Shielding assessment of a mobile electron accelerator for intra-operative radiotherapy.

The purpose of this investigation is to measure, characterize and report stray photon leakage and scatter radiation measurements from the Mobetron, an intraoperative electron linear accelerator designed for use in an operating room environment. The study is needed due to recent changes to the shielding design of the Mobetron, and also to provide specific information that may be required by regulation in various jurisdictions. An analysis is performed on a number of manufactured units to deter-mine an average 3D stray photon radiation map. This information provides a basis for determining patient-based load restrictions and/or additional shielding for the operating room. The data presented evaluates the number of procedures for which the Mobetron may be safely operated in a typical unshielded operating room.