PROBLEM TO BE SOLVED: To solve the following problem: quantitative property of images deteriorates since a condition needed for reconstruction cannot be satisfied in an incomplete measurement area wherein only the X-ray of some angles in rotation measurement are measured in the heretofore known image reconstruction of an X-ray CT apparatus, and there is the possibility of image quality deterioration since the calculation of projection data and the correction of the image are performed including pixels whose quantitative property has deteriorated when the image is used as it is as the initial value of an iterative reconstruction method.SOLUTION: Regarding the X-ray CT apparatus, an area to protrude to the incomplete measurement area in normal photographing is used as an object, the area is moved to a complete measurement area before/after the normal photographing and then photographed. Then, by using a CT image photographed for correction and replacing the incomplete measurement area or a part of complete measurement area in the CT image in normal photographing, the quantitative property of the image is improved. Thus, since the image is successively corrected without incurring he deterioration in the quantitative property, the CT image of high image quality is acquired.COPYRIGHT: (C)2011,JPO&INPIT【課題】 X線CT装置の公知である画像再構成において,回転計測における一部の角度のX線しか計測されない不完全な計測領域では,再構成に必要な条件を満足できない為,画像の定量性が低下する課題がある。このまま前記画像を逐次近似再構成手法の初期値として用いると,定量性の低下した画素を含めて投影データの計算および画像の修正を行う為,画質低下の可能性がある。【解決手段】 本発明はX線CT装置に関し,通常撮影では不完全な計測領域にはみ出す領域を対象として,通常撮影の前/後に完全な計測領域へ移動後,撮影する。次に,補正用に撮影したCT画像を用いて,通常撮影時のCT画像における不完全な計測領域または一部の完全な計測領域を置換することにより,画像の定量性を向上させる。これにより,定量性の低下を伴わず,逐次的に画像の修正を行うため,高画質なCT画像を取得できる。【選択図】 図4
