Our research is focused on the development of improved reactor production and processing methods to provide medical radioisotopes, the development of new radionuclide generator systems, the design and evaluation of new radiopharmaceuticals for applications in nuclear medicine and oncology, and association with Medical Cooperative Programs throughout the world for the further preclinical testing and clinical evaluation of agents developed at ORNL. In the United States, only ORNL has available the combined resources of the stable isotope inventory, a High Flux Isotope Reactor (HFIR), hot cell processing capabilities, and a wide range of support functions required for such research. These collective resources provide unique capabilities for nuclear medicine research and radioisotope production.

The ORNL Nuclear Medicine Program has dedicated research laboratories available for radiochemistry, synthetic chemistry, animal experiments and target preparation, and we also have available hot cells and glove box facilities for radioisotope processing. The ORNL High Flux Isotope Reactor (HFIR) provides a key resource for radioisotope production for our research program, providing a maximum steady state thermal neutron flux of about 2.3 x 10¹⁵neutrons per square centimeter per second, which is the highest of any reactor in the world. The high target volume and versatile HFIR irradiation positions within the core and reflector regions include three online, hydraulically operated systems which provides access to the core of the reactor, for both short and long term irradiations. These capabilities offer unparalleled capability for production of very large quantities of high specific activity radioisotopes. We are currently developing new improved processing and purification procedures and produce  a variety of radioisotopes which are of current interest in medicine and biology, especially for cancer therapy.  A key example is multi-Curie HFIR production of tungsten-188 (from the enriched stable isotope ¹⁸⁶w) , which is the parent of the tungsten-188/rhenium-188 generator system which we developed to provide carrier-free rhenium-188.  Rhenium-188 from our generator is used for both research and also in over 50 clinical trials throughout the world for various forms of cancer therapy and for coronary restenosis therapy.  Other examples of HFIR-produced medical radioisotopes include high specific activity holmium-166 (from natural, high-purity Ho), lutetium-177 (from enriched Lu-176 and ytterbium-176), platinum-195m (from enriched Pt-194 and iridium-193) and tin-117m (from enriched Sn-117).  Most of the enriched stable isotopes used to produce these medical radioisotopes in HFIR are obtained from the ORNL calutrons. Although DOE has decided not to operate the calutrons any longer, varying amounts of these stable isotopes remain in the ORNL inventory. Alternate stable isotope enrichment capabilities are being considered, as are alternate sources (primarily Russia). Our research program also includes production of the alpha-emitting radioisotope actinium-225, which is used in radiotherapy of cancer.  Actinium-225 is routinely extracted from the thorium-229 stock, and ORNL is currently the largest supplier of this medical radioisotope.

Please direct any questions concerning nuclear medicine to:

F. F. (Russ) Knapp, Program Manager • Building 4501, MS-6229 • Oak Ridge National Laboratory • Oak Ridge, TN 37831-6229 • Phone: 865-574-6229• Fax: 865-574-6226 • E-mail: knappffjr@ornl.gov