Freddy Krueger hides out in the CT scanner

March 4, 0001
Bradley M. Tipler, MD

For the past 10 years I have been lecturing on America's Radiation Phobia. Obviously, I am not doing a good job, because it is growing.

For the past 10 years I have been lecturing on America's Radiation Phobia. Obviously, I am not doing a good job, because it is growing. What I find particularly distressing is the problem's growth among radiologists. Recently, phobic radiologists have been publishing and lecturing like rabbits on Viagra.

I have always endorsed and applied ALARA. I heartily endorse the Image Lightly campaign. If there is any risk from medical radiation, it is to children. But I raise cattle on my farm, and I occasionally step in the stuff being printed and propagated by a lot of radiologists now.

While the Biological Effects of Ionizing Radiation (BEIR) reports and the alphabet soup that formulates radiation standards for the U. S. are monumental works of statistics, they are not facts. Historically, they were developed to help us formulate national and international policy on radiation safety and work out radiation regulations. Still today they are based in large part on data gathered from the survivors of Hiroshima and Nagasaki.

The American public's exposure to radiation from medical imaging has nothing in common with that of Japanese atom bomb survivors. The numbers are great for developing radiation regulation guidelines, but they are not appropriate for determining the risk/benefit ratio for an acutely ill patient in an emergency room. What U.S. radiologist in his or her right mind uses Japanese statistics for gastric cancer when reading an upper GI?

Every one of the numbers now being headlined by the lay press is based on the linear no-threshold theory. Is there a radiologist who actually believes the effects of low-dose radiation over a lifetime are the same as those of one massive dose? The LNT made sense in the early development of radiation safety guidelines. Rule-makers need to err on the side of safety.

We all know CT is being overused. And we all know there is one primary reason: money. Clinicians with their own scanners want to produce income for themselves, and good docs who don't own a machine want to avoid generating income for plaintiffs' lawyers.

Radiation regulations are to clinical decision making what highway construction regulations are to NASCAR. You don't see speed limit signs on NASCAR tracks because that would be dumb. It is just as dumb to put theoretical numbers on the risk of a CT scan for an individual patient. If the patient needs the test, the theoretical radiation risk is immaterial. If the patient doesn't need the test, duh, don't do the test. If you are not sure, the American Trial Lawyers Association would love to review your decision later.

As I say in my lectures, this is the classic American approach to risks. We love scary movies, but we want mother hen to eliminate all real risk from our lives. We can save thousands of lives by lowering the speed limits, but we want to drive fast. When we wreck, we hire a lawyer and sue anyone who didn't make our fast driving safer.

We need to emphasize .DAM (“dot DAM,” don't order the test if it doesn't alter management) and make sure we use the lowest possible dose for a given exam. Recent literature has shown we are lousy at the latter. We do not need to complicate the ordering process, especially with biased statistics that were never intended to be applied on an individual basis.

I think putting a note on a CT order form about the theoretical risk of cancer from a single CT means the radiologist is clueless about the conflicts facing the ordering doctor. The radiologist looks like, and probably is, a fool.

Americans like to compare CT doses to our background level of 3 mSv per year. Background radiation on the coast of Brazil exceeds 150 mSv a year. Have you seen those poor, over-irradiated Brazilian beach babes? And they live longer than us.

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