Shortage of radioisotopes reaches US patients.
Hospitals across North America have been forced to cancel tests for cancer and heart disease because the unexpected closure of a Canadian nuclear reactor has led to a sudden shortage of medical isotopes.
The 50-year-old National Research Universal (NRU) reactor located in Chalk River, Ontario, was shut down on 18 November for scheduled maintenance and was due back online by mid-December. But Atomic Energy Canada, which owns and operates the facility, extended the outage to install safety-related equipment, including upgrades to the reactor cooling pumps. The reactor supplies about 60% of the molybdenum isotopes used in medical applications globally, including molybdenum-99, which decays into technetium-99m and is used in about 16 million nuclear medicine procedures annually in the United States.
?It's a disaster for patients,? says Sandy McEwan, president of the Society of Nuclear Medicine. North American hospitals now have 20?30% of the medical isotopes they require, he says.
Hospitals use a generator to extract technetium-99m from a source of decaying molybdenum-99. A technetium-99m isotope has a useful life of about one week, but can be stretched to two. MDS Nordion, an Ottawa-based life-sciences firm and molybdenum supplier to Bristol-Myers Squibb Medical Imaging, says it expects shortages of the radioisotope until mid-January. Molybdenum-99 has a half-life of 66 hours and cannot be stockpiled. Reactors in Australia, South Africa and Brussels also produce molybdenum-99. The shortage has reignited a discussion over securing the US supply of medical isotopes by building a reactor in the United States.
The NRU reactor was to be decommissioned in 2005, but its operating licence was extended until problems with two replacement reactors ? MAPLE 1 and 2 ? could be solved. The two MAPLE reactors and a processing facility were designed to supply the entire global demand for molybdenum-99, iodine-131, iodine-125 and xenon-133. In June, Atomic Energy Canada said that it expected MAPLE 1 and the processing facility to be in service by October 2008, and MAPLE 2 by October 2009.
About this article
Cite this article
Hoag, H. Nuclear-reactor closure hits cancer tests. Nature 450, 927 (2007). https://doi.org/10.1038/450926b