Radiofrequency (RF) employs electrical energy similar to that used in conventional operating room cauterization units. A RITA radiofrequency procedure employs an ablation probe which contains deployable electrodes that are placed directly into the target tissue. The RF current passed through the probe causes ionic agitation in the nearby tissue. This rapid vibration of the ions creates friction and therefore heat. This heat is first created immediately around the electrodes, then gradually is conducted into surrounding tissue in a predictable pattern, ultimately destroying the target area.

Continuous Monitoring
Thermocouples incorporated into the tips of the electrodes allow continuous monitoring of tissue temperatures, preventing both insufficient and excessive heating. The temperature monitoring ability also permits post-ablation confirmation of tissue temperatures as well as temperature guided ablation of the needle track. Ultrasound is also typically used to monitor the ablation process.

Using Heat to Ablate Cells
Heat is a very effective means of killing tissue. As tissue temperature rises above 113° F (50° C), protein is permanently damaged and cell membranes fuse. The process is rapid, requiring 10-15 minutes exposure time. As tissue is heated, dissolved gases (primarily nitrogen) are released from cells, forming micro-bubbles within the tissue. This is visible on ultrasound as a hyperechoic image providing additional information about the ablated area.

Heat decreases rapidly at a specific distance from the electrode tip as equilibrium is reached. The size of the ablated area is determined largely by the size of the probe, the temperature of the tissue, and the duration of time the energy is applied. There is a sharp boundary between dead tissue and unaffected surrounding tissue. Thus unwanted tissue can be ablated without much sacrifice of surrounding normal tissue.