Ultra-fast hierarchical backprojection for Micro-CT reconstruction

This paper introduces a new version of a fast and accurate O(N³logN) reconstruction algorithm for cone-beam CT with a circular source trajectory. This is the first report on the performance of this algorithm with high-resolution large-matrix Micro-CT data. We determined that a software implementation of the FHBP algorithm on off-the-shelf workstations can provide speedups by an order of magnitude or more in Micro-CT reconstruction with no perceptible loss of image quality as compared to state-of-the-art commercial software implementations of conventional reconstruction. This is especially important for Micro-CT reconstructions, where maximum image size can be as large as 8 Ktimes8 K pixels per slice and reconstruction of such image volumes can span days. Owing to its algorithmic acceleration, the FHBP-based code achieves the performance of a cluster of computers on a single PC, and could provide even faster reconstruction rates if running on the entire cluster.