This is a very interesting battle, and even gets my 'Quote of the Week' award! All our 'safe dose' regulations have basically been derived from background radiation (cosmic rays), and the more intense doses of radiation workers. So, we know the amount of dose that doesn't bother anybody, and can even compare an intense dose to some fraction of a cigarette. I, myself, am a big fan of the rising 'Radiation is good for you' school of thought! (8 million years of evolution can't be wrong!)
So, we have these scientists pulling a rabbit of of the hat. They just got together and said that 'non-penetrating' radiation is worse per dose than hot gamma rays because it all stops at the skin. Makes a good story!
Oh, but I have to end with my quote award:
The Office of Science and Technology responded this week to the scientists' letter, saying the scanners have been "tested extensively" by US government agencies and were found to meet safety standards.
Doesn't that just give you the tingles?