Shortage of Tc-99m hitting Canadian hospitals
November 16, 2022
HALIFAX – An unexpected mechanical problem at a nuclear plant in Belgium has doctors in Halifax scrambling to reprioritize and reschedule patients in need of diagnostic imaging. That turmoil will be felt – albeit briefly – throughout Canada, North America and the world, until the supply of Technetium-99m (Tc-99m), the most predominant radioactive isotope used in that imaging, stabilizes.
For now, doctors will be rearranging their patients’ appointments in order of urgency, said Dr. Steve Burrell (pictured), the head of nuclear medicine in the department of Diagnostic Imaging at the Queen Elizabeth II Health Sciences Centre in Halifax.
“We have reasonable supply this week. Next week is going to be very low. And the week after that we’ll not have anything until they come back online,” Dr. Burrell told the Toronto Star earlier this month.
At that point, he said, hospitals will have to use alternative – sometimes not as effective – tests to take the place of those using radioactive isotopes. Ironically, Canada was once a world leader in producing such isotopes, until a federal government decision in 2008 closed the door on continuing.
QEII hospital performs some 6,000 of those diagnostic imaging tests per year. Across Canada that annual figure is close to 1.1 million. The U.S. performs some 15 million tests per year, and the global figure is close to 40 million.
Most of the isotopes used in those tests – the ones that doctors use to help diagnose everything from cancer to heart disease to lung and kidney issues to gastrointestinal problems – are produced by only six reactors across the planet.
The Belgian reactor in question, called BR2, is the largest, production-wise. What it actually produces, what all the reactors actually produce by bombarding uranium targets, is molybdenum-99 (Mo-99) which, over its 66-hour half-life, decays into Tc-99m.
Usually, those six reactors have carefully co-ordinated schedules, ensuring that only a few are offline – generally for refuelling and maintenance – at any given time.
The trouble for BR2 began on Oct. 28, when routine maintenance revealed mechanical troubles which meant it could not go back online as planned. That, combined with the fact that three of the five remaining reactors were offline for their own scheduled maintenance meant that the world’s supply of Mo-99 was severely compromised.
Where initial alerts were projecting a shortage of isotopes that might last into February 2023, Curium – one of the two distributors of the isotopes in Canada – now says that the shortage should be resolved by Nov. 21, according to François Lamoureux, president of the Canadian Association of Nuclear Medicine.
To a large extent the situation has been mitigated by some of the other reactors delaying scheduled shutdowns, restarting early or increasing production. But the current shortage does shine a light on what seems to be a relatively fragile supply chain for a globally critical healthcare element.
“They’re not as rare as we wish they were,” says Alan Packard, a past president of the Society of Nuclear Medicine and Molecular Imaging, of isotope supply issues, likening a reactor’s surprise shutdown to a flat tire.
“I don’t know if fragile is the right word, but it’s a supply chain that’s subject to disruption … you can drive with one flat tire. It’s not going to work very well, but you can, so long as you have to. But if you get two flat tires, you’re in big trouble.”
He says the U.S. Department of Energy has been throwing millions of dollars at projects aimed at developing new ways to produce molybdenum so it would be less dependent on foreign reactors. That funding has just begun to bear fruit, says Packard, noting North Star, a new distributor of the isotope, just coming online.
For Canada, it’s an ignominious position for a country that used to be at the global forefront of the production of these isotopes.
For years, up until 2013, Canada produced about a third of the global supply of the radioactive isotopes used for diagnostic imaging, and more than half of the North American supply.
That was the legacy of the Chalk River NRU reactor, about 180 kilometres northwest of Ottawa. So dominant was Canada in generating these isotopes that when the Chalk River reactor went down for weeks in 2007, the impact was felt all over the globe and it was widely remembered as one of the most severe shortages ever.
In the wake of that incident, a report to then-health minister Tony Clement recommended “expeditious commissioning” of replacement reactors dubbed Maple I and II; but Canada later pulled the plug on that plan, citing persistent technical problems and “economic impediments.”
The Chalk River reactor ceased production in 2016, taking Canada out of the molybdenum business and making the country dependent on foreign reactors for its supply of isotopes.
That, says Lamoureux, was short-sighted. He compares the Stephen Harper government’s shutdown of Canada’s nuclear medicine capabilities to John Diefenbaker’s axing of the Avro Arrow fighter plane in 1959 – Canada squandering its position on the leading edge of technology.
“The same error, with the same type of government; people who don’t have any visions about nuclear medicine,” he says. “Because nuclear medicine is not just a specialty which detects disease, but now it’s a specialty which will treat most of the diseases.”
In Germany, radioactive isotopes are already being used to treat skin cancer, the most common form of cancer, he says. The second-most common cancer in males – prostate cancer – is also already being treated by isotopes.