Radiation risk low with whole-body airport scanners
THE radiation risk from full-body scanners used to improve airport security is low and unlikely to raise an individual’s risk of cancer, US experts have said.
THE radiation risk from full-body scanners used to improve airport security is low and unlikely to raise an individual’s risk of cancer, US experts have said.
Airports in Britain, the Netherlands and Canada plan to use full-body scanners to foil future terror attempts like the Christmas Day attempt to blow up a Detroit-bound flight.
The US has tested 40 scanners as part of a pilot programme started after the September 11 attacks and October last year ordered 150 more.
There are two types of machines — millimetre wavelength imaging and backscatter X-ray scanners. Both are used to see underclothes and identify unusual objects.
Only one — backscatter X-ray machines exposes individuals to ionising radiation such as that used in common medical X-rays.
But the radiation levels are below the threshold that could be considered a risk to an individual’s health, said Dr. James Thrall of the American College of Radiology at Massachusetts General Hospital in Boston.
“When X-rays are used for medical imaging purposes, they have to be energetic to get through the human body.
The X-rays used in the backscatter machines in airports have such low energy that they literally bounce off the skin. That is what backscatter implies,†Thrall said.
Wave scanners in the U.S
The US has 40 millimetre wave scanners now in use in 19 airports. Six machines are used for primary screening at six airports, and 34 are used for secondary or random screening, as an alternative to a pat down at 13 airports.
Millimetre wave scanners beam radio waves over the body to create a three-dimensional image.
The backscatter-type machines use low-level radiation to create a two-sided image. Such scanners only become worrisome when they are used as the primary method of scanning passengers, said David Brenner, director of the Centre for Radiological Research at Columbia University Medical Centre.
For the actual radiation dose, Brenner said the typical backscatter machines deliver about 0.1 microsevert of radiation.
The average chest X-ray, by comparison, delivers 100 microseverts of radiation, and a chest computed tomography or CT scan delivers 10,000 microseverts.
According to the Transportation Security Administration website, the radiation dose from a single scan on a backscatter machine is the equivalent of two minutes of flying on an airplane.
Brenner said as with medical scans, the benefits of the scan need to outweigh the risks. “If the benefit means we are safer, then that probably outweighs the potential risk,†he said.
Reuters
Airports in Britain, the Netherlands and Canada plan to use full-body scanners to foil future terror attempts like the Christmas Day attempt to blow up a Detroit-bound flight.
The US has tested 40 scanners as part of a pilot programme started after the September 11 attacks and October last year ordered 150 more.
There are two types of machines — millimetre wavelength imaging and backscatter X-ray scanners. Both are used to see underclothes and identify unusual objects.
Only one — backscatter X-ray machines exposes individuals to ionising radiation such as that used in common medical X-rays.
But the radiation levels are below the threshold that could be considered a risk to an individual’s health, said Dr. James Thrall of the American College of Radiology at Massachusetts General Hospital in Boston.
“When X-rays are used for medical imaging purposes, they have to be energetic to get through the human body.
The X-rays used in the backscatter machines in airports have such low energy that they literally bounce off the skin. That is what backscatter implies,†Thrall said.
Wave scanners in the U.S
The US has 40 millimetre wave scanners now in use in 19 airports. Six machines are used for primary screening at six airports, and 34 are used for secondary or random screening, as an alternative to a pat down at 13 airports.
Millimetre wave scanners beam radio waves over the body to create a three-dimensional image.
The backscatter-type machines use low-level radiation to create a two-sided image. Such scanners only become worrisome when they are used as the primary method of scanning passengers, said David Brenner, director of the Centre for Radiological Research at Columbia University Medical Centre.
For the actual radiation dose, Brenner said the typical backscatter machines deliver about 0.1 microsevert of radiation.
The average chest X-ray, by comparison, delivers 100 microseverts of radiation, and a chest computed tomography or CT scan delivers 10,000 microseverts.
According to the Transportation Security Administration website, the radiation dose from a single scan on a backscatter machine is the equivalent of two minutes of flying on an airplane.
Brenner said as with medical scans, the benefits of the scan need to outweigh the risks. “If the benefit means we are safer, then that probably outweighs the potential risk,†he said.
Reuters