Evaluation of Photon-Counting Spectral Breast Tomosynthesis

The superposition of anatomical structures often greatly impedes detectability in conventional mammography. Spectral imaging and tomosynthesis are two promising methods used for suppression of the anatomical background. The aim of this thesis is to compare and evaluate the benefits of tomosynthesis and spectral imaging, both in combination and separately. A computer model for signal and noise transfer in tomosynthesis was developed and combined with an existing model for spectral imaging. Measurements were performed to validate the models. An ideal-observer detectability index incorporating anatomical noise was used as a figure of merit to compare the different modalities. For detection of a contrast-enhanced tumor in a breast with high anatomical background, the optimum performance for spectral tomosynthesis was found at a tomo-angle of 10 degrees. The improvement was in the order of a factor 10 compared to non-energy-resolved tomosynthesis with the same angular extent. This was supported by clinical results