@article{oai:repo.qst.go.jp:00044869,
 author = {Torikoshi, Masami and Minohara, Shinichi and Kanematsu, Nobuyuki and Komori, Masataka and Kanazawa, Mitsutaka and Noda, Kouji and Miyahara, Nobuyuki and Ito, Hiroko and Endo, Masahiro and Kanai, Tatsuaki and 取越 正己 and 蓑原 伸一 and 兼松 伸幸 and 小森 雅孝 and 金澤 光隆 and 野田 耕司 and 宮原 信幸 and 伊藤 浩子 and 遠藤 真広 and 金井 達明},
 issue = {Suppl.A},
 journal = {Journal of Radiation Research},
 month = {Mar},
 note = {Clinical trials of carbon radiotherapy started at HIMAC in 1994 using three treatment rooms and four beam ports, two horizontal and two vertical. The broad beam method was adopted to make a three-dimensionally uniform field at an isocenter. A spot beam extracted from an accelerator was laterally spread out by using a pair of wobbler magnets and a scatterer. A bar ridge filter modulated the beam energy to obtain the spread out Bragg peak (SOBP). The SOBP was designed to be flat in terms of the biological dose based on the consideration that the field consisted of various beams with different LET. Finally, the field of 20 cm in diameter with +- 2.5 % uniformity was formed at the isocenter. The width of the maximum SOBP was 15 cm. When treating the lung or liver, organs that move due to breathing, the beam was irradiated only during the expiration period in a respiration-gated irradiation method. This reduced the treatment margin of the moving target. In order to prevent normal tissues adjacent to the target volume from irradiation by an unwanted dose, a layer-stacking method was developed. In this method, thin SOBP layers which have different ranges were piled up step by step from the distal end to the entrance of the target volume. At the same time, a multi-leaf collimator was used to change the aperture shape to match the shape of each layer to the cross-sectional shape of the target. This method has been mainly applied to bone and soft-tissue cancers. Only a few serious problems in the irradiation systems have been encountered since the beginning of the clinical trials. Overall the systems have been working stably and reliably.},
 pages = {A15--A25},
 title = {Irradiation System for HIMAC},
 volume = {48},
 year = {2007}
}