213Bi is an alpha-emitting radionuclide with potential uses in the treatment of certain types of cancer. Beta radiation is inefficient at destroying cancer cells and has a range of several mm in body tissue. By contrast, alpha particles are thousands of times more efficient at destroying cancer cells and have a range of only a few mu m, resulting in less peripheral tissue damage. New radiation-stable ion exchangers need to be developed to cleanly separate 213Bi from the parent nuclide, 225Ac, to allow the manufacture of a 213Bi generator. Two classes of zirconium phosphonates have already achieved good bismuth separations from americium (a surrogate for actinium) and these results will be improved upon during Phase I. Ion exchange kinetics will also be evaluated and suitable eluants identified. Phase II will use radioisotopes at Argonne National Laboratory to optimize the 213Bi/225Ac separation, further materials will be synthesized at Texas A&M University, and the design and fabrication of a prototype 213Bi generator will be carried out at Lynntech in consultation with the University of Chicago Hospital. This team allows advances in separation science to be utilized to construct a user-friendly 213Bi generator for use in clinical testing. Manufacture of a 213Bi generator will greatly facilitate research into the therapeutic uses of alpha-emitting radionuclides by providing a source of pure 2i3Bi, allowing alpha therapy to be used on a routine basis rather than in research trials.
Alpha particles are more effective at destroying cancer cells than beta or gamma particles and also cause less damage to surrounding healthy tissue. Production of a generator to supply 213Bi would allow a major advance in radioimmunotherapy (RIT) by enabling alpha emitters to be safely used at medical centers distant from the source of supply of the alpha emitting isotopes, thus facilitating basic cancer research. 0nce approved for medical use, the market for such a product would be millions of dollars per year.
