This technical report applies only to those aspects of the installation ensuring the safety of the PATIENT, the OPERATOR and other persons during the RADIOTHERAPY EQUIPMENT use. General construction requirements are not addressed in this technical report. The installations considered in this technical report are those in which are located RADIOTHERAPY EQUIPMENT delivering IONIZING RADIATION used for therapeutic purpose, such as MEDICAL ELECTRON ACCELERATORS, GAMMA BEAM THERAPY EQUIPMENT AND GAMMA-RAY AFTERLOADING EQUIPMENT. RADIOTHERAPY SIMULATOR installations are not included in this technical report. A particular RADIOTHERAPY EQUIPMENT installation may generally consist of several rooms, such as: – the TREATMENT ROOM in which the RADIATION BEAM is emitted and in which the PATIENT is located during the IRRADIATION, including all enclosed spaces where a person could remain inadvertently during the IRRADIATION; – the control room in which the TREATMENT CONTROL PANEL is located and from which the OPERATOR controls the IRRADIATION and other functions of the RADIOTHERAPY EQUIPMENT; – other rooms which may contain other parts of the RADIOTHERAPY EQUIPMENT, but where IRRADIATION is not carried out.