According to this USA Today article, the National Academies of Science have finally been asked to evaluate the safety of x-ray backscatter naked scanners. This seems a bit of putting the cart before the horse since the scanners were already used on millions of travelers before being pulled. (And, remember, they were pulled because Rapiscan didn't come up with a software upgrade for "privacy" quickly enough.)
I haven't had a chance this week to look at it more closely, so I am posting it here without further comment. If these machines were truly safe, then that is, of course, a good thing that people were not made ill by government ineptitude in this case.