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

In this paper we present a complete description of the breathing synchroniz ed radiotherapy (BSRT) system, which has been jointly developed between the University of California Davis Cancer Center and Varian Associates. BSRT i s a description of an emerging radiation oncology procedure, where simulati on, CT scan, treatment planning, and radiation treatment an synchronized wi th voluntary breath-hold, forced breath-hold, or breathing gating. The BSRT system consists of a breathing monitoring system (BMOS) and a linear accel erator gating hardware and software package. Two methods, a video camera-ba sed method and the use of wraparound inductive plethysmography (RespiTrace) , generate the BMOS signals. The BMOS signals and the synchronized fluorosc opic images are simultaneously recorded in the simulation room and are late r analyzed to define the ideal treatment point (ITP) where organ motion is stationary. The BMOS signals at TTP can be used to gate a CT scanner or a l inear accelerator to maintain the same organ configuration as in the simula tion. The BSRT system allows breath-hold or gating. This dual role allows t he 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 rue not ideal for volunta ry breath-hold. (C) 2000 American Association of Physicists in Medicine. [S 0094-2405(00)00402-8].