The medical community has begun to accept that the use of X-rays as a first-response, default diagnostic tool often is questionable. The amount of radiation a person can accumulate over a lifetime of X-ray exposure can be significant and risky (see our post about the overuse of such scans.).
One such use of X-ray technology doesn’t even have a medical application-airport security screening. Last year we wrote about the American Medical Association’s call for more research about the health risks of Transportation Security Administration X-ray screening. Now, as reported earlier this month by ProPublica, the federal agency has been removing X-ray body scanners from major airports in favor of other devices believed to be safer in terms of radiation exposure.
Not that the TSA believes X-ray scanners pose health concerns-officials said that at some large, busy airports, the scanners were clogging up the security checkpoints and were removed to process more passengers in timely fashion. And they’re not getting rid of the X-ray scanners-they’re simply moving them to smaller airports where, as ProPublica notes, passengers will still be exposed to radiation, but far fewer of them.
Known as “backscatters,” the X-ray devices have been replaced at Boston Logan, Los Angeles International Airport, Chicago O’Hare, Orlando International and JFK in New York.
The scanners began to appear after the underwear bomber episode on Christmas Day in 2009, and have been subject to criticism since. They emit a small dose of ionizing radiation which, at high levels, has been linked to cancer. And privacy advocates object to the naked-body images they produce, although they’re blurred and viewed by personnel at a remote location who can’t see the subjects in person.
As explained by ProPublica, the replacement devices-“millimeter-wave scanners”-use low-energy radio waves similar to those in cellphones. They’re faster at detecting potential threats and they display cartoon images of passengers’ bodies.
A spokesman said the remove-and-replace initiative will be rolled out slowly to enable the TSA to analyze processing time and staffing requirements at the airports receiving the suspect machines. The risk of radiation and the concerns about privacy played no role in the decision to reallocate scanning devices.
So it’s not about safety, it’s about efficiency. The backscatter machines still are used at a few of the country’s 25 largest airports, but the TSA won’t say which ones. Even more objectionable, the feds awarded three companies potential contracts of as much as $235 million for the next generation of body scanners, one of which uses backscatter X-ray technology.
Its use of such machines has made the U.S. an outlier in the global airport community. The European Union, for example, banned the machines last year “in order not to risk jeopardizing citizens’ health and safety,” it said in a statement.
Studies have shown that the radiation dose from the X-ray scanner is extremely small, less than the dose received from cosmic radiation during two minutes of airplane flight. The associated risk, radiation experts have said, ranges from six to 100 additional cancer cases among the 100 million people who fly annually.
Many scientists call that trivial, given that the same 100 million people would develop 40 million cancers over the course of their lifetimes. Others have said that so much is unknown about low levels of radiation that such estimates shouldn’t even be made.
Some scientists are concerned about the potential risks. They say the TSA unnecessarily endangers the public because the alternative-the millimeter-wave machine-is highly effective at finding explosives.
“Why would we want to put ourselves in this uncertain situation where potentially we’re going to have some cancer cases?” David Brenner, director of Columbia University’s Center for Radiological Research, told ProPublica last year.
In its efficiency-over-safety posture, the TSA says that having both technologies encourages competition, leading to better detection capabilities at a lower cost.
Even that claim is iffy-tests in Europe and Australia suggest the millimeter-wave machines were found to have a high false-alarm rate, ranging from 23 percent to 54 percent. Manchester Airport officials told ProPublica that the false-alarm rate for the backscatter was less than 5 percent.
But no study comparing the two machines’ effectiveness has been released. The TSA says its own results are classified.
To see a side-by-side comparison of the two different devices-what they look like, how they work, etc.-click here. If you’re concerned about radiation exposure and are traveling through an airport that uses scanning devices, ask the TSA agent if it’s a backscatter machine. If so, remember–you have the right to request a physical pat-down instead of X-ray scanning.