Nuc med providers brace for long moly-99 shortage

May 29, 2009

Nuclear medicine providers can expect molybdenum-99 shortages until at least September while North America’s primary source of medical isotopes is shut down for repairs.

Nuclear medicine providers can expect molybdenum-99 shortages until at least September while North America's primary source of medical isotopes is shut down for repairs.

The National Research Universal reactor at Chalk River will remain out of service for at least three months, according to operator Atomic Energy Canada Limited. An emergency shutdown of the 50-year-old reactor was ordered May 14 after a heavy water leak was discovered. During normal operations, the facility accounts for the production of about one-third of the world's medical isotopes.

In a May 27 written release, AECL noted that it is too early to set a definitive timeline for the reactor's return to service. Heavy water leakage was discovered at the base of the reactor vessel in a corroded area on the outside vessel wall. Officials have slowed the initial leakage of 5 kg/hr by drawing water from the containment vessel, but more corrosion has been found around its circumference. Though some radioactive tritium has escaped into the atmosphere, the quantity was not high enough to threaten the health of reactor workers or the general public, AECL said in a release.

Shortages have become critical for some nuclear medicine providers. As of midday on May 29, the nuclear medicine department at the University of Iowa Medical Center had not received new technetium generators from GE Healthcare for two weeks, and its last generator was expected to run dry by the end of the day, said Dr. Michael Graham, chair of nuclear medicine.

The situation there would have been worse without an arrangement with a Davenport, IA, radiopharmacy that is supplying the hospital at Iowa City with daily shipments of technetium-99m from 60 miles away. The radiopharmacy is getting its generators from Lantheus Medical Imaging, a radiopharmaceutical supplier in North Billerica, MA, Graham said.

To address the shortfall, the department has delayed performing bone scans. It has shifted to thallium-201 for myocardial perfusion imaging and rubidium-82 PET for selected cardiac applications.

"This is not a total shutdown, but it is irritating," Graham said. In San Francisco, the shortage began affecting operations at California Pacific Medical Center less than a week after the reactor shutdown.

GE is delivering about 50% of the usual allowance of bulk Tc-99m, said Dr. Stephen R. Bunker, clinical director of nuclear medicine at CPMC. GE cautioned customers to not expect supplies to improve soon.

Bunker's group has cut dosages in half and lengthened imaging times for bone scans and other routine procedures that require Tc-99m. Unscheduled time slots were available for the longer appointments in the usually busy department because of the Memorial Day holiday.

Bunker shifted to Th-201 for myocardial perfusion studies last week. He was planning to use iodine-123 hipparan for renal studies before discovering that it is no longer manufactured.

"This is going to get worse before it gets better," he said.

GE issued a statement indicating that it is working with Lantheus, its supplier of technetium generators, to minimize effects of the supply shortfall. The company noted that it had successfully managed previous events, including the recent forced shutdown of the High Flux reactor at Petten, the Netherlands. It is working closely with various industry partners to get maximum use from every dose of available isotope, said GE spokesperson Ryan Fitzgerald.

In a separate development, the Canadian Natural Resources Minister announced plans May 28 to sell AECL's commercial nuclear reactor construction and engineering division. AECL is a crown corporation involving public oversight of its private management.

In a report by the Canadian Broadcast Corporation, Minister of Natural Resources Lisa Raitt said that planning to sell off a portion of the operation began several months ago and is unrelated to the problems at Chalk River. Media reports list GE and SNC-Lavalin, a Canadian company, as potential partners.