Proton beams are already being employed for radiation therapy in 15 ce
ntres worldwide and over a dozen more are planned. Good clinical resul
ts have been reported in uveal melanomas and in sarcomas of the skull
base. Calculated dose distributions for the treatment of brain, lung,
head and neck and pelvic tumours predict an improvement relative to mu
ltiple-held or conformal photon radiotherapy. Protons may well provide
high-precision radiotherapy that will lead to improved treatment of c
ertain tumours in specific anatomical locations.