Published online 23 October 2008 | Nature | doi:10.1038/news.2008.1186

News

Europe's isotope shortage will continue into 2009

Hospitals forced to use substitute procedures for medical scans.

Petten reactorThe High Flux Reactor in Petten, the Netherlands, is facing an extended shut-down.NRG

A Europe-wide shortage of medical isotopes will continue for at least three months while a Dutch nuclear reactor is repaired. Governments and regulators are now bending their rules concerning the use and transport of radioactive materials so that patients can still undergo diagnostic tests during the supply crisis.

The High Flux Reactor in Petten has been out of action since the end of August (see 'Isotope shortage could delay cancer treatment') after tiny bubbles of gas were found escaping from a pipe into the reactor's cooling system during a routine maintenance inspection. Although the cause of the leak has now been traced back to corrosion between the pipe and its concrete casing, the reactor needs complex repairs. Its operator, the Nuclear Research and Consultancy Group (NRG), says that the reactor will not restart until 16 February 2009 at the earliest, much later than it had initially estimated. It denies that the situation was caused by any negligence.

Petten provides about 30-40% of the world's medical isotopes, and its closure is causing acute problems with the availability of molybdenum-99. Nuclear-medicine specialists rely on this isotope to generate technetium-99m — the most commonly used radioactive isotope for diagnostic nuclear imaging scans.

Molybdenum-99 is also made at reactors in Canada, South Africa, France and Belgium. These sites have ramped up production where possible, but supplies of the isotope to European hospitals and clinics have fluctuated between 20% and 100% of normal since the end of August on a week-by-week basis.

Bending the rules

Some hospitals are making the most of their limited supplies by performing examinations when the radioisotope source is most active. If the molybdenum-99 is delivered on a Friday, for example, then patients may be called in over the weekend. Hospitals are also arranging high priority scans for early in the morning when the technetium-99m has just been extracted from the radioisotope source. "But some hospitals are finding it very difficult to alter their normal working patterns because they don't have workforce flexibility," says Gill Vivian, a nuclear medicine specialist at Derriford Hospital in Plymouth, UK, and president of the British Nuclear Medicine Society in London.

“Without investment, we are going to have this problem again and again.”

Adil Al-Nahhas
Imperial College, London

Some examinations involving technetium-99m are being replaced by scans that use imaging agents not affected by the supply crisis. For example, several institutions are switching to positron emission tomography imaging with radioactive sodium fluoride (Na18F) for bone scans. This compound is not commercially available and is licensed for use only in clinical trials, so regulatory authorities have had to sanction the switch.

But these compromises are not ideal. "The alternative tests are not always as accurate," says Wolfram Knapp, director of the nuclear medicine clinic at Hannover Medical School in Germany, and president-elect of the European Association of Nuclear Medicine, based in Austria. "Also, depending on the hospital's size and facilities, it may not be able to switch tests so easily."

Some European countries have temporarily eased their transport regulations to allow radioactive pharmaceuticals made in university hospital cyclotrons to be distributed to neighbouring sites. In Germany, for example, such transport is usually against the law, but some state authorities are allowing radioactive sodium fluoride to be moved within and between counties while molybdenum-99 remains in short supply.

Future proofing

The European Association of Nuclear Medicine is lobbying the European Commission to make the supply of medical isotopes more secure by building a new, dedicated nuclear reactor. "It is the only solution," says Adil Al-Nahhas, a nuclear medicine specialist at Imperial College London, and secretary of the association. "Without this investment, we are going to have this problem again and again. The three reactors we have in Europe are close to 50 years old. They are past middle age."

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The High Flux Reactor at Petten will close at the end of 2015. The operating capacity of its replacement, due to open in 2016, will be split equally between medical isotope manufacture and scientific research work. Another reactor capable of making medical isotopes is being built in France, although this facility will also have significant commitments to materials testing research.

Two reactors commissioned in Canada in 1996 had been expected to meet global demand for molybdenum-99 and other medical isotopes. However, the projects were cancelled earlier this year after several delays and spiralling costs owing to unresolved design problems. 

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