Nuclear medicine uses small amounts of radioactive materials to diagnose and treat disease. The Society of Nuclear Medicine [local] has an informative Web-site.

Radioimmunoassay was co-invented by Rosalyn Sussman Yaslow [local] for which she shared the 1977 Nobel prize. Positron Emission Tomagraphy, or PET scanning, reveals much important information. The production [local] of positron-emitting isotopes is a major problem for PET scanning -- positron emitters are very unstable, so their production must be nearby, in time, to the site of their use. Several radioisotopes [local] are used in medicine.

Although radioactive materials are not used in magnetic resonance imaging, this technique is possible because many atomic nuclei behave like magnets.