This International Standard, with the inclusion of type test (3.2.70) and site test (3.2.58) ,applies to the design, manufacture, installation, and maintenance of the radiotherapy treatment planning system (RTPS) (3.1.14) as well as communication of the radiotherapy treatment planning system (RTPS) (3.1.14) with other devices used in medical practice; that imports data either through input by the operator (3.2.39) or from other devices; that outputs data to other devices; and that is intended to be for normal use (3.2.36) , under the authority of appropriately qualified person (3.1.12), by operator (3.2.39) having the required skills and training; used and maintained in accordance with the recommendations given in the instructions for use (3.2.23) , and used within the environmental conditions specified (3.2.61) in the technical description. This standard applies to any software application that is used for the development, evaluation, or approval of a treatment plan (3.1.18) , whether stand-alone or part of another system. NOTE Such software applications include prescribing systems, contouring systems, quality assurance (3.2.45) systems, plan analysis systems, or plan review systems.