关键词: 代数重建法（ART）, 图像重建, 投影系数, Siddon算法

Abstract: Algebraic Reconstruction Technique (ART) is an important image reconstruction algorithm in CT, which is fit for reconstruction from incomplete projection data. The disadvantage of ART is that the reconstructing is time-consuming, in which the projection coefficient computation takes up over 90% of the reconstruction time. A fast algorithm for projection coefficient computation is presented in this paper, which can determine the grid index and calculate the length of the grid intercepted by the ray only requiring a simple incremental algorithm. The result shows that our algorithm is very effective and we can get a reconstruction speedup of over 6 times compared with the Siddon algorithm.

Key words: algebraic reconstruction technique (ART), image reconstruction, projection coefficient, Siddon algorithm