also called RFA. Treatment that uses high-energy radio waves to heat and destroy abnormal tissues. In cancer treatment, a thin, needle-like probe is guided into the tumor by ultrasound or computed tomography (CT) scan. A high-frequency current is then passed through the probe, which heats and kills nearby cells. RFA is sometimes used to treat certain types of tumors in the liver, lung, kidney, and other organs. See also computed tomography scan, ultrasound.