The radioactive isotope yttrium-90 is especially efficient in the radioimmunotherapy fight against cancer. And ironically, cancer centers' favorite source for yttrium-90 is the Department of Energy's Pacific Northwest National Laboratory, producer of plutonium for nuclear warheads.
"We have here a large amount of fission waste material from years of producing plutonium," said Dr. Thomas. S. Tenforde, whose Radio Isotopes Program at the laboratory's Hanford site in Richland, Washington, has been generating the yttrium-90 for sale since 1991. "Ours is the purest yttrium-90 on the market and we can supply large quantities."
Radioimmunotherapy involves binding certain isotopes, like yttrium-90, to the surfaces of specific antibodies which then carry the radioactive material to the surface of the cancer cell. As the yttrium-90 decays during its half-life of 64 hours, it emits plenty of cancer-killing energy. Tenforde calls this method of therapy - which has shown promise in treating patients with advanced leukemia and lymphoma, for instance - the "smart bullet" approach. But for the treatment to work, the yttrium-90 has to be as pure as possible.
"[The lab's] quality control is so sharp and so consistent that they can offer the really pristine product needed for very new and selective cancer treatment," said Dr. Hubert M. Vriesendorp, a radiation oncologist at the Arlington Cancer Center, one of around 20 institutions, including the Stanford Medical Center and the University of California, Davis, that buys its yttrium-90 from the DOE's Pacific Northwest National Laboratory.
"I have no strong sympathy for warheads, and I'm very happy to be part of a better use of one of the by-products," Vriesendorp said.
Yttrium-90 is a product of decaying strontium-90, which comes from smashing Uranium-238 atoms. Each week, Tenforde explains, his team uses a patented process to "milk the yttrium-90 from the strontium-90 like a cow."
The DOE charge US$13,000 for one curie of yttrium-90, which will provide for around 20 patients. But when filling an order, the Pacific Northwest National Laboratory has to keep the isotope's 64-hour half life in mind. For example, 24 hours after shipping the yttrium-90, almost a quarter of it will already have decayed. That's why Tenforde promises US delivery within a day, two if you're in Europe.
