A full-body scanner is a device that detects objects on or inside a person's body for security screening purposes, without physically removing clothes or making physical contact. Unlike metal detectors, full-body scanners can detect non-metal objects, which became an increasing concern after various airliner bombing attempts in the 2000s. Some scanners can also detect swallowed items or items hidden in the body cavities of a person. Starting in 2007, full-body scanners started supplementing metal detectors at airports and train stations in many countries.
Three distinct technologies have been used in practice: