Airport body scans have created a great deal of anxiety about the safety of such devices due to the potential exposure to radiation. This discussion will only about the safety of such scans, not about the effectiveness of these scanner as an antiterrorist tool.
Background:
After 9/11, airport anti-terrorist measures were in part directed to screening carry-on luggage and checked baggage with xray scanners. Passengers were not exposed to the radiation nor were the airport workers. Passengers were and are asked to walk through metal detectors with the thought that metallic items like guns, knives and explosive devices could be easily identified. Several years ago, especially after the "shoe bomber" was able to smuggle an incendiary device in his shoe, and the availability of plastic explosives and non-metallic weapons, it was felt that the passenger needed to have a full body pat- down or have a body scan to detect such devices.
What are airport body scanners?
There are two types of body scanners:
1. Millimeter wave unit body scanners: One type emits a radiofrequency wave ove the body, reaching just below the clothing and over the surface of the skin to create an image of the surface of the body, just below the clothing, but not through the body itself. There is no radiation at all from this scanner.
2. Xray body scanner backscatter unit: This type of scanner emits a very low amount of radiation that penetrates the clothing, and slightly into the body cavity, like the rectum and vagina. The scanner reconstructs an image of the body beneath the clothing and detects any foreign objects, whether they be metal or non metallic.The ability to penetrate the body cavities is probably limited and variable based on the passengers weight and body shape. This type of scanner does expose the patient to radiation and is the scanner of concern.
What is radiation?
Basically radiation is an energy force that comes in various degrees of strength, from infrared light, ultraviolet light, radio waves and others. Ionizing radiation is the more pwerful type of radiation that can actually interact and change human cells. This is the type of radiation used in medical Xray devices such as chest xrays, CT scans, mammograms etc..The radiation in medical applications can be very powerful such that they penetrate the body and create images of the inside of the body, unlike ariport scanners which only cover the surface of the body. At extremely high and concentrated form of Xray beams are used to actually treat and destroy certain types of cancers.
How much radiation is safe?
It is generally recommended to limit ones Xray exposure to the bare minnum possible. We are constantly exposed to radiation which comes from the enviroment from radioactive decay in rocks and from the atmosphere. People who live at high altitudes such as Denver, Colorado receive more radiation from the atmosphere than those at sea level. Flyng in a plane going cross country at 30,000 ft exposes one to radiation. In truth it is not known for sure what dose can cause cancer and in whom. We do know that certain body parts are more sensitive to radiation, for instance, the breast tissue and thyroid are much more sensitive than the heart to the effects of radiation.
How much radiation dose the airport scanner release to the passanger?
Think of it like this: chest xrays, mammograms and dental Xrays all expose us to much higher doses of radiation than the airport body scan, and none of these medical tests have been shown to cause cancer.
To equal the radiation from:
1. Mammogram: you would have to go through the body scanner 1,300 times
2. Chest Xray: you would have to go throught the body scanner 1,000 times
3. Dental xray: you would need to go through the body scanner 200 times
4. Airline flight: you need to be flying at 35,000 ft for one minute to get the radiation of one body scan
Bottom line:
It is my feeling that the airport body scanners pose no safety risk and I would not hestiate going through it many tens of times. However, it makes common sense that if you are a pilot or stewardess, there are other means to screen to avoid repeated exposure to the scanner, however small the risk.
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