The study’s authors say airport scanner radiation is minimal compared to the levels of background radiation we’re exposed to daily. Going through one airport body scan delivers as much radiation as six to nine minutes of living, or one or two minutes of flying in an airplane.

So what’s the cancer risk of the scans? The authors calculate that among 100 million passengers who take 750 million flights a year, there would be an additional six cancers over a lifetime attributed to radiation from scanners — that’s on top of the estimated 40 million cancers that would be expected to occur anyway.

The authors also looked at the the lifetime cancer risk in a more vulnerable group: children. They estimated that among 2 million 5-year-old girls taking a round-trip flight once a week for a year, there would be one additional case of breast cancer per 2 million girls over a lifetime, on top of the 250,000 breast cancers that would be likely occur otherwise.