2021
Free‐breathing 3D cardiac T1 mapping with transmit B1 correction at 3T
Han P, Marin T, Djebra Y, Landes V, Zhuo Y, Fakhri G, Ma C. Free‐breathing 3D cardiac T1 mapping with transmit B1 correction at 3T. Magnetic Resonance In Medicine 2021, 87: 1832-1845. PMID: 34812547, PMCID: PMC8810588, DOI: 10.1002/mrm.29097.Peer-Reviewed Original ResearchConceptsFlip-angle estimationCardiac T<sub>1</sub> mappingGradient echo readoutThrough-plane spatial resolutionImaging timePractical imaging timesFree breathingPhantom studyB1 correctionAccelerated imagingIn-planeT)-spaceMyocardial T<sub>1</sub> valuesSubspace-based methodsSpatial resolutionImaging experimentsAcquisition schemeT)-space dataSubject-specific timeCorrectionModified Look-Locker inversion recoveryLook-Locker inversion recoveryTime of data acquisitionAverage imaging timeInversion-recovery sequence
2020
Dynamic Cardiac SPECT for diagnostic and theranostics applications: latest results
Bläckberg L, Sajedi S, Anderson O, Feng Y, Fakhri G, Furenlid L, Sabet H. Dynamic Cardiac SPECT for diagnostic and theranostics applications: latest results. 2020, 00: 1-3. DOI: 10.1109/nss/mic42677.2020.9508002.Peer-Reviewed Original ResearchCsI:Tl crystalsMPPC arraysTl crystalsCsI:Tl scintillatorGamma-ray energiesCardiac SPECTCsI:TlLow energy resolutionCardiac SPECT imagingGamma cameraConventional gamma cameraResolution recovery techniquesSensL SiPMsEnergy resolutionStopping powerTl scintillatorDetector modulesReadout electronicsDynamic cardiac SPECTPinhole collimatorHigh power lasersPhantom studyCollimatorDetectorSiPM
2019
PET Image Deblurring and Super-Resolution With an MR-Based Joint Entropy Prior
Song T, Yang F, Chowdhury S, Kim K, Johnson K, Fakhri G, Li Q, Dutta J. PET Image Deblurring and Super-Resolution With an MR-Based Joint Entropy Prior. IEEE Transactions On Computational Imaging 2019, 5: 530-539. PMID: 31723575, PMCID: PMC6853071, DOI: 10.1109/tci.2019.2913287.Peer-Reviewed Original ResearchContrast-to-noise ratioStructural similarity indexHoffman phantomImage deblurringDigital phantomPhantom studyPeak signal-to-noise ratioSuper-resolution frameworkQuantitative accuracySimilarity indexSignal-to-noise ratioSpatial resolutionPhantomImage quantitationSuper-resolutionTau imaging studiesImage qualityPET imagingDeblurringHigh-resolution MR imagingRoot mean square errorSimulation studyBrainWebPost-processingPenalty function
2017
Joint reconstruction of Ictal/inter‐ictal SPECT data for improved epileptic foci localization
Rakvongthai Y, Fahey F, Borvorntanajanya K, Tepmongkol S, Vutrapongwatana U, Zukotynski K, Fakhri G, Ouyang J. Joint reconstruction of Ictal/inter‐ictal SPECT data for improved epileptic foci localization. Medical Physics 2017, 44: 1437-1444. PMID: 28211105, PMCID: PMC5462456, DOI: 10.1002/mp.12167.Peer-Reviewed Original ResearchConceptsSPECT reconstruction methodDifferential imagingLow-noise datasetConventional subtraction methodLesion contrastSPECT projection dataEpileptic focus localizationHoffman phantomPatient studiesReconstruction methodJoint methodSPECT projectionsHead phantomPhantom locationsSubtraction methodPhantom studyNuclear medicine physiciansAttenuation backgroundPhantomConventional subtraction approachFocus localizationConventional subtractionReceiver operating characteristicLow noiseProjection dataFeasibility 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
2014
Myocardial Defect Detection Using PET-CT: Phantom Studies
Mananga E, Fakhri G, Schaefferkoetter J, Bonab A, Ouyang J. Myocardial Defect Detection Using PET-CT: Phantom Studies. PLOS ONE 2014, 9: e88200. PMID: 24505429, PMCID: PMC3914931, DOI: 10.1371/journal.pone.0088200.Peer-Reviewed Original ResearchConceptsMyocardial defect detectionFiltered back projectionChannelized Hotelling observerPhantom studyActivity distributionSubset expectation maximizationDefect detectionCardiac PET studiesMyocardial defectsHotelling observerNoise levelBack-projectionPET-CTPhantomExpectation maximizationOP-OSEMReconstruction schemePET studiesOSEMDefectsNoise
2013
Simultaneous 99mTc‐MDP/123I‐MIBG tumor imaging using SPECT‐CT: Phantom and constructed patient studies
Rakvongthai Y, Fakhri G, Lim R, Bonab A, Ouyang J. Simultaneous 99mTc‐MDP/123I‐MIBG tumor imaging using SPECT‐CT: Phantom and constructed patient studies. Medical Physics 2013, 40: 102506. PMID: 24089927, PMCID: PMC3785531, DOI: 10.1118/1.4820977.Peer-Reviewed Original ResearchConceptsScatter correctionDual-radionuclideContrast recoveryPhantom studyAnthropomorphic torso phantomPatient studiesTumor uptakeTumor imagingSPECT projectionsTorso phantomMonte-CarloPhantom dataPhantomIterative reconstructionOSEMProjection dataDR dataIncrease patient throughputNoise realizationsSPECT-CTImage reconstructionClinical studiesTumorTumor projectionPoisson noise
2011
Monitoring proton radiation therapy with in-room PET imaging
Zhu X, España S, Daartz J, Liebsch N, Ouyang J, Paganetti H, Bortfeld T, Fakhri G. Monitoring proton radiation therapy with in-room PET imaging. Physics In Medicine And Biology 2011, 56: 4041-4057. PMID: 21677366, PMCID: PMC3141290, DOI: 10.1088/0031-9155/56/13/019.Peer-Reviewed Original ResearchConceptsIn-room positron emission tomographyIn-roomProton therapy treatment roomPositron emission tomography systemProton range verificationSoft tissue-equivalent materialMonte Carlo predictionsTissue-equivalent materialsPositron emission tomography acquisition timesProton radiation therapyPositron emission tomographyBiological washoutRange verificationProton therapyList-modeActivity distribution patternsPhantom studyTreatment roomPET acquisitionSoft tissue regionsIn vivo verificationDeep-siteOff-line modalityPositron emission tomography dataAdenoid cystic carcinomaImpact of Time-of-Flight PET on Whole-Body Oncologic Studies: A Human Observer Lesion Detection and Localization Study
Surti S, Scheuermann J, Fakhri G, Daube-Witherspoon M, Lim R, Abi-Hatem N, Moussallem E, Benard F, Mankoff D, Karp J. Impact of Time-of-Flight PET on Whole-Body Oncologic Studies: A Human Observer Lesion Detection and Localization Study. Journal Of Nuclear Medicine 2011, 52: 712-719. PMID: 21498523, PMCID: PMC3104282, DOI: 10.2967/jnumed.110.086678.Peer-Reviewed Original ResearchConceptsLocalization receiver operating characteristicsTime-of-flight PETLong scan timesArea under the LROC curveScan timeFunction of scan timePatient sizeTime-of-flight (TOFLROC curveLow-uptake lesionsTOF imagesTOF kernelLesion detection taskTOF-PETWhole-body oncologyLesion detection performanceScanner fieldPhantom studyPatient body mass indexProbability of correct localizationLesion detectionSphere dataBody mass indexLarger patientsReceiver operating characteristic
2009
SU‐FF‐J‐129: In‐Room Proton Range Verification Using Mobile NeuroPET ‐ Feasibility Study
Knopf A, Zhu X, Parodi K, Paganetti H, Bortfeld T, Fakhri G. SU‐FF‐J‐129: In‐Room Proton Range Verification Using Mobile NeuroPET ‐ Feasibility Study. Medical Physics 2009, 36: 2506-2506. DOI: 10.1118/1.3181421.Peer-Reviewed Original ResearchProton range verificationRange verificationPET/CT scannerCommercial PET/CT scannersWater equivalent rangePositron emission tomographyBiological washoutPMMA phantomProton fieldsProton beamActivity depth profilesProton treatmentPhantom studyTreatment roomIn-roomPositron emission tomography scanPositron emission tomography dataPatient repositioningPhantomPositron emission tomography imagingProtonDepth profilesPET/CT imagingRadiation treatmentTotal dose
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
2005
Performance of a novel collimator for high‐sensitivity brain SPECT
Fakhri G, Ouyang J, Zimmerman R, Fischman A, Kijewski M. Performance of a novel collimator for high‐sensitivity brain SPECT. Medical Physics 2005, 33: 209-215. PMID: 16485427, DOI: 10.1118/1.2143140.Peer-Reviewed Original ResearchConceptsSphere activity concentrationNPW-SNRStandard collimatorSphere-to-background activity ratiosAttenuation of countsPhantom centerActivity concentrationsPoint spread functionCentral regionCollimatorPhantom studyStriatal phantomCylindrical backgroundResolution recoveryPhantomSpherical lesionsRamp filterCrystal surfaceSpread functionSignal-to-noise ratioCentral brain structuresFitting imageHealthy volunteersBrain SPECTSphere activity
2003
A Multi-Scanner Evaluation of PET Image Quality Using Phantom Studies
Surti S, Badawi R, Holdsworth C, Fakhri G, Kinahan P, Karp J. A Multi-Scanner Evaluation of PET Image Quality Using Phantom Studies. 2003, 4: 2425-2427. DOI: 10.1109/nssmic.2003.1352384.Peer-Reviewed Original ResearchSignal-to-noise ratioImage signal-to-noisePET image qualityImage signal-to-noise ratioDiameter phantomImage qualityPhantom diameterPET scannerNEC ratesPhantom studyMeasures of image qualitySignal-to-noisePhantomAcquisition modeFilter observerSpecific tasksAccurate measurementRate dropsSinogramScannerPreliminary resultsECAT