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Winnipeg Free Press - PRINT EDITION

Research could end shortages of medical isotopes

Canadian scientists develop way to make them without reactors

By: Tamsyn Burgmann

Posted: 02/21/2012 1:00 AM | Comments: 0 (including replies)

VANCOUVER -- Thousands of patients with life-threatening illnesses were told they'd just have to sit tight when crucial medical tests were delayed over 2009 as Canada suddenly found itself amidst a severe shortage of medical isotopes.

Canadian researchers now say they have generated a solution that erases the need for a nuclear reactor and weapons-grade uranium.

The discovery of a pinhole-sized radioactive water leak forced a shutdown of the Chalk River, Ont., nuclear reactor that had produced the bulk of the world's medical isotopes, leaving doctors scrambling as repairs stretched from a month to more than one year.

The scarcity crisis shook the medical community, reverberated into the political sphere and triggered a scientific quest to prevent a recurrence.

By upgrading equipment already stored in a dozen hospital basements across Canada, the scientists say they can manufacture the medically-necessary isotopes without the nuclear component.

"It's essentially a win-win scenario for health care, because you end up removing your dependence on a single source of technetium-99m, but you also make other isotopes more widely available," said Francois Benard, scientific director for the B.C. Cancer Agency, referring to the specific isotope that's been produced.

Benard was part of a team led by TRIUMF, a renowned subatomic physics lab based in Vancouver, that made the announcement on Monday to a gathering of global scientists at the American Association for the Advancement of Science annual meeting.

The process involves retooling a cyclotron -- a type of particle accelerator -- of which there already exist 18 in 12 facilities across Canada. At least 350 exist around the world, said Benard, citing a 2006 report by the International Atomic Energy Agency.

"Our collaboration has been able to produce a significant quantity of this isotope in two different provinces in Canada on different brands of cyclotron," said Paul Schaffer, the head of TRIUMF's Nuclear Medicine Division.

"(It) is a very exciting result, setting what we hope is the stage for a model for the rest of the world to look and see how technetium can be produced in an alternative fashion."

The medical isotopes are needed for tens of millions of diagnostic imaging procedures each year in diseases of the heart, bones and elsewhere in the body. At present, 95 per cent of the world's supply is produced by just five reactors around the world.

Using only one cyclotron, the new method could produce a fresh supply for a large metropolitan area every day, Benard said.

"For the price of one nuclear reactor, you can buy hundreds of cyclotrons, and by buying cyclotrons, not only do you make technetium available but you also make the other isotopes for PET imaging," he said.

The aging Chalk River reactor faces full shutdown in 2016. The U.S. has also notified Canada it will decrease or stop exporting the necessary, highly-enriched uranium by 2019.

Localizing the process will be of huge benefit, said Jane Aubin, chief scientific officer with the Canadian Institute of Health Research.

"The procedure is quite time- and cost-effective, so we should eventually be able to save money," she said in an interview, adding it has already proven successful at facilities in B.C. and Ontario.

"It's not just a fluke that it was able to work in one (facility), but the fact that it was done in two suggests it's a procedure that can be taught and learned across different parts of the country, and for that matter, internationally."

The federal institute partially funded the research, putting out a call for scientists to devise an alternative to the traditional nuclear method when the Chalk River facility and another global provider of isotopes in the Netherlands closed.

The combination triggered a world-wide isotope shortage.

-- The Canadian Press

Republished from the Winnipeg Free Press print edition February 21, 2012 A11

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