Abstract / Summary
Successful Gamma Knife radiosurgery (GKRS) depends on accurate dose delivery and carefully optimised treatment planning, particularly for intracranial meningiomas located near critical neural structures. In this study, we evaluated agreement between planned and measured doses together with treatment plan characteristics in patients treated with hypofractionated or multistage GKRS. The analysis included 30 patients with intracranial meningioma, comprising 15 patients treated with hypofractionated GKRS and 15 treated with multistage GKRS. Planned doses from the treatment planning system (TPS) were compared with measured doses calculated from the recorded treatment time and dose rate. Comparison of planned and measured doses showed close agreement within both treatment groups, with mean planned-minus-measured differences of −0.008 Gy and −0.007 Gy for the hypofractionated and multistage groups, respectively. The overall mean dose deviation was 0.15 ± 0.38%. Mean target coverage was 0.96 ± 0.02 in the hypofractionated cohort and 0.89 ± 0.04 in the multistage cohort, while mean selectivity was 0.79 ± 0.04 and 0.74 ± 0.07, respectively. Mean gradient index values were 2.72 ± 0.17 and 2.78 ± 0.22, respectively. Mean beam-on time was 18.63 ± 12.71 min in the hypofractionated cohort and 36.86 ± 11.66 min in the multistage cohort. All analysed treatment plans met the institutional ±5% quality-assurance acceptance criterion for dose deviation. The observed differences in treatment plan characteristics are presented descriptively and should be interpreted in the context of clinically determined treatment selection.