Heading out of town? Expect to be examined by full body scanners at 11 major airports including those at Oakland and San Jose within the next few weeks.
The scanners can look under passengers' clothing in order to detect weapons and explosives.
According to USA Today, Boston Logan International Airport received a new scanner this week and will get two more next week. All will go into the same terminal. Among the other airports getting the scanners are Los Angeles International, San Diego and Chicago O'Hare. So far, San Francisco International is not on the list.
The Transportation Security Administration plans to buy 1,000 of the machines over the next two years. Homeland Security Secretary Janet Napolitano ordered the installation accelerated after the failed Christmas Day bombing attempt of an airliner over Detroit.
The scanners, made by California-based Rapiscan, are 9 feet long and 6½ feet wide, much larger than metal detectors. Airport screeners view images from the machines in a nearby closed room.
Airports with scanners will continue to use metal detectors, both as an alternative for passengers who want to avoid the machines and in checkpoints without the scanners. Passengers who opt to skip a scanner will go through a metal detector and be hand-searched by a screener.