Bl2023, I received proton Beam SBRT at Mayo Clinic Rochester. Not certain whether ViewRay or TrueBeam offer both Proton and Photon Beam options. The Proton Beam provides a radiation which enters the Prostate but does not exitafter performing its function. Photons enter and then exit which means they may have a higher chance of negatively impacying healthy cells outside the Prostate. This treatment required that I make the trip from Portland, OR to Minnesota for treatment... well worth the effort.
Best wishes for a successful outcome regardless of treatment choice.