@jeffmarc

My laywoman guess is to stop post RT inflammation 🤷‍♀️. This patient has a lot of inflammation going on in both regions - urinary tract and his guts : ((((.
Proton can cause the same RT effects as photon - it is all individual as always.

My husband talked to 6 physicists and his RO (they had some conversations that were not related to his RT, they wanted to meet him) and he was told that proton is not that precise as people like to think since it is very hard to determine what actual energy is needed to start the reaction to make proton particle go the EXACT length and stop at the EXACT place since it is very heavy particle and sometimes it stops too soon and sometimes it passes through and stops in wrong place, and so on . Physicists are actually still working on perfecting proton and as of now it has the best results with tumors that are close to surface of the body, etc.

I just want to reiterate once more that I am totally ignorant of this field and this is how I understood explanation of proton particles. Unfortunately there is just NO perfect method and no treatment that does not produce possible SA now or later and it is all so individual .