In orthopedic surgery the image magnification is usually figured to be 1.15 or so. For films where measurement is required such as when fabricating custom implants (which many companies have lost fortunes trying to do.)Which brings up the obvious thought: since X-Rays are essentially shadows, shot by consummated "light", they are always at 1:1. Does this make them macros?
there are distance standards that consist of a rectangular rod of lucite with two ball bearings suspended at 100mm spacing. This is held at the plane of interest when the film is shot. Then the mag can be determined the same way we would do it with a stage micrometer.
The Skyscan is a way cool gadget. On their website they had a scan of a piece of very complicated cable and you could see individual wires in the shielding. I want one!
There are also ones in between sizes. I went back to visit the orthopedic surgery lab I used to work in and they had a CT that was sized to shoot small mammals up to about a rabbit or so. It had the same kind of stretcher a human one has that steps through the smaller sized ring. Like a scale model. So cool I could hardly stand it. I didn't get to ask how much it cost.