March 29, 2011
No Health Risk Found From Airport Body Scanners
Posing no risk of radiation harm to travelers, airport use of backscatter x-ray machines by the Transportation Security Administration (TSA) has been declared safe for those being scanned at airports throughout the US, AFP reports.
University of California researchers have released a study highlighting that fliers would have to undergo 50 airport body scans to equal the amount of radiation received from a single dental x-ray.
One would also need to undergo 4,000 scans to match the radiation exposure from a mammogram or 200,000 scans to equal that from an abdominal CT scan.
"The radiation doses emitted by the scans are extremely small; the scans deliver an amount of radiation equivalent to 3 to 9 minutes of the radiation received through normal daily living. And since flying itself increases exposure to ionizing radiation, the scan will contribute less than one percent of the dose a flyer will receive from exposure to cosmic rays at elevated altitudes," the researchers wrote.
Recent news of leaks from a nuclear power plant in Japan has heightened concerns around the world of the dangers of radiation.
Dr. Rebecca Smith-Bindman, a radiology professor at the University of California, San Francisco, whose study appears in the Archives of Internal Medicine, tells Reuters, "There is such a vast difference between super-low doses of radiation and the really high doses that happen if you are in the middle of a nuclear accident."
"Because they are all called radiation, we are tempted to put them all in the same category. That is a mistake."
The TSA website explains that the machines have safety systems in place to prevent radiation levels higher than the established limits. Manufacturers perform radiation tests on each scanner before it leaves the factory and after installation at the airport.
Periodic radiation tests are done either by the manufacturers or maintenance contractors. TSA employees can also request a radiation test, Bloomberg reports.
"There really should be no concern I would hope a piece like this would eliminate people's concerns," explains Ella Kazerooni, director of Cardiothoracic Radiology at the University of Michigan Health System in Ann Arbor.
The research team divided travelers into three groups: all flyers, frequent fliers and 5-year-old girls who are frequent fliers, because children are more sensitive to the effects of radiation.
If there are a total of 750 million flights taken per year by 100 million passengers, there would be an additional six cancers over the course of their lifetimes. Forty million cancers would be normally expected to develop among people in a group this size, Reuters reports.
For people who fly 60 hours a week, that might be four extra cancers on top of the 600 extra cancers just from flying -- which exposes people to more solar radiation -- and 400,000 cancers that normally would occur over their lifetime.
For 2 million 5-year-old girls who travel one round-trip a week, scanners would cause one additional cancer out of the 250,000 breast cancers that are set to occur in this group over their lifetimes.
Richard Morin, chairman of the American College of Radiology's Safety Committee and a professor at Mayo Clinic in Jacksonville, Florida, tells Bloomberg that radiation is not easily understood. "The levels we're talking about are lower than actual background radiation."
"I would certainly not worry about the radiation. I would be reassured that it's good to check for bombs. I'd like to make sure that there isn't a terrorist on board."
The TSA has deployed 486 scanners at 78 airports with about 1,000 scanners to be deployed, depending on budget approval.
On the Net:
- Transportation Security Administration (TSA)
- University of California, San Francisco
- Archives of Internal Medicine