RADT-25. IMPACT OF SAME-DAY MASK CREATION ON GAMMA KNIFE TREATMENT

Abstract OBJECTIVE Technological advances have allowed stereotactic radiosurgery (SRS) to be administered using fixation with a noninvasive mask, rather than with a stereotactic frame. While the use of such masks offers advantages including the ability to hypofractionate SRS and improved patient comfort, there has been criticism that it eliminates the possibility of same-day, “wheels in to wheels out” SRS. Our study examines the feasibility of conducting mask fitting and SRS treatment on the same day versus the conventional different-day approach. METHODS Eligible participants had either underwent single-fraction-SRS (SF-SRS) or were in their initial session of hypofractionated-SRS (HF-SRS). 100 patients who underwent SRS from September 2020 to June 2021 were assessed. 52 patients underwent same-day fabrication and treatment, and 48 patients received treatment at least one day following mask fabrication. The Leksell Gamma Knife (LGK) console data was processed, and operator reports from each patient were extracted and analyzed. RESULTS The average number of pauses, pause time, and number of gates was greater for same-day patients. There was no significant difference in the number of positioning alarms between the groups. There were no significant differences in percent overestimation of treatment time or number of treatment alarms. Treatment gates occurred on average 19 minutes earlier for same-day patients then different-day patients, which likely corresponds to “mask fatigue,” due to spending 20 minutes longer on the treatment table, while the masks are being fabricated. CONCLUSION Mask-based SRS can be done safely and efficiently in a single day, mirroring the approach of frame-based treatments.