Geometrical Improvement of a Noninvasive Core Temperature Thermometer based on Numeric Modeling and Experiment Validation.

This paper describes the improvement of a transcutaneous core temperature thermometer by modifying the configuration, in terms of height and radius, of the thermometer using the so-called dual-heat-flux (DHF) method. The motivation of these modifications is to decrease the volume of the thermometer so as to reduce the transverse heat flow inside, in other words, to preserve the underlying assumption of the DHF method that heat flows from the inner part of human body through skin onto the thermometer longitudinally. The modificationâ s effect is evaluated by both numeric modeling based on finite element method and experiment. The results of simulations and experiments show that a lower-in-height and larger-in-radius configuration will improve the accuracy of the thermometer. Prototypes of 22.0 mm radius can attain satisfactory accuracy with error less than 0.5 ï °C when heights are 8.0 mm or less.