I had protein beam radiation treatment at the Mayo Clinic in Phoenix January 2019. I had 20 treatments and don't think the 5 treatment option was available to me. I did talk to a man who had 5 treatments at the Rochester Mayo Clinic in 2018. He was part of a trial to see how severe were the side effects. I saw a study report that the side effects were no greater than with the 20 treatments that I had. The person I talked to was pretty satisfied with the 5 treatments. He had to travel several hours each day to get the treatments, so he appreciated only needing 5 treatments.