I think that your best bet would be to go to your local hospital or to go on the web site of your local hospital.
If you went on the web site of your local hospital, you could e mail someone in the Radiology Department, and ask them what kind of training they look for.
To the best of my knowledge, a "Radiology Technician" is a trade school course of study and certification. I would assume that one could do that through a Community College.
Here is the web site for The American Society of Radiologic Technologists...
https://www.asrt.org/
Whenever you are planning a course of study that has a certification behind it, it is always a good idea to look up who governs that certification.
You might desire to go to the International Student area of this (College Confidential) web site in order to learn more of your past high school work and how to obtain your transcripts and all of that.
Good luck. And, 40 is not old at all!