Truncation Robust C-Arm CT Reconstruction for Dynamic Collimation Acquisition Schemes

Abstract

Volume-of-interest (VOI) C-arm computed tomography (CT) imaging is a promising approach to acquire anatomical information in a pre-defined target volume at low dose, using both axial and trans-axial collimation. However, also the region outside the target volume, below referred to as peripheral region (PR), could contain some valuable information for image guidance. The potential use of a fast dynamically changing collimator would allow for new acquisition schemes, that acquire projection data in a way that allows for both a high-quality reconstruction of the diagnostic VOI and a low-quality reconstruction of the peripheral region, still at a low overall dose. In this paper, we present a novel reconstruction algorithm for an acquisition scheme that acquires a large portion of the projections in a collimated manner, while acquiring a small portion of the projections in a non-collimated manner. Experimental results indicate that few non-truncated projections can help to improve the image quality compared to a conventional VOI acquisition, while simultaneously providing valuable information about the peripheral region.