Abstract
Microwave energy is a unique electromagnetic (EM) energy source for tissue ablation due to optimum size match between EM wavelength and ablation equipment for use in human tissue. This results in the ability to broadcast EM waves at MW frequency from the antenna, as opposed to conducting alternating current from active to dispersive electrode as in radiofrequency ablation (RFA). The EM field surrounding the MW antenna establishes the MW near-field, and the clinically utilized MW frequencies are optimal to effect dielectric heating of biologic tissue within the near-field allowing for intense tissue heating with shortened ablation times as well as a more defined minimum ablation size. Conventional heat transfer still plays a significant role in final ablation size; however, to a lesser extent than seen with RFA. The shape of the MW near-field and the deposition of MW energy into tissue can be modulated by altering the MW antenna design to minimize reflected energy due to impedance mismatch. Given these potential physical advantages over RFA, microwave ablation is becoming increasingly utilized for hepatic and other soft tissue ablation.
