteringFast 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
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 estimationCompensation for Patient and Detector Scatter and Crosstalk Contamination in111In SPECT Using Fast Monte Carlo-based Iterative Reconstruction
Ouyang J, Fakhri G, Zimmerman R, Moore S. Compensation for Patient and Detector Scatter and Crosstalk Contamination in111In SPECT Using Fast Monte Carlo-based Iterative Reconstruction. 2006, 5: 2851-2853. DOI: 10.1109/nssmic.2006.356471.Peer-Reviewed Original Research
2005
Fast 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
2004
A general-spectral method for improved quantitative SPECT imaging of indium-111
Moore S, Park M, Fakhri G, Gerbaudo V, Zimmerman R. A general-spectral method for improved quantitative SPECT imaging of indium-111. 2004, 6: 3682-3684. DOI: 10.1109/nssmic.2004.1466680.Peer-Reviewed Original ResearchRadiotherapy treatment planningList-mode dataFree of scatterQuantitative SPECT imagingScatter compensation methodsList-mode acquisitionDown-scatterScattered photonsPhoton scatteringPhotopeakQuantitative SPECTOSEM reconstructionSPECT imagesLeastsquares procedureDose specificationAttenuation projectionNoisy projectionsScatteringTreatment planningSphere activitySphere locationIndium-111PhotonsContrast valuesSphere position
2003
Evaluation of a Monte Carlo Scatter Correction in Clinical 3D PET
Holdsworth C, Badawi R, Santos P, Van den Abbeele A, Hoffman E, Fakhri G. Evaluation of a Monte Carlo Scatter Correction in Clinical 3D PET. 2003, 4: 2540-2544. DOI: 10.1109/nssmic.2003.1352408.Peer-Reviewed Original ResearchScatter correctionUncorrected imagesPET imagingChannelized Hotelling observerHotelling observerPatient dataPatient imagesQuantitative accuracyLesion detection sensitivityPatient sizePhantomLesion sensitivityPatientsMonteLesionsLesion detectionCorrectionROI analysisIntensity varianceDetection sensitivityPETScatteringAverage absolute bias
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 nodesA 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 layerAbsolute activity quantitation in simultaneous 123I/99mTc brain SPECT.
El Fakhri G, Moore S, Maksud P, Aurengo A, Kijewski M. Absolute activity quantitation in simultaneous 123I/99mTc brain SPECT. Journal Of Nuclear Medicine 2001, 42: 300-8. PMID: 11216530.Peer-Reviewed Original ResearchMeSH KeywordsAlzheimer DiseaseBenzamidesBrainCerebellumCerebral CortexCerebrovascular CirculationCorpus CallosumHumansIodine RadioisotopesMonte Carlo MethodNeural Networks, ComputerParkinson DiseasePhantoms, ImagingPutamenPyrrolidinesRadiopharmaceuticalsSensitivity and SpecificityTechnetium Tc 99m ExametazimeTomography, Emission-Computed, Single-PhotonConceptsOrdered-subset expectation maximizationDistance-dependent collimator responseActivity quantitationActivity distributionIterative ordered-subsets expectation maximizationZubal brain phantomAsymmetric windowsSimulated normal populationPathological studiesDecay photonsBrain SPECTCollimator responseNonuniform attenuationDual-isotope imagingBrain phantomMonte Carlo simulationsCorpus callosumNormal populationPartial volume effectsCarlo simulationsCortical lobesAssessment of brain perfusionScatteringCross-talkBrain perfusion
2000
Relative impact of scatter, collimator response, attenuation, and finite spatial resolution corrections in cardiac SPECT.
El Fakhri G, Buvat I, Benali H, Todd-Pokropek A, Di Paola R. Relative impact of scatter, collimator response, attenuation, and finite spatial resolution corrections in cardiac SPECT. Journal Of Nuclear Medicine 2000, 41: 1400-8. PMID: 10945534.Peer-Reviewed Original ResearchConceptsDepth-dependent collimator responseSpatial resolution correctionCollimator responseFinite spatial resolutionBull's-eye mapCardiac SPECTActivity quantitationAttenuation correctionScatter correctionResolution correctionSpatial resolutionCollimator response correctionsSignal-to-noise ratioFrequency-distance principleImpact of scatteringLeft ventricleMonte Carlo simulationsCardiac phantomScatteringCarlo simulationsLV cavityAbsolute quantitationImproved contrastLV regionsProcessing schemeShould scatter be corrected in both transmission and emission data for accurate quantitation in cardiac SPET?
El Fakhri G, Buvat I, Almeida P, Bendriem B, Todd-Pokropek A, Benali H. Should scatter be corrected in both transmission and emission data for accurate quantitation in cardiac SPET? European Journal Of Nuclear Medicine And Molecular Imaging 2000, 27: 1356-1364. PMID: 11007518, DOI: 10.1007/s002590000304.Peer-Reviewed Original ResearchConceptsTransmission dataSingle-photon emission tomographyActivity distributionSignal-to-noise ratioCardiac single-photon emission tomographyAttenuation-corrected imagesAmount of scatterNarrow transmission windowHot compartmentActivity quantitationTransmission scanEmission dataEmission acquisitionTransmission windowReduced signal-to-noise ratioTransmission scatteringScatteringScattering componentPhantomQuantitative accuracyReduced scatteringAttenuating mediaReconstructed imagesLine sourceEmissionA 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. 2011 IEEE Nuclear Science Symposium Conference Record 2000, 2: 13/48-13/52 vol.2. DOI: 10.1109/nssmic.2000.949989.Peer-Reviewed Original ResearchK-shell X-raysEnergy window imagesAnthropomorphic torso phantomScatter correction methodPoisson noise realizationsGa-67 studiesPhotoelectric absorptionPhoton interactionsWindow imagesTorso phantomArtificial neural networkCoherent scatteringMonte Carlo simulationsScatter correctionGa-67Reconstructed volumeNeural networkCarlo simulationsCollimatorNoise realizationsScatteringGa-67 imagingArtificial neural network learningPrimary distributionError backpropagationRealistic 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
1999
Respective roles of scatter, attenuation, depth-dependent collimator response and finite spatial resolution in cardiac single-photon emission tomography quantitation: a Monte Carlo study
El Fakhri G, Buvat I, Pélégrini M, Benali H, Almeida P, Bendriem B, Todd-Pokropek A, Di Paola R. Respective roles of scatter, attenuation, depth-dependent collimator response and finite spatial resolution in cardiac single-photon emission tomography quantitation: a Monte Carlo study. European Journal Of Nuclear Medicine And Molecular Imaging 1999, 26: 437-446. PMID: 10382086, DOI: 10.1007/s002590050409.Peer-Reviewed Original ResearchConceptsDepth-dependent collimator responseCollimator responseMonte Carlo simulationsActivity underestimationSingle-photon emission tomographyCarlo simulationsSignal-to-noise ratioSpatial resolutionCardiac phantomFWHM spatial resolutionCardiac single-photon emission tomographyQuantitative accuracyAnthropomorphic cardiac phantomPhysical effectsInfluence of scatteringEffect of scatteringScatter countsFull-widthIncreased SNRPoor spatial resolutionScatteringMap homogeneityPhantomMonteImaging system
1998
Artificial neural network as a tool to compensate for scatter and attenuation in radionuclide imaging.
Maksud P, Fertil B, Rica C, El Fakhri G, Aurengo A. Artificial neural network as a tool to compensate for scatter and attenuation in radionuclide imaging. Journal Of Nuclear Medicine 1998, 39: 735-45. PMID: 9544691.Peer-Reviewed Original ResearchConceptsEnergy spectrumCompton scatteringRadioactive sourcesImages of radioactive sourcesScatter correctionArtificial neural networkNeural networkNumerical Monte Carlo simulationsMonte Carlo simulationsPelvis scansIncident photonsMultilayer neural networkProjection imagesScatteringComptonCarlo simulationsDiffusion mediaSource distributionSpectrum acquisitionEnergyGeometric sourcesHomogeneous mediumCorrectionSpectraNetwork