A full body scanner is a security device that uses millimeter wave or x-ray technology to generate a full body image. These devices are sometimes employed in airports and other high-security venues as a means of scanning all entrants for weapons or concealed objects. The use of full body scanners is a highly controversial issue for several reasons, including concerns over illegal search methods, fear of increased radiation created by the machines, and worries about the effectiveness of the machines as a security tool.
Many full body scanners use a type of technology known as a backscatter x-ray, developed by American inventor Martin Annis in the late 20th century. This form of full body scanner creates an image by bouncing x-rays off a target and building a composite image from the reflected radiation. While organic materials, such as body tissue, will show up as translucent outlines, inorganic materials tend to create a contrasting outline.
Millimeter wave scanners, by contrast, use high-frequency radio waves to create a three-dimensional image. The outlines created by the image are typically sharper, but the image takes longer to construct. Millimeter wave scanners are less commonly used than backscattering machines, mostly due to convenience and speed issues.
Both types of full body scanner are primarily used at airports, though some courthouses and governmental buildings have also adopted the technology. In general, the machines are placed at the entrance to an airport terminal, where passengers with tickets can pass through the machines before reaching the gate area. The rise in popularity of the full body scanner is largely attributed to increased security concerns in the wake of terrorist attacks on airplanes. The first full body scanner was placed in 2007, at Schiphol Airport in the Netherlands. Use of the machines has spread throughout Europe and the United States, with a few scanners also in place in Africa, Asia, and South America.
One of the largest controversies surrounding the use of full body scanners is the potential risk to personal privacy and human rights. Both types of scanners create a nude image of the subject, though some features may be blurred. In a widely publicized incident, more than 100 images were leaked online, despite official claims that the images could not be stored or saved. Some critics suggest that the use of a full body scanner constitutes an illegal search in some areas, since the subjects are not under reasonable suspicion of committing a crime.
Radiation concerns are also present in the debate over the full body scanner. Medical experts have come up with varying results and interpretations regarding the dose of radiation created by backscatter machines, as well as its potential impact on vulnerable subjects, such as pregnant women. A wealth of conflicting claims lead to little consensus as to the potential for radiation damage caused by full body scanners.