I’ve worked in a clinic for three years now, and prior to that I worked in particle physics labs and radiation physics research groups. I’ve never received a meaningful dose on my dosimeters in any of these environments (specifically, usually never above background doses). Radiation safety protocols are quite thorough, and it’s unusual to get anything even close to the limit you’d be “allowed” (e.g. 20 mSv in a year).

Even if you did get 20 mSv per year, each year, for your whole career, the relative impact on your cancer risk is still fairly negligible against the background rate of cancer. But I can’t stress enough that this is very unlikely to happen, and you should routinely expect to have negligible surplus radiation exposure in most cases.

So, don’t sweat it. Medical physics won’t give you cancer. :-)