TERRE HAUTE —
This is a story of international finance and politics, involving such entities as Mo-99, Thallium 201, 73-hour half-lives and a medical industry character known as “Aunt Minnie.”
This is also a story that should remind us that when we grudgingly swallow some sort of dye or offer our arm for an IV so our innards can be scanned, most of us have no clue about the infinitely complex and miraculous realm of science behind the process.
I happened upon the realm when my mother’s cardiologist called to say there was one slot on one day, and one day only, for her to have a nuclear heart scan — unless she would like to wait several weeks, which isn’t an option.
“What in the world is going on?” I asked the scheduling nurse, not suspecting that “the world” is precisely the arena in which we are playing.
“There’s a worldwide shortage of thallium,” she said. “It’s been going on a long time and we thought it would get better, but it’s not. I’ve had to reschedule 30 patients.”
I went to the Internet, Googled “thallium shortage” and — days later — found myself swimming in information about what in the world is going on.
Thallium, you probably don’t remember from high school chemistry, is a non-precious mineral that doesn’t look like much — sort of like tin — when you dig it up. For a long time, it was used in crude form to poison rodents (and some people, too, because it’s tasteless), but science, the electronics industry and medicine discovered magical properties in thallium, especially when it’s run through a cyclotron and transformed into nuclear isotopes.
Thallium-201 has been a utility player for decades in the imaging of internal organs, and it is particularly useful in detecting blocked arteries, confirming a heart attack, indicating why someone has chest pain and predicting how much exercise a person’s heart can endure.
The thallium shortage, however, hasn’t been caused by something as simple as an explosion in global demand for nuclear heart scans. No, it’s the result of a different shortage of a really exotic element — literally an element on the Periodic Chart of Elements — called technetium.
Technetium is a radioactive metal that appears in minuscule amounts in nature, but can be made via nuclear fission. Technetium Tc 99m is the favored medical isotope for just about every kind of super-fine organ and interior body imaging — from heart to lungs to bones to lymph nodes and cell structure. Doctors like it because it produces great pictures and has a short half-life (the measurement of atomic decay), which means it can be administered in small doses, minimizing radiation exposure for the patient.
Without enough technetium to satisfy a world demand of about 20 million diagnostic imagings each year, medicine has had to turn to cyclotron-manufactured thallium.
— Time out: If you retain nothing else today, remember that technetium is pronounced “tek-NEE-shum.” You can impress your friends or maybe win some money if you ever get on “Jeopardy.” —
Technetium is actually a byproduct of nuclear fission involving high-grade uranium and the element, molybdenum — think “Mo-99” — thus it must be produced in a specially outfitted nuclear reactor.
The bad news: There are only about a half-dozen of those babies in the whole world. The worse news: Not one of them is in the United States, even though we use about 50 percent of the world’s supply of Mo-99 technetium. The worst news of all: The two biggest producers of technetium are both on the disabled list — down, idled, off line — and have been for months.
One reactor, at Petten in the Netherlands, was shut down in July 2009, put back online, then shut down again this past February. It’s scheduled to be back up and running late next month. But, as I learned while isotope surfing on the Web, nuclear reactors don’t always meet re-boot schedules.
The other big reactor, in Ottawa, Canada, was shut down three times in 18 months and has been down-down since May 2009. Radioactive water leaks have been the most recent problem.
Both the Dutch and Canadian reactors are old and nearing the end of their lives, yet they ordinarily supply about two-thirds of the globe’s technetium. Talk about a need for alternative sources.
A bipartisan bill in Congress, the American Medical Isotopes Production Act of 2009, aims to end our dependence on foreign radionuclides.
Passed by the House of Representatives last fall and now sitting in the Senate, awaiting action, the bill would appropriate more than $160 million to kick-start a medical technetium industry in this country. Needless to say, HR 3276 has not threatened health care or financial reform for floor-debate time or news media coverage.
According to a news story on ImageBiz.com, the Obama Administration is working with the Nuclear Regulatory Commission, the Department of Energy and the Food and Drug Administration to find new sources of technetium here among our few U.S. nuclear production sites.
But as we learned with Mom’s nuclear stress test in Terre Haute — and as Robert W. Atcher, a past president of the Society of Nuclear Medicine, said recently — “The United States needs a reliable domestic isotope supply now more than ever.”
If you’ve made it this far in the story, perhaps you have a greater appreciation for what goes on behind the scenes when you or a relative is told to go in for a nuclear imaging test. Because you’ve made it this far, I’ll end with Aunt Minnie.
She, or rather it, is the name of a website for radiologists and medical imagining professionals that was founded in 1999 by the late Dr. Phillip Berman, a radiologist, innovator and entrepreneur. Aunt Minnie’s “About” page explains that another pioneering radiologist, Dr. Ben Felson of the University of Cincinnati, coined the term “Aunt Minnie” in the 1940s. It refers to “a case with radiologic findings so specific and complex that no realistic differential diagnosis exists. In other words: If it looks like your Aunt Minnie, then it’s your Aunt Minnie.”
As I said, it’s a whole different realm out there in the land of nuclear medicine. And don’t forget: Tek-NEE-shum.
Stephanie Salter can be reached at (812) 231-4229 or firstname.lastname@example.org.