Microwave ablation: principles and applications.

Microwave ablation is the most recent development in the field of tumor ablation. The technique allows for flexible approaches to treatment, including percutaneous, laparoscopic, and open surgical access. With imaging guidance, the tumor is localized, and a thin (14.5-gauge) microwave antenna is placed directly into the tumor. A microwave generator emits an electromagnetic wave through the exposed, noninsulated portion of the antenna. Electromagnetic microwaves agitate water molecules in the surrounding tissue, producing friction and heat, thus inducing cellular death via coagulation necrosis. The main advantages of microwave technology, when compared with existing thermoablative technologies, include consistently higher intratumoral temperatures, larger tumor ablation volumes, faster ablation times, and an improved convection profile. Microwave ablation has promising potential in the treatment of primary and secondary liver disease, primary and secondary lung malignancies, renal and adrenal tumors, and bone metastases. The technology is still in its infancy, and future developments and clinical implementation will help improve the care of patients with cancer. Copyright RSNA, 2005.