2023
Attenuation correction for PET imaging using conditional denoising diffusion probabilistic model
Dong Y, Jang S, Han P, Johnson K, Ma C, Fakhri G, Li Q, Gong K. Attenuation correction for PET imaging using conditional denoising diffusion probabilistic model. 2023, 00: 1-1. DOI: 10.1109/nssmicrtsd49126.2023.10338188.Peer-Reviewed Original ResearchDiffusion probabilistic modelGenerative adversarial networkConditional encodingAttenuation correctionDenoising diffusion probabilistic modelLow-level featuresProbabilistic modelAttenuation coefficientAdversarial networkExtract featuresPET/MR systemsEncodingPET acquisitionNovel methodDiffusion encodingMagnetic resonanceImagesPET imagingCorrectionMR imagingUNetAttenuationNetworkFeaturesResonance
2022
Cardiac PET/MR Basics
Petibon Y, Ma C, Ouyang J, El Fakhri G. Cardiac PET/MR Basics. 2022, 21-35. DOI: 10.1007/978-3-031-09807-9_2.Peer-Reviewed Original ResearchMeasuring organ motionPET motion correctionFront-end electronicsScintillation detectorOrgan motionMotion correctionAttenuation correctionPET/MR scannersAbility of MRISimultaneous imaging modalityPET/MR technologyAttenuation propertiesHybrid PET/MR scannerPET/MRPre-clinicalImaging modalitiesClinical applicationMRIOrgan systemsCardiac applicationsImaging opportunitiesCorrectionDetectorSpatiotemporal resolutionElectron
2020
Attenuation correction using deep Learning and integrated UTE/multi-echo Dixon sequence: evaluation in amyloid and tau PET imaging
Gong K, Han P, Johnson K, El Fakhri G, Ma C, Li Q. Attenuation correction using deep Learning and integrated UTE/multi-echo Dixon sequence: evaluation in amyloid and tau PET imaging. European Journal Of Nuclear Medicine And Molecular Imaging 2020, 48: 1351-1361. PMID: 33108475, PMCID: PMC8411350, DOI: 10.1007/s00259-020-05061-w.Peer-Reviewed Original ResearchConceptsAttenuation correctionResultsThe Dice coefficientPseudo-CT imagesMR-based AC methodsAccurate ACAC accuracyPET imagingDice coefficientQuantitative accuracyAtlas methodAC methodGradient echoNear verticesTau imagingTau PET imagingAlzheimer's diseaseUltrashortCorrectionTau pathologyRapid acquisitionDeep learning methodsMonitoring of Alzheimer’s diseasePET/MRAmyloidMR‐based PET attenuation correction using a combined ultrashort echo time/multi‐echo Dixon acquisition
Han P, Horng D, Gong K, Petibon Y, Kim K, Li Q, Johnson K, Fakhri G, Ouyang J, Ma C. MR‐based PET attenuation correction using a combined ultrashort echo time/multi‐echo Dixon acquisition. Medical Physics 2020, 47: 3064-3077. PMID: 32279317, PMCID: PMC7375929, DOI: 10.1002/mp.14180.Peer-Reviewed Original ResearchConceptsLinear attenuation coefficientPositron emission tomography attenuation correctionPhysical compartmental modelAttenuation correctionShort T<sub>2</sub> componentPET attenuation correctionRadial k-space trajectoryMagnetic resonance (MR)-based methodK-space trajectoriesRadial trajectoryK-spaceAttenuation coefficientDixon acquisitionsPositron emission tomographyWhole white matterMuting methodImage reconstructionImaging speedMR signalMRAC methodPositron emission tomography imagingCorrectionGray matter regionsPhantomMatter regions
2019
Attenuation correction using 3D deep convolutional neural network for brain 18F-FDG PET/MR: Comparison with Atlas, ZTE and CT based attenuation correction
Blanc-Durand P, Khalife M, Sgard B, Kaushik S, Soret M, Tiss A, Fakhri G, Habert M, Wiesinger F, Kas A. Attenuation correction using 3D deep convolutional neural network for brain 18F-FDG PET/MR: Comparison with Atlas, ZTE and CT based attenuation correction. PLOS ONE 2019, 14: e0223141. PMID: 31589623, PMCID: PMC6779234, DOI: 10.1371/journal.pone.0223141.Peer-Reviewed Original ResearchConceptsZero echo timeAC mapsAttenuation correctionPET attenuation correctionCT-based ACComputed tomographyAC methodPhoton attenuationZTE-ACInvestigation of suspected dementiaMR imagingBrain computed tomographyAtlas-ACBrain metabolismZTE-MRIConvolutional neural networkEcho timeHead atlasFDG-PET/MRPET imagingLow biasRegions-of-interestPatientsCorrectionNeural network
2018
Attenuation correction for brain PET imaging using deep neural network based on Dixon and ZTE MR images
Gong K, Yang J, Kim K, Fakhri G, Seo Y, Li Q. Attenuation correction for brain PET imaging using deep neural network based on Dixon and ZTE MR images. Physics In Medicine And Biology 2018, 63: 125011. PMID: 29790857, PMCID: PMC6031313, DOI: 10.1088/1361-6560/aac763.Peer-Reviewed Original ResearchConceptsU-Net structureU-NetModified U-net structureAttenuation correctionDeep neural network methodBrain PET imagingPET attenuationDeep neural networksPatient data setsAttenuation coefficientDixon-based methodNeural network methodData setsConvolution moduleNetwork inputNeural networkDixon MRPET/MR hybrid systemImage reconstructionPET imagingNetwork methodNetworkNetwork approachNetwork structureQuantification errors
2017
Joint estimation of activity image and attenuation sinogram using time-of-flight positron emission tomography data consistency condition filtering
Li Q, Li H, Kim K, Fakhri G. Joint estimation of activity image and attenuation sinogram using time-of-flight positron emission tomography data consistency condition filtering. Journal Of Medical Imaging 2017, 4: 023502-023502. PMID: 28466027, PMCID: PMC5405780, DOI: 10.1117/1.jmi.4.2.023502.Peer-Reviewed Original ResearchData consistency conditionsMaximum likelihood attenuation correction factorsAttenuation sinogramConsistency conditionsJoint estimationJoint log-likelihood functionPET emission dataAttenuation correction factorsTime-of-flight (TOFActive imagingJoint estimation methodLog-likelihood functionPoisson noiseReconstruction resultsAttenuation correctionSinogram filteringPrevent convergenceEmission dataSinogramPositron emission tomography dataEstimation methodComputer simulationsPositron emission tomographyIterative methodCorrection factor
2016
Penalized MLAA with Spatially-Encoded Anatomic Prior in TOF PET/MR
Kim K, Yang J, Fakhri G, Seo Y, Li Q. Penalized MLAA with Spatially-Encoded Anatomic Prior in TOF PET/MR. 2016, 1-4. DOI: 10.1109/nssmic.2016.8069514.Peer-Reviewed Original ResearchSynthetic CT imagesAlternating direction methodAttenuation correctionImage qualityMR-based attenuation correctionTOF-PET dataPET emission dataPET image qualityTime-of-flight (TOFDirection methodCost functionCT imagesPET/MR scannersNoise componentsConsistency conditionsAnatomical MRIterative processComputer simulationsPET dataMLAAPET/MR scansImagesBone signalEmission dataTOF
2015
National Electrical Manufacturers Association and Clinical Evaluation of a Novel Brain PET/CT Scanner
Grogg K, Toole T, Ouyang J, Zhu X, Normandin M, Li Q, Johnson K, Alpert N, Fakhri G. National Electrical Manufacturers Association and Clinical Evaluation of a Novel Brain PET/CT Scanner. Journal Of Nuclear Medicine 2015, 57: 646-652. PMID: 26697961, PMCID: PMC4818715, DOI: 10.2967/jnumed.115.159723.Peer-Reviewed Original ResearchConceptsNoise-equivalent count rateCount rateLoose cutsMaximum noise-equivalent counting rateSpatial resolutionDetector ringSilicon photomultipliersBrain phantomContrast recoveryAttenuation correctionPET/CT systemCrystal blockPET/CT scannerImage qualityRadial offsetNational Electrical Manufacturers AssociationActivity distributionUnique mobility capabilitiesAxial extentTransverse resolutionPhantomAxial resolutionActivity concentrationsHuman scansLayer 1 cmContinuous MR bone density measurement using water- and fat-suppressed projection imaging (WASPI) for PET attenuation correction in PET-MR
Huang C, Ouyang J, Reese T, Wu Y, Fakhri G, Ackerman J. Continuous MR bone density measurement using water- and fat-suppressed projection imaging (WASPI) for PET attenuation correction in PET-MR. Physics In Medicine And Biology 2015, 60: n369-n381. PMID: 26405761, PMCID: PMC4607313, DOI: 10.1088/0031-9155/60/20/n369.Peer-Reviewed Original ResearchConceptsAttenuation correctionUltrashort echo timeMR-based attenuation correctionProjection imagesPET attenuation correctionMR attenuation correctionPET-MRPulse sequenceEcho timeDensity variationsPET imagingCorrectionBone density variationWASPIDensity measurementsAttenuation variationsPhantomMR sequencesLack of signalPulseAttenuationAccelerated acquisition of tagged MRI for cardiac motion correction in simultaneous PET‐MR: Phantom and patient studies
Huang C, Petibon Y, Ouyang J, Reese T, Ahlman M, Bluemke D, El Fakhri G. Accelerated acquisition of tagged MRI for cardiac motion correction in simultaneous PET‐MR: Phantom and patient studies. Medical Physics 2015, 42: 1087-1097. PMID: 25652521, PMCID: PMC4312342, DOI: 10.1118/1.4906247.Peer-Reviewed Original ResearchConceptsPET motion correctionMotion correctionSimultaneous PET-MRTMR dataPET list-mode dataPET-MRList-mode dataCardiac motion correctionPET-MR scannersImage qualityParallel imagingAcquisition timePET imagingRespiratory motionCompressive sensingMotion fieldAttenuation correctionDefect contrastModerate acceleration factorsDegradation of image qualityTagged MRCardiac phantomLong acquisition timesPhantomAccurate motion field
2014
Quantitative simultaneous positron emission tomography and magnetic resonance imaging
Ouyang J, Petibon Y, Huang C, Reese T, Kolnick A, Fakhri G. Quantitative simultaneous positron emission tomography and magnetic resonance imaging. Journal Of Medical Imaging 2014, 1: 033502-033502. PMID: 26158055, PMCID: PMC4306197, DOI: 10.1117/1.jmi.1.3.033502.Peer-Reviewed Original Research
2013
Bias Atlases for Segmentation-Based PET Attenuation Correction Using PET-CT and MR
Ouyang J, Chun Y, Petibon Y, Bonab A, Alpert N, Fakhri G. Bias Atlases for Segmentation-Based PET Attenuation Correction Using PET-CT and MR. IEEE Transactions On Nuclear Science 2013, 60: 3373-3382. PMID: 24966415, PMCID: PMC4067048, DOI: 10.1109/tns.2013.2278624.Peer-Reviewed Original ResearchAttenuation correctionBias imagesLung density variationsPET attenuation correctionPET-MR scannersAttenuation mapFat identificationOriginal CTPET reconstructionOverall standard deviationPET-MRMR imagingVariation of biasDensity variationsCT-based studyPET accuracyPET-CTStandard deviation of biasCorrectionFat segmentationTissue classesPatientsSoft tissueAttenuationLung
2010
SU‐GG‐J‐149: Feasibility of In‐Room PET Imaging for in Vivo Proton Beam Range Verification
España S, Zhu X, Daartz J, Liebsch N, Fakhri G, Bortfeld T, Paganetti H. SU‐GG‐J‐149: Feasibility of In‐Room PET Imaging for in Vivo Proton Beam Range Verification. Medical Physics 2010, 37: 3180-3180. DOI: 10.1118/1.3468372.Peer-Reviewed Original ResearchRange verificationIn-roomProton therapyIn vivo range verificationProton beam range verificationPassive scattering proton therapyBeam range verificationIn-room measurementsOff-line protocolsFalloff positionsBiological washoutTreatment couchCount ratePET imagingTreatment positionPET scannerAttenuation correctionTreatment roomPET scansCo-registration accuracyCT numbersCalculated uncertaintiesPatient studiesWashout modelTreatment planning
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 improvementFBPScatteringClinical Myocardial Perfusion PET/CT
Di Carli M, Dorbala S, Meserve J, Fakhri G, Sitek A, Moore S. Clinical Myocardial Perfusion PET/CT. Journal Of Nuclear Medicine 2007, 48: 783-793. PMID: 17475968, DOI: 10.2967/jnumed.106.032789.Peer-Reviewed Original ResearchConceptsCoronary artery diseaseMyocardial perfusion PETPerfusion PETDiagnosing obstructive CADClinically useful risk stratificationObstructive coronary artery diseaseAnatomic coronary artery diseaseMyocardial perfusion PET/CTMultivessel coronary artery diseaseLeft ventricular functionEvaluation of patientsQuantify myocardial perfusionVentricular functionIschemic burdenPharmacological stressRisk stratificationCardiac PETArtery diseasePET/CT technologyMyocardial perfusionAttenuation correctionNuclear cardiologyFunctional consequencesSPECTPET
2001
Absolute Activity Quantitation From Projections Using an Analytical Approach: Comparison With Iterative Methods in Tc-99M and I-123 Brain SPECT
Fakhri G, Kijewski M, Moore S. Absolute Activity Quantitation From Projections Using an Analytical Approach: Comparison With Iterative Methods in Tc-99M and I-123 Brain SPECT. IEEE Transactions On Nuclear Science 2001, 48: 768. DOI: 10.1109/23.940161.Peer-Reviewed Original ResearchVariable collimator responseI-123 studiesOrdered subsets-expectation maximizationI-123Tc-99mTc-99Brain phantomAttenuation correctionAnthropomorphic brain phantomDigital brain phantomTc-99m studiesMonte Carlo simulated projectionsCollimator responseActivity quantitationPathological patientsBrain structuresBrain SPECTActivity distributionPoor spatial resolutionSPECT activityQuantitative accuracyFitting procedurePartial volume effectsCaudate nucleusCorpus callosum
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 schemeAbsolute 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