PhotonsTomography, Emission-Computed, Single-PhotonLightScattering, RadiationElementary ParticlesPhantoms, ImagingRadiometryMonte Carlo MethodScintillation CountingMicroscopy, Fluorescence, MultiphotonRadiation DosageOrganotechnetium CompoundsParticle AcceleratorsTime FactorsRadiopharmaceuticalsRadiotherapy Planning, Computer-AssistedImage Processing, Computer-AssistedLasersEquipment DesignEquipment Failure AnalysisSpectrometry, FluorescenceTechnetium Tc 99m ExametazimeFluorescenceMagnetic Resonance ImagingThallium RadioisotopesReproducibility of ResultsTechnetiumSensitivity and SpecificityTomography, Emission-ComputedRadiotherapy DosageFluorescent DyesOximesAlgorithmsRadiotherapy, Intensity-ModulatedOptics and PhotonicsRelative Biological EffectivenessDose-Response Relationship, RadiationPhotometryTelluriumLuminescent MeasurementsRadiotherapy, High-EnergyComputer SimulationImage EnhancementLuminescenceProton TherapyOptical ProcessesIodine RadioisotopesPhotoreceptor CellsSemiconductorsTomography, OpticalRetinal Rod Photoreceptor CellsSpectrum AnalysisPhotosynthesisElectronsBrainDiagnostic ImagingVision, OcularCadmium CompoundsSynchrotronsRadiationDark AdaptationGamma CamerasRhodopsinRadioisotopesPositron-Emission TomographyX-RaysModels, TheoreticalQuantum TheoryTomography, X-Ray ComputedPain MeasurementDarknessAdaptation, OcularImage Interpretation, Computer-AssistedIofetamineSpectrometry, GammaPhotochemistryLutetiumRadiotherapy, ConformalRadionuclide ImagingHeavy Ion RadiotherapyModels, BiologicalCerebrovascular CirculationLinear Energy TransferInfrared RaysThalliumNeutronsMicroscopy, FluorescenceArtifactsXenon RadioisotopesComputer-Aided DesignTechnetium Tc 99m SestamibiProtonsColorMolecular ImagingOrgans at RiskTechnetium Tc 99m PyrophosphateChlorophyllTransducersIodobenzenesCalibration