Abstract:
The Feldkamp-Davis-Kress (FDK) algorithm has the advantages of a simple structure, fast calculation speed, and high reconstruction quality, and it remains the mainstream algorithm for cone-beam computed tomography (CBCT) analytical reconstruction. However, if the cone angle for the reconstructed point is too large, the reconstruction exhibits artifacts characterized by an axial density drop. Numerous methods for suppressing this artifact have been proposed, including projection weighting, cone-beam rebinning, and introducing compensation terms. The compensation method has high computational efficiency and achieves good artifact suppression when the cone angle is not more than 16°. However, for cases with larger cone angles, the effectiveness of this algorithm is diminished. Thus, further optimization of the reconstruction algorithms and scanning geometry is required to accommodate industrial and clinical demands. Based on the two compensation terms for FDK reconstruction, this study extends cone-beam CT geometrically to the case of dual source in the z-direction distribution, further suppressing cone-beam artifacts by reducing the average cone angle of the reconstructed points. A cone-angle weighting method is proposed for dual-source reconstruction, to fuse the reconstructed results of the two sources and obtain the final reconstructed image. The simulation results show that the proposed algorithm can improve the quality of the reconstructed image more effectively than single-source case.