Looking again at your post, Andy, I see you are already involved in medical imaging (ultrasound?).
Capital Medical used to have an x-ray module as one of their training courses at Kidderminster, and this may have re-emerged as one of the new modules at Falfield (but you would need to check with both those establishments ... I have no "inside knowledge" of either).
In the United States there are two well-known x-ray training schools:- see
DITEC and
RSTI. We can only speculate as to why they are located in the same small city (and again I have no inside track) ... all I know is that RSTI was founded by Terry Speth, a name that I recognise. DITEC was started by Manny Roman, and is staffed by ex-US armed forces people (which is OK by me). Wouldn't it be great to do any of those courses?
Notice that the RSTI website now has a Tech Forum.
Most training on modern x-ray kit would be from the manufacturer. Other than that it's a question of being self-taught, which (depending on what it is you're actually planning to do) again is OK by me! If you've already got a technical background (especially in medical imaging), I don't see that as a problem. Just get stuck in, and "hoover up" information as you go along, and grab whatever courses come up (bearing in mind that the OEM's may not be keen on training anyone but their own people) ... that's the best way (in my opinion), unless you can afford trips out to Solon, Ohio.
