I've just travelled from Frankfurt am Main to Denver, Colorado, and back again with a bunch of medium format film in the ISO 100-200 range. I did some research but it was all very contradictory so I decided to just ask the security staff to inspect my bag of film + loaded camera by hand. In Frankfurt a security person very kindly explained that their x-ray machine was safe up to ISO 1600 so I had them run everything through. The Denver airport website said that the TSA just installed a CT scanner which, according to the internet, pretty much immediately exposes any film. Again, I asked the lady who was guiding people into the different queues whether they could inspect my camera bag by hand. She said it was no problem at all, I had to wait a couple of minutes after passing through the scanner for an employee to look in the bag, do a swab and I was on my merry way.
I've scanned several rolls and they are all just dandy. No fogging, no nothing.