These full-body scanners fall into two main categories: millimeter wave and backscatter. The first directs radio waves over a body and measures the energy reflected back to render a 3D image. The latter is a low-level X-ray machine that creates 2D images. The scanners can detect items such as nonmetallic weapons and explosives not picked up by metal detectors.
Millimeter wave scanners produce 30 to 300 gigahertz electromagnetic waves, and reveal explosives if they are denser than other materials. This means that these scanners emit less radiation than a typical cell phone, according to Transportation Security Administration (TSA).
The backscatter machines are low-level X-ray machines that expose bodies to as much radiation as about two minutes of flying in an airplane does. In other words, if you already use a cell phone and you already fly, you are already exposing your body to more radiation than these scanners will.
We are constantly exposed to radiation from the environment. While no radiation is good the radiation used by airport scanners are miniscule and do not add much to the amount received in treatment. They are not concentrated at one area of the body as radiation treatment is-but the whole body. When a patient that received local radiation is told that they can not get any more radiation it means they can not get radiation treatment to the area that was treated before. This still does not mean that they can not get X rays CT and PET scans. This is because the radiation doses there are small compared to the one used in the treatment. However, whenever any radiation exposure is planned the benefit of the test should be weighted carefully against the potential risk of radiation exposure.
