Hospitals in Halifax expect to run out of radioactive injections for critical medical tests on Friday.

Ten hospitals in Nova Scotia have been affected by a nationwide shortage. About 200 diagnostic tests have already been cancelled and more cancellations are expected.

The QEII Health Sciences Centre in Halifax hopes to get more medical isotopes on Monday, but there are no guarantees.

Dr. Andrew Ross, a nuclear medicine specialist, said the plan is to help doctors find alternative ways to diagnose patients, besides "keeping our fingers crossed" that a generator arrives.

Radioactive isotopes are used in diagnostic tests, including scans for cancer and heart and lung disease. They are injected into the body, then photographed.

But the main supplier of isotopes, the government-run nuclear reactor in Chalk River, Ont., is shut down for maintenance that could run into mid-January.

Radioisotopes cannot be stockpiled because they have a short shelf life.

Nova Scotia Health Minister Chris d'Entremont said the province is working with Health Canada to find more.

"I'm not going to prejudge it right now because I don't want to give false hope here. But there is another supplier and we're trying to see if we can source something through them," he said Thursday.

A reactor in Belgium is ramping up its production by 30 per cent. However, there's no word yet on where that extra product will go.

Ross said time is running out.

"If this stretches out much into next week, I think the scenario changes in that because we're going to be adversely affecting patient management decisions and how they're treated," he said.

New Brunswick's isotopes available for emergencies

Fiona Kirkpatrick Parsons, who has a condition that makes her blood susceptible to clotting, is one of the hundreds of patients whose scans have been cancelled.

Though she's not in immediate danger, Kirkpatrick Parsons still worries about a recurrence of a pulmonary embolism.

"But I'm really more worried about the people who are in more acute situations, with doctors trying to figure out what's wrong with them," she said.

Kirkpatrick Parsons considers this a lesson for health officials because, she notes, there was no contingency plan.

D'Entremont said this situation is unusual.

"We've never had problem with this. This has been a company of choice for all hospitals so it's a difficult one for us," he said.

Two hospitals in New Brunswick still have isotopes. A doctor said they would be willing to help in an emergency, but so far, Nova Scotia has not made any requests.

Late Thursday afternoon, Canada's nuclear safety commission said it will keep staff at the Chalk River facility around the clock so they can restart it the moment operators finish their maintenance.