Reactor-produced radionuclides are central to clinical practice ad biomedical research. They currently can be divided naturally into three categories:
molybdenum-99 for generators of technetium-99m, the workhorse of diagnostic nuclear medicine;
radionuclides used routinely in medicine (phosphorus-32, phosphorus-33, chromium-51, cobalt-58, cobalt-60, yttrium-90, iodine-131, xenon-133, cesium-137, iridium-192, gold-198) and in research laboratories (hydrogen-3, carbon-14, sulfur-35, phosphorus-32, phosphorus-33, iodine-125); and
radionuclides for research that promise to be of clinical use in the near future.
It appears that current Canadian supplies of molybdenum-99 backed up by supplies from Western European facilities should be more than adequate to meet U.S. requirements. An additional backup source for this critical radionuclide could be from the reprocessing of spent fuel from the University of Missouri Research Reactor (MURR) and other research and test reactors.
With the closing of many government-run reactors, it is essential that one or more reactors be maintained for isotope production and other uses as well. The research reactor at the University of Missouri is already engaged in this activity and should be supported by federal funds.
Because reactors have finite lifetimes, the committee also recommends that plans for the Advanced Neutron Source at Oak Ridge National Laboratory include a radionuclide production capability.
Accelerator-produced radionuclides play an important role in current nuclear medicine practice and promise to play a greater one in the future. As with reactor-produced isotopes, these, too, can be divided into three categories:
Short-lived, positron-emitting radionuclides (carbon-11, nitrogen-13, oxygen-15, and fluorine-18) produced by hospital cyclotrons that are the cornerstone of current positron emission tomography (PET) activity. An important concern to PET facilities is the continued and adequate supply of stable nitrogen-15 and oxygen-18 required for the production of oxygen-15 and fluorine-18, respectively.
Radionuclides that are routinely used in clinical practice and that can be produced by accelerators operating at 30 million electron volts (MeV) or less (gallium-67, indium-111, iodine-123, and thallium-201). All of the major commercial radiopharmaceutical suppliers own and operate such accelerators, and they back each other up in emergencies.
Research radionuclides that can be produced by accelerators operating at greater than 70 MeV with appropriate beam currents. Experience has shown that radionuclides and pharmaceuticals found to be promising in research can be transferred to clinical practice only when a reliable and adequate source can be assured. For this reason the committee strongly recommends the creation of a facility dedicated to the production of ac-