Microwave Ablation Applicator with Sensing Capabilities for Thermal Treatment of Malignant Tissue

Recent developments on microwave ablation aim to provide a curative intervention instead of being applied as palliative care. For this purpose, information about the temperature development and coagulation status of the targeted tissue during the treatment is needed. This approach is pursued with an advanced ablation applicator that detects relative permittivity changes by applying a one port calibration scheme. Dielectric properties are extracted at the tip of the applicator with air and two NaCl solutions as calibration standards. Measurements with liquid phantoms mimicking the dielectric contrast of tumor and normal tissue exhibit a relative resolution of $\Delta\varepsilon_{r}=3.4\ \%$. Moreover, the ablation performance is evaluated by ablating ex-vivo bovine liver tissue with an input power of 10 W for four minutes. Temperature probes are placed in varied radial distances to monitor the temperature distribution of the ablation zone resulting in a lesion zone of around 2 cm3.