Determining ablation zones using microwave transmission measurement

In this paper, a measurement method is presented that determines the propagation of the heat front that is generated during microwave ablation (MWA) for monitoring purposes. A measurement setup is implemented that emulates an MWA scenario and consists of a microwave emitter in the ISM band at 2.45 GHz via a slot applicator. These microwaves are transmitted through a phantom body with two different materials, Triton X-100 70% and Triton X-100 30%, representing warm and cold tissue of liver. The transmitted wave is received via a bowtie dip antenna. The transmitted power is 10 dBm. The radial extent of the hot zone is changed from 5 mm up to 20 mm in 5 mm steps using a sliding device on top of the phantom body. The changes in time delay between the emitted and received wave are detected. From these values, the propagation zone of the heat front is determined mathematically using the time difference of arrival method (TDOA).