Ontario nuclear plant to produce material for life-saving cancer treatment


Ontario announced plans Thursday to produce a nuclear medical isotope that forms the essential component in a life-saving treatment for liver cancer, one of the leading causes of cancer deaths.

The plan involves creating the medical isotope yttrium-90 (also known as Y-90) at the Darlington nuclear generating station in partnership with a pair of Ottawa-based companies, which transform the radioactive raw material into a cancer-fighting drug called TheraSphere.

The two companies — BWXT Medical and Boston Scientific — already manufacture the treatment in Ontario but until now, have had to import their supply of isotopes from nuclear reactors outside of Canada.  

The deal to produce the isotope at Darlington will ease concerns about access to the raw material for TheraSphere, which has been provided to more than 100,000 liver cancer patients worldwide, said Peter Pattison, president of Boston Scientific’s interventional oncology franchise in Ottawa. 

“Now we have a situation where we have increased capacity, increased reliability and increased proximity, so we couldn’t ask for a better partner,” said Pattison in an interview. 

Health Minister Sylvia Jones and Energy Minister Todd Smith announced the deal Thursday afternoon at Ontario’s biggest cancer treatment centre, Princess Margaret Hospital in Toronto. Government officials provided CBC News with information in advance of the news conference. 

An enlarged image of a blue glass sphere and a vial of TheraSphere.
TheraSphere is a targeted therapy for liver cancer, made by Boston Scientific, a medical device company with 47,000 employees worldwide. BWXT Medical manufactures the product under contract at its facility in Ottawa. The treatment consists of millions of microscopic glass spheres containing radioactive yttrium-90. (Boston Scientific Corp.)

The isotope production is to be led by Laurentis Energy Partners, a wholly owned subsidiary of Ontario Power Generation, the provincial Crown corporation that runs Darlington. 

“We’re using our nuclear power generation in Ontario to produce these life-saving medical isotopes,” said Jason Van Wart, president and CEO of Laurentis, in an interview. “While we’re seamlessly making electricity, we’re also saving lives.”  

Growing use of isotopes in cancer treatment

Various medical isotopes have long been used for diagnosis, particularly in scans of the brain and other organs. With advances in technology, they are increasingly being used in treatment. 

Rather than blasting a cancerous tumour with radiation, running the risk that surrounding healthy cells are killed along with the cancerous ones, radioactive medical isotopes can be injected to target a tumour directly. The technique is used in treatment of a range of cancers, including liver and prostate. 

Canada was long the world leader in production of the most common medical isotopes.

But since the national research reactor at Chalk River, Ont. closed in 2018, Canadian hospitals have been largely reliant on medical isotopes produced in other countries, including Russia and South Africa. 

Over the last 15 years, hospitals worldwide have faced at times acute global shortages of some medical isotopes. 

WATCH | Treating liver cancer with medical isotopes: 

How microscopic glass beads fight liver cancer

Peter Pattison, president of Boston Scientific’s interventional oncology franchise, describes how TheraSphere, a made-in-Ottawa treatment for liver cancer works differently from traditional radiation therapy.

Having a reliable supply of medical isotopes is crucial to diagnosing and treating a whole range of cancers and other diseases, says Dr. Christopher O’Brien, past president of the Canadian Association of Nuclear Medicine. 

“Without them there’s no ability to assess the state of the disease or the function of the organ,” said O’Brien in an interview. 

Fresh push for Canadian production 

The new plan to produce yttrium-90 in Ontario is part of a recent push to ramp up domestic production of medical isotopes at Canada’s nuclear power stations.

Bruce Power’s nuclear plant on the shore of Lake Huron now produces Lutetium-177, a medical isotope used in treatment of prostate cancer. 

Laurentis’s system for producing medical isotopes at Darlington began operating in December 2022, starting with molybdenum-99, used widely in diagnostic imaging for detecting cancers and heart disease.

That system at Darlington will also produce the yttrium-90 isotopes used to make TheraSphere, the treatment for liver cancer, the fourth-most common cause of cancer deaths worldwide. 

Jason Van Wart photo
Jason Van Wart is president and CEO of Laurentis Energy Partners, a wholly owned subsidiary of Ontario Power Generation. Laurentis will lead production of the medical isotope yttrium-90 at OPG’s Darlington nuclear generating station. (Submitted by Laurentis Energy Partners)

TheraSphere is made up of microscopic glass beads containing the radioactive material. Health Canada approved it for use in 2002.   

The treatment is created by putting the glass beads inside the nuclear reactor along with a supply of yttrium in its non-radioactive state, known as Y-89. In a process that takes three days, the yttrium atoms pick up an additional neutron to become radioactive Y-90. 

The radioactive beads are then transported to BWXT Medical and Boston Scientific’s neighbouring facilities in Ottawa, where the companies transform them into a medical-grade intravenous serum, before shipping it to hospitals around the world. 

“There’s quite a number of steps in the process, it’s quite technical, and we’re very excited that our reactor allows us to be part of that,” said Van Wart in an interview with CBC News. 

O’Brien, who is not directly involved in the companies producing TheraSphere, said it’s important for Canada to have a domestic supply of medical isotopes. 

“The further away your supply lines are, the more chances of issues disrupting patient care,” he said. “When you’re relying on sources from around the world, will the plane show up? Will it get through customs? Will there be a production issue at source?”

O’Brien said treatments like TheraSphere that deliver the radioactive isotopes directly to the tumour provide a more targeted attack on the cancerous cells than general radiation and are generally better for patients. 

“Rather than going through the skin, the bone, the muscles and then to the organ, we are supplying the medical isotope directly to the tumor,” he said. “The area that’s affected by the medical isotope or the radiation is much narrower and smaller in size, so there’s less collateral damage, if you will, to the surrounding healthy tissues.”


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