Establishes requirements for a satisfactory level of radiation safety for medical electron accelerators used in human medical practice for therapy under the jurisdiction of a qualified person. Applies to accelerators which deliver a useful beam of either X-radiation or electron radiation, with energies in the range 1 MeV to 50 MeV, and at maximum absorbed dose rates between 0,001 and 1 Gy s-1 at 1 m from the radiation source and at normal treatment distances between 0.5 m and 2 m from the radiation source.