At LAX and other major airports, the Transportation Security Administration is replacing full-body scanners that have been criticized for creating potential health risks and privacy violations with a type of scanner that has not been condemned as harshly.
The TSA said Monday that the move is intended to relocate faster scanners to busier airports.
The TSA operates more than 700 body scanners at about 180 airports across the country. The machines were introduced at the nation's airports after Umar Farouk Abdulmutallab tried to blow up a U.S. airliner near Detroit with explosives hidden in his underwear on Christmas Day 2009.
About half of those scanners employ "backscatter" technology that uses low-level X-rays to create what resembles a nude image of passengers to detect weapons. The faster scanners use low-level radio waves, or millimeter waves, and instead use a generic avatar figure to show hidden objects.
The backscatter machines have been criticized by academics and privacy advocates who say the radiation they emit poses a health risk and the images they create violate the privacy of passengers.