2023
Super-resolution in brain positron emission tomography using a real-time motion capture system
Chemli Y, Tétrault M, Marin T, Normandin M, Bloch I, El Fakhri G, Ouyang J, Petibon Y. Super-resolution in brain positron emission tomography using a real-time motion capture system. NeuroImage 2023, 272: 120056. PMID: 36977452, PMCID: PMC10122782, DOI: 10.1016/j.neuroimage.2023.120056.Peer-Reviewed Original ResearchConceptsBrain positron emission tomographySuper-resolutionEvent-by-event basisReal-time motion capture systemSR reconstruction methodTracking cameraVisualization of small structuresPET reconstruction algorithmMoving phantomMeasure target motionLine profilesPET/CT scannerMeasured shiftsImprove image resolutionMotion capture systemMotion tracking devicePositron emission tomographyReconstruction algorithmSpatial resolutionMeasured linesPhantomReal-timeEstimation frameworkIncreased spatial resolutionReconstruction method
2017
Iterative Low-Dose CT Reconstruction With Priors Trained by Artificial Neural Network
Wu D, Kim K, Fakhri G, Li Q. Iterative Low-Dose CT Reconstruction With Priors Trained by Artificial Neural Network. IEEE Transactions On Medical Imaging 2017, 36: 2479-2486. PMID: 28922116, PMCID: PMC5897914, DOI: 10.1109/tmi.2017.2753138.Peer-Reviewed Original ResearchConceptsArtificial neural networkIterative reconstruction algorithmNeural networkLow-dose CT reconstructionReconstruction algorithmUnsupervised feature learningReconstructed imagesFeatures of imagesImprove reconstruction qualityNormal-dose imagesDecreasing radiation riskDevelopment of artificial neural networksFeature learningComplex featuresAuto-encoderReconstruction qualityData fidelityMachine learningSuppress noiseSmoothness constraintPhoton fluxPreservation abilityGrand ChallengeNoise reductionPriors
2016
Investigation of cone-beam CT image quality trade-off for image-guided radiation therapy
Bian J, Sharp G, Park Y, Ouyang J, Bortfeld T, Fakhri G. Investigation of cone-beam CT image quality trade-off for image-guided radiation therapy. Physics In Medicine And Biology 2016, 61: 3317-3346. PMID: 27032676, DOI: 10.1088/0031-9155/61/9/3317.Peer-Reviewed Original ResearchConceptsImage-guided radiation therapyCone-beam CTFiltered-backprojectionImage quality trade-offConventional filtered-backprojectionShort-scan reconstructionsFiltered-backprojection algorithmFan-beam reconstructionTV-based algorithmIterative reconstruction algorithmCatphan phantomRadiation therapyAngular rangeTotal-variationOptimal exposure levelClinical scannerScanning configurationReconstruction algorithmImaging conditionsCatphanPhantomExposure levelsTherapyConfigurationRange
2015
Non-Local and Motion-Based Low-Rank Regularizations for Gated CT Reconstruction
Kim K, Fakhri G, Li Q. Non-Local and Motion-Based Low-Rank Regularizations for Gated CT Reconstruction. 2015, 1-3. DOI: 10.1109/nssmic.2015.7582219.Peer-Reviewed Original ResearchLow-rank regularizationNon-local weightsRegistration matrixLow-rank propertyMulti-frame imagesHigh noiseNon-local regularizationImage patchesMotion blurring artifactsConcurrent executionIterative reconstruction algorithmBlurring artifactsMotion-basedReconstruction algorithmMotion patternsNon-localReduce noiseImage qualityLow-dose conditionsComputer simulationsMotion artifactsNoiseGated computed tomographyGated CTRegularization
2014
Preliminary Investigation of CBCT Imaging Optimization for Image-Guided Radiation Therapy
Bian J, Sharp G, Park Y, Bortfeld T, Fakhri G. Preliminary Investigation of CBCT Imaging Optimization for Image-Guided Radiation Therapy. 2014, 1-4. DOI: 10.1109/nssmic.2014.7430871.Peer-Reviewed Original ResearchImage-guided radiation therapyCone-beam CTCone-beam CT image qualityImprove CBCT image qualityCBCT image qualityCone-beam CT imagesOptimization-based reconstruction algorithmsReduce patient doseImage qualityCBCT dataImages of improved qualityImaging doseReconstruction algorithmIterative reconstruction techniqueASD-POCSImage reconstruction algorithmPatient doseImprove image qualityRadiation therapyDose reductionRadiation doseImage-guidedDosePoor image qualityExposure levelsTof-Pet Ordered Subset Reconstruction Using Non-Uniform Separable Quadratic Surrogates Algorithm
Kim K, Ye J, Cheng L, Ying K, Fakhri G, Li Q. Tof-Pet Ordered Subset Reconstruction Using Non-Uniform Separable Quadratic Surrogates Algorithm. 2014, 963-966. DOI: 10.1109/isbi.2014.6868032.Peer-Reviewed Original ResearchSignal-to-noise ratioQuadratic surrogatesTOF-basedAlgorithm timeNoise ratioReconstruction algorithmReconstructed imagesAlgorithmConvergence rateImage qualityPET reconstructionTransmission reconstructionComputer simulationsTOF PET reconstructionTOF-PETEmission reconstructionAccurate imagingImagesSmall regionConvergenceComputerReconstructionNon-uniformityOSEM
2013
Magnetic Resonance-Based Motion Correction for Positron Emission Tomography Imaging
Ouyang J, Li Q, Fakhri G. Magnetic Resonance-Based Motion Correction for Positron Emission Tomography Imaging. Seminars In Nuclear Medicine 2013, 43: 60-67. PMID: 23178089, PMCID: PMC3508789, DOI: 10.1053/j.semnuclmed.2012.08.007.Peer-Reviewed Original ResearchConceptsMotion correctionClinical whole-body PET scannersMotion-corrected PET imagesWhole-body PET scannerPET motion correctionNonrigid image registration algorithmAcquired MR imagesRespiratory motionImage registration algorithmPET scannerSimultaneous PET/magnetic resonancePET reconstructionSimultaneous PET/MRPatient motionImage qualityIterative PET reconstructionPET/MR studiesPET/magnetic resonanceAttenuating mediaImage artifactsRegistration algorithmSpatial resolutionReconstruction algorithmPositron emission tomographyMR imaging techniques
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 deformation
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
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
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 ResearchFast 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