Abstract: A microwave radiometric sensor probe module configured to fit within at least an external portion of an auditory or ear canal of a patient encloses a microwave integrated circuit and associated waveguide printed probe. The probe is configured to receive microwave radiation from a dielectric rod antenna of the module oriented into the auditory canal towards a tympanic membrane. Radiation from the tympanic membrane is coupled into the rod antenna, projected towards the printed probe, and received at the integrated circuit. A communications interface connects the integrated circuit to a temperature monitor and control unit for receiving the sensor output and for deriving at least a measure of patient brain temperature from the sensor output. The temperature monitor and control unit may be connected to a targeted temperature management system for controlling the temperature of a patient on the basis of the derived brain temperature.