Just in time for the holiday travel crush, concern is on the rise about radiation exposure from the X-ray full-body scanners that are being deployed around the U.S. in an effort to thwart terrorist attacks.
The controversial technology works by bouncing an X-ray beam off a person to create a full-body image that reveals contours, including natural curves as well as any bumps and protrusions from potential weapons that might escape a metal detector such as plastics and ceramics.
The image is displayed on a computer screen in a private room. The person's face is never shown -- and their identity, in theory, is unknown to the airport screener. Passengers can skip the scan and opt instead for a pat-down, which is criticized for being overly personal in the groin area.
Privacy concerns about the scans and pat-down reached fever pitch in recent days when San Diego software engineer John Tyner refused both -- and captured the action with his cell phone's video camera. His blog posts and YouTube videos about the encounter went viral.While Tyner received a full refund for his ticket and gained Web celebrity status, other interested parties -- ranging from pilots and passengers to esteemed scientists -- are worried that radiation exposure from the X-rays could increase risk of cancers.
The Transportation Security Administration says the amount of radiation from scans amounts to about a thousandth of the amount a person receives from a standard chest X-ray.
Peter Rez, a physics professor at Arizona State University in Tempe, did his own calculations and found the exposure to be about one-fiftieth to one-hundredth the amount of a standard chest X-ray. He calculated the risk of getting cancer from a single scan at about 1 in 30 million, "which puts it somewhat less than being killed by being struck by lightning in any one year," he told me.
While the risk of getting a fatal cancer from the screening is minuscule, it's about equal to the probability that an airplane will get blown up by a terrorist, he added. "So my view is there is not a case to be made for deploying them to prevent such a low probability event."
A group of scientists at the University of California at San Francisco laid out their concerns in a letter to the U.S. Food and Drug Administration, highlighting in particular the potential for the X-ray dose concentrated on the skin to pose a health concern for children and other vulnerable populations, such as people with HIV...
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