Sustained Utilization of Gamma Knife Radiosurgery across Four Technological Generations and Increasing Repeat Treatment Capacity over 27 Years
Abstract
Purpose
Gamma Knife radiosurgery (GKRS) has undergone multiple technological transitions over the past two decades. This study evaluates long-term utilization trends at a single academic institution to assess whether GKRS has remained a durable and adaptable treatment modality, with particular emphasis on repeat treatment capacity across platform generations.
Methods
Retrospective review of intracranial Gamma Knife treatments delivered between 1998 and 2025 was performed. Patient-level data including demographics, treatment date, diagnosis, and prescription were collected with first versus repeat treatments identified using patient identifiers and treatment dates. Platform assignment was based on institutional commissioning dates. Annual treatment volumes were analyzed using ordinary least squares linear regression to assess temporal trends. Platform-specific differences in first and repeat treatments were evaluated using one-way ANOVA, with statistical significance defined as p<0.05.
Results
A total of 7,267 Gamma Knife treatments were analyzed. Overall annual treatment volume increased significantly over time, driven primarily by growth in metastatic disease (slope=6.50 cases/year, p<0.001; mean 135.9±55.1 cases/year). Meningioma and schwannoma treatments also demonstrated sustained growth (p<0.001), while glioma treatments declined significantly (p<0.001). Other disease categories remained stable. Repeat treatments demonstrated the most pronounced and clinically meaningful growth, increasing by approximately two cases per year (p<0.001, R²=0.92). Platform-specific analysis showed significant differences in both first and repeat treatment volumes. While first-treatment volume increased modestly with newer platforms, repeat treatments increased substantially across successive generations (ANOVA, p<0.001). Repeat treatments were uncommon during the Model B era, increased modestly with Model C, and rose markedly following the introduction of Perfexion, with sustained high volumes during the Icon era.
Conclusion
Gamma Knife radiosurgery has demonstrated sustained clinical relevance over 27 years despite major technological transitions. The substantial and consistent increase in repeat treatment utilization with newer platforms highlights GKRS as a durable, adaptable modality aligned with evolving survivorship and retreatment demands.