Two medical trade groups this week laid off concerns over radiation exposure from airport full-body scanners.

Passengers will have to face scanners more than before following a Nigerian man who carried explosives in his underwear with an aim to bomb a jetliner traveling from Amsterdam to Detroit on Christmas Day.

Travelers however fear that cancer risk increases due to the use of these scanners. Claiming that the machines are safe the American College of Radiation and American Roentgen Ray Society gave a statement regarding this.

Two types of systems have been used by the Transportation Security Administration for scanning. One of them is millimeter wave technology. Low-level radio waves are used in the millimeter wave spectrum in this system. For scanning a passenger he is covered from head to toe by two rotating antennae with low level radio frequency energy.

The second system uses low-level X-rays that are extreme. This delivers less than 10 microRem of radiation per scan which is equal to two minutes radiation received at 30, 000 feet while traveling inside airplane. It is called backscatter technology.