@misc{oai:repo.qst.go.jp:00072422,
 author = {Saotome, Naoya and Furukawa, Takuji and Saraya, Yuichi and Mizushima, Kota and Hara, Yousuke and Tansho, Ryohei and Shirai, Toshiyuki and Noda, Koji and 早乙女 直也 and 古川 卓司 and 皿谷 有一 and 水島 康太 and 原 洋介 and 丹正 亮平 and 白井 敏之 and 野田 耕司},
 month = {Jul},
 note = {Purpose: At the National Institute of Radiological Sciences (NIRS), we have been commissioning the rotating- gantry system for the carbon-ion radiotherapy in 2015. It is world’s first rotating-gantry with super-conducting magnet and achieved a more compact, lighter rotating gantry than the typical gantry. During the commissioning of the rotating gantry, we adjusted the beam position using a steel sphere located at isocenter and verified the accuracy using a scintillation screen and CCD system. We employ the digital QA system to verify the geometrical accuracy easily and quickly.
\nMethods: The 300 ton rotating gantry can deliver carbon ions having 430 MeV/u to the isocenter over 360 degrees, having the capability of performing three-dimensional scanning irradiation. the mechanical isocenter was verified using the laser tracker system. To verify the coincidence of the isocenter for irradiation system and the patient positioning system, we used a steel sphere located at isocenter. As a part of the verifying of the treatment beam position, scintillation screen viewed by a CCD camera mounted on the gantry downstream of the sphere. Total 201energy carbon beams with that were in the range from 48 to 430 MeV/u were measured sequentially. A starshot test was also performed to verify the gantry angle and beam direction visually using a scintillator block and a CCD camera. For the starshot test, 13 beam energy were selected. 
\nResults: From the result of the test using a sphere, the maximum displacement of the beam position was within 0.5mm at all gantry angles. The gantry starshot shows accuracy of the gantry angle was less than 0.5 degree. 
\nConclusion: The isocentricity of the compact super-conducting rotating gantry for carbon ion therapy dedicated to the highly precise treatment were within 1mm. Two of digital measurement system brought high-efficient beam adjusting and commissioning., 59th AnnualMeeting of American association of Physicists in Medicine (AAPM2017)},
 title = {Isocenter Verification of a Compact Rotating Gantry for Carbon Ion Therapy},
 year = {2017}
}