Passengers should not fear new airport scanners, said an article published in Archives of Internal Medicine.

Nearly 500 of the full-body X-ray machines, called backscatters, have been rolled out by the Transportation Security Administration at 78 airports as the latest weapon against airborne terrorism. They use ionizing radiation, a known carcinogen, to identify hidden items.

The cancer risk from exposure to the backscatter scan, which takes only a few seconds, contributes less than 1% of the radiation dose a flier would receive from cosmic rays during the actual flight, according to researchers at the University of California San Francisco. They found that even frequent fliers are unlikely to face any increased cancer risk.

For every 100 million passengers who take seven flights per year, there may be six extra cancer deaths over a lifetime.

“A lot of people are fearful of radiation, and I think they need to be conscious that all radiation is not the same,” says study author Dr. Rebecca Smith-Bindman, a California radiologist. “I don't think the risk is worth us worrying about because it is so low.”

The TSA says the devices are safe for all passengers, including children and pregnant women.