In radiofrequency ablation (RFA), heat is generated locally by a high frequency, alternating current that flows from the electrodes. A probe is inserted into the center of the tumor and the non-insulated electrodes, which are shaped like prongs, are projected into the tumor. The local heat that is generated melts the tissue (coagulative necrosis) that is adjacent to the probe. This results in a 3 cm to 5.5 cm sphere of dead tissue per treatment session. The probe is left in place for about 10 to 15 minutes.
Radiofrequency ablation has been used for thermal ablation in bone, liver, kidney, heart, prostate, breast, brain, lymph nodes, nerve ganglia, and soft tissue. Radiofrequency ablation has various clinical applications including treating arrhythmias (abnormal heart rhythms), tumors, osteoid osteoma, and nerve ganglion ablation.
The cells killed by radiofrequency ablation are not removed, but are gradually replaced by fibrosis and scar tissue. Over the coming months, the treated tissue shrinks. If there is local recurrence, it occurs at the edge, and in some cases may be retreated.
Heat has been used in medicine as long as history. Thousands of years ago, Hindu medics used heated metal bars to stop bleeding. Hippocrates said "what is not cured by the knife may be cured by fire." Electrocautery has been used for many decades in surgery to stop bleeding, coagulate blood vessels, and cut tissue. The radiofrequency ablation generator uses a slight modification of this old technology to deposit the energy over a larger tissue volume. Radiofrequency ablation also cauterizes tissue as it heats it, thus limiting blood loss. The needle pathway may also be treated, further reducing the risk of bleeding.