QUALITY ASSURANCE FOR GAMMA-KNIFE STEREOTAXIC RADIOSURGERY

Purpose: This quality assurance program is designed for stereotactic r adiosurgical units, gamma knife, to check and maintain the unit to pre clude accidents and comply with current regulations. Materials and Met hods: Over 58 stereotactic radiosurgical units using 201 focused (CO)- C-60 beams have been installed in the last 7 years and are in use at h ospitals throughout the world, with at least 11 additional units being prepared to come on-line in the next year, This system has been in us e at the University of Pittsburgh Medical Center (UPMC) for 7 years, A comprehensive quality assurance program has been developed, It includ es the physics and dosimetry parameters and safety checks required by regulatory agencies, The program, based on over 7 years of experience in measurements, and used during the treatment of over 1500 patients, is separated into three aspects, namely physics, dosimetry, and safety , The UPMC program hopefully will indicate out-of-tolerance problems, Some quality assurance items are checked on a daily basis prior to pat ient treatment, while other aspects are checked on a weekly, monthly, and/or annual basis, A complete list of items with their respective ti me tables and tolerances is provided. Results: Although experience sho ws very small margins of error, larger values were chosen to account f or variations in equipment and techniques, Conclusions: Items included in this quality assurance program should indicate and/or preclude pro blems encountered in the use of this unit.