Hi rcs, I started my proton therapy 2 years ago tomorrow. I had 20 treatments at Phoenix Mayo over 4 weeks. My experience was similar to those mentioned with slight exception. They wanted my bladder full and then inserted a balloon in the rectum and filled with water. This was to hold the prostrate in place. The actual scan was less then a minute. Before the scan, they use the tattoos and carbon inerts placed in the prostrate during the prep stage a week or so before treatment. At that time using scans they program the computer to locate the prostrate. Before each treatment, they used xray and laser machines to focus the robotic arm of treatment table so the prostrate is in the correct position. Only real issue was drinking water before hand to fill bladder. If you don't time it right, you may need to urinate before the treatment and start over. The best part is when you get to ring the bell after the last treatment to indicate you are now cancer free.

Not sure if you are taking Antigen Deprivation Therapy as well. I've talked to some patients at your level who did not need it. If you are, you've probably had the first injection. There's another alternative to Lupron that acts faster and you recover faster, but can't find reference right now.