My understanding is that the scanner operator can turn up the gain on the sensor but cannot turn up the X-ray dose.
Here's Kodak's current (2003) bulletin (which doesn't address that particular issue, but covers lead bags, what X-ray fog looks like, and other topics) on X-ray scanners and film--
http://www.kodak.com/global/en/service/tib/tib5201.shtml
Here's Kodak's current (2003) bulletin (which doesn't address that particular issue, but covers lead bags, what X-ray fog looks like, and other topics) on X-ray scanners and film--
http://www.kodak.com/global/en/service/tib/tib5201.shtml