Investigation of optimal planning strategy in gamma knife perfexion for vestibular schwannoma tumor using hybrid plan technique

Abstract

Purpose. Stereotactic radiosurgery (SRS) for vestibular schwannoma (VS) is clinically challenging because of surrounding critical structures. We generated and compared the forward plan (FP), inverse plan (IP), and hybrid plan (HP) for the optimal planning strategy in Gamma Knife stereotactic radiosurgery (GKSRS) for vestibular schwannoma tumors (VS). Methods and materials. In this study, 51 planning scenarios of 17 patients with VS were planned for GKSRS using FP, IP, and HP in Leksell Gamma plan (LGP10.1) using the TMR10 algorithm. The planning images were obtained using the following MRI (GE, USA) scan parameters: T1W images-MPRAGE sequence, FOV-256 mm × 256 mm, matrix size-512 mm × 512 mm, and the slice thickness 1 mm. The total dose was prescribed12Gy and normalized at 50% isodose level. Results and discussion. The plan parameters were compared dosimetrically by maintaining FP as a base plan. The statistical analysis, including one-factor, repeated measures ANOVA and Bonferroni correction tests, were performed. The p-value for planning parameters such as brainstem dose, beam ON time, and gradient index significantly favored HP. Conclusion. Overall results show that HP is an efficient method for GKSRS of VS The p-value was less than 0.001 and statistically significant for various plan indices.