Advanced Medical Isotopes
ORNL researchers produce a wide range of medical radioisotopes
Like fuel-cycle researchers, scientists in ORNL's isotopes program have a vested interest in exploring the production and processing of radioisotopes—in this case for medical applications. Dating back to 1946, the laboratory's radioisotope program relies heavily on the production capabilities of the High Flux Isotope Reactor. Since its construction in the mid-1960s, researchers have used HFIR to produce a wide range of medical radioisotopes and have greatly advanced the design and testing of new radiopharmaceuticals.
The production of different isotopes requires neutrons with various energy levels. HFIR is one of two facilities in the world that provides enough neutrons in a specific energy range to enable the production of several critical isotopes. These radioisotopes are used in a variety of therapeutic applications in nuclear medicine, cancer research and other specialties, including therapies for liver and skin cancer. Other applications of ORNL-produced radioisotopes include treating rheumatoid arthritis and relieving bone pain associated with the spread of prostate, breast and lung cancers. These painrelieving treatments don't kill cancer cells, but they greatly increase the quality of life for terminally ill patients.
ORNL's Nuclear Medicine Program develops technologies for both the production and use of radioisotopes and has participated in several clinical trials involving isotope-based treatments. The program also collaborates with the International Atomic Energy Agency and other institutions around the world on research into radioisotopes as well as their medical applications.
Some of this research entails investigating new techniques for purifying isotopes for use in imaging and treating tumors. These efforts involve developing and testing processes for attaching radioisotopes to molecules, antibodies and nanoparticles that zero in on specific biological features of tumors. Among the radioisotopes being applied in this way are HFIR-produced therapeutic agents, such as rhenium-188, used in the treatment of bone, liver and skin cancers; bismuth-213, used to treat acute myeloid leukemia; and radon-223, expected to be useful in the treatment of bone pain.
Another prospect on the program's horizon is harvesting isotopes from used nuclear fuel, or even proactively tweaking the composition of new fuel to yield specific isotopes in its waste stream. The thought among some isotope researchers is that if waste products are treated as the source of valuable medical isotopes, rather than strictly as a liability, recycling used fuel could become a more attractive option.—Jim Pearce