[evgen]

If this procedure causes 800 cancers per year then the flights themselves would be causing nearly a hundred thousand cancer cases per year. The radiation from the scanner is far, far safer than the exposure you receive during the flight that caused you to get scanned in the first place.

[pjscott]

Also, we should keep in mind that the health effects of radiation may not be something you can linearly extrapolate to low doses, and there is evidence to suggest that they aren't.

http://en.wikipedia.org/wiki/Linear_no-threshold_model