Blog | Monday, April 4, 2011

QD: News Every Day--Airport scanners are 'planely' safe

In preparation of Internal Medicine 2011 in San Diego this week, the unavoidable choice to make isn't which sessions to attend, but even before arriving: Will you pass through the airport's security scanners, or opt for the pat down?

Physicians themselves are split on the issue, with some physicians opting out of repeat scanning in favor of the pat down search.

"I do whatever I can to avoid the scanner," one physician told CNN. Other physicians interviewed were split on the issue one way or another. But as a frequent flier, this doctor was concerned about the cumulative effect. "This is a total body scan--not a dental or chest X-ray. Total body radiation is not something I find very comforting based on my medical knowledge."

The Archives of Internal Medicine looks at the safety of the scanners, which haven't been independently examined outside of the government's own analysis of their safety. They apply radiation, specifically for the backscatter scanners, the more common ones used in the United States, which use ionizing radiation. Low doses cause biological damage, but cells repair it quickly. Backscatter X-ray scans use exceedingly low doses, the report said, "... so low that it is really not known whether there is any potential for causing harm."

But, 750 million air passengers a year, even a small risk per person could potentially become a significant number of cancers.

Ionizing radiation occurs naturally, and is widely used in industry and medicine, the article points out. The National Council on Radiation Protection and Measurements reports that common sources of exposure are medical procedures and ubiquitous background radiation from the sun and cosmic rays, and from radon released from the earth. Backscatter X-ray scanners expose people to the equivalent of 3 to 9 minutes of what they'd get anyway from daily living.

Those who fly are exposed to more radiation anyway, but backscatter X-ray machines still equal only the radiation exposure that occurs for 1 to 3 minutes of flight time, or an increase of less than 1% for a cross-country flight.

The article points out that it takes 50 airport scans to equal the exposure of a single dental radiograph, 1,000 to equal a chest radiograph, 4,000 to equal the exposure of a mammogram, and 200,000 to equal an abdominal and pelvic CT scan.

"Based on what is known about the scanners, passengers should not fear going through the scans for health reasons, as the risks are truly trivial," the authors concluded. "If individuals feel vulnerable and are worried about the radiation emitted by the scans, they might reconsider flying altogether since most of the small, but real, radiation risk they will receive will come from the flight and not from the exceedingly small exposures from the scans."