Research on the Relationship between Projection Number and Image Noise Level in FBP Reconstruction

Abstract

The number of projection affects the reconstruction quality in computed tomography system. Larger projection number will lead to better reconstruction quality. On the other hand, less projection number can reduce the radiation dose, save time and keep the patients comfortable. The optimal number of projection compromises both the mathematical accuracy and practical requirement. The purpose of this paper is to find the relationship between the projection number and the noise properties of reconstructed cross-section. It can provide references for researchers on CT application. A micro-CT system is utilized to validate the relationship between projection number and reconstruction quality in fan beam geometry. Full-scan and short-scan method are applied to reconstruct the specimen. Compared with full-scan method, short-scan can reduce radiation dose with the same step angle, and it can achieve better results with the same projection number when the sample data is sufficient.