Research Of Image Optimization For Digital Breast Tomosynthesis

Digital breast tomosynthesis (DBT) has strong promise to improve sensitivity for detecting breast cancer. DBT reconstruction estimates the breast tissue attenuation using projection views (PVs) acquired in a limited angular range. Because of the limited field of view (FOV) of the detector, the PVs may not completely cover the breast in the x-ray source motion direction at large projection angles. The voxels in the imaged volume cannot be updated when they are outside the FOV, thus causing a discontinuity in intensity across the FOV boundaries in the reconstructed slices, which we refer to as the truncated projection artifact (TPA).Most existing TPA reduction methods were developed for the filtered backprojection method in the context of computed tomography. In this study, we developed two methods to reduce TPAs. One method uses image processing technique after reconstruction. Another method, which we refer to as optimized simultaneous algebraic reconstruction technique (SART), reduce TPAs during DBT reconstruction using SART. The effectiveness of the new methods was evaluated by comparing the visual quality of the reconstructed slices of simulated data, phantom case and DBT patient case with and without artifact correction. The results demonstrated that the proposed methods reduced the TPA while preserving the detailed tissue structures. The visibility of breast obscured by the TPA was improved after artifact reduction. In comparison, optimized SART showed more stability.