PhotonsTomography, Emission-Computed, Single-PhotonElementary ParticlesLightScattering, RadiationRadiometryMonte Carlo MethodPhantoms, ImagingScintillation CountingMicroscopy, Fluorescence, MultiphotonOrganotechnetium CompoundsParticle AcceleratorsRadiation DosageRadiopharmaceuticalsTechnetium Tc 99m ExametazimeThallium RadioisotopesTechnetiumMolecular Sequence DataTomography, Emission-ComputedOximesEquipment Failure AnalysisRadiotherapy Planning, Computer-AssistedEquipment DesignRelative Biological EffectivenessIodine RadioisotopesTelluriumRadiotherapy, High-EnergyRadiotherapy DosageTomography, OpticalTime FactorsProton TherapyComputer SimulationSemiconductorsOptics and PhotonicsLasersOptical ProcessesImage Processing, Computer-AssistedGamma CamerasDose-Response Relationship, RadiationRadioisotopesElectronsKineticsLuminescent MeasurementsPhotometryAmino Acid SequenceIofetamineModels, BiologicalRadiationQuantum TheoryRetinal Rod Photoreceptor CellsSpectrometry, GammaRhodopsinSpectrum AnalysisDiagnostic ImagingLutetiumBase SequenceBrainCadmium CompoundsSynchrotronsAlgorithmsSensitivity and SpecificityPositron-Emission TomographyLuminescenceX-RaysHeavy Ion RadiotherapyModels, TheoreticalVision, OcularRadionuclide ImagingFluorescenceThalliumPhotosynthesisPhotoreceptor CellsSpectrometry, FluorescenceXenon RadioisotopesLinear Energy TransferReproducibility of ResultsTechnetium Tc 99m SestamibiTomography, X-Ray ComputedProtonsRadiotherapy, Intensity-ModulatedTechnetium Tc 99m PyrophosphateCerebrovascular CirculationIodobenzenesNeutronsFluorescent DyesX-Ray TherapyComputer-Aided DesignPhotochemistryModels, StructuralRadiotherapy, ConformalDarknessEnergy TransferMineralsAstronomical ObjectsTomographyRadiusDark AdaptationFast NeutronsHeartImage Enhancement