The first full-body scanners are coming to Midway Airport, federal homeland security officials are expected to announce on Tuesday.

The advanced imaging technology is designed to identify explosives, weapons and other banned items underneath passengers’ clothing or inside folds of skin. It cannot detect objects inside a body cavity or under skin.

O’Hare International Airport received its first body scanner in March. O’Hare now has 23 of the imaging devices, according to the Transportation Security Administration.

Midway will be among 28 airports that are next to receive at least one of the latest security-screening devices, according to the Department of Homeland Security. It was not immediately known exactly how many machines will be initially deployed at Midway or when they will arrive.

“It will be sometime later this year,” Transportation Security Administration spokeswoman Ann Davis said. The agency is using federal economic stimulus funds to buy the devices, she said.

Passengers are scanned by the devices by stepping between the two imaging units and raising their hands for about five seconds. The units bounce low-dose X-rays off of the passenger’s front and back to generate images of their physical structure. A filter blurs the face and features.

The scan process takes about 30 seconds, and the passenger never comes in contact with the Transportation Security Administration screener who views the image from a windowless cubicle. The image is erased after the passenger is screened.

Critics have objected that the high-tech screening process amounts to a virtual strip search. But Transportation Security Administration officials said the scanned images do not look like photographs and that passengers who object to being scanned can instead opt for a pat-down by security officers and a metal-detector screening.

Use of the full-body equipment is intended to address weaknesses in U.S. aviation security that since the 9/11 attacks have permitted two terrorist suspects — the infamous shoe and underwear bombers — to board airliners with explosives on their bodies.

(Source: Chicago Tribune)