Abstract: Improving the calculation speed of simulation projection has been the important research of CT(computed tomography) simulation technique. Aiming at the projection calculation of pixel phantom, a fast algorithm of generating simulation projection was proposed. Firstly,the original pixel index and its vertical distance intersected by the ray and the pixel phantom boundary were determined. Then, the other pixel index and intersection length intersected by the ray were calculated in turn using the distance, the projection data was obtained from cumulative sum simultaneously. Experimental result shows that the proposed algorithm can improve the calculation speed of projection greatly, we can get a speedup about 7 times compared with the Siddon algorithm. The reconstructed result also shows the proposed algorithm is correct.

Key words: Simulation proj ection, Image reconstruction, Siddon algorithm, Pixel phantom