[Evaluation of daily quality assurance for proton therapy at National Cancer Center Hospital East.].

It is very important for proton therapy to make and carry out a quality assurance (QA) program. Operators and medical personnel have to avoid any trouble during treatment and provide patients with high quality and reliable treatment. A proton therapy machine consists of an accelerator, gantry and various beam modifying devices. Although QA for proton therapy is complicated and difficult, we tried to realize daily QA for proton therapy. Two main purposes in daily QA are stable operation of the accelerator and reliable control of the irradiation system. In order to determine the daily QA issues, past problems were considered. We made a daily QA program and used it for one year. In this paper, we show the daily QA program and report our results. The daily QA was clearly effective for stable operation of the accelerator and for controlling quality of the irradiation system.