[Pendulum irradiation of the middle part of the esophagus with rapid electrons and ultrahard X-rays (author's transl)].

In order to find out whether the moving field irradiation with rapid electrons and ultrahard X-rays of a 42 MeV betatron is suitable for the radiotherapy of the esophagus carcinoma, we took measurements on the Alderson phantom. By both methods--irradiation with rapid electrons as well as mono-axial pendulum irradiatin with ultra-hard X-rays--we did not achieve a satisfactory dose distribution, because lung segments of different sizes or the spinal marrow were reached by a relative dose which was too high. The bisegmental pendulum irradiation is the only one which leads to a dose distribution producing a good concentration in the target volume and sparing the surrounding tissues.