Microwave Imaging Algorithm Based on Waveform Reconstruction for Microwave Ablation Treatment

Microwave ablation (MWA), intended for treating malignant tissues, must be monitored in real time for effective treatment and patient safety. In this article, we propose an imaging algorithm that corrects for errors that typically arise at the boundary of an ablation image when the tissue's dielectric properties are a little affected by ablation. Conventional imaging algorithms exploit the difference in the propagation time of signals through nonablated and ablated tissues in order to monitor the dimensions of an ablation in real time, but this time difference does not account for the drop in conductivity that occurs as the tissue dries out, causing nonnegligible errors, particular in lower ablation impact case. In order to address this problem, the method that we propose incorporates waveform reconstruction in accounting for the change in conductivity. We test this method with 2-D and 3-D numerical simulations of microwave signals propagating in two computational phantoms of breast tissue with different densities. Simulations with differently affected tissues show that the proposed method improves upon the accuracy of conventional MWA monitoring techniques, with an acceptable increase in the computation time.