Characterization and validation of an intra-fraction motion management system for masked-based radiosurgery.

Purpose: Characterize the intra-fraction motion management (IFMM) system found on the Gamma Knife Icon (GKI), including spatial accuracy, latency, temporal performance, and overall effect on delivered dose.

Methods: A phantom was constructed, consisting of a three-axis translation mount, a remote motorized flipper, and a thermoplastic sphere surrounding a radiation detector. An infrared marker was placed on the translation mount secured to the flipper.