After the terrorist attacks in the U.S. on September 11, 2001, Americans faced the reality that terrorists could leverage commercial airplanes as powerful weapons. Consequently, fliers have had to endure the inconvenience and discomfort of more rigorous security checks at airports so they can feel safer. One of the technical innovations designed to speed up and improve accuracy in these security checks is the backscatter X-ray system.
Backscatter X-ray scans are weaker than X-ray scans you might get at the doctor, only penetrating slightly past the surface of the skin. When used for full-body scanning at airports, backscatter X-rays provide security personnel with pictures of what passengers might be hiding under their clothes. This includes organic and inorganic items that metal detectors alone would have missed.
Civil rights groups have protested the extent to which the U.S. Transportation Security Administration (TSA) uses backscatter X-rays at airports. Groups like the American Civil Liberties Union (ACLU) are concerned that the X-ray image shows details of a person's body that are otherwise hidden by clothing, including attached medical devices such as a colostomy bag or portacath. Currently, the only alternative to the backscatter X-ray is a thorough and equally controversial pat down by a TSA official.
Our article How Backscatter X-ray Systems Work takes an even closer look at this technology. Next, let's look at a technology that examines the mind as well as the body.