Assessment of scattered radiation doses in betatron operation

Doses from scattered radiation outside the useful beam of a 42-MeV Siemens Betatron have been assessed. Measurements were carried out in various depths of a plexiglas phantom at various distances from the primary beam. For relating the measured values to the patient analogous experiments were performed with an Alderson phantom. Moreover, results of comparative measurements are given for the scattered radiation using fields of various sizes. The measured values were referred to the maximum dose measured in the primary beam for the given field and radiation energy and are used as a basis for estimating the critical organ exposure of patients treated with betatron radiation. (author)