PROBLEM TO BE SOLVED: To provide an X-ray CT scanner that correctly indicates a scanning region even if a subject changes in thickness.SOLUTION: In the X-ray CT scanner that comprises the top to carry a subject on, an X-ray tube for irradiating X-ray to the subject, and an X-ray detector disposed facing the X-ray tube and comprising a plurality of X-ray detection elements arranged in a plurality of rows, the scanner includes a collimator provided between the X-ray tube and the detection elements and obstructing the X-ray at least partially, a collimator driving means to move the collimator in the direction of the rows, a floodlight to irradiate the laser beam to the subject and indicate an X-ray irradiation range to the subject, and a means to change the laser beam irradiation angle so that the laser light irradiated to the subject may become nearly parallel with the X-ray having transmitted the end of the collimator.COPYRIGHT: (C)2011,JPO&INPIT【課題】被検体の厚みが変化した場合であっても正しくスキャン領域を示すことが可能なX線CT装置を提供する。【解決手段】被検体を載置可能な天板と、X線を前記被検体へ照射するX線管と、前記X線管に対して対向配置され、列方向に沿って複数列に並べて配置されたX線検出素子からなるX線検出器とを備えるX線CT装置において、前記X線管と前記検出器との間に設けられ、前記X線の少なくとも一部を遮るコリメータと、前記コリメータを列方向に沿って移動させるコリメータ駆動手段と、前記X線の照射範囲を示すレーザ光を前記被検体へ照射する投光器と、前記被検体へ照射されるレーザ光が前記コリメータの端部を透過したX線と略平行になるよう、前記レーザ光の照射角度を変化させる照射角度変更手段とを有することを特徴とする。【選択図】 図3
