Exhibit Hall | Forum 3
Purpose: Patients treated on the GammaKnife Icon are immobilized in a custom mask and actively monitored for motion using a High Definition Motion Management (HDMM) system. The treatment is automatically interrupted if the patient moves outside a user-defined positional tolerance for 30 seconds. The purpose of this study was to 1.) Evaluate patient motion using HDMM log files, 2.) Measure added treatment time from interrupts, and 3.) Determine the effectiveness of patient coaching in preventing interrupts.
Methods: Patients were continuously monitored during treatment using the HDMM system. When patient motion approached the positional tolerance, the patient was verbally instructed via the intercom system in an attempt to coach the patient back into position. HDMM log file data was used to evaluate coaching sessions to determine if they were successful. A session was defined as successful if the cumulative patient motion dropped below the user defined threshold and there were no interrupts.
Results: Patient motion was evaluated for a total of 25 patients for a total of 101 treatment fractions. The cumulative motion threshold to trigger an interrupt was set to 1.5-mm for 76 fractions (75%), 2.0-mm for 7 fractions (7%), and 2.5-mm for 18 fractions (18%). There was a total of 90 occurrences where the motion measured with the HDMM system exceeded the user define threshold. A total of 62 were classified as successful coaching sessions (69%) and 28 as unsuccessful coaching sessions (31%). For 8 fractions, all treatment HDMM interrupts were prevented through coaching. For 30 factions, at least one HDMM interrupt was recorded in the log files.
Conclusion: Coaching was found to be an effective method in reducing the number of treatment interrupts. Without coaching, an 62 additional HDMM interrupts would have added a total of 651 minutes of treatment time.