June 13, 2009

Medical Isotopes Shortage Puts Hospitals, Patients In Dire Straits

A scarcity of medical isotopes has forced physicians at scores of U.S. and Canadian hospitals to begin curbing the number of a variety of standard diagnostic tests they prescribe.  Hospital officials say they see no quick-fix in the immediate future.

In May, Canadian health officials were forced to close down a nuclear reactor in eastern Ontario that provides roughly a third of the world's supply of medical isotopes that are used in a variety of now commonplace medical screenings to check for conditions such as impending heart attacks or the spread of cancer.

According to officials at the Chalk River reactor, the necessary repairs may take up to three months to complete "” that is, if the damage turns out to be reparable at all. 

The Ontario reactor is one of only five aging plants worldwide capable of producing the substance known as molybdenum-99, the most commonly used medical isotope. The incredibly unstable chemical decays within 67 hours of production, making it impossible for hospitals to stockpile.

"We are seeing a shortage," said Dr. Peter Conti of the University of Southern California in Los Angeles, explaining that physicians at the university's three hospitals have already had to start rationing supplies by being more stringent in their criterion for who gets screened and who doesn't.

Dr. Conti added that a prolonged shortage of molybdenum-99 could threaten to interrupt crucial clinical trials for experimental cancer drugs if participating patients are unable to get needed scans on time and are thus forced to drop out of the studies.

The Society of Nuclear Medicine reported the results of an e-mail study they conducted this week in which 91 percent of the 375 participants"”including doctors and nuclear medicine technicians at hospitals across North America"”said that they had been directly affected by the shortage, with 60 percent saying that they were forced to postpone procedures and another 31 percent reporting that they had had to cancel at least one scheduled screening.

Physicians at the University of Chicago Medical Center have already begun recommending alternative diagnostic tests that do not require the medical isotope but may more expensive and less effective.

"Pretty much every reasonable-sized medical center is going to have a nuclear medicine department that relies very heavily on this isotope," said Dr. Daniel Appelbaum, head of the university's nuclear medicine department.

Meanwhile at the University of Southern California's medical facilities, Dr. Conti said that physicians there are performing only the most urgent tests, which usually includes checking for immediately threatening heart disease. He added that screenings for bone cancer "have gone by the wayside."

Conti explained that a number of cancer patients will have to be switched to a more expensive procedure known as positron emission tomography scans, or PET scans. Though the test has been approved by the U.S. Food and Drug Administration it is not covered by Medicare.

"For Medicare, we're going to have to eat some of those costs. We'll try to bill on the private side," he said.

The Toronto-based MDS Inc, which distributes the Canadian reactor's medical isotopes worldwide, has also been hit hard by the unexpected scarcity of the substance, reporting on Thursday a $17 million loss for the second quarter of 2009.

The privately-owned Massachusetts-based Lantheus Medical Imaging, which specializes in processing isotopes for medical use, received the majority of its supply from the Ontario facility. Last month the company was forced to make impromptu arrangements with other suppliers in attempt to make up for the shutdown of the Chalk River reactor.

Another major U.S. supplier, Covidien, receives most of its isotopes from a reactor in the Netherlands, and has thus been able to protect most of its clients from the Canadian shutdown. But that could all change next month when the Dutch reactor closes for four weeks for scheduled maintenance work.

In an official letter posted last month on the FDA website, representatives for Covidien wrote: "Even with numerous global efforts and collaborations now underway, there will be challenges meeting full market need."

Dr. Robert Atcher, president of the Society of Nuclear Medicine, has suggested a potential solution for dealing with the short-term shortage.   He has recommended the acceleration of plans to convert a U.S. Department of Energy research reactor at the University of Missouri into a producer of medical isotopes.


Image Caption: Some cancer patients will have to be switched to a more expensive procedure known as positron emission tomography scans, or PET scans. (Jens Langner/Wikipedia)


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