Canadian reactor ramps up to renew supply of technetium

The Canadian nuclear reactor critical to the supply of technetium (Tc-99m) in the U.S. has restarted, but the raw material that MDS Nordion processes into the medical isotope needed for nuclear medicine studies will not be in full production until the end of this week.

Emergency legislation, issued by the Canadian Parliament late Dec. 12, ordered the restart of the nuclear reactor at Chalk River, Ontario, that makes molybdenum (Mo-99). A spokesperson for MDS Nordion said the company is fully prepared, once shipments of Mo-99 are received, to begin turning them around for distribution to the medical community. Processing typically requires one to two days.

The reactor shutdown, initiated Nov. 18 for scheduled maintenance, initially was extended because of the need to upgrade an electrical back-up system. Early estimates of a quick return to full production in mid-December were revised to early or mid-January, triggering an outcry from the nuclear medicine community, which conducts about 25 million scans or treatments annually with medical isotopes obtained from the Canadian reactor.

The reactor shutdown cut the supply of Mo-99 by 50% to North American sites, sharply curtailing nuclear studies that depend on Tc-99m, the isotope generated by Mo-99. The response by Canadian authorities to restart the reactor is not expected to raise any safety issues regarding operation of the reactor.

In an earnings conference call Dec. 13, MDS Nordion CEO Stephen DeFalco blamed the extended shutdown on a "miscommunication" between Atomic Energy of Canada Limited, which runs the reactor, and its regulator. He noted that MDS Nordion had no influence over what happened, but was encouraged by the Canadian government's response.

"I am seeing support by the government and understanding of the role we play in the global market," DeFalco said.

MDS Nordion supplies Mo-99 for sale and distribution in the U.S. by Mallinckrodt Medical, a subsidiary of Covidien, and Bristol-Myers Squibb. Because of the six-hour half life of Tc-99, the nuclear medicine community depends on specially processed containers of Mo-99 from which the medical radioisotope is extracted on site.

Since the shutdown of the Canadian reactor, Mallinckrodt Medical has tapped another Mo-99 source, this one located in the Netherlands. But Mallinckrodt cannot fully make up for the Mo-99 deficit with its European source, according to the American College of Radiology (ACR), which reports severe cutbacks in the number of nuclear medicine procedures.

"Radiologists are making every effort to employ alternative imaging methods to provide the information needed by patients and their primary physicians until the supply issue can be resolved," according to a statement from the ACR.

Unit doses of Tc-99m cardiac imaging radiopharmaceuticals are being rationed, according to the ACR. Urgent nuclear cardiology studies can be performed with a different radiopharmaceutical, Thallium-201 (thallous chloride), but few practical alternatives exist for noncardiac applications, such as tests for cancer and other disorders, according to the ACR. The reactor shutdown is also affecting the supply of iodine-131. Although this isotope has no diagnostic purposes, it is widely used in the treatment of hyperthyroidism.