A real-time respiration position based passive breath gating equipment for gated radiotherapy: a preclinical evaluation.

Purpose: To develop a passive gating system incorporating with the real-time position management (RPM) system for the gated radiotherapy.

Methods: Passive breath gating (PBG) equipment, which consists of a breath-hold valve, a controller mechanism, a mouthpiece kit, and a supporting frame, was designed. A commercial real-time positioning management system was implemented to synchronize the target motion and radiation delivery on a linear accelerator with the patient's breathing cycle.