U of A facility could meet Alberta’s isotope needs, but faces hurdles
EDMONTON The University of Alberta’s Medical Isotope and Cyclotron Facility has the ability to become self-sufficient in the production of medical isotopes in about five years.
For Albertans who need it, a radioactive isotope has the ability to detect cancer in the heart or bones.
Although tests conducted over the past few months have shown that the U of A facility is capable of meeting the province’s need for 1,000 diagnostic procedures a day, there are still hurdles to overcome and its future use for producing technetium is still unclear.
The country’s federal and provincial governments will need to determine whether they want to use cyclotrons to replace reactors for medical isotopes, and continue to rely on outside reactors or use the technology as a backup when there is need, according to a news release from the U of A’s faculty of medicine and dentistry.
But research lead and university oncology department chairman Sandy McEwan sees a silver lining.
“Our work now allows a conversation to start on the future of precision medicine with imaging,” he said Friday.
A medical isotope is the drug that pinpoints tumours.
“So if you think of (the medical isotope) as a harpoon, the harpoon is what is used to target the disease that we want to look at,” McEwan said. “On the back of the harpoon we stick the isotope so we can detect where that harpoon is gone to in the body.”
There are three isotopes that are commonly used — technetium99m, a radioactive molecule of fluorine used in PET (positron emission tomography) scanning, and an isotope of iodine, used to detect and treat thyroid cancers.
Technetium-99m is the most common of these, and has a halflife of six hours, meaning that only half of it remains after that time. This is advantageous because the imaging scan is quick and the technetium doesn’t linger around in the body. This also means that the isotope must be produced quickly.
In the cyclotron, McEwan said it takes about six hours to make enough technetium-99m for the province each day.
“So we can’t supply it outside of the province,” he said.
The U of A technology shows that the isotope can be made locally and the science replicated across the country.
As it stands now, a dose of technetium-99m produced by the cyclotron at U of A is about 10 per cent more expensive compared to a dose of technetium-99m produced by traditional reactors.
“But that includes costing everything,” McEwan said. “It includes costing the cyclotron, the building, the research, the operations — everything.”
McEwan said the technetium99m produced by the cyclotron is of a slightly higher purity profile than from what you get from a reactor.
Also, most of the reactors are extremely old, said John Wilson, manager of the facility.
More than 80 per cent of today ’s diagnostic radiopharmaceuticals are based on technetium, but the supply chain has proven fragile in recent years. In 2009 and 2010, reactors in Canada and the Netherlands unexpectedly went out of service at the same time and required long-term maintenance, causing worldwide shortages and major disruptions in patient care. The reactor at Chalk River, Ont., has been shut since 2016 and the home grown technetium-99m supply is now gone, making Canada dependent on outside sources, Wilson said.
“Nuclear reactors are the highest capacity source for technetium99m but are very, very expensive and create nuclear waste,” he said. “No one wants a reactor built close to where they live.”
Jan Andersson, a researcher at the facility said as the supply stands now, reactors produce molybdenum-99, which has a half-life of 66 days and decays into technetium-99m, which is used in patients. This allows isotope to be supplied from far away but only if the reactors are running.
McEwan believes that technetium PET imaging will soon fade to give way to newer technologies, and the cyclotron is wellpositioned to handle that.
“The cyclotron is Canadian,” he said. “We have a made-in-Canada solution.”