Joint System and Algorithm Design for Computationally Efficient Fan Beam Coded Aperture X-ray Coherent Scatter Imaging

TL;DR

This paper presents a joint system and algorithm design for fan beam coded aperture X-ray scatter imaging, significantly reducing computational time while maintaining accurate reconstructions using symmetry-based optimizations.

Contribution

It introduces a novel joint design approach that leverages physical symmetries to accelerate forward and backward model computations in X-ray scatter tomography.

Findings

Achieved 146x speedup in forward model computation

Achieved 32x speedup in backward model computation

Validated models and algorithms on simulated data

Abstract

In x-ray coherent scatter tomography, tomographic measurements of the forward scatter distribution are used to infer scatter densities within a volume. A radiopaque 2D pattern placed between the object and the detector array enables the disambiguation between different scatter events. The use of a fan beam source illumination to speed up data acquisition relative to a pencil beam presents computational challenges. To facilitate the use of iterative algorithms based on a penalized Poisson log-likelihood function, efficient computational implementation of the forward and backward models are needed. Our proposed implementation exploits physical symmetries and structural properties of the system and suggests a joint system-algorithm design, where the system design choices are influenced by computational considerations, and in turn lead to reduced reconstruction time. Computational-time speedups of approximately 146 and 32 are achieved in the computation of the forward and backward models, respectively. Results validating the forward model and reconstruction algorithm are presented on simulated analytic and Monte Carlo data.