Analysis of failure of helical tomotherapy multi-leaf collimator system

Objective To analyze the failure and processing methods of helical tomotherapy multi-leaf collimator (MLC) and summarize relevant maintenance experience, aiming to accurately identify the faulty parts, shorten the downtime and enhance the work time. Methods The failure data of the helical tomotherapy MLC system in the past 48 months were analyzed to identify the common faulty parts, causes and processing methods. Results During the previous 48 months, the MLC failure occurred for 20 times, 11 times for air compressor failure, 4 times for position verification board failure, twice for leaf driver failure, twice for cushion valve failure and once for the slip of leaf position verification rod. The MLC failure was significantly correlated with the humidity of high-pressure gas. The work time of machine exerted significant effect upon the service time of MLC parts. Conclusions The structure of the helical tomotherapy MLC system is complex. The high-intensity work increases the failure rate. The humidity of high-pressure gas affects the normal operation of the MLC equipment. The faulty parts can be identified, the downtime can be reduced and the work time can be enhanced by summarizing the experience of MLC maintenance. Key words: Tomotherapy; Multi-leaf collimator; Binary pneumatic blade; Failure processing