Development of a new type proton irradiation system built in a rotating gantry

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The object of this study is to propose a new type of an irradiation system for the proton cancer therapy. This system is developed to make good use of the rotating gantry system which is suitable to select various rotating angles of axis of opposing pair field. This study has main two subjects to improve the present state of the art of the proton cancer therapy to make it use for any person who will hope it.The fist is to develop a more compact, smaller, simpler and cheaper system to make the intensity distribution of a typical beam extracted from an accelerator as a penciliform beam with narrow Bragg-peak modify to uniformly irradiate the extended width of the target volume to the highest dose. As a result of this research, we proposed a new energy filter which plays both roles of a scattering system for transverse spreading of proton beam and of a bar ridge filter for modulating the range of the Bragg curve.The second is to develop a simple irradiation method to improve the conformity of the highest dose region of 3-D dose distribution of the proton beam to the target region. As a result, it was clearly shown that it is important to make positively use of non-uniformity of a transverse profile and of an axial profile within a spread of Bragg-peak of a 3-D dose distribution.