Breathing‐synchronized radiotherapy program at the University of California Davis Cancer Center

TLDR

BSRT synchronizes simulation, planning, and radiation delivery with breath‑hold or gating to minimize organ motion during treatment. This study presents a complete description of the BSRT system jointly developed by UC Davis Cancer Center and Varian Associates. The BSRT system integrates a breathing monitoring system—using video camera or inductive plethysmography—with gating hardware/software, records BMOS signals and fluoroscopic images to identify an ideal treatment point, and then gates a CT scanner or linear accelerator to maintain that organ configuration, allowing both breath‑hold and gating for different patient groups.

Abstract

In this paper we present a complete description of the breathing synchronized radiotherapy (BSRT) system, which has been jointly developed between the University of California Davis Cancer Center and Varian Associates. BSRT is a description of an emerging radiation oncology procedure, where simulation, CT scan, treatment planning, and radiation treatment are synchronized with voluntary breath‐hold, forced breath‐hold, or breathing gating. The BSRT system consists of a breathing monitoring system (BMOS) and a linear accelerator gating hardware and software package. Two methods, a video camera‐based method and the use of wraparound inductive plethysmography (RespiTrace), generate the BMOS signals. The BMOS signals and the synchronized fluoroscopic images are simultaneously recorded in the simulation room and are later analyzed to define the ideal treatment point (ITP) where organ motion is stationary. The BMOS signals at ITP can be used to gate a CT scanner or a linear accelerator to maintain the same organ configuration as in the simulation. The BSRT system allows breath‐hold or gating. This dual role allows the system to be applicable for a variety of patients, i.e., the breath‐hold method for those patients who can maintain and reproduce the ITP, and the forced breath‐hold or gating method for those who are not ideal for voluntary breath‐hold.