Design of the submillimeter-pencil beam transport system for carbon ion microsurgery therapy

Kashiwagi, Hirotsugu; Oikawa, Masakazu*; Shimada, Hirofumi*; Yuri, Yosuke; Agematsu, Takashi; Ishii, Yasuyuki; Saito, Yuichi; Sakai, Takuro; Okumura, Susumu; Kurashima, Satoshi; Sato, Takahiro; Yokota, Wataru; Kamiya, Tomihiro; Yusa, Ken*; Fukuda, Mitsuhiro; Nakano, Takashi*; Arakawa, Kazuo

The areas of age-related macular degeneration, tumor in brain pituitary and vascular lesions such as AVM (Arterio Venous Malformation) to be treated are 11 mm, 3030 mm and 33 mm respectively. To treat these by heavy ion beam instead of surgical operation, not only the spatial resolution of the beam should be 100 micrometer to 1 mm, but also the formation of it be pencil-shaped, so that the diameter of beam hardly depends on the depth of it in the target. The pencil beam transport system was studied and designed for carbon microsurgery therapy, as a part of the 21st century COE program. In this study, one of the vertical beam lines of a heavy ion therapy facility to be constructed in Gunma University was a model for beam optics calculations. The parameters of the magnetic components such as bending magnets and quadrupole ones, were optimized to obtain a sub-millimeter beam on the target. The range shifter is inserted in the beam line to form spread out bragg peak. Effect of inserting range shifters were also estimated, especially for growth of beam emittance by scattering in the further calculation. The total layout of this system and the beam optics simulations are explained in detail in the poster session.