FOURIER-BASED FORWARD AND BACK-PROJECTORS IN ITERATIVE FAN-BEAM TOMOGRAPHIC IMAGE RECONSTRUCTION

Fourier-based forward and back-projection methods have the potential to reduce computation demands in iterative to-mographic image reconstruction. Interpolation errors are a limitation of conventional Fourier-based projectors. Re-cently, the min-max optimized Kaiser-Bessel interpolation within the nonuniform Fast Fourier transform (NUFFT) ap-proach has been applied in parallel-beam image reconstruc-tion, whose results show lower approximation errors than conventional interpolation methods. However, the exten-sion of min-max NUFFT approach to fan-beam data has not been investigated. We have extended the min-max NUFFT framework to the fan-beam tomography case, using the rela-tionship between the fan-beam projections and correspond-ing projections in parallel-beam geometry. Our studies show that the fan-beam Fourier-based forward and back-projection methods can significantly reduce the computation time while still providing comparable accuracy as their space-based coun-terparts. 1