A type of medical test similar to a CT scan but involving the use of slightly and temporarily radioactive materials to more clearly show up certain aspects of the body’s organs; also called radioisotope scanning or radionuclide imaging. These are invasive procedures, in which the radioactive materials are introduced into the body, as by injection or inhalation. The principle behind nuclear scanning is that various kinds of substances tend to be absorbed or concentrated in specific body organs; the material introduced will depend on which organ is to be studied, and its concentration in that organ can indicate if there is any abnormality, such as a liver problem or a tumor. In the pet scan, for example, radioactive glucose helps indicate the functioning of the circulatory system.
Diagnostic technique making use of radiopharmaceutical injection, inhalation, or ingestion for the purpose of studying the structure and function of an area of the body or organ.