Advances in Proton Therapy for the Management of Head and Neck Tumors.

Proton therapy (PBRT) is a form of external beam radiotherapy with several dosimetric advantages compared with conventional photon (x-ray) radiotherapy. Unlike x-rays, protons deposit most of their dose over a finite range, with no exit dose, in a pattern known as the Bragg peak. Clinically, this can be exploited to optimize dose to tumors while delivering a lower integral dose to normal tissues. However, the optimal role of PBRT is not as well-defined as advanced x-ray-based techniques such as intensity-modulated radiotherapy.