PhotonsTomography, Emission-Computed, Single-PhotonOrganotechnetium CompoundsTechnetium Tc 99m ExametazimeOximesThallium RadioisotopesRadiopharmaceuticalsTomography, Emission-ComputedIofetamineTechnetiumIodine RadioisotopesIodobenzenesCerebrovascular CirculationXenon RadioisotopesTechnetium Tc 99m SestamibiThalliumTechnetium Tc 99m PyrophosphateTropanesAmphetaminesBrainPositron-Emission TomographyPhantoms, ImagingRadiationCardiac-Gated Single-Photon Emission Computer-Assisted TomographyDiagnostic ImagingRetinal Rod Photoreceptor CellsTomography, X-Ray ComputedAcetazolamideMagnetic Resonance ImagingLightMyocardial Perfusion ImagingSensitivity and SpecificityHeartCinanserinOrganophosphorus CompoundsOrganometallic CompoundsGamma CamerasDopamine Plasma Membrane Transport ProteinsScattering, RadiationRadioisotopesImage Processing, Computer-AssistedMonte Carlo MethodSpectrometry, GammaVision, OcularIndium RadioisotopesExercise TestTechnetium Tc 99m MedronateRhodopsinRadiusRadionuclide ImagingThalamic DiseasesFrontal LobeCerebral RevascularizationNight VisionElementary ParticlesLight Signal TransductionSpondylolysisPhotoreceptor CellsRadiation DosageNortropanesTissue SurvivalMolecular ImagingNiobiumMultimodal ImagingPhotoreceptor Cells, InvertebrateImage EnhancementTechnology, RadiologicRadioactive TracersRegional Blood FlowTechnetium Tc 99m Aggregated AlbuminModels, StructuralTime FactorsDominance, CerebralDipyridamoleRadiometryEquipment DesignMoyamoya DiseaseScintillation CountingReproducibility of ResultsPredictive Value of TestsBufo marinusTemporal LobeMyocardial IschemiaFlumazenilImage Interpretation, Computer-AssistedPyrrolidinesSkull NeoplasmsWhole Body ImagingDark AdaptationNuclear MedicineTissue DistributionCoronary DiseaseMicroscopy, Fluorescence, MultiphotonSturge-Weber SyndromeMineralsGallium RadioisotopesGated Blood-Pool ImagingCoronary AngiographyOccipital LobeParticle Accelerators