Radiation Concerns About Airport X-ray Scanners

New airport security scanners, also known as naked scanners, are causing quite a bit of controversy relating to people's privacy. Though they'd been talked about before, these scanners rose to prominence following the Underwear Bomber's attempt to blow up a plane on Christmas day. A lot of people have a huge problem with the fact that these machines look underneath your clothes for weapons, and many raise the very valid point that we don't know who's scanning us or what happens to the images when we've continued on our journey.

However, though these are rational causes for concern, NPR reveals that there is another reason we should be wary of the machines two out of three of us will have to use by the end of 2011. According to scientists at the University of California, San Francisco, about half of these machines will be so-called X-ray back-scatter scanners. The fact that they use low-energy X-rays to scan people is worrying scientists.

"Many people will approach this as, 'Oh, it must be safe, the government has thought about this and I'll just submit to it,'" David Agard, a biochemist and biophysicist at the University of California, San Francisco told NPR. "But there really is no threshold of low dose being OK. Any dose of X-rays produces some potential risk."

"Ionizing radiation such as the X-rays used in these scanners have the potential to induce chromosome damage, and that can lead to cancer," Agard says.

Current calculations estimate that a person would have to pass through one of the machines 5,000 times to equal the 100-microsievert dose of a single chest X-ray. However, Agard and his colleagues think the manufacturer, Rapiscan, and government officials have miscalculated the dose that the scanners deliver to the skin.

The biochemist and biophysicist, along with John Sedat, a molecular biologist; Marc Shuman, a cancer specialist; and Robert Stroud, also a biochemist and biophysicist, wrote to John Holdren the president's science adviser, requesting a more detailed examination of the risks these machines pose to passengers.

The UCSF scientists aren't the only ones who are concerned. One of the experts who helped write the guidelines for the scanners back in 2002 now says he wouldn't have signed off on the report if he had known they were going to be used on so many people. David Brenner, head of Columbia University's Center for Radiological Research, is quoted as saying, "There really is no other technology around where we're planning to X-ray such an enormous number of individuals. It's really unprecedented in the radiation world."

Brenner's concerns are not the same as those presented by the UCSF scientists. While the UCSF group is worried about cancer, causing immune-system problems, effects on developing fetuses and sperm cell mutations, Brenner is more concerned with the 5 percent of the population who are especially sensitive to radiation. He argues that one person in 20 has a gene mutation that makes them less able to repair X-ray damage to their DNA.

"I don't know if I'm one of those 5 percent. I don't know if you're one of those 5 percent," Brenner told NPR, "And we don't really have a quick and easy test to find those individuals."

Read the full story here.

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