23 May 2012
Whole-body security scanners like the one currently on trial at Manchester Airport are safe even for frequent users, a panel of experts has concluded.
Their decision clears the way for the European Commission to lift its ban on new trials of x-ray scanners, which it introduced in November 2011, and potentially to allow their permanent use.
Passengers and staff generally prefer scanning to pat-down checks, though some people have expressed concerns that the equipment produces ‘naked’ (albeit anonymous) images.
Software is under development that would highlight areas of interest on an avatar instead of an actual body image.
The EC’s Scientific Committee on Emerging and Newly Identified Health Risks (SCENHIR) examined two types of x-ray scanner for passenger screening: backscatter and transmission.
The backscatter technique uses reflected low-energy radiation to form an image of the subject’s body and any dense objects they are wearing or carrying.
It is this type that is used in Manchester and at some US airports.
The transmission technique relies on higher-energy x-rays that pass through the body and could show objects within body cavities.
The SCENHIR panel says that frequent flyers passing through transmission scanners could exceed the public dose limit of 1mSv per year, assuming 4u[MU]Sv per dose.
However, with a backscatter dose ten times smaller (0.4[MU]Sv), cumulative effective doses would remain below the limit “even with highest plausible scan frequences of three scans every working day of the year”. Most passengers would be unlikely to approach even a constrained dose limit of 0.25-0.5mSv, though it could potentially be exceeded by flight crew and ground staff.
In view of the low doses from backscatter scanners, the experts said there is no scientific basis for separately considering potentially vulnerable groups such as children and pregnant women in their risk assessment.
A Manchester Airport spokesman commented SCENHIR group’s conclusion was what it had expected, confirming similar studies by the UK Health Protection Agency and its US equivalents.
Ken Mann, aviation technical director of Rapiscan Systems, told E&T that there had been an “overwhelmingly favourable” public and staff response to the Manchester scanner.
Speaking at the recent Counter Terror Expo in London, he explained that eliminating pat-downs eased the physical strain on staff from bending and reaching.
Mann also confirmed that Rapiscan staff are developing avatar imaging, though it is not yet in use.
Rapiscan is the official security equipment and systems supplier for the London 2012 Olympic and Paralympic Games.