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Dec 12, 2010 10:46PM
Thanks for the report about your recent trip. I'm glad to hear that you didn't set off the metal detector, weren't "selected" to go through the scanner, and weren't subjected to a pat-down any closer than 8 inches from your crotch. That's good news, I guess...
It's pretty common for passengers to be told, as you heard, that the radiation risks from the scanner are low. You said, "We've found information that the radiation amount is the same as something like 400 X-Rays, and less than one dental X-Ray."
I didn't realize anyone was comparing the radiation from a scanner to what would be experienced from a dental X-ray. When I have a dental X-ray, the assistant always covers my body with a lead apron, from neck to knees. So, the amount of radiation my body is getting is actually much less than what the machine is emitting. Since the backscatter X-ray machine is designed to irradiate the entire body -- both front and back -- trying to cover up a radiation-sensitive area would be counterproductive. I've read that the estimates of radiation exposure from the backscatter machines is incorrect, because it was calculated as exposure through the entire volume of the body, when the backscatter rays really focus on the skin. I've read that they penetrate approximately 1/4 inch, which sometimes produces an image of the bones of the lower legs, knees, and face (since those bones are close to the skin surface). The fear among the skeptics is that, with so much radiation focused on the skin, people who are especially susceptible to skin cancer will be at high risk with multiple trips through the backscatter machines. Ironically, he article you cited provides a good discussion of the concerns about the backscatter radiation, including the refusal of TSA to reveal the actual numbers from the tests they commissioned.
And, alas, the image in the article you cited was not the image produced by a backscatter X-ray machine like the one used on your friend. The image in that article was from a millimeter wave scanner, which does not use radiation at all. Here's the millimeter wave image from the TSA's own website: http://www.tsa.gov/graphics/images/approach/mmw_large.jpg
Here is an example of a backscatter X-ray image from the TSA website: http://www.tsa.gov/graphics/images/approach/backscatter_large.jpg
See the bones of the shins and knees in those pics? Critics of the imaging program who are knowledgeable about the backscatter machines argue that the backscatter picture provided on the TSA site (the one I've shown above) has been "censored". The censorship was necessary, they say, because the real images are too detailed and graphic, and would be considered pornographic; so the TSA doctors them for public use.
The image seen by the man or woman in that darkened room is supposedly much more realistic than what I've shown above. Here is a picture of a backscatter image that the TSA had been using until recently as an example of what the backscatter machines do. The TSA doesn't like this image to be used anymore. They say that's because the face is shown, and the machines in the airports are supposed to blur the face. Everything else shown in this image would be as seen by the man or woman in the viewing room: http://www.scottosphere.org/images/backscatter-xray-scan.jpg
The fact that some unknown man might be sitting in a dark room by himself, studying "thousands" of images like this in a day's work, doesn't comfort me even a little bit. BTW, he isn't really "alone" -- he is in direct contact via radio headset, with the person who directed you into the scanner and who will decide whether you need your body to be examined in more detail with an enhanced pat-down. YMMV, though. None of this seems to bother some people.
2008, IDC, Stage IA, Grade 2, 0/3 nodes, ER+/PR-, HER2-