The new full-body scanners in place at 60 airports across the country have been causing outrage in recent weeks – and that’s putting it pretty mildly.
From lawsuits being lodged against the Transportation Security Administration due to their “intrusive” pat-down procedures, to passengers getting into scuffles with TSA agents, these new scanners are creating a lot of turmoil. And as the busiest travel days of the year fast approach – with more than 1.6 million Americans expected to flock to airports over the Thanksgiving holiday weekend – there’s no telling how some passengers are going to react.
But let’s move past all of that for now and concentrate on the safety of the backscatter X-ray scanners. What I want to know is – are we putting our health at risk every time we walk through one these machines at an airport? And because I’m an OB-GYN, I am also concerned about women who are pregnant. Could these scans affect a fetus?
To get a little insight into that, we contacted Dr. David Schauer, executive director of the National Council on Radiation Protection & Measurements (NCRP) in Bethesda, Md.
Q. How much radiation does one of these backscatter X-ray scanners actually emit?
A. Radiation exposure is reported in units called millirem (mrem). The effective dose per scan of 0.01 mrem is 100 times less than the annual negligible individual dose (NID) of 1 mrem recommended by the NCRP. It would therefore require at least 100 scans of the same individual in a year to reach an amount that is considered negligible.
To put that into perspective, a typical chest X-ray is over a thousand times greater than what a person is exposed to per scan when they walk through an airport full-body scanner.
NOTE: Remember, radiation is all around us. We are exposed to it every day while we walk, breathe, eat and sleep. On average in the United States, a person is exposed to approximately 620 mrem (whole-body exposure) per year from all sources. According to the TSA, one scan is about the same as a person would get from flying for about three minutes in an airplane at 30,000 feet, where atmospheric radiation levels are higher than on the ground.
Q. How do these scanners differ from your typical medical X-ray machines?
A. It’s important to note that backscatter X-ray systems are not like standard medical X-ray machines that operate in a transmission mode. That is to say, medical X-rays are transmitted though a patient’s body. Backscatter X-rays are not transmitted through a person’s body, they are, as the name would suggest, backscattered (or reflected) to a detector that is used to create an image. As a result of this fundamental difference, doses from backscatter X-rays are orders of magnitude less than doses from medical imaging with X-rays.
Q. In your opinion, do these scanners pose a risk to a fetus? Are we potentially putting women in danger?
A. Given the low levels of effective dose involved per scan (and the resultant low levels of equivalent dose per scan to the embryo or fetus of a pregnant woman), no special precautions are required for the embryo or fetus of a pregnant woman, for infants, or for children.
Q. And finally – in general – should the general public be concerned about these scanners?
A. It is important that all scanned individuals be well informed about the security screening process, its benefits and its potential risks. Information, in lay language, about the security screening process, its benefits and its potential risks should be provided to individuals prior to their being scanned.
In an email, Dr. David Brenner, director of the center for radiological research at Columbia University in New York City, told us the bigger concern is the overall population risk.
“Even though the individual risk is very small, the impact on the population may not be small if the exposed population is large. This is potentially the case with airport X-ray scanners. We know the individual risk is very small, but multiply that by the number of people going through airport security each year in the U.S. – currently about 700 million, maybe one billion a decade from now – then we start to have a concern about the population risk.”
So – what’s the bottom-line here? Should we be really concerned?
“From an individual personal-risk perspective, the risks of going through the scanner just a few times are very small, even for a child,” Brenner told us in an email. “So while the pat down is an option, the radiation exposure is not something to be too concerned about from the perspective of individual risk, assuming you are going through the scanners just occasionally.”
Whatever you decide to do the next time you have to travel – remember this – you can always opt for a good old fashioned road trip with your family or hop on a train. You might just see the country in a whole new way, especially since there are still a lot of unknowns about these airport scanners.