A dearth of studies, along with lingering questions about their safety are leading more U.S. passengers to opt out of walking through powerful backscatter X-ray machines used by Transportation Security Administration officials at some airport checkpoints.
A security official demonstrates a full body scanner during a photocall at Departure Gate 2 at Hamburg Airport September 27, 2010.
Instead, more passengers are choosing the pat-down option, despite the TSA's horrible reputation for it, because they figure that's still safer than being exposed to the radiation emitted by the backscatter machines.
That concern was summarized by Yolanda Marin-Czachor recently in an interview with The New York Times. She told the paper she usually opted for the pat-downs before she got pregnant, but is insistent on avoiding the radiation-emitting machines altogether now.
"I had two miscarriages before this pregnancy," Marin-Czachor, 34, of Green Bay, Wis., told the paper, "and one of the first things my doctor said was: 'Do not go through one of those machines. There have not been any long-term studies. I would prefer you stay away from it.'"
In all, there are 244 of the machines in use at 36 airports around the country operating nearly non-stop, according to the TSA. Other airports use millimeter wave scanners - those which look like glass telephone booths and don't incorporate ionizing radiation - or metal detectors, the Times reported.
Questions remain about safety
And while most experts believe that as long as the X-ray machines are operating properly, they only expose passengers to extremely low ionizing radiation doses. But that factor alone doesn't account for a number of other questions many passengers and analysts alike have regarding long-term exposure to such machines, properly and timely calibration and whether they are examined as often as they should be.
For example, one recent study by the Marquette University College of Engineering found that the X-ray signal emitted by the machines was enough to reach organs beyond the skin, though it said the dose was well within safety limits. Another found that a billion backscatter scans per year would only lead to perhaps 100 radiation-induced cancers in the future.
But there is enough additional anecdotal evidence to continue to raise suspicions.
The European Union has banned the use of such machines - or any devices that emit radiation - out of safety concerns. In fact, in several European countries, the Times noted, it's against the law to X-ray someone without a medical reason (that used to be the prevailing though in the U.S. as well).
In addition, Johns Hopkins University's Applied Radiation Lab distanced itself from a reference to the institute on a web page of the TSA, where the agency was touting the safety of the backscatter machines.
"Advanced imaging technology screening is safe for all passengers, including children, pregnant women, and individuals with medical implants," the TSA said on its site before mentioning a study done by the Johns Hopkins lab which says the machine's radiation doses are below the limits set by the American National Standards Institute.
Sorry - We can't talk about it
According to International Business Times, the university said "its study only demonstrates that the radiation dosage is under the limit set by ANSI," and that a Johns Hopkins spokeswoman said those who conducted the testing weren't happy with the way the TSA characterized it.
The way the machines work is like this: a narrowly focused beam of high-intensity radiation moves quickly across the body. David Brenner, director of the Center for Radiological Research at Columbia University Medical Center, told the Times he worries that mechanical malfunctions in the machines could cause the beam to stop in a single place for even a few seconds, which would result in longer radiation exposure.
But few could know that because the TSA has kept much about how the machines actually operate a secret.
Naturally, the agency is touting their safety. Officials say that, in addition to the Johns Hopkins lab, the Food and Drug Administration, as well as the U.S. Army Public Health Command, have all assessed the machines.
"But," the Times reported, "researchers at these institutions have not always had direct access to the scanners in use, and some of the published reports about them have been heavily redacted, with the authors' names removed. Independent scientists say limited access has hampered their ability to evaluate the systems."
So, the secrecy - and the potentially unsafe operation of the machines - continues. Pat-down, anyone?
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