Your radio oncologist will discuss all this with you before you start. They like to make sure you're really clear on everything so you can sign a consent form. The treatment itself is painless, a bit like a scan. Reactions can vary, but most common are skin reactions which can be anywhere from a slight pinkness to quite severe skin breakdown. You will be monitored really closely, like a few times a week, and nurses will assist you to care for your skin before, during and after. Hope this is helpful.