Induced radiation studies and personnel dose assessment in a carbon ion therapy facility

Carbon ions have become the most widely used particles in heavy-ion tumor therapy due to favorable physical and biological characteristics. The beam delivery system (BDS) and tumor tissues are directly bombarded with accelerated carbon ions, resulting in activation products in the components and the patient’s body. The results of an experimental study and a Monte-Carlo simulation for the radioactivity induced in a treatment room under a uniform scanning mode were presented in this study. They indicated that the multi-leaf collimator (MLC) and the patient’s body were the main sources of induced radioactivity. The half-lives of the main produced radionuclides ranged from a few minutes to tens of minutes for single irradiation and from dozens of days to hundreds of days for long-term irradiation. The personal dose of medical staff working in the treatment room and the additional dose of the patient from the induced radioactivity were estimated. Finally, some suggestions were made to reduce the unwanted radiation exposure of the medical staff, patients, and carers.