Radionuclides are radioactive elements. Radioactivity can be defined as the release of alpha and beta particles from atoms, and/or gamma rays that takes place when the nuclei of certain unstable substances spontaneously disintegrate. It is during this disintegration process that they emit radiation. The two main types of radiation released during such processes are termed ionizing, or of sufficient strength to forcibly eject electrons from their orbit around an atoms nucleus, producing ions, and non-ionizing,of less strength and incapable of displacing electrons and forming ions. Ionizing radiation is highly significant because when it occurs within the atoms of molecules in living things, it is capable of causing biological damage such as the death of cells or the unnatural reproduction of cells. We term this unnatural reproduction of cells cancer.

Radionuclides occur in the environment both naturally and as a result of human industry. Some naturally-occurring radionuclides...