TORONTO - The critical shortage of medical isotopes appears to be forcing some clinics and hospitals to reschedule or cancel some imaging appointments, with shortages even arising with a type of isotope that is considered a backup.
The problem, which has been ongoing since last May's closure of the nuclear generator at Chalk River, Ont., has deepened this week because of temporary suspension of production from the three remaining generators that have been picking up the global slack.
"It's a chronic shortage of isotopes and unfortunately this week, it's an acute one," Dr. Jean-Luc Urbain, president of the Canadian Association of Nuclear Medicine, said Tuesday in an interview.
Urbain said Canadian medical facilities have been operating with about 50 per cent of their normal supply of isotopes -- used in imaging tests to diagnose some cardiovascular conditions and cancers -- since the Chalk River shutdown.
But for this week and potentially two or three more, the supply is even more limited - down to a quarter of the normal supply, Urbain said.
Last week the U.S. based Society of Nuclear Medicine projected the severe shortage of Technetium-99 isotopes would stretch for a two-to-three week period.
That's because the three nuclear reactors that produce the radioactive substance Molybdenum-99, which is needed to generate Technetium-99, were taken offline for much-needed maintenance and refuelling, the society said.
Canada's NRU reactor at Chalk River, Ont., supplied a third of the world's medical isotopes until it was shut down last May to repair a pinprick-sized radioactive water leak. Atomic Energy of Canada Ltd. had predicted the reactor would be back up by spring, but to date there is no word on when the reactor will be brought back online.
The loss of the Chalk River supply has been exacerbated by the fact that the Petten reactor in the Netherlands has also been taken out of production, leaving only reactors in Belgium, France and South Africa to carry the load.
To mitigate the shortage, some facilities are resorting to an older type of isotope, Thallium, when possible. It does not produce as clear images as Technetium-99, but can be used in a pinch.
Urbain said in Eastern and Central Canada, facilities have had to front-end load tests in the early part of the week, because of the short half-life of the product and the fact that they aren't getting repeat deliveries later in the week.
Some parts of the country appear to be faring a bit better, however.
Learning from shutdown of the Chalk River reactor in 2007, British Columbia decided to co-ordinate its ordering when it heard last May of the latest Chalk River production disruption.
Heather Gibson, director of medical imaging for the Vancouver Island Health Authority and chair of the provincial imaging council, said British Columbia has also had the advantage of having two suppliers, allowing them to mitigate the effect somewhat.
When they learned supplies were going to get tighter still, B.C. imaging facilities raced to work through as many appointments as they could, trying to ensure they had no backlog of patients when the shortage descended.
That type of response -- working through weekends when isotopes are available, for instance -- has helped lessen the impact on patients in B.C., Gibson said. But she suggested it has been tough on personnel.
"I have to say it's really hard on the staff. Because they just don't know from week to week what their week's going to look like, what's going to happen," Gibson said.
"For the first two months (it was) -- 'Hey, we'll pitch in, we'll do it.' Now after 11 months, it's wearing on them."
