Specifies requirements for the safety, design and construction of gamma beam equipments when used for radiotherapy in human medical practice. Applies to equipment which is intended to deliver a gamma radiation beam(s) at normal treatment distances greater than 5 cm using a sealed radioactive source(s). It is the purpose of the requirements contained in this standard to ensure that the proposed irradiation conditions are met and the actual settings retained during irradiation and that unintentional exposure to irradiation of the patient, operating personnel and the environment is kept as low as reasonably achievable.