Backscatter X-ray
[2] In the United States, the FAA Modernization and Reform Act of 2012 required that all full-body scanners operated in airports by the Transportation Security Administration use "Automated Target Recognition" software, which replaces the picture of a nude body with the cartoon-like representation.
[3] As a result of this law, all backscatter X-ray machines formerly in use by the Transportation Security Administration were removed from airports by May 2013, since the agency said the vendor (Rapiscan) did not meet their contractual deadline to implement the software.
This scan is much faster than a physical search and could potentially allow a larger percentage of shipping to be checked for smuggled items, weapons, drugs, or people.
[11] Since in addition to weapons, these machines are designed to be capable of detecting drugs, currency and contraband, which have no direct effect on airport security and passenger safety, some have argued that the use of these full body scanners is a violation of the Fourth Amendment to the United States Constitution and can be construed as an illegal search and seizure.
[12] Backscatter x-ray technology has been proposed as an alternative to personal searches at airport and other security checkpoints easily penetrating clothing to reveal concealed weapons.
worry that viewing the image violates confidential medical information, such as the fact a passenger uses a colostomy bag, has a missing limb or wears a prosthesis, or is transgender.
[13] According to the Transportation Security Administration (TSA), in one trial 79 percent of the public opted to try backscatter over the traditional pat-down in secondary screening.
[14] It is "possible for backscatter X-raying to produce photo-quality images of what's going on beneath our clothes", thus, many software implementations of the scan have been designed to distort private areas.
[16][17] In light of this, some journalists have expressed concern that this blurring may allow people to carry weapons or certain explosives aboard by attaching the object or substance to their genitals.
This concern may delay the introduction of routine backscatter scanning in UK airports, which had been planned in response to the attempted Christmas Day 2009 attack on Northwest Airlines Flight 253.
[24][25] Unlike cell phone signals, or millimeter-wave scanners, the energy being emitted by a backscatter X-ray is a type of ionizing radiation that breaks chemical bonds.
[31] However, the FDA has created a webpage comparing known estimates of the radiation from backscatter X-ray body scanners to that of other known sources, which cites various reasons they deem the technology to be safe.
[32] Four professors at the University of California, San Francisco, among them members of NAS and an expert in cancer and imaging, in an April 2010 letter[33] to the presidential science and technology advisor raised several concerns about the validity of the indirect comparisons the Food and Drug Administration used in evaluating the safety of backscatter x-ray machines.
Regarding the UCSF concerns over the high-risk population to sensitive organs, the letter states that such an individual "would have to receive more than 1,000 screenings to begin to approach the annual limit".
Smith demonstrated this difference with two experiments using plastic (with a similar rate of absorption as body tissue), copper (the image subject), and an x-ray scanner.
At the high altitudes typical of commercial flights, naturally occurring cosmic radiation is considerably higher than at ground level.
[54] In medical radiography the x-ray beam is adjusted to expose only the area of which an image is required, so that generally shielding is applied to the patient to avoid exposing the gonads,[55] whereas in an airport backscatter scan, the testicles of men and boys will be deliberately subjected to the direct beam in order to check for weapons in the underpants, and some radiation will also reach the ovaries of female subjects.
[57][58] Other scientists at Columbia University have made the following statements in support of the safety of body scanners:[59] "A passenger would need to be scanned using a backscatter scanner, from both the front and the back, about 200,000 times to receive the amount of radiation equal to one typical CT scan," said Dr. Andrew J. Einstein, director of cardiac CT research at Columbia University Medical Center in New York City.
These features, combined with fault analysis, ensure that failure of any subsystem results in non-operation of the x-ray generator to prevent accidental exposures.
[64] In a study published in the Archives of Internal Medicine on March 28, 2011, researchers at the University of California "calculated that fully implementing backscatter scanners would not significantly increase the lifetime risk of cancer for travelers".
[69][70] In April 2012, Corbett released a second video interviewing a TSA screener, who described firearms and simulated explosives passing through the scanners during internal testing and training.
[71] Backscatter scanners installed by the TSA until 2013 were unable to screen adequately for security threats inside hats and head coverings, casts, prosthetics and loose clothing.
[75] In Germany, field tests on more than 800,000 passengers over a 10-month trial period concluded that scanners were effective, but not ready to be deployed in German airports due to a high rate of false alarms.
Not all backscatter X-ray devices necessarily comply with ANSI N43.17; only the manufacturer or end user can confirm compliance of a particular product to the standard.
Some people wish to prevent either the loss of privacy or the possibility of health problems or genetic damage that might be associated with being subjected to a backscatter X-ray scan.
