PhotonsLightTomography, Emission-Computed, Single-PhotonScattering, RadiationElementary ParticlesDarknessMyosin Light ChainsRadiometryPhantoms, ImagingScintillation CountingMonte Carlo MethodLight Signal TransductionMicroscopy, Fluorescence, MultiphotonPhotoreceptor CellsRadiation DosageOrganotechnetium CompoundsPhotosynthesisParticle AcceleratorsRadiopharmaceuticalsEquipment DesignOptics and PhotonicsTechnetium Tc 99m ExametazimeLasersThallium RadioisotopesEquipment Failure AnalysisDark AdaptationSemiconductorsTechnetiumRetinal Rod Photoreceptor CellsOptical ProcessesVision, OcularDose-Response Relationship, RadiationPhotometryTomography, Emission-ComputedTime FactorsOximesAdaptation, OcularRadiotherapy Planning, Computer-AssistedTomography, OpticalRelative Biological EffectivenessLuminescent MeasurementsTelluriumCuring Lights, DentalPhotochemistryFluorescenceRadiotherapy, High-EnergyLuminescenceColorIodine RadioisotopesRadiotherapy DosageUltraviolet RaysCircadian RhythmSpectrum AnalysisChlorophyllProton TherapyImage Processing, Computer-AssistedInfrared RaysPhotoreceptor Cells, InvertebrateElectronsRadiationPhotochemical ProcessesGamma CamerasDiagnostic ImagingRetinaComputer SimulationPhotobiologyRadioisotopesSynchrotronsQuantum TheoryCadmium CompoundsIofetaminePhotoperiodSensitivity and SpecificityLutetiumX-RaysSpectrometry, FluorescenceSpectrometry, GammaPhotic StimulationPositron-Emission TomographyPhotosystem II Protein ComplexHeavy Ion RadiotherapyModels, BiologicalReproducibility of ResultsRefractometryRhodopsinRadionuclide ImagingThalliumXenon RadioisotopesComputer-Aided DesignLinear Energy TransferFluorescent DyesAlgorithmsBrainReflex, PupillaryMyosin-Light-Chain KinaseModels, TheoreticalKineticsRetinal PigmentsNeutronsTechnetium Tc 99m Sestamibi