Airport X-Rays: How Worried Should We Be?

Sandra Adamson Fryhofer, MD


September 10, 2013

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Hello. I am Dr. Sandra Fryhofer. Welcome to Medicine Matters. The topic: the safety of airport security scanners. Here is why it matters. Airport security is a must for public safety, but are the methods used to scan safe? Could the radiation emitted hurt us? What about privacy issues?

These questions and more were answered in a new report from the AMA Council on Science and Public Health.[1] Exposure to ionizing radiation can damage DNA. Infants are more sensitive to cancer-causing effects of radiation than are adults. For fetuses, radiation exposure in the womb can increase the risk for birth defects. Cancer risk from radiation exposure decreases as we get older, but one should understand that not all scanners are the same.

The so-called backscatter models use low levels of ionizing radiation to create images. The newer millimeter wave models use radio waves instead, so there is no ionizing radiation. But even radiation exposure from the backscatter units is low intensity. Most exposure is to the skin and most of the rays are reflected back by the skin. Some radiation is absorbed by internal organs, but not that much.

The amount of radiation exposure from one backscatter x-ray security scan is very small: less than a tenth of a microsievert, which is less radiation exposure than you get from eating a banana. The radiation you get from a regular chest x-ray is 20 microsieverts. A mammogram is 400 microsieverts. A chest CT is 7000 microsieverts. The reality is that all of us are exposed to background radiation from the atmosphere. High altitudes from air travel increase radiation exposure due to cosmic rays. You get 700 times more radiation exposure from a transatlantic flight, 70 microsieverts, than you do from 1 backscatter scan.

Privacy issues are another matter. They are a concern. These scanners produce detailed images of your body -- very detailed images. Some might call them R-rated. This has been passengers' concern. It also has the attention of Congress, which is why Congress mandated special scanner software to make these images more generic and less embarrassing.

Note that the company that makes the backscatter machines could not meet the software deadline, so its contract was not renewed. This means that the backscatter scanners are now history, at least in airports. The Transportation Security Administration (TSA) was supposed to replace them all with millimeter wave machines as of June 2013.

For Medicine Matters, I'm Dr. Sandra Fryhofer.


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