By Janet Raloff

Web edition: September 9, 2009

Today, the House Subcommittee on Energy and the Environment held a hearing about ongoing shortages of the world’s most widely used radioactive isotope in diagnostic medical imaging: technetium-99m. Chairman Edward Markey (D-Mass.) undoubtedly convened the event to get more attention for a bill he introduced in late July, the American Medical Isotopes Production Act of 2009 (H.R. 3276).

It calls for development of domestic sources of Tc-99m’s feedstock – molybdenum-99. For the past several decades, reactors outside the United States have been producing that moly. But no longer reliably.

So it makes sense to reduce America’s dependence on the geriatric foreign reactors. But at this afternoon’s hearing, Michael Duffy, Vice President and General Counsel of Lantheus Medical Imaging, offered another potent argument for reducing reliance on foreign moly: You get more technetium.

Buying foreign moly is akin to “buying ice on a warm day,” Duffy said. Much of it’s gone before you get it home.

Tc-99m's feedstock is a radioactive substance that rapidly decays from the instant that it’s produced. Given the long distances that European-, South African- and Australian-made moly must travel, roughly one-third will decay away before it ever reaches the United States, Duffy says. By contrast, 95 percent of the moly made by a Canadian reactor – one that unfortunately has been out of service since May – is lost to decay before it reaches Lantheus and other makers of the molybdenum-packed canisters from which technetium is retrieved.

The value of proximity when it comes to moly production “cannot be overstated,” Duffy says. “Shorter transport time means less decay. Less decay means more efficient use of radioactive targets and facilities” – not to mention fewer radioactive wastes attributable to unused moly.

At today’s hearing, others also rallied for domestic moly production. Among them, Parrish Staples with the Energy Department’s National Nuclear Security Administration. Staples reported that his and other federal agencies have been “directed by the White House to investigate options to produce molybdenum-99 in the short-term to supplement the available supply while new longer-term production capabilities are developed.”

The next print issue of Science News has more on the goals of this interagency working group and on the cadre of organizations working to bring moly production home again – perhaps, if only on a temporary basis, within just a few months.

UPDATE: House passes medical isotopes bill