Dottorato in TECNOLOGIE DELL'INFORMAZIONE E DELLE COMUNICAZIONI (ICT)

Titolo della tesi: Dielectric spectroscopy in Microwave thermal ablation applications

Microwave thermal ablation (MTA) is an electromagnetic-based therapy for local treatment of malignant tissue at microwave frequencies. MTA treatments are mostly performed in liver tissue, but the application is spreading also in the lung. At present, real-time monitoring options for the technique are very limited and its success is assessed only post-treatment with very expensive and health-compromising equipment such as computed tomography and magnetic resonance imaging. Therefore, recent research was devoted to the development of real-time in-situ techniques for real time monitoring of MTA procedures. In this respect, the most eligible piece of equipment for this role is the MTA applicator itself. In this study, a dielectric spectroscopy technique applicable to different types of MTA antenna was developed and stressed out in different simulated measurement setups and tissues to identify the possibilities and main challenges of the technique. Following typical procedures in MTA designs, the technique was developed and analyzed focusing on MTA treatments of liver tumors. However, it was proved in lung tissue also. Given that lung tissue is poorly characterized in the literature, an extensive campaign to measure and interpret dielectric properties of the lung was performed also. Finally, to overcome observed limitations in the proposed spectroscopy technique, an algorithm for data purification was invented. The numerical studies are backed up with physical measurements in liver and lung tissue using a prototype of one of the antennas developed for the study.