Do Full-Body Scanners Pose a Radiation Risk?
The recent terrorist scare on Christmas Day has prompted the Transportation Security Administration (TSA) to accelerate the deployment of full-body scanners at security checkpoints in airports in the United States. This move has triggered many people to raise the question: do full-body scanners pose a radiation risk?
Full-body scanners provide more details than typical x-rays: they are capable of viewing under layers of clothing, revealing any prosthetics under the skin and both metallic and non-metallic objects. A full-body scanner functions in a way similar to a magnetic resonance imaging (MRI) machine and, like an MRI, is considered to be safe.
To address the concerns regarding the risk of radiation associated with full-body scanners, the American College of Radiology has issued a statement saying it is not aware of any evidence that passengers would be exposed to any significant biological effects from either of the full-body scanning technologies that the TSA is considering.
The TSA has deployed two different types of full-body scanners. One uses low-level radio waves in the millimeter wave spectrum. This involves two rotating antennae that cover the individual from head to toe with low-level RF (radiofrequency) energy. The other involves backscatter technology, which delivers extremely weak x-rays, less than 10 microRem of radiation per scan. This is the equivalent amount of radiation that a person receives inside an airplane that flies for two minutes at 30,000 feet.
The National Council on Radiation Protection and Measurement reports that an airline passenger would need to experience 2,500 backscatter scans per year before he or she would reach what is known as a Negligible Individual Dose. Therefore, passengers who fly across the country are exposed to more radiation during their flight than from a full-body screening.
The American College of Radiology notes that everyone is exposed to radiation from natural sources all the time. The average person in the United States receives about 3 mSv (millisievert; another way to measure radiation) per year from the natural environment and cosmic radiation from outer space. During a coast-to-coast round trip in a commercial airplane, passengers are exposed to about 0.03 mSv. On the ground, the largest source of background radiation comes from radon gas in homes (about 2 mSv annually). The amount of radiation from one chest x-ray is equivalent to the amount of radiation people are exposed to from natural surroundings in ten days.
The bottom line is that full-body scanners do not pose a radiation risk. Consumers who want to learn more about radiation associated with imaging techniques can visit the American College of Radiology information webpage.
American College of Radiology