Radioactivity in Physiotherapy?

Hello, I'm doing research at the moment into radioactivity as part of a Access to Higher education course. I have applied to university to study physiotherapy and would like, if possible, to make this project relevant to my interest and application.

So my question is: Are there any applications for radioactive isotopes in physiotherapy? I'm aware of some investigation methods such as X-ray but thought I'd ask the pro's to see if there's something exciting that I haven't thought of/can't find.

Thanks for any responses!