The Radiation Post


What You Need to Know About Backscatter X-Rays and Safety

The good news for most Americans is that X-ray backscatter scanners are no longer used in airports, and therefore, they are no longer a source of daily radiation for regular travelers. Whether these devices were a threat – and how much of a risk they posed – has yet to be determined. In the meantime, the majority of these questionably risky devices have been removed and replaced with a different type of body scanning technology, one that doesn’t rely on ionizing radiation, called Advanced Image Technology (AIT).

The good news for Americans and other travelers making their way through the security scans at more than 200 airports around the nation, these AIT body scanners are not only safer (they use benign, millimeter wave scanning technology), they are also far less intrusive than their backscatter x-ray counterparts. You can Click Here to view a recent list of all U.S. airports using full-body scanners as part of their security checkpoints.

Is Backscatter X-Ray Technology Harmful?

According to an article by the science gurus at How Stuff Works, the Transportation Security Administration (TSA) explains that whole-body scanning devices are essential for airport and flight security because they are able to detect weapons, explosives and other threats potential terrorists are trying to hide on or inside their bodies to activate later on.

After September 11, 2001, Americans and other travelers were understandably concerned about the safety and wellbeing of themselves, other passengers and the nation. As a result, the feds quickly engaged the FAA Modernization and Reform Act of 2012, and TSA hurried to install x-ray backscatter machines in the security areas of major airports. The idea was that these units would use “Automated Target Recognition” software to replace the rather accurate anatomical images with more cartoon-like representations that would show any areas of concern (obvious weapons, non-anatomical pieces/parts, etc.), so security personnel could follow-up accordingly.

Instead, the public went up in arms – largely due to the fact most Americans and international travelers felt these images were still a large violation of privacy. More importantly, many were concerned there simply wasn’t enough data to support the risk/benefits of the operation – most notably because like other forms of x-ray technology, backscatter x-ray machines exposed humans to low-doses of ionizing radiation.

As Wikipedia points out:
“…the energy being emitted by a backscatter X-ray is a type of ionizing radiation that breaks chemical bonds. Ionizing radiation is considered carcinogenic even in very small doses but at the doses used in airport scanners this effect is believed to be negligible for an individual. If one-million people were exposed to 520 scans in one year, one study estimated that roughly four additional cancers would occur due to the scanner, in contrast to the 600 additional cancers that would occur from the higher levels of radiation during flight.”

As the result of widespread findings like these, and reports, speeches and letters written by scientists and medical experts in the field, backscatter x-ray machines came quickly under suspicion. They were banned by the European Union in 2012, which furthered resistance here in the U.S. In May of 2013, the original versions of backscatter x-ray machines were removed. Some have been replaced by AIT or millimeter wave scanning devices, but the 25 largest US airports still rely on newer, “more improved,” backscatter x-ray technology for some of their security scanners.

Difference Between Backscatter X-Ray Scanners and Millimeter Wave Scanners

AIT or millimeter waver scanners work slightly differently from x-rays in that the waves work similarly to microwaves. Unlike x-rays, which penetrate and move through the entire human body, millimeter wave (mmw) scanners use waves that are similar to microwaves, a non-iodizing source or radiation. These microwaves waves are larger than those emitted by x-ray backscatter machines, so they are less able to negatively impact smaller human proteins and DNA.

Here is a description from the folks at How Stuff Works on the difference between x-ray and mmw technology:

Backscatter x-ray machines:

“Backscatter machines use rotating collimators to generate X-rays, which pass through a slit and strike a passenger standing inside. The X-rays penetrate clothing, bounce off the person’s skin and return to detectors mounted on the machine’s surface. The radiation also bounces off weapons, explosives or other threats concealed in clothing or lying against the skin. By sensing and analyzing this so-called backscatter, the machine is able to create an image of a person, as well as any organic or inorganic items carried on that person.”

Millimeter wave scanning machine (AIT):

“Millimeter wave scanners use small, disc-like transmitters to make an image. Each transmitter emits a pulse of energy, which travels as a wave to a person standing in the machine, passes through the person’s clothes, reflects off the person’s skin or concealed solid and liquid objects and then travels back, where the transmitter, now acting like a receiver, detects the signal. One disc would only scan a small portion of the test subject, so a single machine contains two stacks of discs connected by a bar that pivots around a central point. Because there are several transmitter/receiver discs stacked vertically and because these stacks rotate around the person, the device can form a complete picture, from head to toe and front to back.”

In terms of safety, experts agree that AIT scanners are preferred. However, in terms of efficacy, backscatter x-ray machines are less likely to provide false results than their AIT, millimeter wave scanning counterparts. Even so, we feel false reports – which result in TSA personnel performing more in-depth body scans – are worth the risk.

You Have the Right to Refuse Full-Body Scanning in the US

If you aren’t convinced, or prefer not to take any risk, you have the right to refuse full-body scans at airports. If you choose to opt-out, we recommend adding another 10 to 15 minutes to your airport security process to accommodate the extra steps required. When you get to the security area and are ready to line up for the scan, let the TSA personnel know you’re opting out.

They will divert you from the line-up of those entering the scanner, and will call for a same-gendered TSA employee to provide a personal scan. You’ll walk through the standard metal detector, after which they’ll perform a respectful pat down of your entire body. The process takes no more than five- to 10-minutes (once the assigned TSA employee is able to perform the check), and then you can grab your bags and be on your way.

The team here at Lancs Industries wishes you a safe and healthy summer travel season. While our radiation shielding products aren’t allowed to be worn in x-ray backscatter or millimeter wave scanning machines, they are recommended for use in most industrial applications where radiation exposure is a risk. Contact us to learn more.

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