PROBLEM TO BE SOLVED: To provide an apparatus for displaying volume data seen from a direction vertical to a dental arch from a photographing condition without a need for complicated designation work or the like.SOLUTION: An X-ray CT photographing apparatus comprises: an X-ray irradiation unit 110 an X-ray detection unit 120 for performing output according to incident X rays a turning arm 3 which moves a pair of the X-ray irradiation unit 110 and the X-ray detection unit 120 around a subject O, with the X-ray irradiation unit 110 and the X-ray detection unit 120 opposed to each other across the subject O storage means 22 which stores, as frame data with data indicating the position of photographing specified, the electric signals output by the detection part 120 while the turning arm 3 moves the X-ray irradiation part 110 and the X-ray detection part 120 around the subject O image reconstruction means 24 which reconstructs the frame data stored in the storage means 22 to obtain a CT image and turning angle calculation means which calculates an angle between a midline direction and a looking-straight direction of a region of interest to determine a turning angle of the turning arm 3 at which photographing is started in the looking-straight direction of the region of interest. The image reconstruction means 24 starts image reconstruction from the frame data for which photographing was started.COPYRIGHT: (C)2014,JPO&INPIT【課題】 撮影条件から歯列弓から見たボリュームデータを複雑な指定作業等を必要とせずに表示させる装置を提供する。【解決手段】 X線照射部110と、入射するX線に応じて出力するX線検出部120と、X線照射部110とX線検出部120の対を、被検者Oを挟んで互いに対向させた状態で被検者の周りを移動させる旋回アーム3と、旋回アーム3がX線照射部110及びX線検出部120を被検者Oの周りを移動させることに伴って検出部120が出力する電気信号をフレームデータとしてどの位置で撮像したデータかを関係づけて記憶する記憶手段22と、記憶手段22に記憶されたフレームデータを画像再構成演算してCT画像を得る画像再構成手段22と、関心領域の正視方向と正中方向との間の角度を算出し、関心領域の正視方向から撮影開始するために旋回アーム3の旋回角度を算出する旋回角度算出手段を備え、画像再構成手段24は、撮影が開始されたフレームデータから画像再構成を開始する。【選択図】 図25
