Area hospitals are canceling hundreds of cardiac exams, cancer scans and other crucial medical tests because they don’t have the radioactive isotopes needed to perform them.

“The bulk of the routine work has come to a significant halt,” said David Simms, medical director for Central Maine Medical Center’s School of Nuclear Medicine.

The problem: One Canadian nuclear reactor supplies nearly all of the medical isotopes used in North America. That reactor was shut down on Nov. 18 for what was supposed to be five days of routine maintenance. It has remained off-line since for additional work.

Hospitals have been told the reactor may not be working again until early-to-mid January and they may not get their isotopes until the end of that month. Doctors need those isotopes to perform a variety of crucial medical tests, including those that diagnose heart problems, pinpoint the best spot for a breast cancer biopsy and help determine whether cancer has spread to the bone.

Local hospital officials say Pharm-Corp of Maine, which supplies isotopes to the area, is rationing what it sends out. With the supply down to a trickle, hospitals have canceled routine scans and scans that use a larger isotope dose, such as cardiac stress tests.

The shortage has so far affected 70 to 80 percent of the scans done with the isotope at Central Maine Medical Center in Lewiston. The hospital, which runs a heart center, had been doing a handful of cardiac tests a day using the isotope.

“That’s pretty much gone down to essentially none,” Simms said.

In Farmington, Franklin Memorial Hospital has canceled 70 percent of its isotope-required exams, including cardiac tests and bone scans that determine whether cancer has spread. In Norway, Stephens Memorial Hospital has canceled 60 to 75 percent of its cases, though its cardiac scans have not been affected because the hospital, going against trend, uses a different isotope than the one that’s unavailable.

“It’s kind of paying off for us,” said Tim Ingram, director of clinical diagnostics for Stephens Memorial.

So far, the shortage has only affected about 15 percent of isotope scans – or about 10 patients – at St. Mary’s Regional Medical Center in Lewiston. The bulk of the hospital’s scans, including those for gallbladder and kidney problems, use small doses of the isotope, and those have continued without interruption.

The shortage hasn’t affected Rumford Hospital at all. The 25-bed critical access hospital doesn’t often do the scans that require the isotope.

For hospitals that are affected by the shortage, doctors are prioritizing emergency and urgent scans. Some are using different isotopes for some scans, including cardiac stress tests. They’re also asking doctors to, when possible, use other tests – such as CT scans and ultrasounds – in lieu of scans that need large isotope doses.

“They can sometimes spot what we’re looking for,” Ingram said. “But it really is a case-by-case basis.”

When hospitals can’t find a way around it, they’re rescheduling scans for January, when the isotopes should be available again.