On Friday, February 19, 2010, the nuclear reactor in the Dutch town of Petten shut down for maintenance. At the same time, repairs at the Chalk River reactor in Canada are taking longer than planned. This knocks out 70% of the world’s production of medical isotopes (radiopharmaceuticals), as reported by the Dutch TV program Nieuwslicht on February 18.
The main radioisotope used in medicine, technetium-99, is a decay product of the radioisotope molybdenum-99, which is produced by these reactors. Technetium is not stable; it emits radiation while it decays into other isotopes.
Technetium compounds can for example be tailored to target certain tissues in the body, such as bone tissue or heart muscle, and then administered to patients. The radiation given off by the technetium reveals where this technetium has ended up in the body. This may reveal, say, sections of bones with tumors in them, as the technetium would occur in higher concentrations at those sites (and give off more radiation).
This radiation can be imaged, just as in X-ray imaging where the radiation is applied from outside the body. This does not target specific tissue types, except that some types of tissue – and tissue affected by some processes in them – appear denser in the images.
The reactor in Petten supplies 30 to 40% of the world’s medical isotopes, also for the UK. That means that the reactor in Canada also produces 30 to 40% of the world’s medical isotopes.
See this 2007 IAEA document on radiopharmaceuticals for more information on radiopharmaceuticals and this page for more about molybdenum-99 and technetium-99.
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Note: A common misconception is that all isotopes are radioactive. Only radioisotopes are radioactive. Regular molybdenum (Mo) is stable, hence not radioactive. It does not decay into technetium. It bears similarities to tungsten (W) and chrome (Cr).
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