Implementation of Katsevich algorithm for helical cone-beam computed tomography using CORDIC

Katsevich algorithm is the first exact cone-beam reconstruction algorithm for helical cone-beam computed tomography (CT) reconstruction. The commonly used Feldkamp-Davis-Kress (FDK) reconstruction algorithm is an approximate algorithm. The Katsevich algorithm is of filtered backprojection (FBP) type and is an exact algorithm. Although the acceleration of Katsevich algorithm on CPU or GPU have been widely studied, the FPGA implementation is yet to be explored. In this paper, a parallel and pipeline architecture for Katsevich algorithm has been implemented in Xilinx Virtex 4 FPGA. COordinate Rotation DIgital Computer (CORDIC) algorithm has been used to compute complex mathematical and trigonometric functions. We have also analyzed the effect of various windowing techniques for implementation of Hilbert transform on the reconstruction of the CT image. The architecture is able to reconstruct a CT volume image of size 256³ in 7s.