[en] With the recent significant development of linear accelerators (LINACs) as equipment for use in radiotherapy, the requirements for high reliability, safety, precision and operational performance are becoming more rigorous. To satisfy these requirements, the new Model ML-15MIII has been developed on the basis of the klystron technology used in the previous clinical accelerator, Model ML-15MIIB. The new technological developments incorporated include a double-focusing achromatic bending system, which offers long focus and no aberration and uses integrated circuits combining high reliability, safety, precision and operational performance with the high power and stability that characterized the previous model. The article gives a general description of the new model. (author)