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TSA Does The Airport X-ray Scanner Shuffle

November 6, 2012
Written by: , Filed in: Abdominal Imaging, Medical Ethics
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The Transportation Security Administration is quietly removing controversial X-ray scanners from major airports—but not because of the worries some have expressed over radiation exposure. Or body exposure.

Nor is the TSA junking the machines. According to an article last month by Michael Grabell of the investigative journalism organization ProPublica, the agency is simply moving them to smaller airports. The article quoted TSA spokesman David Sastelveter as saying:

They’re not all being replaced. It’s being done strategically. We are replacing some of the older equipment and taking them to smaller airports. That will be done over a period of time.

The TSA uses two types of full-body scanners. The devices being shuffled are backscatter X-ray machines. They look like two refrigerator-size blue boxes. Controversy erupted because they use ionizing radiation and because their monitors display what some consider a way too revealing body image.

Replacing them at Boston Logan, Los Angeles International, Chicago O’Hare, Orlando, Charlotte, and New York Kennedy and LaGuardia airports are millimeter-wave scanners, which use low-energy radio waves similar to those generated by cell phones. As far as anybody knows, millimeter waves present no health hazards.

Millimeter-wave scanners look like round glass phone booths. (Ask your parents what a phone booth was.) They generate a mannequin-like generic image of the body. Software looks for potential hidden weapons or other areas of concern and flags any questionable spot with a yellow box superimposed on the body outline. TSA workers then search the suspect areas.

The TSA and outside experts agree that the backscatter machines, assuming that they’re working properly, deliver a tiny dose of radiation—less than the extra radiation the passengers will get from the flight itself. (The higher the airplane, the less atmosphere there is to block cosmic radiation.) The TSA is moving the machines not because they’re dangerous but rather because they’re slow. That’s why they’re being reinstalled in less-crowded airports without long security lines.

The millimeter-wave machines take just two seconds to scan, according to the Associated Press. A computer immediately processes the image and looks for contraband. The backscatter X-ray machines take longer to scan, and then a TSA employee must visually examine the image. They also require more space than the millimeter-wave scanners.

So why is the TSA still messing around with X-ray machines? Because they’re more accurate. ProPublica reported that tests in Europe and Australia found that the millimeter-wave scanners carry a false-positive rate of 23 percent to 54 percent. Officials at Manchester Airport in England told ProPublica that the X-ray machines’ false-positive rate was less than 5 percent. TSA, understandably, does not release data on its scanners’ effectiveness.

The technology will improve, as it always does. In September, the TSA awarded contracts to three companies for the next generation of body scanners. One of the systems uses backscatter X-ray technology. So the controversy will continue, as it too always does.

Related seminar: ALARA–CT (As Low As Reasonably Achievable)


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One Response to “TSA Does The Airport X-ray Scanner Shuffle”

  1. Radiology Daily»AlertArchive » X-ray Scanners Leaving U.S. Airports By June on January 21st, 2013 at 12:52 pm

    […] had already removed them from seven major airports in October and sent them to smaller airports, as we reported back in November. The reason given was that they’re much slower to scan than the other type of full-body […]