Computed tomography, also called “CT,” is a diagnostic tool that rotates around the body and takes multiple X-rays of targeted organs or areas from various angles. These images are assembled by a computer into three-dimensional cross sections that provide much greater clarity and detail than ordinary X-rays.

CT scans are the biggest breakthrough ever in diagnostic radiology. They’re fast and comfortable for patients, and they allow physicians a noninvasive way to assess everything from head trauma and abdominal pain to blocked arteries and fractures.

So it’s not surprising that the use of these scans is exploding, with close to 70 million done annually in the U.S. What does come as a surprise to most people, however, is that CT scans have a very dark side.

As much radiation as A-bomb survivors

These scans subject patients to incredibly high doses of radiation – as much as was received by survivors of the Hiroshima and Nagasaki atomic bombs!

The multiple images taken by CTs expose you to levels of radiation that are at least 100 times what you’d get with conventional X-rays. Although they make up only 12 percent of medical procedures involving radiation, they bombard us with half of our total radiation dose!

Surveys of radiologists and emergency room physicians reveal that three-quarters of them gravely underestimate the radiation doses these scans exude. More disturbing, 91 percent of the ER docs and 53 percent of the radiologists did not feel the scans increased the risk of cancer.

Research supports cancer connection

Folks, when I compared the amount of radiation some patients receive from CT scans to that of Hiroshima and Nagasaki survivors, I wasn’t doing it for dramatic effect.

David Brenner and colleagues from the Columbia University Medical Center reported in the New England Journal of Medicine that the typical radiation dose for a single CT scan is 15 millisieverts (a common unit for measuring radiation), and most tests involve two or three scans for a total of 30-45 mSv. Often, repeat scans are ordered every few months to follow patients’ progress.

Japanese atomic bomb survivors who received what was considered a “low” dose of radiation (an average of 40 mSv) had a significant increase in cancer risk. Furthermore, a large study of 400,000 workers in the nuclear industry who had a mean exposure of 20 mSv showed they, too, had a marked increase in their cancer risk.

The Columbia researchers concluded that CT scans and consequent radiation exposure are responsible for about 2 percent of all cases of cancer in this country. They are particularly concerned about children, who receive 4 million CT scans per year, because their small, developing bodies are more sensitive to radiation’s adverse effects. And with the growing popularity and unbridled overuse of this technology, the cancer burden will only increase.

Questionable uses

Of course, there’s an answer and an easy one: Eliminate unnecessary CT scans. One in three of these scans could easily be replaced with safer modalities such as ultrasound or MRI – or done away with altogether.

Examples of questionable uses include managing seizures, chronic headaches and blunt trauma; diagnosing acute appendicitis in kids; and using them as “defensive medicine” to avert future lawsuits.

Also troubling is the upsurge in CT scans as a screening tool for colon cancer (“virtual colonoscopy”), lung cancer, and heart problems – as well as full-body scans, which doctors use to look for anything out of the ordinary. These screenings are often advertised directly to the public, a strategy that’s obviously working.

Full-body scans: Not what they’re cracked up to be

According to one study, 73 percent of the 500 people surveyed would opt to receive a full-body CT scan in lieu of $1,000 in cash. Ironically, they were enthusiastic about the scans as a screening tool for cancer!

The problems with full-body scans go beyond radiation. The majority of individuals who fall for the hype and pay for a scan, usually out of their own pocket, are perfectly healthy. They believe scans will detect problems in their early stages when they are treatable and, as a result, save lives.

This is nonsense. Full-body CT scans are more likely to reveal abnormalities of dubious importance, which, not surprisingly, funnel patients into further testing and unnecessary medical procedures. No research supports the benefits or safety of full-body CT scans. In fact, the American College of Radiology and other medical organizations actively discourage their use.

Look before you leap

Realistically, CT scan use isn’t likely to ease up any time soon – there’s just too much money at stake. Most hospitals, many doctors’ offices and growing numbers of screening facilities have CT scanners, so there is a strong economic incentive to use them.

My advice to you, before consenting to a CT scan (or any diagnostic test for that matter), is to have a heart-to-heart with your doctor. Aggressively question its appropriateness. Exactly what is it they are looking for? Would test results change the current treatment plan? Would it make any difference in the ultimate outcome?

If you’re convinced that a CT scan is necessary, express your concerns about radiation, and find out how much radiation you’ll be exposed to. Most important, ask if another, safer diagnostic test – such as an ultrasound, MRI, or regular X-ray – could be used instead.

In closing, don’t have a full-body CT scan just to “make sure everything’s okay.” In addition to receiving unnecessary radiation that may increase your risk of cancer, you’re stepping onto a slippery slope of more testing and unnecessary medical intervention.

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