Iterative scatter correction for digital tomosynthesis using composition ratio update and GPU based Monte Carlo simulation

In digital tomosynthesis (DTS), accurate scatter correction is often necessary for quantitative analysis. This is especially important because low energy x-ray of 10-40 keV, which is widely used for the breast imaging to enhance the contrast between adipose and glandular, results in high scatter fraction. In this paper, we propose an iterative scatter correction for digital tomopsynthesis using composition ratio update and GPU based Monte Carlo simulation (MCS). One of the technical difficulty in scatter estimation using MCS for tomosynthesis is that accurate segmentation of 3D volume is very difficult due to the low resolution of the reconstruction object. Thus, an intermediate surrogate object is introduced to represent composition ratio between adipose and glandular. We show that the composition ratio can be calculated using average attenuation coefficients. Another technical challenge is extremely high computational cost of MCS. We overcome this using GPU based ultra-fast MCS. Our results demonstrate that our iterative scatter correction using composition ratio update is indeed effective in improving the quality of the reconstruction object in a reasonable time frame.