How does Proton compare with fractionated stereotactic radiosurgery?
I had to look that up. It seems like it's very similar but Proton is newer. The deal about proton therapy is that it targets JUST the cancerous cells. The protons are focused to release their energy inside the tumor only. The flesh and bone it goes through is minimally affected. I was told it was sorta like a grenade launcher in that it flies through the hips and the rectum is moved out of the way as much as possible, and the protons explode inside the tumor. The software focuses the beam to the exact millimeter to stop and burn the tumor. They first put a BB inside your prostate and measure how far inside you it is. Each session ( I had 39) they first line you up with an "X" on the BB with x ray. They cut blocks of plastic about 2 inches thick to put in front of the beam. Each block is specially cut to the depth needed to make the beam strongest in the middle and weakest at the edges. The put a balloon up your rectum and inflate it to push your rectum out of the way. Also, you drink a certain amount of water to inflate your bladder before treatments. All of this is planned out before your first treatment and remains the same to the end.
www.https://protonbob.com/ will give you a downloadable book that talks all about it, even the details.