Ever since the September 11th terrorist attacks on the United States, the need for airport security has led to a steady increase in the use and improvement of technology.  One new kind of screening system, called "the Backscatter", is somewhat controversial, but may soon be used in several airports.

An artist's conception of how the screening would take place

Some U.S. airports will soon begin using what's known as "backscatter x-ray technology" to screen passengers.  The harmless technology can see through materials such as clothing -- and that raises concerns.

As one female traveler said, “That's crazy, kind of invasive. So no, I wouldn't really enjoy that very much.”

The virtually naked images are considered by some as an invasion of privacy.  And that has prompted officials to modify the scanners.  Altered images will show cartoon-like black and white outlines of passengers.

Airline passengers had mixed reactions.  “It is national security.  Anything to protect our country,” said one woman. Another passenger agreed. “I'd almost feel more secure about that because of the number of guys get on airplanes and do stuff with guns.” But another woman was concerned about the public viewing of the screenings. “…and hopefully, it doesn't have a big screen so everybody sees you as you're walking through.

A screen image with simulated display of hidden weapons

The virtual strip search is being tried first at Phoenix Sky Harbor International Airport in the western state of Arizona.  Initially, the system is being used only on volunteers and on travelers whom officials decide require extra screening.  Passengers are offered the option of being photographed from the front or the back. 

Transportation officials say the new machines may one day replace the metal detectors that are now used -- if they can be improved to take less than the 15 to 20 seconds they currently require.  The new scanners are already up and running in Phoenix.  A small number of other U.S. airports will have them in place this month, as part of a nationwide pilot program.