Author Description

Tomosynthesis uses a limited number of low-dose x-ray projections to produce a 3D tomographic reconstruction of the breast. The scatter effect on tomosynthesis image quality was investigated. Monte Carlo simulated scatter point spread functions were convolved over the field of view to estimate the distribution of scatter for tomosynthesis projections. The calculated scatter-to-primary ratio for the average breast is quite high (∼0.4), and increased with increased breast thickness. Scatter results in cupping artifacts and reduced accuracy in reconstructed attenuation values. The effect of scatter on contrast and signal-difference-to-noise ratio (SDNR) was measured as a function of tumor size. For example, for the central slice of a simulated lesion (14 mm dia.), contrast was degraded by 30%, attenuation values were reduced by 28%, and the SDNR was reduced by 60%. Despite this, the contrast and SDNR in the reconstructed tomosynthesis slice is higher than that of conventional mammography acquired at an equivalent total exposure.