倒置结构断层CT的重建算法

与传统的Ｘ线透射成像相比，倒置式Ｘ线透射成像结构有着投影数据信噪比高的优点，可提高透射图像的密度分辨率．提出了倒置结构断层计算机层析成像术（Ｃｏｍ ｐｕｔｅｄ Ｔｏｍ ｏｇｒａｐｈｙ，ＣＴ）的概念，针对平行束和扇形束投影两种情形，给出了倒置结构断层ＣＴ的完全重建条件及重建算法，并就仿真模型进行了计算机模拟．结果表明，倒置结构断层ＣＴ在极大地减少康普顿散射对成像质量影响的同时，仍然获得了比较好的重建结果．

Reconstruction Algorithm of the Reverse Geometry Based on 2DCT

Com pared w ith the conventionalconfiguration of X radiography system , reverse geom etry X radiography im aging m ay obtain X ray projections w ith high SNR, contrast and sensitivity due to the m inim alscatter detection. This paper first borrowed the concept ofreverse geom etry and extended it to 2DCT. Then itderived the fully reconstruction condition and the relevantreconstruction algorithm in view of parallel beam projection and fan beam projection. Finally, the perform ance of the algorithm w as evaluated using m athem atic phantom . Itis concluded that 2DCTwith reverse geom etry not only reduces Com poton scatter's influence to the im aging quality butalso obtains a betterreconstructed result.