LutetiumMetals, Rare EarthNeodymiumSilicatesYtterbiumDysprosiumSamariumScandiumCeriumYttriumPhotosensitizing AgentsEuropiumSilica GelTomography Scanners, X-Ray ComputedDigestive System Physiological PhenomenaLanthanumPhotochemotherapyPhantoms, ImagingMagnetsCottonseed OilPositron-Emission TomographyIron IsotopesEquipment DesignGastrointestinal TransitOxidesSoilEvolution, PlanetaryExobiologyEvolution, ChemicalMetals, Alkaline Earth