OTTAWA - Researchers in Saskatoon will try to prove that Canada doesn't need a troubled, old nuclear reactor to make the isotopes used by doctors in a whole host of medical tests.

A demonstration facility will be built at the Canadian Light Source to prove that a high-energy linear accelerator can make the isotopes used in medical imaging and diagnostic procedures. The National Research Council, which is backing the project, says the new method does not require a nuclear reactor or weapons-grade uranium.

"It's a system by which you're not using uranium as your fuel or your target to produce your medical isotope. Instead, you're basically radiating small coin-sized discs ... to produce the isotopes in question," Raphael Galea, a research officer with the council, said in a phone interview from Ottawa.

"As a result, you're not producing any of the long-lived radioactive waste and you don't have any concerns about non-nuclear proliferation and the like."

The project is one of four that the federal government announced Monday in its quest to find a new source of technetium-99m -- the most widely used isotope for medical imaging.

Ottawa will give the projects $35 million to develop ways of producing the isotope without a reactor.

"These investments will help us move towards a more diversified supply chain -- one that is robust and less vulnerable to disruption," Natural Resources Minister Christian Paradis said in a statement.

Disruptions have been a big problem in Canada's isotope field.

The bulk of the world's medical imaging isotopes was produced with the nuclear reactor in Chalk River, Ont. But the plant was shut down in May 2009 when a pinhole-size radioactive water leak was found. What was originally supposed to be a month-long shutdown dragged on for more than a year.

Doctors were scrambling to make do with an erratic supply of medical isotopes to diagnose cancer and heart ailments.

Chalk River resumed operations last August but is scheduled to close by 2016. The Conservative government ruled out building a new reactor and said it would find ways to make isotopes.

The four projects will use cyclotron and linear accelerator facilities.

In addition to the Canadian Light Source in Saskatoon, work will be done by Manitoba-based Prairie Isotope Production Enterprise. Advanced Cyclotron Systems Inc., will use pilot cyclotron facilities at the Centre Hospitalier Universitaire de Sherbrooke in Quebec and the University of Alberta. TRIUMF, a subatomic physics laboratory, and the B.C. Cancer Agency will also try to develop an alternative medical isotope production technology.

Thomas J. Ruth, senior research scientist at TRIUMF and the B.C. Cancer Agency, welcomed news of the funding.

"This technology will take advantage of existing infrastructure to develop and demonstrate the capability for manufacturing technetium at multiple sites across the country using the most diverse collection of commercially available cyclotrons," Ruth said in a news release.

Saskatchewan has been trying to get into the medical isotope field for a number of years. In August 2009, the province, working with the University of Saskatchewan, pitched a plan to the federal government to develop a 20-megawatt, low-enriched uranium research reactor in Saskatoon.

Saskatchewan Innovation Minister Rob Norris said Monday that if the research project is successful, it could be the source of "robust" isotopes for the country.

"What we want to do is see if there's a way that we can better serve Saskatchewan people and perhaps export as well some of these isotopes if and as needed," said Norris.

The projects are expected to report their findings by mid-2012, but it could be 2014 before commercial work is up and running.