Department of Energy plans to dispose of uranium 233 could rob the nation of an important source of isotopes for medical and scientific research, according to a report by the DOE Office of Inspector General.

"Should the department elect to proceed as planned, it may dispose of a national resource that is irreplaceable," the report said. "The potential for isotopes produced from uranium 233 to help save the lives of thousands of American cancer patients is widely accepted."

DOE has uranium 233 at the Idaho National Laboratory and the Oak Ridge National Laboratory in Tennessee that can be used to produce actinium 225 and bismuth 213 by first producing thorium 229.

"Both actinium and bismuth are extremely rare isotopes that are now being used in clinical trials and cancer research at organizations such as the Memorial Sloan-Kettering Cancer Center in New York," the report said. "Early research results have been promising, showing improved cancer survivability rates."

The materials also could have applications in developing proliferation-resistant nuclear power reactor fuel cycles and as an alternative to plutonium 238 for powering flights deep into space, the report said. Uranium 233 also is used in a national nuclear security program.

However, Congress has directed DOE to end the practice of extracting thorium 229 from uranium 233, which allows the production of actinium and bismuth. DOE plans to begin preparing the Tennessee inventory for disposal in 2012.

In addition, DOE began shipping the Idaho inventory of uranium 233 to the Nevada Test Site for disposal as waste in January, according to the report.

"Once the planned disposal of uranium 233 is complete, the department will not have the means to increase isotope production to meet the dramatic projections of future needs for actinium and bismuth," the report said.

About 650 millicuries per year of actinium 225 is produced now in the United States. However, the National Institutes of Health projects a demand for 1,700 millicuries this year and 6,000 millicuries in 2009.

Security and proliferation concerns prohibit DOE from making the source material directly available to universities or industry to permit the development of a private sector source of isotopes, the report said.

Although the private sector is pursuing some other options to create the isotopes, it is not known if the technologies will prove viable, the report said.

"At present, no viable alternative methods of production of actinium and bismuth have been demonstrated or proven," the report said.

One top DOE official estimated that the isotopes could be used to treat 6,000 patients annually. Research is being done to use isotopes derived from uranium 233 to treat acute myeloid leukemia, non-Hodgkin lymphoma, lung cancer, pancreatic cancer and kidney cancer. It's also being investigated for treatment of AIDS and for bone marrow transplants, according to the report.

DOE responded that a merit-based peer review would be conducted to examine the needs and priorities for actinium and bismuth, according to the report.