针对ART(algebraic reconstruction technique)算法重建速度慢的问题，提出了一种射束与像素的快速遍历和求交算法。该算法通过一个距离参数来确定射束穿过的像素索引并计算出射束覆盖像素的面积，距离参数采用增量计算，因而运算效率很高。利用该算法在图像重建过程中实时计算权因子，不但节省了大量的内存空间，而且大大提高了图像重建的速度。实验结果表明，提出的算法非常有效，与传统方法相比取得了17倍以上的重建加速比。

To solve the problem of slow reconstruction speed of algebraic reconstruction technique, this paper presents a fast traversal and intersection algorithm of ray beam-pixels. The algorithm determines the pixel index traversed by ray beam and calculates area overlapped by the ray beam through a distance parameter. The distance parameter can be calculated with an incremental method, thus the operation is of high efficiency. Applying this algorithm to calculate the weight coefficients on real-time during the process of reconstruction, not only large amount of memory is saved, but also the speed of image reconstruction is improved greatly. The experimental result shows that the algorithm is very effective and the reconstruction speed is improved about 17 times compared with the conventional method.