Secondary and activated X(γ)radiation of SPHIC particle therapy facility

摘要

We report the secondary X(γ)radiation from the accelerator in a normal operating state and activated X(γ)radiation from the accelerator devices when the accelerator stops operating in the cancer treatment facility of the Shanghai Proton and Heavy Ion Center(SPHIC).These radiation measurements show us the structural radiation distribution along the beam lines and devices inside the accelerator room when the beam is on and off and can support the radiation protection design of the accelerator facility used for cancer treatment and help evaluate the accumulated radiation dose in the case of an emergency,such as a personal safety system failure or a radiation accident.The radiation dose rate measured in this facility shows that the facility is safe from the radiation protection point.After shooting the quality assurance(QA)beam,the radiation dose rate in the treatment room was also measured to investigate the radiation dose space distribution and decay time dependence.In addition,the time period before safely entering the treatment room after determining the shooting of the QA beam is recommended to be approximately 5 min.