- © 2008 Canadian Medical Association or its licensors
Two recent CMAJ news articles gave good insights into last December's medical isotope crisis.1,2 It was inspiring to read how our colleagues in nuclear medicine coped with the interruption in the isotope supply.
It may not be widely known that the manner in which medical isotopes are produced in Canada is unintentionally exacerbating the problem of nuclear terrorism. Uranium contains 2 isotopes, uranium 238 (U 238) and uranium 235 (U 235). Natural uranium consists of 0.7% U 235 whereas highly enriched uranium consists of more than 20% U 235. Most of the medical isotopes produced at the Chalk River facility are made from weapons-grade highly enriched uranium. Highly enriched uranium is one of the main ingredients in homemade nuclear bombs, and its theft and smuggling cannot reliably be detected.3
Canada's MDS Nordion, one of the 4 major international suppliers of medical isotopes, imports about 20 kg of weapons-grade highly enriched uranium from the United States annually to produce its isotopes. In the process of making medical isotopes, about 97% of the bomb-grade material remains unused. These ever-increasing leftovers, sufficient to make several Hiroshima-sized bombs, are deposited in commercial sites that constitute a long-term security risk.
There is another option. The production of medical isotopes can be converted from the use of highly enriched uranium to the use of low-enriched uranium (which cannot be used to make a nuclear bomb) without technical obstacles.4 This is being done successfully in smaller facilities in Argentina, Indonesia and Australia. For Canadian suppliers, the conversion would entail an initial cost for retooling, but thereafter the production costs would be comparable to those with highly enriched uranium.5 In the long term, there may actually be savings as the costs of storing weapons-grade highly enriched uranium would be eliminated. As the sole purchasers of medical isotopes, health care professionals have leverage and can put pressure on MDS Nordion to use low-enriched uranium.
Footnotes
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Competing interests: None declared.