Another dose of worry has been produced over radiation exposure in America, upping the concerns of those who claim there is too much medical scanning going on.

A study in the prestigious New England Journal of Medicine suggests that nearly 70% of the population had at least one medical scan that exposed them to radiation. This follows a National Council on Radiation Protection and Measurements study from March that concluded Americans living in 2006 were exposed to over seven times more radiation from such scans than those living in 1980.

Both studies attributed much of the radiation to computed tomography scans.

“While the risk to any individual for a single test may be small, the overall risk to the population becomes a concern if one considers the large number of these procedures being performed each year,” says Brahmajee Nallamothu, and author on the NEJM paper and a doctor at the University of Michigan (press release).

The researchers found 18.6 people per 1,000 got high doses of radiation and 1.9 per 1,000 got very high doses. What’s really stoking the fires here though is not the research itself but a strongly worded commentary running alongside it.

In this piece Michael Lauer, of the National Heart, Lung, and Blood Institute, Bethesda, writes:

Physicians are referring their patients for so many imaging tests that as many as 2% of cancers may be attributable to radiation exposure during CT scanning.

…

Most physicians who order imaging tests experience no consequences for incurring costs for procedures of unproven value. On the contrary, they or their colleagues are paid for their services, and their patients don’t complain because the costs are covered by third parties.

…

Overall, we must conclude that with a few exceptions — such as mammography — most radiologic imaging tests offer net negative results. There is little high level evidence of benefit, whereas cumulative radiation exposure can produce real harm, even if it may not be possible to trace adverse outcomes to individual patients who have been exposed.

The American College of Radiology has issued an equally strongly worded response, calling Lauer’s article “ill-advised and misinformed” and saying some of the statements in it are “patently false”.

Trying to keep the peace is Rebecca Smith-Bindman, a radiologist and epidemiologist at US San Francisco.

“It’s not that we should stop imaging,” she tells the Baltimore Sun. “But the sense is that all imaging is good. Some is good. Some is harmful. We need to get appropriate imaging.”

More coverage

Two-thirds get medical tests with radiation dose – AP

Study Finds Radiation Risk for Patients – NY Times

Too much radiation from medical testing? – LA Times

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