Feasible Cone Beam Scanning Methods for Exact 3-D Tomographic Image Reconstruction

Considerable efforts have been made for visualizing 3-D structures of human organs by x-ray tomography. From the view point of the data collection time, the cone beam method with a circular source motion is promising for this purpose. However, the exact 3-D image reconstruction from the cone beam projections is a troublesome and time-consuming problem, because the solution cannot be decomposed into 2-D transaxial slices. For this difficulty, approximate reconstruction algorithms are proposed and practically used in many application areas [1,2]. Unfortunately, these algorithms suffer from the degradation of reconstructed images when the cone angle is large.