Radioactive source

A radioactive source can be of natural or artificial origin (manufactured source). A manufactured source of radiation is typically used for industrial, research, or medical applications, i.e. Iodine-131(131I) for radioisotope therapy of thyroid cancer, Caesium-137 (137Cs) or Cobalt-60 (60Co) for industrial radiography in non destructive testing and inspecting materials for hidden flaws.
See: nuclear medicine