Abstract: An apparatus for thermal treatment of the human body, using electromagnetic waves (200 to 2500 Mc/s) and radiometric receivers for monitoring and possibly controlling the temperature reached by the living tissues. A generator at ultra high frequency delivers a power of about one Watt into a coaxial cable terminated by a probe emitting electromagnetic waves in the organ to be heated by dielectric losses in the medium. A multichannel receiver, switched at intervals, analyzes the radiation reemitted by the living tissues through the probe, then utilized as a receiving antenna. The temperature reached in a region surrounding the probe is deduced therefrom and can be utilized for controlling the power emitted through a servocontrol system.