Filtered back-projection reconstruction technique for coherent-scatter computer tomography

Abstract

For the first time, a reconstruction technique based on filtered back-projection (FBP) using curved 3D back-projection lines is applied to 2D coherent-scatter computed tomography (CSCT) projection data. It has been demonstrated, that CSCT yields information about the molecular structure of an object. So far, the acquired projection data are reconstructed with the help of algebraic reconstruction techniques. Due to the computational complexity of iterative reconstruction, these methods lead to relatively long reconstruction times. In this contribution, a reconstruction algorithm based on 3D FBP is introduced and tested with simulated projection data as well as with projection data acquired with a demonstrator setup similar to a multi-line CT scanner geometry. Within a fraction of computation time at least a comparable image quality is achieved when using FBP reconstruction. In addition, it has the advantage, that - in contrast to iterative reconstruction schemes - sub-field-of-view reconstruction becomes feasible. This allows a selective reconstruction of the scatter function for a region of interest. The method is based on a row by row high-pass filtering of the scatter data, with or without fan to parallel beam rebinning. The 3D back-projection is performed along curved lines through a volume defined by the in-plane spatial coordinates and the wave-vector transfer.