Your Health: Learn about full-body x-rays at the airport

With the arrival of summer, many of us will be traveling by airplane. Those of us who are older than 50 can remember going in and out of airports free of any type of security measures. Now, to board a plane, we have to nearly disrobe, get patted down and, most recently, pass through full-body scanners that take an image of our body.
About 500 full-body scanners are in use at airports throughout America, falling into one of two types: Half are millimeter-wave scanners, and half are backscatter x-ray scanners.
Millimeter-wave scanners use radio waves to create an image of the body and produce no ionizing radiation. Backscatter x-ray scanners use ionizing radiation, which is the type of radiation that can cause tissue damage and cancer.
So, are full-body scanners safe? Depends who you listen to.
There is not much concern about side effects from the millimeter-wave scanners. Regarding backscatter x-ray scanners, a study done by radiation experts at the University of California, San Francisco, School of Medicine concludes that they are safe. The study states it would take more than 50 full-body scans by the backscatter x-ray scanner to equal the radiation exposure of one dental x-ray; 1,000 scans to equal a chest x-ray; and 200,000 scans to equal a CAT scan.
The study also provides many statistics to show that the use of x-ray scanners would produce only a trivial increase in cancer, such as six more cases of cancer among 100 million people scanned.
Other investigators have calculated a higher, although still extremely low, risk of cancer from the x-ray scanner. There are many who would argue that this is a small risk and may be acceptable, given the possibility of stopping a terrorist.
I assume the statistics I quoted from the study are probably correct, but I have several questions:
**Are the machines working properly to give the correct amount of radiation?
**Is any risk of increased cancer, albeit extremely small, worth the risk?
**If we have the non-ionizing millimeter-wave scanner that appears to be safe, then why would the backscatter x-ray scanner be used at all?
Each of us needs to decide what to do when we go through airport security. As for myself, I wouldn’t think twice about going through the millimeter-wave scanner. But, although I think that the risk of harm from the backscatter x-ray scanner is probably very small, if I have the luxury of time before boarding my plane, I’ll choose to get a pat-down as opposed to the x-ray scan.
Terry Hollenbeck, M.D., is an urgent-care physician at Palo Alto Medical Foundation Santa Cruz in Scotts Valley. He invites readers to view his previous columns on his website, valleydoctor.wordpress.com, or e-mail him at va**********@sb*******.net. Information in this column is not intended to replace advice from your own health care professional. For any medical concern, consult your own doctor.