A glimpse into the CyberKnife robotic radiosurgery system: technical specifications and developments during thirty years

The CyberKnife system is a state-of-the-art technology widely used in the treatment of cancer. It incorporates a 6 MV X-band linear accelerator mounted on a six-degree-of-freedom (6DOF) robotic arm, combined with an image-guidance platform, to deliver high-dose stereotactic body radiation from a variety of unique angles with sub-millimeter accuracy to the targets in the body. As a frameless and semi-automated treatment, CyberKnife also enables patients to breathe normally during treatment while the robotic arm dynamically tracks and corrects their motion. This review aims to provide an overview of the evolution of the CyberKnife system from its introduction in 1994 through 2026, summarize target-tracking strategies, assess accuracy in both static and moving targets, and highlight its clinical applications, including re-irradiation settings, dose prescriptions and survival outcomes. Additionally, the advantages, challenges, and recent advances of the CyberKnife system are discussed to provide a comprehensive perspective on its role in modern radiotherapy.