The radiation risk from full body scanners used to improve airport security is very low and unlikely to raise an individual's risk of cancer, according to US experts.
Plans to implement full-body scanners across airports in the UK, the Netherlands and Canada are currently underway in an attempt to combat future terrorist attempts such as the foiled Christmas day plot to bomb a Detroit-bound plane.
Millimeter wavelength imaging and backscatter X-ray technology have been used to look beneath clothes and identify unusual objects, both of which expose individuals to ionising radiation.
Massachusetts General Hospital (Boston) chief of radiology James Thrall said that the radiation levels are, however, below the health risk threshold.
The backscatter machines typically deliver about 0.1 microsevert of radiation, which is lower than the average chest X-ray radiation that delivers 100 microseverts or CT scans that deliver 10,000 microseverts.
A total of 40 millimeter wave scanners are currently in use at 19 US airports.
Six machines are used for primary screening at six airports, while 34 machines cater to secondary or random screenings at 13 further airports.