During the past decade or so nuclear medicine has advanced to become a specialty field all of its own. Highly technological radioisotopic detection devices and improved radiopharmaceuticals are the major reasons. Anyone interested in nuclear medicine for clinical practice should acquaint himself with radiopharmaceuticals and instrumentation.
The composition of a radiopharmaceutical; how they are obtained, their characteristics, and how radiopharmaceuticals are used to obtain information are some of the principles involved in all radioisotopic procedures. Radiopharmaceuticals are not used to produce a pharmacological effect. They all contain a radioisotope that is used for diagnostic imaging.
Technetium, an isotope, is one of the most important radiopharmaceuticals used in nuclear medicine today.
Because of its short half-life of six hours, technetium (99m) is used in nuclear medicine today for diagnosis, using the gamma camera. Since technetium lasts such a short time it cannot be kept in stock, so it is prepared by the beta decay of molybdenum. Molybdenum is kept in a shielded container while decaying, yielding technetium. It decays by a procedure called isomeric transition to a lower energy state, giving it a longer half-life. Every morning technetium is needed and extracted from its parent by a brine solution. This procedure is also used in other areas.
Radiopharmaceuticals play an important role in nuclear medicine. In diagnostic procedures small amounts of isotopes may aid in gaining necessary information concerning normal and abnormal life processes. The usage of these radiopharmaceuticals belongs under the supervision of the U.S. Atomic Energy Commission and licenses are issued only after institutions’ facilities are inspected by the commission. Chart No. 2 on the previous page indicates the Radiopharmaceuticals used in diagnostic imaging and the standard adult doses for nuclear medicine scans.