Revived rhenium isotope generators answer call for prostate cancer research and other therapies

Revived rhenium isotope generators have emerged as a promising solution for targeted prostate cancer research and other medical therapies, according to recent findings from the Department of Energy's Oak Ridge National Laboratory (ORNL). ORNL, one of the few places worldwide capable of producing specialized isotopes, including rhenium-188 (Re-188), is making strides in modernizing the technology for producing these generators.

A key player in this development is graduate student Haswitha Sabbineni, whose research is building upon the work of her mentor, Professor Nancy Carrasco, and colleague Alejandro Llorente-Esteban. These researchers successfully cloned the DNA coding for the sodium/iodide symporter (NIS), a protein that successfully delivers targeted radioactive iodine treatments to thyroid cancer cells. Sabbineni is now investigating whether this strategy can be applied to treat prostate cancer in a mouse model.

To test her hypothesis, Sabbineni required radioactive perrhenate, which contains the rare isotope Re-188. ORNL, however, had not produced tungsten-rhenium generators since 2011. But radiochemist Becca Hoerres stepped in to revive the technology and modernize it. Hoerres, who had previously worked on actinium-225, a medical isotope used in cancer treatment, eagerly took on the challenge.

ORNL's High Flux Isotope Reactor (HFIR) is capable of producing tungsten-188 (W-188) by irradiating W-186. The process involves creating generators—columns of W-188 from which Re-188 can be eluted, translating reactor-based innovative discovery science into practical tools for medical research. The generators are then shipped to customers who can separate the Re-188 decay product as needed.

The half-life of W-188 is approximately 60 days, meaning a generator should last between 1 to 18 months. This long half-life allows generators to be shipped to any location in the world, expanding access to U.S.-produced medical isotopes. Hoerres has made some design tweaks to simplify the process and reduce costs, making it easier for researchers and clinicians to use the generators outside a national lab.