I've read that the regular ones - when you just pass through the "gates" and hand held are not harmful, those the new ones at the airport where you stand with your hands up in front of transparent wall and the machine scans you - potentially can be a bit harmful but it's sort of new, so no enough research has been done.
I don't think it will. I went through one a couple weeks back n I'm fine. 38+1 :)