In medicine, ablation is defined as the “surgical removal of body tissue,” usually through the direct application of
chemical or thermal therapies. Microwave ablation applies the same heat-conversion process used in a microwave
oven (see Technology Brief 3), but instead of using microwave energy to cook food, it is used to destroy cancerous
tumors by exposing them to a focused beam of microwaves. The technique can be used percutaneously (through
the skin), laparoscopically (via an incision), or intra-operatively (open surgical access). Guided by an imaging
system, such as a CT scanner or an ultrasound imager, the surgeon can localize the tumor and then insert a thin
coaxial transmission line (∼ 1.5 mm in diameter) directly through the body to position the tip of the transmission line
(a probe-like antenna) inside the tumor (Fig. TF4-1). The transmission line is connected to a generator capable of
delivering 60 W of power at 915 MHz (Fig. TF4-2).
The rise in temperature of the tumor is related to the amount of microwave energy it receives, which is equal to the
product of the generator’s power level and the duration of the ablation treatment. Microwave ablation is a promising
new technique for the treatment of liver, lung, and adrenal tumors.