Verification of the performance of respiratory synchronisation radiation switchgear by using imaging technique

This study has developed respiratory synchronisation beam switchgear that can perform the real-time gating of treatment beam by synchronising with respiratory signal in order to compensate for the motion of normal tissue or organs which is generated by respiration for radiation applied to tumour in radiotherapy. Respiratory signal obtained by the belt system is applied to the self-developed switchgear motor control program so that the AC servo motor of switchgear can be operated in connection with actual respiration. To verify correct respiratory synchronisation operation, motion data of irradiation area which changes according to respiratory signal is obtained by CCD camera-using imaging technique and compared with original respiratory signal. According to the result, it has been confirmed that the correlation coefficient of two signals is higher than 0.98, showing that the motion pattern of beam switchgear was very similar to actual respiration.