@northoftheborder (how is Canada these days)
Never heard of the photo (SBRT) causing the inability to ever take shirt off. But I am not as familiar with photon as I am with proton. Did the photon radiation subject your entire chest area to significant radiation?

It would make sense if it had because photon radiation burn on skin is like a bad repeated sun burn so could make it sensitive to sun burns. But why so much in chest area and not just around entry sites.

I had pencil beam proton. It is a very precise beam and depth of release radiation. My areas of skin tanning were on the top of each side of hips but only a couple of inches. I have a ICD/Pacemaker and UFHPTI physics department recommend the pencil beam proton for me to keep radiation away from my ICD/pacemaker.

You are right on proton. R/O expalined the intensity of proton radiation going in is very much lower than the intensity of the radiation at the programmed release depth.

My R/Os explained (like yours did) why they don't just radiate biopsied areas, or MRI areas, as take a chance of a cancer cells being missed in prostrate or in the margins ouside the prostrate.

I worry sometimes when I read radiation treatments directly targeting the MRI confirmed cancer areas only or biopsied confirmed cancer areas only. You would think this would increase the chances of missing cancer cells.