@misc{oai:repo.qst.go.jp:00071747,
 author = {Mizushima, Kota and Iwata, Yoshiyuki and Furukawa, Takuji and Satou, Shinji and Shirai, Toshiyuki and Noda, Koji and 水島 康太 and 岩田 佳之 and 古川 卓司 and 佐藤 眞二 and 白井 敏之 and 野田 耕司},
 month = {Sep},
 note = {Purpose: In scanned carbon-ion therapy, the narrow beam is required to reduce extra dose to healthy tissue around the target tumor. Since the energy absorbers increase the beam size by the multiple scattering, the accelerator system must output therapy beams with various energies to perform irradiation without using them. In addition, it is also required that the beam properties, such as position, size and spill, are reliable for all energies to ensure irradiation accuracy.
Methods: At the Heavy Ion Medical Accelerator in Chiba (HIMAC), multiple-energy operation has been developed to produce the carbon-ion beams with different energies of more than 200 steps between 56 and 430 MeV/u in a single cycle of the synchrotron. By using this operation, the accelerator system can change the output beam energy quickly. We carried out the experiments to verify that the output beams would meet therapy requirements.
Results: The beam properties were measured in the treatment room. The beam spot position and size were stable, and the fluctuations of them were small for all experimental conditions. The beam intensity could be controlled as required from the irradiation control system. The ripple of the beam spill was low in the wide intensity range between 107 and 109 particles per second (pps).
Conclusions: We confirmed that the accelerator system can provide the beams meeting the therapy requirements for all available energies. We will report the experimental results of our system in our presentation., The 7th Korea-Japan Joint Meeting on Medical Physics},
 title = {Upgrade of synchrotron operation for scanned carbon-ion therapy at NIRS-HIMAC},
 year = {2014}
}