The University of Missouri Research Reactor has filed an application to produce molybdenum-99, a precursor isotope to technetium-99m, a radiotracer used in more than 16 million nuclear medicine procedures in the U.S. every year.
Molybdenum-99 (Mo-99) is produced at a select few reactors across the world, with none located in North America after the October closing of the National Research Universal Reactor in Ontario, Canada. Once approved, the Missouri reactor would serve as the sole domestic source of molybdenum, fulfilling almost half of the U.S. demand.
The University of Missouri Research Reactor (MURR) and partners General Atomics and Nordion were awarded a cooperative agreement from the Department of Energy’s National Nuclear Security Administration in 2015, supporting their efforts to develop a domestic source of molybdenum. This application is the culmination of those efforts, according Ralph Butler, Executive Director of MURR.
"This [application] shows the Nuclear Regulatory Commission that we will have all of the technology, expertise and safety measures needed to begin producing Mo-99 in place and ready to go once approval has been received,” he said in a statement. "As a public research institution, we are proud to play a partnership role with General Atomics and Nordion in helping America secure a new, domestic source of Mo-99."
A domestic source is important, both for stability in the worldwide supply chain and for affordable access to technetium in the U.S.
The Mo-99 worldwide supply chain has been plagued by aging reactors and a dearth of production facilities: 95 percent of production is limited to seven large reactors in Australia, Europe and South Africa. Four of those reactors are over 50 years old and three are in the midst of large-scale modernization projects, making unanticipated shutdowns a distinct possibility according to a U.S. National Academy of Sciences report.
While the supply chain is stable in the short term, reserve supply is insufficient in the case of an unplanned shutdown, said the Organization of Economic Co-Operation and Development. In 2009 and 2010, the U.S. experienced a shortage of molybdenum due to foreign reactor shutdowns, leading to the disruption or delay of procedures for an estimated 50,000 patients per day.
When Mo-99 supplies are disrupted radiologists are occasionally able to use other nuclear tracers or move certain patients to other modalities, but nothing is guaranteed.
“We could shift a heart or bone patient to a PET scanner, but there’s less availability. We have seven gamma cameras, but only one PET machine,” said University of Chicago Chief of Nuclear Medicine Daniel Appelbaum, MD. “There’s a reason they were ordered as nuclear tests first.”
Much of the time the solution is brutally simple: The patient doesn’t receive the test.
“Sometimes it isn’t required, sometimes the doctors are able to use blood work or clinical information to make their decision,” said Appelbaum.
On the other hand, a domestic source of Mo-99 would insulate radiology from the shifting international trade priorities of the current White House administration. President Donald Trump followed through on his campaign promise to withdraw from the Trans-Pacific Partnership on the first day of his presidency, ending America’s participation in the free trade deal with eleven Pacific nations including Australia—a key supplier of Mo-99.
Trump’s mindset of “Buy American, Hire American” could attempt to limit the purchase of goods manufactured abroad and the administration is currently preparing new executive orders to re-examine U.S. bilateral trade deals. These executive orders will include the current free trade agreement with Australia, as reported by Politico.
Regardless of what happens in Washington, D.C., MURR will start producing Mo-99 in mid-to-late 2018 if all goes according to plan, according to Phil Larabie, Vice President of Medical Isotopes for Nordion.
"Filing this license amendment is a key step in our efforts to stabilize and support the nuclear medicine community in North America and beyond for decades to come,” he added.