[First experience with the electron accelerator "Therac 20-Saturne" in clinical practice. 1st communication: technical data and dosimetry of photon radiation (author's transl)].

The fundamental principles of construction, the operational data, handling and safety devices of the first linear electron accelerator type Therac 20-Saturne (CGR MeV) installed in Germany are described. Relevant characteristics of the radiation field for therapy with 12 and 18-MV photons and also the dosimetric data are reported. Observance of the tolerances recommended by the IEC is guaranteed with this accelerator.