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Designing image reconstruction algorithms for Digital Breast Tomosynthesis (DBT) has attracted much attention in recent years as the modality is increasingly employed for mammographic screening. While much recent research on this has focused on iterative image reconstruction, there may still be fundamental aspects of DBT image quality that can be addressed and improved with analytic filtered back-projection (FBP). In particular, we have been investigating conspicuity of fiber-like signals that can model blood vessels, ligaments, or spiculations. The latter structures can indicate a malignant tumor. It is known that the visual appearance of fiber-like signals varies with fiber orientation in the DBT slice images, and recently we have sought to quantify this orientation dependence with simulations involving phantoms with fibers placed at various angles with respect to the direction of the X-ray source travel (DXST). Employing FBP with a standard Hanning filter results in a marked decrease in conspicuity of fibers aligned nearly parallel with the DXST. Employing DBT-specific FBP filters proposed in the literature recovers conspicuity of such fibers. In this work, we propose a different modification to the FBP filter where the standard Hanning filter is combined with the same filter – but rotated 90° – forming a 2D filter. We illustrate the potential advantages of this new FBP filter design for DBT image reconstruction.
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