Optimization of matrix inverse tomosynthesis

Digital tomosynthesis is a method for reconstructing arbitrary planes in an object from a series of projection radiographs, acquired with limited angle tube movement. Conventional 'shift and add' tomosynthesis suffers from the presence of blurring artifacts, created by objects located outside of each reconstructed plane. Matrix inversion tomosynthesis (MITS) uses known geometry, and a set of coupled linear algebra equations to solve for the blurring function in each reconstructed plane, enabling removal of the unwanted out-of-plane blur artifacts. For this paper, both MITS and conventional tomosynthesis reconstructions were generated for a simulated impulse located at varying distance from the detector, and also an anthropomorphic chest phantom. Exploration of the effects of total angular tube movement, number of projection radiographs acquired, and number of planes reconstructed via matrix inversion tomosynthesis, on residual out-of-plane blur ensued. We conclude that optimization of image acquisition and plane reconstruction parameters can improve slice image quality. In all examined scenarios, the MITS algorithm outperforms conventional tomosynthesis in removing out-of-plane blur.