PROBLEM TO BE SOLVED: To provide a radiotherapy system which enhances the accuracy in coincidence of a position of a virtual isocenter in a z-axis direction with respect to a position of a body surface marker of a patient immediately before imaging and a position of an isocenter of an X-ray CT apparatus in the z-axis direction, to reduce the number of times of re-imaging due to non-coincidence of each position and reduce the unnecessary exposure to the patient.SOLUTION: A radiotherapy system 1 includes: a radiotherapy apparatus 50 which performs a radio therapy a bed 31 on which a subject can be placed and an X-ray CT apparatus 20 which stores an X-ray tube 21 and an X-ray detector 23 and is provided with a frame G which can be moved forward and backward in a z-axis direction. Guides Ua, Ub are provided on a side face of the frame G, the guides Ua, Ub each including a reference mark for aligning with visible lights Na, Nb as reference lights irradiated from outside the frame G.COPYRIGHT: (C)2014,JPO&INPIT【課題】放射線治療システムにおいて、撮像直前における患者の体表マーカと、X線CT装置のアイソセンタのz軸方向の位置とに対する、仮想アイソセンタのz軸方向の位置の一致の精度を向上させ、各位置の不一致に伴う撮像のやり直しを削減させて患者の不要被曝を低減すること。【解決手段】放射線治療を行なう放射線治療装置50と、被検体を載置可能な寝台31と、X線管21及びX線検出器23を収容しz軸方向に前進及び後退可能な架台Gを備えるX線CT装置20と、を設ける放射線治療システム1において、架台Gの側面に、架台Gの外側から照射される基準光としての可視光Na,Nbとの位置を合わせるための基準マークをそれぞれ含むガイドUa,Ubを有する。【選択図】 図2
