@kmlnj Very interesting comment, km. That your highly experienced radiation oncologist NEEDED PHOTON, not Proton. I was looking for, but could not find, information on when Photon is perferred over Proton. I suspect that my oncologist also takes that view, although I am not sure of that--or--if she lacks the knowledge of the two systems as well as it should be. Also i suspect that since Photon is more readily available, a professional may lean toward that treatment. Maybe someone else knows (read) why Photon is preferred over Proton in some cases. I am assuming the side affects of Photon is greater than Proton.