In order to optimize quality and security in the delivery of radiation treatment, the French SFRO (Société française de radiothérapie oncologique) is publishing a Guide for Radiotherapy. This guide is realized according to the HAS (Haute Autorité de santé) methodology of "structured experts consensus". This document is made of two parts: a general description of external beam radiation therapy and chapters describing the technical procedures of the main tumors to be irradiated (24). For each procedure, a special attention is given to dose constraints in the organs at risk. This guide will be regularly updated.