Active Breathing Coordinator Reproducibility of liver position using Active Breathing CoordinatorTM for liver cancer

The purpose of this paper is to describe the reproducibility of liver position using Active Breathing Coordinator in a larger series of patients with more advanced liver cancer, consecutively planned for SBRT delivered in six fractions over two weeks. In this study, repeat megavoltage (MV) verification imaging, real-time beams-eye-view MV movies, conventional kV fluoroscopy, cone beam kV fluoroscopy and deformable registration of repeat CT scans in the breath hold position are used to measure liver stability during active breathing coordination and intrafraction reproducibility of the liver position relative to the vertebral bodies.