TDOA-based microwave imaging algorithm for real-time monitoring of microwave ablation

Microwave ablation (MWA) is widely recognized as a promising treatment tool for cancer. Real-time monitoring of the dimensions of the ablation zone is indispensable for ensuring an effective and safe treatment. In this paper, we propose a microwave imaging algorithm for monitoring the evolution of the ablation zone. This algorithm estimates the boundary of the ablation zone by exploiting the time difference of arrival (TDOA) between pre- and during-ablation signals received at external antennas surrounding the tissue, using the interstitial ablation antenna as the transmitter. A notable advantage of this method is that it requires few assumptions about the spatial distribution of dielectric properties of the propagation media. Also the simplicity of the signal processing, wherein the TDOA is determined from a cross-correlation calculation, allows real-time monitoring and provides noise-robust estimations. We investigate the performance of this approach using simulated array measurements obtained from FDTD simulations of MRI-derived numerical breast phantoms. The results demonstrate that our proposed method offers the potential to achieve millimeter order accuracy in estimating the boundary of the ablation zone in heterogeneous and dispersive breast tissue.