The Fuji salesman was even so kind to phone me. I think his fear was (also) that I was ordering something I didn't understand: he asked what I was going to use it for and how I wanted to develop the film since it is originally intended for medical use. He knew I wasn't a doctor. I told him it would be done with "ordinary" B&W developers and that there were good examples at the forum. This was quite new to him. It's my guess he never considered the possibility of using the X-ray film as a "normal" photo negative.
So it will be a nice way to test & learn LF photography and tray development, since this is new to me.
I also got me some Maco Genius film 18x24 very cheap. I made my first shots this week and will try tray developing this weekend for the first time. If it works out all right, I'll use the negatives in a course for Casein Printing in 2 weeks time.
And when I'll get the hang of it, I'll also use some Ilford FP4+ film later, I'm going to order through the Ilford ULF 2013 run.