This collateral standard applies to X-ray equipment and to subassemblies of such equipment, where radiological images of a human patient are used for diagnosis, planning or guidance of medical procedures. The object of this collateral standard is to establish general requirements for protection against X-radiation in X-ray equipment, in order that the irradiation of the human patient, the operator, staff and members of the public can be kept as low as reasonably achievable, without jeopardizing the benefit of the radiological procedure. Particular standards may specify their appropriate values and/or measures for general requirements specified in this collateral standard. The implementation of the general requirements or the reference to the particular standard instead, shall be justified in the risk management process. This collateral standard considers radiation protection aspects related to X-radiation only. Requirements for the control of the electrical energy used to generate X-radiation, which is also an important aspect of radiation protection, are included in IEC 60601-1 and in particular standards for the safety and essential performance of the equipment concerned. This document cancels and replaces the first edition of IEC 60601-1-3, published in 1994 (which replaced IEC 407 issued in 1973). It constitutes a technical revision. This edition has been restructured and aligned to IEC 60601-1(2005) and focussed on general requirements for RADIATION PROTECTION that apply to all diagnostic X-RAY EQUIPMENT. Requirements particular to specific equipment have been removed and will be covered in particular standards. For a description of the changes, see the mapping in Annex C.