In a breakthrough, Canadian researchers develop a new way to produce medical isotopes

VANCOUVER — The Globe and Mail

A cyclotron, used in the production of medical isotopes. (Globe files/Globe files)

The solution to the global shortage in the supply of crucial medical isotopes – a scarcity pegged to problems at Ontario’s aging Chalk River nuclear reactor – may be lying in the basements of Canadian hospitals.

The 54-year-old facility, set to close in 2016, provides half the world’s supply of medical isotopes, including meeting most of North America’s demand.

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But in what is being described as a medical breakthrough, a research team has come up with a way to adapt existing cyclotrons – particle accelerators – in Canadian hospitals and institutions so they can be used to produce technetium-99m. Until now, the key diagnostic isotope has been available only from nuclear reactors.

The development could alleviate the dearth of the radioactive isotope, which is used for the medical imaging of organs and in diagnosing breast, prostate and lung cancers, among other things.

Jane Aubin, chief scientific officer with the Canadian Institutes of Health Research, said the finding should generate excitement in medical facilities around the world.

“It should be huge,” she said of the anticipated international reaction.

François Bénard, from the British Columbia Cancer Agency, said there are 13 cyclotrons in operation across the country and they could be retrofitted for as little as $500,000 each.

He said medical trials are needed to ensure the technetium-99m made in cyclotrons is of the same quality as that produced by the traditional supplier – Chalk River – and that could take up to two years. But retrofitting existing machines is relatively easy, he said, and Canadian hospitals could be capable of producing their own supply of the vital isotope within months.

There has been a worldwide shortage of diagnostic isotopes because of problems at Chalk River, run by Atomic Energy of Canada Ltd. The reactor has been shut down several times in recent years, most notably in 2009 when a heavy water leak occurred.

Dr. Bénard said the research team, led by scientists from TRIUMF, Canada’s national laboratory for particle and nuclear physics, has come up with “a practical, simple solution” to a problem that has long plagued medical facilities in Canada and around the world.

“Not only will this improve the availability of technetium, it will also improve the availability of other isotopes that are used for PET imaging, which is really the novel, growing area in medical imaging,” said Dr. Bénard, referring to positron emission tomography scanning, one of the most frequently used molecular imaging procedures in hospitals today.

Dr. Bénard said the B.C. Cancer Agency spent $1.5-million to upgrade its cyclotron as part of the research effort, but that resulted in a machine capable of producing large, commercial scale quantities of technetium-99m.

“It could cost much less if you don’t want to scale it up so much. … We wanted to prove the principle that large-scale production was possible. … I think anywhere from half a million to 1.5 [million dollars]would give you a [cost]range,” he said.

Dr. Bénard said there are currently cyclotrons in most major centres, including Vancouver, Edmonton, Winnipeg, Toronto, Montreal and Halifax .

“I don’t have a detailed idea but I would think that half a dozen to a dozen cyclotrons could easily meet the demand across Canada,” he told a press conference in Vancouver on Monday at the close of the annual convention of the American Association for the Advancement of Science.

Tom Ruth, senior scientist at TRIUMF and lead investigator for the research team, said one cyclotron can make enough technetium-99m to supply a metropolitan area such as Vancouver.

Talks are under way to work out how and where production can begin. “We are in discussions with several industrial partners and regional health authorities about how to start implementing this vision. The science and the technology are essentially ready,” he said.

Frank Prato, a member of the research team and director of the Lawson Health Research Institute, said the method will be applicable widely, because the cyclotron used in the experiment is in common use.

“We achieved a global first with the demonstrated production of technetium on a GE cyclotron. Almost half of the existing cyclotrons in the U.S. are GE machines,” he said.

Dr. Aubin said the research team produced technetium-99m in two different facilities in Canada, one in Ontario and one in B.C.

“The fact that it could be duplicated in more than one place gives … great hope that this is a technology that can be rolled out much more widely and in a very reasonable period of time,” she said.

The Canadian Institutes of Health Research and the Natural Sciences and Engineering Research Council of Canada provided initial funding for the research. Working on the project were TRIUMF, the B.C. Cancer Agency, the Lawson Health Research Institute and the Centre for Probe Development and Commercialization, a non-profit organization that helps researchers move their discoveries from the lab to the global market.

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