Application of a video-optical beam imaging system for quality assurance of medical accelerators

Method validation techniques were developed and experiments were carried ou t using a beam imaging system (BIS, Wellhofer Dosimetrie, Schwarzenbruck, G ermany) for routine quality assurance of medical accelerators. The routine quality assurance tasks include x-ray beam flatness and symmetry check, lig ht/radiation field congruence test, beam energy constancy for electrons and mechanical checks for couch and collimator rotations. Comparisons were mad e between the BIS application and conventional quality assurance methods th at use radiographic films or detector arrays. In this work, we have demonst rated efficiency and accuracy of the BIS to perform some of the routine qua lity assurance tasks for medical linear accelerators.