Contrast Source Inversion Enhanced Confocal Imaging for Highly Heterogeneous Breast Media in Microwave Mammography

This study introduces accuracy-enhanced confocal imaging (CI) algorithm for highly heterogeneous breast media that can be used in microwave mammography. In the presence of heterogeneous backgrounds, such as breast media, CI accuracy highly depends on several background assumptions, such as homogeneity, multilayered structure, and adipose-dominant tissue. In the case of a highly dense breast dominated by fibroglandular tissue, the traditional CI suffers from inaccuracy due to a large discrepancy between the actual and assumed backgrounds. In this study, we used contrast source inversion (CSI) known as a promising inverse scattering approach, which could provide an accurate estimation of total fields in the region of interest. This feature enables us to generate accurate propagation models as the Green's functions. The numerical tests using realistic breast phantoms show that our method significantly enhances reconstruction accuracy without any prior knowledge of the background media, thus highly contributing to cancer tissue detection.