Nuclear medicine departments worldwide are again facing the challenge of tight supply for molybdenum-99 (Mo-99) as two major production sites remain offline.
Last month, the Nuclear Research and Consultancy Group (NRG) powered down its High Flux Reactor in Petten, Netherlands, for maintenance, while Atomic Energy of Canada (AECL) continued repairs to its National Research Universal nuclear reactor in Chalk River, Ontario.
The Petten facility will be offline until August, while a March 10 update from AECL anticipates a restart in May.
The situation is nothing new for nuclear medicine practitioners. The supply of medical isotopes has remained fragile for the past several years due to planned and unexpected production problems across the globe.
An informal poll by SNM in February found that 63% of respondents (46 of 73 replies) "strongly agree" that the Mo-99 shortage will affect their ability to care for patients, while 27% (20 replies) "agree" the shortage will have an effect. The remaining 10% either "disagree," "strongly disagree," or were "unsure."
Reason for optimism
Still, there is reason for optimism, as nuclear medicine departments learn from previous experiences and when inspiration came from desperation.
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| Dr. Michael Graham, Ph.D. Image courtesy of SNM. |
Nuclear medicine departments, for example, have become more creative by scheduling scans when Mo-99 is available. "We will have to operate on weekends sometimes, because the molybdenum is there on weekends," said Graham, who also serves as director of nuclear medicine at the University of Iowa in Iowa City. "It is decaying away on weekends, and if you don't use it, you lose it."
At Brantford General Hospital in Brantford, Ontario, Dr. Christopher O'Brien, medical director of nuclear medicine, said the adverse effects from the tight Mo-99 supply have not been too severe. To help alleviate any strain on Mo-99 supply, the facility converted almost all of its cardiac studies to thallium to continue to offer that service to area patients.
"That has liberated enough technetium, which is our workhorse radiopharmaceutical medical isotope, to do our nonurgent cancer studies, lung scanning for blood clots, and our pediatric population," O'Brien said. "We have not had to cancel any patients or have any barriers to emergency access."
Weekend shifts
Brantford also has moved to weekend shifts with the possibility of working longer hours to image patients when the medical isotope is available.
O'Brien recalled that Mo-99 supply issue was much worse last year when the Chalk River reactor went offline last May due to a major water leak and supplies dwindled dramatically in June. The shortage was further exacerbated in August when production was halted for a time at both Chalk River and Petten. Since then, companies have used their resources effectively to ensure some stability in supply.
"That doesn't mean we are out of the woods yet, because we are relying on international medical isotope supplies for Canada and North America," O'Brien added. "If there is any disruption -- ranging from a delayed flight to a pilot saying he doesn't want to bring the medical isotopes on board -- we dry up very quickly, because there is no reserve supply. That's how tight the situation is."
SNM's Graham said SNM has spoken with suppliers Covidien of Dublin, Ireland, and Lantheus Medical Imaging of North Billerica, MA, and both companies "have been assured they are doing what they can" to ensure as much supply as possible.
Brantford's supply of Mo-99 comes from both Lantheus and GE Healthcare of Chalfont St. Giles, U.K.
Thallium production
GE manufactures and distributes its molecular imaging products for North America and the rest of the world from its facility in Arlington Heights, IL. "In many cases, our products are manufactured and injected into a patient in less than 24 hours," said site leader Rick Cornell.
Arlington Heights feeds three primary customer bases -- 30 GE-owned radiopharmacies in the U.S. and Canada; more than 300 radiopharmacies owned by other companies, such as Cardinal Health of Dublin, OH; and therapy providers around the world.
The licensed nuclear site has seen a "significant increase" in the demand for thallium-201, which has tracked the fluctuations in the Mo-99 supply. "We try to anticipate when there will be a shortfall," Cornell added. "Then we will bump our thallium [production] up. Right now, we are in a 12-week window where it is particularly tight because of the reactor in Petten that is down."
Cornell estimated that thallium demand is up 30%, with the company distributing approximately 1,000 vials a week, and doesn't expect demand to wane until more Mo-99 becomes available.
Covidien also has increased its production of thallium-201 as a substitute, when clinically applicable, but the Mo-99 shortage also has prompted Covidien to halt generator production for four days later this month. In its latest Mo-99 supply update to customers, the company anticipates a "significant shortage to generator standing orders" during the week of March 21.
Foreign sources
Last month, Covidien signed an agreement with the Institute of Atomic Energy in Poland (IAE Polatom) to augment Covidien's supply of Mo-99. The plan is designed to help meet the needs of more than 1 million additional patients globally in the first six months after the Maria research reactor begins supplying the isotope.
The company also is working with the U.S. Food and Drug Administration (FDA) to use Mo-99 from the Maria reactor in the U.S. Although there is no specific date for supplies to arrive in the U.S., Covidien believes the additional supply in Europe will have a positive ripple effect in the U.S.
In its March 4 update, Lantheus has warned its customers that its Mo-99 supply also "will be significantly lower due to maintenance cycles at the remaining operating reactors" from March 21 through March 25. "Clarity on available Mo-99 supply for the month of April is still being determined, although we do expect it to be consistent with our Mo-99 supply level for February and March of this year," the company noted.
Lantheus, meanwhile, has finalized an arrangement with the Australian Nuclear Science and Technology Organisation (ANSTO) in December to receive Mo-99 produced from low-enriched uranium (LEU) targets in ANSTO's new Open Pool Australian Lightwater (OPAL) reactor.
The LEU-derived Mo-99 has been tested and validated by Lantheus for use in its TechneLite generator line. In the meantime, Lantheus and ANSTO are working with the FDA and Health Canada for the necessary LEU Mo-99 approvals for the U.S. and Canadian markets.
"The problem is the longer-term one that this is going to be a recurring problem," said SNM's Graham. "These reactors are at their lifetimes and they are going to continue to have problems. We definitely need to address alternative ways to provide molybdenum-99, but there are some creative ideas out there that are moving forward."
By Wayne Forrest
AuntMinnie.com staff writer
March 12, 2010
Related Reading
NRG powers down Petten reactor, February 19, 2010
Covidien signs deal to produce Mo-99 at Polish reactor, February 17, 2010
AECL confirms delay for Chalk River, January 29, 2010
Covidien to halt generator production, January 22, 2010
Lantheus to get Mo-99 shipments, December 18, 2009
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