부산대학교 도서관

A two-dimensional (2D) beam imaging system with a fluorescent intensifying screen and highspeedcharge-coupled device (CCD) camera was developed to observe the fluctuations of the beamposition and size. This system can perform imaging of the beam spot and the calculation of bothits position and size from the obtained image with a cycle-time of 20 ms. For quality assurance ofscanned carbon-ion therapy, we measured the stability of the unscanned-beam position and size byusing this system at the isocenter in a treatment room. We confirmed that the fluctuation rangesof its position and size were less than the tolerance for scanning irradiation.