Combination of photon and proton radiation therapy for chordomas and chondrosarcomas of the skull base: the Centre de Protontherapie D’Orsay experience. - Noel,G.; Habrand,J.L.; Mammar,H.; Pontvert,D.; Haie-Meder,C.; Hasboun,D.; Moisson,P.; Ferrand,R.; Beaudre,A.; Boisserie,G.; Gaboriaud,G.; Mazal,A.; et al. (Internat J Radiat Oncol Biol Phys, 2001)