A sad end has come to one of Canada’s most important contributions to medical science. The Chalk River nuclear reactor northwest of Ottawa is being shut down. That brings to a close its 70-year role in the production of medical isotopes.
A brilliant coup, Chalk River was the first reactor built outside the U.S. Since coming online in 1945, it has been a major supplier of the world’s medical isotopes.
These radioactive materials are used as imaging aids to diagnose a range of ailments, including heart disease and cancer. Between 30 million and 50 million patients across the globe benefit each year.
To digress for a moment, it’s worth pondering the astonishing rate of progress that led to the production of isotopes. The earliest hints of radioactivity were detected in 1896. Marie Curie first isolated radium in 1910. Yet just 35 years later, Chalk River began operating.
(As often happens, Curie paid a price for her trail-blazing. She died of a radiation-induced illness, as did one of her two children, Irène, who was accidentally exposed to the second element her mother discovered — polonium. Marie’s handwritten notes, a hundred years later, are still so radioactive they’re stored in lead containers.)
The reasons for closing Chalk River are somewhat murky. It suffered breakdowns in 2007 and again in 2009, but no one has declared the plant unsafe.
Like all reactors, it produces radioactive waste, but that seems a price worth paying for its medically vital role. No one associated with the prior federal government, which made the original decision to decommission the plant, or the current administration, which confirmed the decision, has offered a credible explanation.
Whatever the reason, the shutdown has alarmed clinicians everywhere. While there are a number of research reactors around the world, Chalk River was always considered one of the most productive.
In theory, there should be sufficient capacity at the remaining facilities to fill the gap. But if just one of them suffered a setback, a worldwide shortage of isotopes might result.
Part of the problem is that the isotope most commonly used — technetium-99 — has a half-life of just six hours, meaning it cannot be stockpiled. A constant, uninterrupted supply is critical.
At this point, however, a striking new possibility has emerged. Scientists working with a particle accelerator at the University of B.C. have shown that technetium can be created without a nuclear reactor.
Basically, a non-radioactive target is bombarded with subatomic particles and technetium is formed. The process is being tested at the B.C. Cancer Agency, which is conducting a clinical trial with isotopes generated in this manner.
There are several reasons for optimism. First, the process is relatively cheap.
Technetium can be created with accelerators costing somewhere between $1 million and $5 million. That means it should be possible to locate them at remote sites, such as Prince George or even closer to home in Victoria. There is an additional price tag associated with building a facility to house the machine — in the $10-million to $30-million range.
But basically, this is an affordable technology that can be located anywhere in the province, an important point when the material you’re creating has a half-life of only six hours.
Second, unlike reactor-produced isotopes, those generated in an accelerator leave no nuclear waste to be disposed of. That in itself is a huge advantage if the new technology proves out.
We should know within the next 12 to 18 months what kind of output to expect from these new machines. But scientists associated with the project are confident that it should be possible, over time, to supply enough isotopes for the entire province.
The spirit of Marie Curie lives on.
