PROBLEM TO BE SOLVED: To enable the correction of a high-precision scattering according to the size of a specimen or the like.SOLUTION: An X-ray tube and an X-ray detector are arranged facing each other sandwiching the specimen to reconstruct a CT image from a projection data obtained by scanning the subject. The X-ray CT system is provided with a means for determining the transmission length of X rays transmitted from the projection data, a means which determines the angle of scattering of scattered rays entering respective X-ray detection surfaces from the transmission length previously determined and the positional relationship with the X-ray detector, a means which determines differentiated sectional areas of the respective scattered rays from information by which the relationship is previously regulated between the angle of scattering determined and the differentiated sectional areas of scattering according to the angle of scattering, a means which determines a scattering coefficient indicating the ratio of the intensity of the scattered rays with respect to the intensity of the X rays transmitted from the differentiated sectional areas determined and a means which carries out the correction of scattering in the projection data from the intensities of X rays detected on the respective X-ray detection surfaces and the scattering coefficients determined corresponding to the respective X rays transmitted.COPYRIGHT: (C)2008,JPO&INPIT【目的】 被検体サイズ等に応じてより精度の高い散乱補正を行えることを課題とする。【構成】 被検体を挟んで相対向するX線管及びX線検出器を備え、被検体をスキャンした投影データに基づきCT断層像を再構成するX線CT装置において、投影データに基づき透過X線の透過長を求める手段と、前記求めた透過長とX線検出器との位置関係に基づき各X線検出面に入射する散乱線の散乱角を求める手段と、前記求めた散乱角により予め散乱角と散乱の微分断面積の関係を規定した情報に基づき各散乱線の微分断面積を求める手段と、前記求めた微分断面積に基づき透過X線強度に対する散乱線強度の割合を表す散乱係数を求める手段と、各X線検出面で検出されたX線強度と、各透過X線に対応して求められた散乱係数とに基づき投影データの散乱補正を行う手段とを備える。【選択図】 図9
