There are not more side effects though with MRLinac SBrT since it is so targeted and very tight margins and the ability to change target on the fly, in fact less because of the tight margins and control with the MRI movie and the gating of the machine, I watched the gate work as I was holding my pee my prostate jumped and it instantly gated. The prostate can also change shape during treatment and this new tech catches all that. Proton beam is easily deflected by calcification causing lateral scatter and not as controllable as the adverts make you think. There are studies talking about this. If you were going to consider Proton I would look at San Diego Proton since they offer pencil beam and much newer tech than Loma Linda. I had very minor side effects for less than two weeks and even had “relations” 4 days after treatment with no issues. After a month it was nothing whatsoever happened. I have to say that UCLA was the absolute best experience I have ever had in any treatment center, they are 100% on the ball.. For a full explanation on SBRT watch this. At least have a consult with Michael Steinberg or Kishan at UCLA, the man knows his radiation and cancers. He answered every question with knowledge.