Using Cone Beam Computer Tomography for stereotactic space verification during frame-based Leksell Gamma Knife ICON radiosurgery

Leksell Gamma Knife frame-based radiosurgery is considered the «gold standard» of neuro radiosurgery. This is due to both the high precision of the radiation treatment and the large amount of the global clinical data gathered over 50 years of using this radiosurgery system. To date, Leksell Gamma Knife Icon is the most modern model of Gamma Knife and provides the ability to conduct a frame -based stereotactic radiation treatment as well as both mask-fixated frameless hypofractionation and radiosurgery . The integrated Cone Beam CT is used for the positional delivery accuracy. Also the CBCT can be used for defining Leksell stereotactic space instead of the traditional stereotactic frame. The purpose of this work is to analyze different studies to investigate the reasons of the observed deviations in the definition of the stereotactic spaces. It was found that the occurrence of the deviations could be associated with the frame placements uncertainties, MR/CT co-registration errors, MRI distortions and the CBCT artifacts.