March 23, 2010 - The introduction of full body x-ray screening and explosive trace detection portals at airports will increase the levels of security and the comfort of passengers and aviation employees but it may be at a cost. There is a growing concern that flight crews, and frequent flyers maybe at risk. In addition it may pose legal questions for children who are being x-rayed.  

The studies on X-ray based body scanners have successfully demonstrated that the ionization of the body that they provoke remains below 1 millisivert (mSv). Under this threshold it is generally considered that the risks on health are negligible. A regular passenger who flies only occasionally should in principle not be afraid of going through such scanners.

However, those studies do not take into account that the ionization absorbed by the body is cumulative over time. Intensive or very frequent exposures to even small doses of x-ray ionization can result in unacceptable cumulative levels of radiation.

This is exactly what our experts think could happen to air crew. Air crew are already exposed to cosmic radiation because they fly at high altitudes and because of other natural phenomena related to sun activity. Therefore, just with their ordinary work, air crews accumulate between 3 and 6 mSv per year. Experts are highly concerned about the negative effects of increasing even further air crews' annual exposure to radiation from X-ray based body scanners.

The ACLU and the Electronic Privacy Information Center are opposed to this use of the technology, currently in use in the U.S. at 18 airports, four court houses, and a correctional facility. The ACLU refers to backscatter x-rays as a "virtual strip search". In one Transportation Security Administration (TSA) trial, 79 percent of the public opted to try backscatter over the traditional pat-down in secondary screening.

It is "possible for backscatter X-raying to produce photo-quality images of what's going on beneath our clothes," thus, according to the TSA, the images have been distorted with the private areas being blurred. According to the TSA further distortion is used in the Phoenix airport's trial system where photo-quality images are replaced by chalk outlines. The TSA has also commented that setting up screening procedures such as having the screener viewing the image located far away from the person being screened could be a possibility.

In light of this, some journalists have however expressed concern that this blurring may allow people to carry weapons or certain explosives aboard by attaching the object or substance to their private parts.

The British newspaper The Guardian has revealed concern among British officials that the use of such scanners to scan children may be illegal under the Protection of Children Act 1978, which prohibits the creation and distribution of indecent images of children. This concern may delay the introduction routine backscatter scanning in UK airports, which had been planned in response to the attempted Christmas Day 2009 attack on Northwest Airlines Flight 253.