Microwave technology for image-guided thermal ablation

Thermal ablation treatments are gaining an increasing interest in the clinics thanks to their reduced invasiveness and their capability of treating non-surgical patients. They exploit local heating to induce coagulative necrosis of tumour cells. In particular, in microwave thermal ablation, which has recently progressed in the clinical practice, the heating source is represented by an electromagnetic field at microwaves frequencies. However, effectiveness of thermal ablation treatments and their impact in the hospital’s routine would significantly increase if paired with a monitoring technique able to control the evolution of the treated area in real-time. This is particularly relevant in microwave thermal ablation, given its capability of treating large tumours in a short time. Since currently adopted monitoring techniques suffer from several limitations, microwave tomography has been recently proposed as an alternative modality, based on the significant, temperature-dependent, changes that occurs to the dielectric properties of tissues during thermal ablation. In addition, microwave tomography is appealing as it exploits low-cost devices and components, thus being economically sustainable. This chapter explores the potential of microwave tomography to address this open clinical issue. First, the main features of microwave ablation procedure and the basic aspects of microwave tomography are recalled. Then, the results of an experimental proof-of-concept validation on ex vivo bovine liver sample, which confirms the capability of microwave tomography to image the transition between ablated and untreated tissue, are reported