Radiologists are changing dosages, switching radioisotopes, and rethinking medical imaging requirements in response to unsteady technetium-99m supplies.
The shutdown last fall of a nuclear reactor in Canada continues to roil the practices and hospitals that depend on the nuclear material produced at that reactor and elsewhere.
In response to unsteady supplies of technetium-99m, radiologists have switched to different radioisotopes, adjusted technetium-99m dosage, and taken different approaches to imaging.
At St. Joseph's Hospital in Phoenix, Chief of Nuclear Medicine Frank Schraml, MD, explains how the hospital dealt with a similar shortage several years ago.
"The radiopharmacies in the area essentially give us priority, because we order a lot of isotopes," Schraml says.
During a severe shortage of technetium-99m two years ago, Schraml thought St. Joseph's might have to turn to thallous chloride 201, a suboptimal isotope, but instead decided to make its supply of technetium-99 go a little further.
"We compensated by lowering our doses slightly… you can maintain the same quality by slightly increasing the time of imaging," Schraml says. "We were able to continue business as usual, essentially."
Eventually, the shortage abated, and the hospital resumed its original dosages and dosage times.
Regarding the current shortage reports, "I don't know how dire things will be," Schraml says. "I put a lot of reliance on my technologists and my manager. They seem to always come through, so if the shortage isn't any worse than it was a couple of years ago, then I think we'll be fine."
The PET Alternative
Technetium-99 is used between 70,000 and 80,000 times per day in U.S. healthcare, primarily as a cardiac perfusion imaging agent, says Paul Crowe, chairman and chief executive officer at NuView Life Sciences, based in Dallas.
"It actually shows how well the blood is being moved through the heart, and it is a clinical assessment for the doctor to determine the cardiac output by ability of the muscle, and to help the physician diagnose a patient's condition," Crowe says.
Technetium-99 has been used for decades by clinicians in private offices that have their own nuclear medicine cameras, as well as in hospitals. "Over the last 10 years, there [have] been intermittent shortages of the product that cause cancellations of patient procedures," he says.
One alternative in use is a product of rubidium-82, a PET biomarker. "The difference is that the cameras that utilize the rubidium are larger, they're much more expensive, [and] you have limited facilities in the United States that offer these services for cardiac imaging," says Crowe.
"Most PET imaging cameras are used for staging cancer and observing response to therapy. But there's a growing demand for rubidium as a PET perfusion imaging agent for the heart, because it has higher image quality. It has less artifact that may or may not influence the accuracy of the diagnosis," he says. "Also, the imaging times are lower."
Another reason rubidium-82 could make inroads: MRI and PET cameras are being integrated, aiding earlier detection of heart tumor or plaque, Crowe says.
"If you can diagnose a medical disorder more efficiently, you can treat it more efficiently, and you eliminate a lot of unnecessary tests in between," he says.
NuView plans to reopen a shuttered Texas manufacturing facility to produce both rubidium-82 and technetium-99, Crowe says, and the company aims to have both radioisotopes on the market in 16 to 18 months.
NuView is also working on new radioisotopes, in conjunction with Peter Conti, MD, PhD, professor of radiology and director of the at Keck School of Medicine Molecular Imaging Center at the University of Southern California, utilizing adenosine.
The new products will be available in the next 34 [or] 36 months, providing clinicians with alternatives to technetium-99 or rubidium-82, Crowe says.
Scott Mace is the former senior technology editor for HealthLeaders Media. He is now the senior editor, custom content at H3.Group.