Insight Web Extra
November 2009—The most important of the medical isotopes used to detect, diagnose, treat or evaluate illnesses such as cancer and heart disease is in short supply. Shortages of technetium-99m (Tc-99m) are catching the eye of practitioners and policymakers alike.
Technetium-99m is used in about 80 percent of nuclear medicine procedures. It is derived from another element, molybdenum-99 (Mo-99), which is produced in uranium-fueled research reactors.
After injection into the body, technetium-99m goes to specific disease sites in the body or concentrates in organs such as the heart. Imaging devices such as PET scanners then pinpoint the exact locations and extent of disease and help identify the best treatment. The procedures can also be used to monitor patients’ responses to treatment.
Technetium-99m has a short half-life—radioactive decay depletes its strength by half every six hours. It decays in the body quickly without giving the patient a large radiation dose, but because of this short half-life, the isotope must also be produced and delivered quickly. Therefore, only a few days can elapse between ordering and using the material.
The vast majority of the worldwide supply of molybdenum-99 is produced in nuclear facilities located in five countries: Belgium, Canada, France, South Africa and the Netherlands. Until recently, two reactors—one in Canada, the other in the Netherlands—each produced approximately one-third of the world’s supply. About 80 nations use molybdenum-99 based procedures, and the United States consumes nearly one-half of the worldwide supply.
However, these isotope-producing reactors have been operating for an average of 45 years and increasingly are being shut down for extended periods of maintenance. Canada’s facility has been undergoing major repairs since May and is not expected to be back online until the first quarter of 2010. The Dutch reactor is also expected to be out of commission for up to six months next year, as will France’s. Both the Canadian and French reactors will shut down permanently in 2015. And although a new Dutch reactor has been proposed, it will not come online at least until 2016. These events are disrupting the production of molybdenum-99 and affecting medical care throughout the world.
Increasing unavailability of technetium-99m is already leading to delayed diagnoses and treatment. A recent survey suggests that 75 percent of physicians are delaying diagnostic procedures by at least a day, and a third have delayed them longer than a month.
The situation has caught the attention of Congress and the White House. Legislation (
H.R. 3276) introduced last summer by Reps. Edward Markey (D-Mass.) and Fred Upton (R-Mich.) to promote the domestic production of these materials could soon pass into law.
It is recognized that encouraging U.S. production of this important isotope is a high priority. One potential source is the University of Missouri Research Reactor, which could meet up to half of U.S. demand with minimal changes to the present design. Other promising designs include a Babcock & Wilcox aqueous reactor concept, and various accelerator-based facilities. However, these solutions are years down the road.
—Read more articles in Nuclear Energy Insight and Insight Web Extra.