The AAPM/RSNA physics tutorial for residents. Radiopharmaceuticals

Radiopharmaceuticals are essential to the performance of nuclear medicine procedures. These radioactive drugs consist of two components: a drug component for localization in a specific tissue or organ and a radioactive component for diagnostic or therapeutic purposes. The majority of radiopharmaceuticals are used for diagnostic imaging procedures. The radioisotopes used for radiopharmaceuticals are produced in a number of ways: as by-products of fission, by means of neutron activation, by cyclotrons, and by generators. These methods produce isotopes with both desirable and undesirable properties. Approximately 80% of all nuclear medicine procedures performed in the United States use radiopharmaceuticals labeled with technetium-99m. The chemical properties of technetium allow relatively simple preparation of Tc-99m compounds by using reagent kits. Quality control testing of radiopharmaceuticals is routinely performed to ensure compliance with various purity standards such as assay for radioactivity, radionuclidic purity, chemical purity, radiochemical purity, pharmaceutical purity, and biologic purity.