Boundary Extraction Enhanced Distorted Born Iterative Method for Microwave Mammography

This letter focuses on improving the accuracy of the distorted Born iterative method (DBIM)-based inverse scattering algorithm, using accurate boundary extraction in microwave mammography. It is well known that the accuracy of inverse scattering algorithms depends on the initial estimate of the region of interest (ROI). The Envelope algorithm is one of the promising algorithms for accurate ROI estimation. However, in the near-field breast imaging scenario, the coupling effect between an antenna and the breast surface incurs a nonnegligible error for Envelope-based boundary extraction, which is mainly caused by the mismatching between the reference and measured waveforms. To address this problem, this letter introduces the finite-difference time-domain-based waveform reconstruction for improving the accuracy of DBIM-based microwave imaging. The two-dimensional numerical simulations, using realistic breast phantoms derived from magnetic resonance images, demonstrate that our proposed algorithm remarkably enhances the accuracy of the DBIM, even in highly heterogeneous cases.