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Nuclear medicine

Chalk River out of commission for 2009

OTTAWA - Atomic Energy of Canada Ltd said earlier this month it expects its troubled Chalk River nuclear reactor, which produces a third of the world’s medical isotope supply, to be off line until late 2009.

The aging reactor has been out of operation since May 17 because of a heavy water leak. Government-owned AECL had originally estimated it would be back in action after three months.

AECL officials said the best repair method would be determined in the next few weeks. The agency said it would then be able to provide a more definitive timetable for a restart. It said it expects the repair and restart phases to take at least four months.

“It was really only in the last week that all of the threads came together and it became apparent that the timeframe would be longer than the previous guidance,” AECL President and Chief Executive Hugh MacDiarmid told a media briefing.

“That was really what drove us to make this announcement, despite the fact that we do not have the precision of guidance with respect to the outage duration.”

Chalk River, in eastern Ontario, produces most of the isotopes distributed by MDS Nordion, a subsidiary of Canadian health sciences company MDS Inc. The unexpected shutdown of the 52-year-old reactor has sent hospitals in Canada and the United States scrambling to find replacement sources of medical isotopes, which have a short shelf life.

A medical isotope is a very small quantity of radioactive material used to perform nuclear medicine imaging tests. Isotopes are mixed with different solutions and injected into patients, where they give off energy read by a special camera.

Chalk River is one of only a few nuclear reactors able to produce the isotopes, and health experts have warned that the other facilities do not have the capacity needed to make up for the lost Canadian production.

MDS said last month that it was in talks with the Moscow-based Karpov Institute of Physical Chemistry to supply isotopes as it scrambles to cope with the prolonged shutdown of the Chalk River reactor.

The company again called on the Canadian government on Wednesday to restart the Maples nuclear project, which Ottawa shelved last year, citing cost overruns and technical problems. That shutdown prompted MDS to file a C$1.6 billion ($1.5 billion) claim against AECL and the federal government.

The company, whose shares have dropped more than 60 percent in the past year on disappointing results and the isotope concerns, also reiterated that it would take an earnings hit of about US$4 million for each month the Chalk River reactor was out of commission.

Meanwhile, McMaster University in Hamilton says it can produce four times the amount of medical isotopes as the failing Chalk River reactor, in a possible solution to a severe worldwide shortage.
But the school would need $30 million in government funding over the next five years. It has already received $22 million from both the federal and Ontario governments.

As well, it would take about 18 months for the McMaster reactor to get up to speed on producing a regular supply of radioisotopes.

McMaster’s 50-year-old reactor is the only other Canadian facility that can produce Technetium-99m (Tc-99m), the principal medical isotope used in cancer tests. It once filled in for the Chalk River reactor in the 1970s during a shutdown.
Meanwhile, the federal government announced $6 million to fund research into alternatives to Tc-99m, which is produced from molybdenum-99 (Moly-99).
The president of the Society of Nuclear Medicine, Dr. Robert Atcher, is saying the long-term solution to the worldwide isotope shortages isn’t necessarily in building new reactors.

“It turns out that our real problem isn’t that there aren’t enough reactors to make medical isotopes,” Atcher told CTV news. “It’s the production facilities that we use when we take those targets out of the reactor and process them to remove the medically useful isotopes – that capacity around the world is very limited. So we don’t need necessarily to build any more reactors; we need to build those processing facilities.”

Canada had been planning to have two reactors dedicated to producing medical isotopes by now. AECL was building two reactors at Chalk River – the Maple project – that were supposed to be operating by 2000. But after 12 years of development and cost overruns, the reactors never worked well enough to be put into commercial production. AECL concluded last year that the Maple project would have to be cancelled altogether.

Health Canada also has a stopgap, announcing late Monday a new source for Tc-99m.

It said it has authorized Lantheus Medical Imaging of Boston, Mass. to use Moly-99 produced by the Open Pool Australian Light-water (OPAL) reactor to make Tc-99m for Canadian healthcare facilities.

In the meantime, with diagnostic tests being delayed or cancelled, deaths are possible, warns Atcher, because there is little capability to use other imaging technologies in many kinds of diagnosis.

“For patients with lung cancer, prostate and breast cancer, we use nuclear medicine to assess whether the cancer has spread to their skeleton and there’s really no other adequate way for us to do that,” he said.

Posted July 16/09.