Evaluation of Photon-Counting Spectral Breast Tomosynthesis

iii The superposition of anatomical structures often greatly impedes detectability in conventional mammography. Spectral imaging and tomosynthesis are two promising methods used for suppres-sion 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