WASHINGTON — A global shortage of a radioactive drug crucial to tests for cardiac disease, cancer and kidney function in children is emerging because two aging nuclear reactors that provide most of the world’s supply are shut for repairs.
The 51-year-old reactor in Ontario, Canada, that produces most of this drug, a radioisotope, has been shut since May 14 because of safety problems, and it will stay shut through the end of the year, at least.
Some experts fear it will never reopen. The isotope, technetium-99m, is used in more than 40,000 medical procedures a day in the United States.
Loss of the Ontario reactor created a shortage over the last few weeks. But last Saturday a Dutch reactor that is the other major supplier also closed for a month.
The last of the material it produced is now reaching hospitals and doctors’ offices. The Dutch reactor, at Petten, is 47 years old, and even if it reopens on schedule, it will have to be shut for several months in 2010 for repairs, its operators say.
There are substitute techniques and materials for some procedures that use the isotope, Dr. Graham and others said, but they are generally less effective, more dangerous or more expensive. With the loss of diagnostic capability, “some people will be operated on that don’t need to be, and vice versa,” he said.
Dr. Andrew J. Einstein, an assistant professor of clinical medicine at the Columbia University College of Physicians and Surgeons, said the isotope was used to determine if a patient had a coronary blockage that required an angioplasty or stent. Without the test, Dr. Einstein said, those invasive procedures would be performed on some who did not need them. His hospital is already sometimes using smaller doses of the radioactive drug than guidelines specify, he said.
The alternative is to inject a dye, which sometimes does not let the surgeon find the node.
Without the tool, Dr. Graham said, the quality of medical care is “dropping back into the 1960s.”
On Tuesday, Representative Edward J. Markey, a Massachusetts Democrat who is one of the House’s fiercest critics of the nuclear industry, declared that the United States was facing “a crisis in nuclear medicine.”
Mr. Markey, chairman of the House Energy and Commerce subcommittee on energy, called for establishing new production facilities in the United States. He joined the ranking Republican on the subcommittee, Representative Fred Upton of Michigan, to introduce a bill to authorize $163 million over five years to assure new production.
The White House is coordinating an interagency effort to find new sources of supply, involving the Nuclear Regulatory Commission, the Food and Drug Administration and the Energy Department, but officials said the process would take months.
The reactors are typically small — sometimes no larger than a homeowner’s trash barrel — but a complete setup costs tens of millions of dollars.
Tech-99m, as it is abbreviated, emits a gamma ray that makes its presence obvious. It has a half-life of six hours, meaning that it loses half its strength in that period. Thus it does its job quickly, without lingering to give the patient a big dose. But it also means the isotope must be produced and used faster than most other drugs.
Tech-99m is the product of another isotope, molybdenum-99, which also has a short half-life, 66 hours. Thus a week after it is made, less than a quarter of the molybdenum-99 remains. Stockpiling is not practical.
“You lose about 1 percent an hour,” said another expert, Kevin D. Crowley, director of the Nuclear and Radiation Studies Board at the National Research Council. “So time is of the essence.”
Molybdenum-99 is made when uranium-235 is split, but only about 6 percent of the fission fragments are molybdenum. Purification has to be done in a heavily shielded “hot cell.”
The common method is to put a uranium target into the stream of neutrons produced in the reactor as uranium is split. But the preferred material is a high-purity uranium-235, which is also bomb fuel.
Mr. Markey and others are trying to have the industry switch to low-enriched — nonweapons-grade — uranium.
Dr. Crowley said that could be done, although the industry has resisted.
The reactors’ poor condition has been obvious for a while. In 2007, Canadian safety regulators said the Ontario reactor should not restart, but the Canadian Parliament overruled them.
In 1996, the company that purifies the molybdenum from the Ontario reactor, MDS Nordion, contracted with Atomic Energy of Canada Ltd., which owns the reactor, to build two new ones. MDS Nordion paid more than $350 million for them.
But when the new reactors were started up, both showed a problem: as the power level increased, the reactors had a tendency to run faster and faster, a condition called positive coefficient of reactivity. That is a highly undesirable characteristic in a reactor, one that contributed heavily to the Chernobyl disaster in 1986. So Atomic Energy of Canada Ltd., which is owned by the Canadian government, said it would not open them.
For all the years that the Ontario plant was running or the replacements were under construction, other potential manufacturers believed they could not compete, Dr. Klein said. And the business has always been small, he said, adding that a big pharmaceutical company “can make more on Viagra in two days than on tech-99m in a year.”
Several long-term alternatives are available. Babcock & Wilcox, a reactor manufacturer, has proposed a new kind of reactor that would manufacture molybdenum that could be siphoned off continuously.
In a few weeks, a company in Kennewick, Wash., Advanced Medical Isotopes, plans to test a new system, using a linear accelerator, a machine that shoots subatomic particles at high speeds.
Reactors in Belgium, France, South Africa and Argentina could also be used to make small amounts.
The High Flux Reactor at the Oak Ridge National Laboratory in Tennessee, owned by the federal government, and a research reactor at the University of Missouri, could do the work, but neither has the equipment in place to extract the molybdenum from the targets.
For the time being, said Dr. Crowley of the National Research Council, “we are in a triage situation.”