Analysis of utilization-related parameters on a 6-MV linear accelerator.

An analysis of unscheduled downtime and of patient treatment data for a 6-MV linear accelerator is presented for a 7-yr period. Following the initial year of clinical use, the unscheduled downtime has averaged 2.4%, with a corresponding loss of 1.3% in patient treatments. The quality assurance, preventive maintenance, and repairs are handled in-house, with an investment of approximately 500 man-hours annually.