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Elizabeth Wang/MEDILL

Uranium ore on display at Argonne National Lab.

Nuclear scarcity ahead: The need for Mo-99

by Elizabeth Wang
Mar 13, 2014


Elizabeth Wang/MEDILL

Machine used in process to separate Mo-99 from uranium at Argonne National Lab.

Eighty percent of the world’s diagnostic medical imaging tests is possible thanks to nuclear energy. That represents about 30 million procedures annually worldwide – 18 million of which occur in the U.S., according to the U.S. Department of Energy.

Technetium-99m, or Tc-99m, mixed with various solutions and then injected into the body is used to locate and pinpoint internal issues ranging from heart disease to bone density loss to uncovering cancer cells.

But now we may be running out. By 2016, nuclear medical scientists are predicting a shortage due to the discontinuation of supply from the America’s closest and largest provider: Canada.

One underlying problem may be how the word “nuclear” is perceived in society today. When the word nuclear is dropped in conversation, red flags immediately go up. Through years of history and devastation, nuclear energy now carries a heavy burden. It is seen as a weapon and has a reputation as a force of destruction. And because of the weight of the word, the power behind nuclear medicine is getting glossed over.

“When you talk about nuclear threat or dirty bombs, most of it is [about] terroristic effect…that is happening,” said Dr. Gary Dillehay, Northwestern University professor of radiology and president of the Society of Nuclear Medicine and Molecular Imaging. “People are very concerned about radiation. You can’t really do much about that except educate people.”

And nuclear may not be as bad as they say.

“A lot of people are quick,” said Alex Brown, Argonne National Laboratory chemical sciences and engineering division postdoctoral appointee. “They need to blame something. It’s more cathartic to blame. It’s a bit of relief.”

Tc-99m is obtained through the half-life decay of Molybdenum-99, or Mo-99. Mo-99 is created through nuclear fission of highly enriched uranium-235, which is considered weapons-grade uranium in large quantities. Once the Mo-99 is separated from the uranium, it is collected and shipped to hospitals and medical facilities.

The Chalk River National Research Laboratory reactor near Ottawa, Canada remains the primary American source of Mo-99. But due to proliferation concerns surrounding nuclear energy, the lab will stop supplying the isotope by 2016. Now, other national labs like Argonne are trying to find alternative ways to make Mo-99 and meet the demand.

The shortage scare began in 2009. The Chalk River reactor is government owned and contract operated by Atomic Energy of Canada Ltd. The protracted shutdown coincided with the shutdown of the Netherlands reactor, decreasing Mo-99 production by 60 to 70 percent, Dr. Norman Laurin, president of the Canadian Association of Nuclear Medicine, said in an interview with The Canadian Press in 2013.

In mid-February, Atomic Energy of Canada gave the reactor lab a deadline to prove its worth, considering the massive funding and policy conflicts with the use of highly enriched uranium to extract the Mo-99, as well as the “old age” of the reactor – 56 years old. Technicians and radiologists have been fearing another shortage crisis so they have been working toward easing the blow when the reactor is forced to shut down.

“We’re preparing for what’s happening in 2016 when the Canada one goes offline,” Dillehay said. “The community is trying very hard to get a domestic supply … to plan for contingency in case that happens.”

There are a few other nuclear plants overseas that are also supplying Mo-99. Among them are the High Flux Reactor in Petten, Netherlands; the South African Fundamental Atomic Research Installation 1 in Pelindaba, South Africa; and the Open Pool Australian Lightwater reactor in South Sydney, Australia.

Despite the short half-life of Mo-99 (66 hours) and Tc-99m (six hours), Dillehay said that he thinks the shortage may be easily overcome because of the vast options of other reactors to maintain supply. The challenge is overcoming the short half-life--which resulted in the American dependence on the Canadian source.

“It won’t happen again like in 2009,” Dillehay said. “If that should happen again, we’ll have other sites that are online. The situation is a little different.”

Another major concern surrounding the nuclear industry is the idea of proliferation. The use of highly enriched uranium to create weapons remains a fear in the general population and remains high on the level of governmental concern in national security. This affects government funding to national labs using the uranium to separate and collect Mo-99. So labs are now being urged to find ways to use low-enriched uranium or just completely eliminating the use of uranium at all to produce it.

And that is possible – it’s just less efficient and less productive and potentially more expensive.

At Argonne, nuclear scientists have been working on taking the natural element Mo-98, the most common isotope of the element found on Earth, blasting it with neutrons using nuclear fission, therefore adding to its mass to create Mo-99.

Or the process can be reversed. Mo-100 is a rarer form of molybdenum found on Earth. But there is also a way to knock a nucleus off Mo-100 to create Mo-99. The only issue is that it may not be a very strong substance. But neither of these processes involve the use of uranium.

“The problem is it’s weak,” Brown said. “It does not accept neutrons very well.”

Other private companies have been working to commercially buy and sell Mo-99 to maintain the supply in the U.S. Companies such as Mallinckrodt in the Netherlands, Billerica, Mass.-based Lantheus and GE Hitachi have a stake in the nuclear industry to keep up with demand. But the increased costs force medical centers to be conservative in their Tc-99m use.

“There’s a huge push to decrease the amount of highly enriched uranium moved around the country, making it a little bit more expensive,” Dillehay said. “Probably their biggest push is to switch to low-enriched uranium.”

But a switch in mindset of the stigma of nuclear could really push the boundaries for nuclear funding.

“Nuclear doesn’t cause cancer,” Brown said. “Nuclear can find and kill it.”