Glossary Term:






a type of atom that is unstable and prone to break up (decay). Decay releases small fragments of atoms and radiation energy. Exposure to certain radioisotopes can cause cancer. But radioisotopes are also used to find and treat cancer. In certain imaging tests, for example, radioisotopes are injected into the body where they then collect in areas where the disease is active, showing up as brighter areas on the pictures. See also imaging studies, nuclear medicine, radiation.