Designing a novel phantom for daily QA of cyberknife M6 robotic radiosurgery system

Performing daily QA on Cyberknife system includes routine linac output constancy and constancy check for energy. Placing the ionization chamber at 80 cm SAD as specified by the equipment supplier for Cyberknife system is difficult since the system is non isocentric. However, birdcage assembly, an assembly and detector mount for holding the ionization chamber at a fixed distance of 80 CM from the the radiation source can be used to monitor the output. But the measurement chamber is placed in air which is not suitable for 6MV photon beams. Hence a new phantom has been designed which can be fixed to birdcage assembly to monitor output and energy constancy in the medium (Polystyrene)