A new approach to reconstructing images in fan-beam computed tomography

The hybrid algorithm developed previously for image reconstruction in fan-beam computed tomography (CT) can have more desirable noise properties and computational efficiency in comparison with the fan-beam filtered backprojection (FFBP) algorithm. However, the one-dimensional (1D) explicit interpolation along the radial direction involved in the previous hybrid algorithm can lead to a reduced resolution in the reconstructed image. In this work, we proposed a new hybrid algorithm that eliminates such an explicit 1D interpolation by performing the filtration directly in the data space. We used computer simulation studies to evaluate the relative performance of the new hybrid algorithm, the previous hybrid algorithm, and the FFBP algorithm. The results of these studies demonstrated that these reconstruction algorithms respond to the effects of data noise and aliasing differently, and that the image noise properties also are dependent on the fan-beam configurations. For fan-beam configurations with small focal lengths and large size of the field of view which can be used in micro-CT, the new hybrid algorithm appears to provide a good tradeoff between image resolution and image noise uniformity.