This isn't chemistry. This is medical physics / nuclear medicine.
I would go through coursera. Most of their content they link to is free, unless you want to get an exam / certificate.
This one looks to be very thorough. May be a bit stiff if you don't have a solid science background:
https://www.coursera.org/learn/medical-applications-particle-accelerators
Otherwise, youtube may be good for some lighter content. Maybe you can find videos for your particular system. I'd also search the cancer medicine help sites where you may get a perspective for the patient.
Here a varian clip:
https://www.youtube.com/watch?v=iLgzxG7j40U
Super interesting stuff. I was seriously thinking about switching into medical physics mid-career one time.
G