Medical Isotope Shortage Looming

A leaky Canadian reactor which supplies the United States with about half of its medical isotopes will be shut for much longer than first anticipated.

Atomic Energy of Canada, a government-owned reactor maker and operator, said on Wednesday that it will likely take until late this year to repair the device in Chalk River, Ontario.

Speaking on a conference call with reporters, Hugh MacDiarmid, the company’s president, did not rule out longer delays.

The 52-year-old reactor, which has been plagued with problems in recent years, closed on May 15 after a leak of heavy water, which it uses as a moderator, was discovered. At the time, Atomic Energy estimated that repairs would take three months.

The reactor is the only one in North America that produces isotopes used medical imaging and treatments.

Sourcing isotopes from other reactors is difficult because Chalk River is the world’s largest isotope maker. Medical isotopes also have a relatively short shelf life, making it impossible to build up stockpiles to cover periods when the reactor is out of order.

Some medical imaging and nuclear physics experts have speculated that Chalk River may never reopen, a possibility that Mr. MacDiarmid rejected.

In a joint statement, Leona Aglukkaq, Canada’s health minister, and Lisa Raitt, the natural resources minister, said the continued reactor shutdown “will result in a significant shortage of medical isotopes in Canada and in the world this summer.”