Research And Implement Of Cone-beam CT Reconstruction Based On PI-line Method

In this paper, we would follow the development of most famous reconstruction algorithms with emphasis on the Cone-beam CT reconstruction which broadly used by most CT producer, especially the newly proposed PI-line method.FDK algorithm is a novel 3-D reconstruction method. Due to the simplicity in implement, the FDK method has become the most classical method of cone-beam CT reconstruction. However, FDK method doesn't fit all the situation for it is a approximate reconstruction algorithm. It would fit the requirement of the practicality only when the cone angle is very small (4 rows or 8 rows to the detector).If the cone angle increased, there would be badly artifact. A lot of improvements have been proposed to solve this problem; however they can be classified into two kinds. The first is trying to improve the FDK method which results in the P-FDK, T-FDK, HT-FDK, and S-FDK. In this paper we have also proposed a new way to deal with the artifacts problem with the help of 3D weighted function. It has been proved by the experimental evaluation and verification that this method could reduce artifacts as well as improve the quality of the reconstruction image.The second way to reduce the artifact is seeking for exact reconstruction algorithm. Our proposed reconstruction algorithm gets rid of restriction of scanning track, and is able to exactly get the result just by using the data on the PI-arc. The implication of the proposed approach and algorithm appears to be significant in that they can naturally address the long object problem as well as the super-short scan problem, and most importantly, in that they provide the opportunity to reconstruction images within any selected region of interest from minimum data, allowing the use of detector with a reduced size, the selection of a minimum number of rotation angles and thus the reduction of radiation dose delivered to the normal organ.