This paper focuses on radiation protection at proton and light ion accelerators for radiotherapy. The National Centre of Hadrontherapy, which is planned to he built in Italy in the next five years, is considered as a reference facility for applying the various methodologies presented. The shielding design is firstly discussed, together with that of the access maze to the treatment rooms. Subsequently, the main aspects for the estimate of the air activation in the environment hosting the accelerator system are described. The estimate of the dose equivalent due to the activated air transferred to the neighbourhood population is also treated. Outlines are given of the radioactivity induced by the primary beam in the materials constituting the magnets and the patient's personal collimator.