TDOA Prior-Based Contrast Source Inversion for Microwave Ablation Zone Quantitative Imaging

This study presents an efficient quantitative microwave imaging method for ablation zones in microwave breast cancer treatment. To maintain an accurate estimate of complex permittivity changes during the ablation process, we integrate the time-of-difference-of-arrival-based ablation boundary prior into the contrast source inversion (CSI)-based nonlinear inverse scattering framework. This incorporation mitigates the ill-posed problem of the original CSI scheme by restricting the region of interest (ROI) using the time-difference-of-arrival (TDOA) prior. Specifically, by focusing on the characteristics of the CSI cost function, our approach simultaneously determines an appropriate ablation boundary and the temporal decrease of complex permittivity, which is closely correlated with the temperature change of the ablated tissue. The effectiveness of our proposed scheme is validated using the 2-D finite-difference time-domain method with realistic breast phantoms, demonstrating accurate dielectric profile reconstruction.