Radioisotopes are radioactive isotopes. They have unstable atomic nuclei due to an imbalance between protons and neutrons. Radioisotopes are highly energetic as well and emit energy and particles whenever they decay into their more stable form.
Every type of radioisotope has its own disintegration period. This is the amount of time it takes for the radioisotope to return to a stable form. In order to become stable, the radioisotope must emit high-energy particles. These can be in the form of alpha, beta or gamma rays. Many radioisotopes have medical uses. For example, many nuclear medicine procedures utilize quick decaying radioisotopes to visualize certain parts of the body on radiographic film.