Storing radionuclides. Gloved hands handling a bottle containing radioactive isotopes, elements that emit radiation. These radiopharmaceuticals emit gamma rays and are used in the diagnostic technique of radionuclide or gamma scanning. Since gamma radiation is harmful to living tissues, the isotopes are carefully stored and handled to ensure that little radiation is absorbed by workers. When not in use, they are kept in a thick container (lower left) made of materials which absorb gamma rays. The protective gloves and clothing worn by the health worker prevent contamination with radiation and the isotopes are manipulated using metal tongs.