Cutting CT usage and radiation without over-reliance on MRI proves to be a tricky business
This is a bad idea. This neighborhood reeks more of toe-tags than wingtips.”
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“But he’s late. I don’t like it.”
“Here he comes. Tex, you have the stuff?”
“My two best customers, and this is all the greeting I get?”
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“Do you want to party with it or get high like the guys from NASA?”
“Neither and you know it. We’re desperate.”
“For you I have it, but . . .”
“ . . . the price has doubled.”
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“No freaking way. We’ll get our supplies from the Russians or Chinese.”
“They dilute theirs. You know only I have the pure stuff. That’s why you always buy from me.”
“Damn. Pay him, and let’s get out of here.”
“I never dreamt when I did my MRI fellowship that one day I would be scrounging for helium on the streets.”
Helium is the second most abundant element in the universe, but it is actually rare on Earth. Our only source is the result of radioactive decay of uranium and thorium. This byproduct becomes trapped in underground natural gas deposits that took 4.5 billion years to accumulate.
Once helium gets into the atmosphere and escapes into space, it can’t be recovered. No wonder there is a worldwide shortage and even some rationing. At our present rate of use, supplies are expected to be exhausted by the end of the century. That rate of use is not static, however, but increasing dramatically, much like oil consumption, due to exploding worldwide growth. Demand for helium in electronics manufacturing, welding, and MRI has jumped 20% a year.
The National Aeronautics and Space Administration uses trainloads of the stuff to pressurize tanks, flush fuel lines, and test high-speed rockets. The Holloman High-Speed Test Track fills miles of tent with helium to test rockets, so the sleds they run on don’t melt due to friction with the atmosphere.
MRI alone represents 20% of worldwide use, and this figure is growing. With such an accelerating rate, many MRI sites and fellows could possibly close up or find themselves out of a job before 2050.
A recent New England Journal of Medicine article by David Brenner, Ph.D., could further accelerate the need for helium (Computed tomography-an increasing source of radiation exposure. 2007;357: 2277-2284).
Drawing on the data from a $1 billion joint U.S. and Japanese study of Hiroshima and Nagasaki bomb survivors, Brenner demonstrates how the average CT scan increases your risk of cancer to that of being about a mile from ground zero! These risks, he states, “are not based on models or major extrapolations in dose. Rather they are based directly on measured excess radiation-related cancer rates among adults and children who in the past were exposed to the same range of organ doses as those delivered during CT studies.”
And that is for just one CT scan; the risks are actually cumulative. Think of all those patients who get scanned over and over again. Then you have to factor in that children are 10 times more sensitive to radiation than adults, absorb a greater organ dose, and live longer.
“ The largest increases in CT use . . . have been seen in categories of pediatric diagnosis.” This is because the faster scanners have eliminated the need for pediatric anesthesia, making it much easier to order CT scans.
From the same study: “91% of emergency room physicians did not believe that CT scans increased the lifetime risk of cancer.” So true. I am increasingly seeing CT angiograms on 16-year-old girls with syncope to rule out stroke or dissection, asthmatic kids with shortness of breath to rule out pulmonary edema, and kids with gastroenteritis to rule out appendicitis. It is insane, and no one wants to stop because they’re afraid of being sued if they miss something-especially when there is a quick test available to exclude it.
The problem is that small risks applied over large populations can become a public health burden. Brenner’s study estimates that 1.5% to 2% of all cancers in the U.S. are caused by CT. The recommended solution? Increased use of MRI.
But with helium supplies dwindling, MRI may not be a long-term option. Therefore, we are stuck with the problem of how to reduce unnecessary radiation exposure to patients.
Sometimes the simplest solutions are the best. Take, for instance, Schiphol Airport in Amsterdam. The authorities there found that they could dramatically cut maintenance costs in the men’s room by the addition of a tiny fly embossed in the porcelain. It seems having something to aim at decreased backscatter by 80%, which saves on cleaning supplies, janitor salaries, and both the painting and replacement costs of corroded modesty barriers.
A simple change in signage could be just as effective. Instead of the current use of a chest x-ray as the international sign for radiology, I propose the use of a mushroom cloud-a big, red, glowing mushroom cloud, with smoke and sound effects. Kaboom!
A smart uniform can also convey a subtle message with no overt effort. Imagine if technologists were required to wear radiation decontamination suits like those used in the James Bond movie “Dr. No” or a smart Darth Vader ensemble.
“Luke, I am your father, and I don’t think this CT is indicated. Join me on the dark side.”
The FDA may have the most realistic way to influence behavior: by providing immediate feedback to ordering doctors, technicians, and patients. The FDA’s Center for Devices and Radiological Health has initially proposed that manufacturers be required to provide in new fluoroscopy equipment a record of cumulative patient exposure, which in turn could be recorded in patient charts. It is no stretch to imagine that this could easily be expanded to all x-ray-based studies. This information could be immediately downloaded into the patient’s permanent electronic medical record. You could even keep a personal record of your lifetime cumulative dosage. Why not start now?
Is it unreasonable to let patients know what their radiation exposure is and what its associated risks are? No. Can we preserve MRI and better manage a valuable resource like helium without becoming bitter balloon bandits making commando raids on Teenage Ninja Turtle-themed birthday parties? Yes, we can.