[Evaluation of the dose received by organs at risk].

The arrival of new technologies and the increase of the possible planned treatments require tools to evaluate and compare the delivered dose to specific organs at risk. Among several options providing the same tumour control, the choice will be made in favour of those that best spare the organs at risk. The evaluation tools have to report acute and late complications, and to be simple to use. The evaluation of the delivered dose to specific organs at risk is currently based on dose-volume histograms, conformal index and the integral dose. However, many questions remain as to reducing the normal tissue toxicity: is it better to deliver a relatively lower dose over a large volume or a relatively higher dose over a smaller volume? The long-term clinical follow-up of patients remains necessary.