Useless Medicine: CT Scans

The dangerous downside of this diagnostic radiology breakthrough

Computed tomography (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 provide a noninvasive way for doctors 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. What does come as a surprise to most people, however, is the dangerous downside of CT scans.

CT Scans Expose You to Very High Doses of Radiation

The multiple images taken by CT scans expose you to incredibly high doses of radiation—doses at least 100 times what you’d get with conventional X-rays—which increase your cancer risk.

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 mSv (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.

As a point of comparison and illustration, 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. But with the growing popularity and unbridled overuse of this technology, the cancer burden will only increase.

Questionable Uses of CT Scans

Another important fact you should know: One in three CT scans could easily be replaced with safer modalities such as ultrasound or MRI—or done away with altogether.

Examples of questionable uses of CT scans 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 full-body CT scans are often advertised directly to the public, a strategy that’s obviously working. 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!

Full-Body CT Scans: Not What They’re Cracked Up to Be

The problems with full-body CT 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.

What Should You Do Before Consenting to a CT Scan?

Before consenting to a CT scan, you should have a heart-to-heart with your doctor. Express your concerns about radiation, and find out how much radiation you’ll be exposed to. 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?
• Could another, safer diagnostic test—such as an ultrasound, MRI, or regular X-ray—be used instead?

Whatever you decide, 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.

More Dr. Whitaker Advice on Useless Medicine

• Mammograms
• PSA Tests
• Angioplasty