Radiation for refractory PMBCL: proton v photon

I have Primary Mediastinal Large B-cell Lymphoma and the chemo didn't work. Started working and then quit responding. Now I am in between Photon and Proton therapy and not sure what to do. Has anyone on here had any experience in this? The Proton would be at 60Cy and the Photon at 20cy. CAR-T as well.

Anyone have any input?