RadiopharmaceuticalsFluorine RadioisotopesCarbon RadioisotopesPositron-Emission TomographyTomography, Emission-ComputedIsotope LabelingOrganotechnetium CompoundsRadioisotopesIodine RadioisotopesRadioisotope Dilution TechniqueNeuronal Tract-TracersTissue DistributionCarbon IsotopesFluorodeoxyglucose F18Tomography, Emission-Computed, Single-PhotonHorseradish PeroxidaseTechnetiumCopper RadioisotopesRadiochemistryMetabolic Clearance RateNitrogen RadioisotopesThiosemicarbazonesSerum Albumin, Radio-IodinatedDextransNeuroanatomical Tract-Tracing TechniquesWheat Germ Agglutinin-Horseradish Peroxidase ConjugateStilbamidinesIodobenzenesFluorescent DyesBrainKineticsGallium RadioisotopesOximesIsotopesAutoradiographyAir MovementsOxygen RadioisotopesDeuteriumNitrogen IsotopesBiological TransportDeoxyglucoseModels, BiologicalIofetamineZinc IsotopesIndicator Dilution TechniquesTechnetium Tc 99m SestamibiTritiumCapillary PermeabilityRadionuclide ImagingNeural PathwaysTechnetium Tc 99m MedronateHeartThorium DioxideTechnetium Tc 99m ExametazimeOrganometallic CompoundsBiotinLeucineGlucoseTechnetium Tc 99m Aggregated AlbuminThallium RadioisotopesTime FactorsRats, Sprague-DawleyWhole-Body CountingVentilationPotassium RadioisotopesFicollThalliumDideoxynucleosidesImage Processing, Computer-AssistedMolecular ImagingCerebrovascular CirculationDogsPhenylalanineDihydroxyphenylalanineSodium Pertechnetate Tc 99mBromine RadioisotopesLanthanumAntipyrineMicrospheresMisonidazoleWheat Germ AgglutininsReproducibility of ResultsSensitivity and SpecificityMultimodal ImagingMicroscopy, ElectronWhole Body ImagingRadionuclide GeneratorsBlood-Brain BarrierCoronary CirculationAxonal TransportAmphetaminesDiffusionFluorineLiverMyocardiumMathematicsRadioimmunoassayRadiometryFluoresceinsBody Fluid Compartments