Development state of multifrequency microwave radiometer system for noninvasive measurement of infant´s deep brain temperatures

Hypothermia is proposed as a treatment for hypoxia-ischemia in newborn infants who suffer serious cerebral injury or die, if they are brought back early. In this treatment the deep brain temperature monitoring which is noninvasive and continuous is required. Multifrequency microwave radiometry (MWR) is one of the promising candidates for that purpose, and we have been developing a five-band microwave radiometer system and appropriate data processing methods. This paper is to describe the current status of a newly designed MWR system which operates in a normal room with various electromagnetic background noise. Temperature resolutions of the five receivers were obtained by a calibration experiment using a temperature-controlled water-bath. The results of a temperature retrieval simulation experiment is also presented.