Microwave ablation of soft tissues using a triaxial antenna

Microwave ablation is one of several minimally invasive technologies being explored for cancer treatment. Microwave energy offers several theoretical advantages over other ablation technologies, including faster generation of heat, higher generated temperatures, markedly reduced influence of charring or desiccation on system performance, the ability to more precisely treat larger volumes of tissue, and 100% duty, simultaneous multiple-applicator operation. In order to realize these advantages, energy must be efficiently coupled into the tissue without causing undue heating of peripheral tissues. Ideally, the antennas must be safe for percutaneous use in the abdomen or thoracic cavity (i.e., less than ∼1.7 mm in diameter). In this work, I present the design and application of a triaxial antenna system for percutaneous microwave ablation.; Chapter 1 provides and introduction to the relatively new field of minimally invasive cancer treatments, including chemical, ultrasound, laser, radiofrequency and microwave ablation. The fundamentals of microwave ablation, including microwave heating, biological tissue properties and practical considerations will be discussed. The chapter ends with a review of the microwave ablation device literature.; Chapter 2 is a detailed discussion of the numerical and experimental aspects of the design, validation and use of the triaxial antenna for microwave ablation. Preliminary results in ex vivo liver tissue are given.; Chapter 3 outlines the numerical and experimental application of a single triaxial antenna in ex vivo bovine liver. The impact of antenna diameter, input power and application time and schedule on ablation zone size are presented.; Chapter 4 is a presentation of experiments in an in vivo porcine model with a single triaxial antenna. The effects of perfusion and application time on the zone of ablation are described.; Chapter 5 covers the application of multiple antennas in an in vivo porcine model. Large zones of ablation are created in the same application time as a single-antenna and the effects of perfusion become less marked when multiple antennas are used.