PROBLEM TO BE SOLVED: To provide a particle beam treatment apparatus that can acquire an X-ray image having good quality with a simple configuration and requires short treatment time, an operation method therefor, and a movable plate.SOLUTION: A particle beam treatment apparatus 10 comprises: a particle beam irradiation machine 16 for emitting a particle beam B； a rotary gantry 21 that supports the particle beam irradiation machine 16； a movable bed that is constituted by a plurality of movable plates 37 in a rotary gantry 21's revolving direction and forms a horizontal part below a top plate 18 on which a body to be irradiated is placed； an X-ray generator 27a for generating an X-ray； and an X-ray detector 27b for detecting the X-ray arriving through the movable bed. At least one of the movable plates 37 comprises: a first bed member for transmitting the X-ray so that the X-ray can be detected by the X-ray detector 27b； and a second bed member having an X-ray transmission factor smaller than that of the first bed member. The first bed member and the second bed member are made of the same material and a first bed member's thickness is thinner than a second bed member's thickness.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2020,JPO&INPIT【課題】簡素な構成で良質なＸ線画像を取得できるとともに治療時間の短い粒子線治療装置、その運転方法、及び移動板を提供する。【解決手段】粒子線治療装置１０は、粒子線Ｂを出射する粒子線照射機１６と、粒子線照射機１６を支持する回転ガントリ２１と、回転ガントリ２１の周回方向に沿って複数枚の移動板３７で構成され、被照射体を載置する天板１８の下方では水平部を形成する移動床と、Ｘ線を発生するＸ線発生器２７ａと、移動床を介して到達するＸ線を検出するＸ線検出器２７ｂと、を備え、移動板３７の少なくとも１枚は、Ｘ線をＸ線検出器２７ｂで検出可能に透過する第１床部材と、第１床部材よりＸ線透過率の小さい第２床部材と、を備え、第１床部材と第２床部材とは同一の材質であり、第１床部材の厚さは第２床部材の厚さより薄い。【選択図】 図３
