Full-Body Scanners

TSA began deploying state-of-the-art advanced imaging technologies in 2007. This technology can detect a wide range of threats to transportation security in a matter of seconds to protect passengers and crews. Imaging technology is an integral part of TSA's efforts to apply new technologies that promote both the safety and security of flights originating in the United States. Similar technologies are being used in airports around the world.

Passengers who do not wish to utilize this screening will receive an equal level of screening, including a physical pat-down. Multiple signs informing passengers about the technology, including sample images, are displayed in plain sight at the security checkpoints, in front of the advanced imaging units.

The TSA has indicated that it is their opinion that many passengers prefer advanced imaging technology to a physical search, such as a pat-down. In fact, over 98 percent of passengers who encounter this technology during TSA pilots prefer the use of advanced imaging technology to other screening options.

Additionally, passengers with joint replacements or other medical devices that would regularly alarm a metal detector often prefer this technology because it is quicker and less invasive than a pat down.

The Technology

TSA uses two types of imaging technology, millimeter wave and backscatter. Currently, there are 44 imaging technology units in use at 21 airports. There are 40-millimeter wave units in use at 19 airports and four backscatter units in use at two airports. In March 2010, TSA began deploying 150 backscatter imaging technology units, and plans to deploy 450 imaging technology units in 2010.The walk-through imaging technology is designed to detect, without physical contact, metallic and non-metallic threats, including weapons, explosives and other items that a passenger could be carrying on his/her person.

Health and Safety Issues

The TSA contends that advanced imaging technology screening is a "health safe" technology for all passengers, and that the technology meets national health and safety standards. Backscatter technology was evaluated by the Food and Drug Administration’s (FDA) Center for Devices and Radiological Health (CDRH), the National Institute for Science and Technology (NIST), and the Johns Hopkins University Applied Physics Laboratory (APL), and results confirmed that radiation doses are well below those specified by the American National Standards Institute.

All results confirmed that the radiation doses for the individuals being screened, operators, and bystanders were well below the dose limits specified by the American National Standards Institute. For comparison, the energy projected by millimeter wave technology is 10,000 times less than a cell phone transmission. A single scan using backscatter technology produces exposure equivalent to two minutes of flying on an airplane.

Personal Privacy Issues

In addition, the TSA has implemented strict measures to protect passenger privacy, which the Agency claims, is ensured through the anonymity of the image. In essence, the TSA has indicated that the image cannot be stored, transmitted or printed, and is deleted immediately once viewed. Conversely, although not discussed by the TSA, we find it difficult to believe that an image revealing a passenger has an explosive device hidden on their person could not be saved or printed to support legal proceedings against a terrorist. If this image can be saved, it is, we suspect, possible that any image could be saved. It occurs to us that he screen image could, presumably, be photographed by an examiner for their own purposes, although the TSA contends that the officers evaluating images are not permitted to take cameras, cell phones or photo-enabled devices into the resolution room.

How the Technology Works

Backscatter Units

Backscatter technology projects low-level X-ray beams over the body to create a reflection of the body displayed on the monitor.

            

Millimeter Wave

Millimeter wave technology bounces harmless electromagnetic waves off the body to create a black and white three-dimensional image.

                      

What the TSA Sees

Millimeter wave technology produces an image that resembles a fuzzy photo negative, while the
Backscatter technology produces an image that resembles a chalk etching.

          

          

Both technologies are viewed by a Transportation Security Officer in a remote, secure location.

How the TSA Intends to Protect the Privacy of Air Travelers

• According to the TSA, strict privacy safeguards have been built into the TSA’s use of advanced imaging technology to protect passenger privacy and ensure anonymity.
• The officer who assists the passenger never sees the image the technology produces.
• The officer who views the image is remotely located, in a secure resolution room and never sees the passenger person-to-person. In addition, millimeter wave technology blurs all facial features and backscatter has an algorithm applied to the entire image that disguises physical identity.
• The two officers communicate via wireless headset. Once the remotely located officer determines threat items are not present, that officer communicates wirelessly to the officer assisting the passenger. The passenger may then continue through the security process.
• The TSA has publicly stated that their advanced imaging technology cannot store, print, transmit or save the image (and, as stated above, it seems reasonable to assume that output from the system would be needed for prosecuting those conveying explosives or other terrorist devices and thus, we suspect that their must be a way to preserve selected imagery).
• Officers evaluating images are not permitted to take cameras, cell phones or photo-enabled devices into the resolution room.
• Each image is automatically deleted from the system after it is cleared by the remotely located security officer.

What to Expect

Each passenger will walk into the imaging portal. Once inside, they will be asked to pose in different positions for just a few moments while the technology creates an image of the passenger in real time. Once the scan is complete, the passenger exits the opposite side of the portal.

(Note:  All of the images in this article were provided courtesy of the Transportation Security Administration.)