Variances in 3D radiomic shape features between meningioma, acoustic neuroma, and pituitary adenoma and the impact on dosimetric plan quality in Gamma Knife stereotactic radiosurgery

The purpose of this study is to address two questions regarding Gamma Knife Stereotactic Radiosurgery (GKSRS) planning: 1) Are there shape differences among disease types? and 2) Does plan quality vary by disease type? We considered meningioma, acoustic neuroma, and pituitary adenoma. For analysis, we exported a retrospective dataset from the treatment planning system (TPS) in DICOM format, including single fraction treatments with prescriptions at the 50% isodose line from 232 patients, completed between February 2018 and June 2023. The analysis included TPS-reported planning parameters, 3D radiomic shape features, and Gaussian Weighted Conformity Index (GWCI). The results were analyzed using two-sample t-tests and Pearson correlation coefficients. Although there were no statistically significant differences in volume, the cross-section of meningioma was the most circular, as defined by its major and minor axes. Pituitary adenoma exhibited the most flattened shape along its least axis. These results indicate that pituitary adenomas have distinct 3D shape characteristics. Pituitary adenoma required more shots, indicating they are more complex to plan. Acoustic neuromas had a similar number of shots to meningioma but showed better selectivity, implying it was easier to achieve planning guidelines, particularly for coverage. The normalized beam-on time for meningiomas was the shortest and the GWCI of acoustic neuromas was higher than that of the other two diseases, both statistically significant. A weak correlation between normalized BOT and the number of shots was found, suggesting that other factors beyond target shape influence plan complexity. Based on this study, shape differences exist among the considered diseases. Plan quality also varies by disease type. Pituitary adenomas are complex to plan, acoustic neuromas have better selectivity, and meningiomas have the shortest beam-on time. Factors beyond shape can also influence plan complexity.