The Transportation Security Administration has purchased a dozen cameras that use millimeter wave technology and sophisticated algorithms to screen crowds of rapidly moving travelers for weapons from up to 20 meters away.
The SPO threat detection system made by QinetiQ measures waves "naturally emitted by the human body," exposing "cold" objects such as metal, plastic, or ceramics concealed under clothing. A red light on the system's display alerts the operator if you're packing, so there's no need to rely on interpreting images on a screen. It also means no one is ogling your naked body, which was one of the objections when similar technology was deployed at Phoenix Sky Harbor Airport last October.
This imaging technology is safe; the "passive" millimeter wave system generates no emissions itself, but creates an image from reflected body energy, according to the company. Still, if you're nostalgic for the vintage, step-through experience, you can always try this personal fold-up portable metal detector by CI Tech.