I used to opt out when the scans were backscatter X-ray. Now, though, at least all the airports I've been to recently use millimeter wave scanners, which is non

I used to opt out when the scans were backscatter X-ray. Now, though, at least all the airports I've been to recently use millimeter wave scanners, which is non-ionizing radiation. If you use a cell phone, you shouldn't be concerned about the cancer risk of these machines.