Pseudo-Square Tomosynthesis Trajectory for Interventional Lung Procedures

Digital tomosynthesis (DTS) is a 3-D imaging technique with limited depth resolution and can be used to guide a catheter during interventional lung procedures. DTS uses projection data acquired over a limited angular range to create tomographic slices with high in-plane resolution. This limited angular acquisition results in out-of-plane artifacts in the reconstructed volume. This work focused on improving the image quality of the tomosynthesis volume for lung imaging by selecting an acquisition trajectory that increases depth resolution, provides a 2-D blur response, and simplifies analytical reconstruction. We proposed a new pseudo-square acquisition geometry for DTS and performed the quantitative and qualitative comparison with arc (pseudo-linear) and circle acquisition geometries. We reconstructed DTS volumes for various angular ranges and numbers of projections for arc, circle, and pseudo-square trajectories using filtered back-projection and compared them with reference computed tomography (CT) scan using Pearson correlation coefficient (PCC). Based on simulations, we showed that pseudo-square acquisition resulted in better image quality than inbounded arc and inbounded circle geometries. It provided on average 5.5% and 26% higher PCC with reference CT than circle and arc DTS, respectively.