Melbourne, April 1 :Some American airports are using whole body scanners at security checkpoints, which can penetrate people's clothing.

Developed by New York-based L3 Communications, the scanner has become a cause of concern, with reports suggesting that even underwear is visible in the scans.

Due to this ability of the novel scanner, it is being likened to scanners on the 1990 science fiction film Total Recall, which revealed the bodies of Mars-bound passengers beneath their clothing.

Passengers boarding planes are asked to remove metal items, jackets, and shoes before stepping into a small glass chamber.

They then lift their arms over their heads for about three seconds before the scan.

The sensors can detect part of the electromagnetic spectrum that emits energy from the body at wavelengths of one millimetre.

Given that the energy from a human body is radiated at a higher rate than plastic, metal and ceramic, the unit can reveal those objects.

The faces of the scanned passengers are blurred, and the images are not stored.

However, the American Civil Liberties Union considers this technology to be very intrusive because it can project images of mastectomies and catheter tubes.

According to the Daily Telegraph, the Transportation and Security Administration has placed the scanners in airports in Salt Lake City, Las Vegas, Miami, San Fransisco, Tulsa, Okla and Albuquerque, in a pilot program.

It is currently a voluntary system. (ANI)