2017
Feasibility study of using fall‐off gradients of early and late PET scans for proton range verification
Cho J, Grogg K, Min C, Zhu X, Paganetti H, Lee H, Fakhri G. Feasibility study of using fall‐off gradients of early and late PET scans for proton range verification. Medical Physics 2017, 44: 1734-1746. PMID: 28273345, PMCID: PMC5462437, DOI: 10.1002/mp.12191.Peer-Reviewed Original ResearchConceptsProton range verificationProton rangeMonte Carlo simulationsRange verificationFall-offIn-room positron emission tomographyCarlo simulationsResidual proton rangeDose fall-offPostirradiation delayPositron emission tomography imagingSOBP beamProton beamPositron emission tomographyPositron emission tomography scanPhantom studyIn-roomFunction of depthPhantomProtonOff-setMonteAcquisition timeBeamPositron emission tomography signal
2015
Mapping 15O Production Rate for Proton Therapy Verification
Grogg K, Alpert N, Zhu X, Min C, Testa M, Winey B, Normandin M, Shih H, Paganetti H, Bortfeld T, Fakhri G. Mapping 15O Production Rate for Proton Therapy Verification. International Journal Of Radiation Oncology • Biology • Physics 2015, 92: 453-459. PMID: 25817530, PMCID: PMC4431894, DOI: 10.1016/j.ijrobp.2015.01.023.Peer-Reviewed Original ResearchConceptsDecay constantProton treatment planningMonte Carlo predictionsProton therapyPhantom materialTreatment deliveryPhantomThigh activityPositron emission tomographyProduction rateDynamic PET measurementsTreatment planningRabbit thigh muscleClearance rateProtonIsotopesChanges due to therapyRadionuclide speciesOxygen-15ConstantDecayImaging targetsMontePositronEffects of perfusion
2014
Accuracy of Respiratory Motion Compensated Image Reconstruction Using 4DPET-Derived Deformation Fields
Dutta J, Chelala M, Shao X, Lorsakul A, Li Q, Fakhri G. Accuracy of Respiratory Motion Compensated Image Reconstruction Using 4DPET-Derived Deformation Fields. 2014, 1-4. DOI: 10.1109/nssmic.2014.7430924.Peer-Reviewed Original ResearchAttenuation-corrected PET imagesXCAT phantomNon-attenuation-corrected PET imagesMotion-compensated image reconstructionImage reconstructionMotion informationPET imagingMotion estimationPET gatingAttenuation mapBreathing motionPET quantitationSoftware GATEXCATDeformation fieldPhantomAccuracy of motionGround truthGateAnatomical imagesFieldMotionUpper abdomenPulmonary lesionsMonte
2006
Monte Carlo Modeling of Cascade Gamma Rays in PET
Zhu X, Fakhri G. Monte Carlo Modeling of Cascade Gamma Rays in PET. 2011 IEEE Nuclear Science Symposium Conference Record 2006, 6: 3522-3525. DOI: 10.1109/nssmic.2006.353759.Peer-Reviewed Original ResearchCascade gamma raysGamma raysGamma-ray emitting isotopesDetector dead timeMonte Carlo modelPET imagingGamma eventsScatter fractionQuantitative PET imagingTorso phantomSingles ratesMonte Carlo simulationsDecrease of intensityHigh-activity regionsPhantom experimentsReconstructed volumePhantomRaysCarlo simulationsDead timeDetectorReconstructed imagesCascade typeImage intensityMonte
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
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 windowTaskClinicMonte
2001
Absolute 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-99
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 systemA new correction method for cross-talk using artificial neural networks: validation in simultaneous technetium and iodine cerebral imaging
Fakhri G, Maksud P, Habert M, Todd-Pokropek A, Aurengo A. A new correction method for cross-talk using artificial neural networks: validation in simultaneous technetium and iodine cerebral imaging. 2011 IEEE Nuclear Science Symposium Conference Record 1999, 2: 1000-1004 vol.2. DOI: 10.1109/nssmic.1999.845830.Peer-Reviewed Original ResearchEnergy window methodMonte CarloHuman brain phantomI-123 imagingGeometric phantomsBrain phantomMC simulationsTc-99mCorrection methodDual-isotope studiesActivity distributionM imagesI-123PhantomAssessment of brain perfusionCross-talkRadionuclidesTc-99Cerebral imagingCorrectionBrain perfusionClinical potentialBackprojectionMonteCarloMonte Carlo evaluation of quantitation in simultaneous Tc-99m/I-123 brain SPECT using constrained spectral factor analysis
Fakhri G, Moore S, Kijewski M, Maksud P, Todd-Pokropek A. Monte Carlo evaluation of quantitation in simultaneous Tc-99m/I-123 brain SPECT using constrained spectral factor analysis. 2011 IEEE Nuclear Science Symposium Conference Record 1999, 3: 1392-1396 vol.3. DOI: 10.1109/nssmic.1999.842815.Peer-Reviewed Original ResearchSpectral factor analysisTc-99mEnergy window methodDigital brain phantomI-123 imagingUnscattered photonsTc-99m activityBrain phantomFiltered-backprojectionMonte Carlo simulationsPrimary spectraDual-isotope studiesI-123Monte Carlo evaluationPhotonsCarlo simulationsSimultaneous imagingMonteBrain structuresBrain SPECTTc-99PhantomCaudate nucleusSpectraPixel values