A Portable Photoacoustic System for Noninvasive Continuous Personal Heat Strain Monitoring

A portable device for noninvasive and continuous tracking of human core temperature has sparked intense interest among researchers and the industry. A novel photoacoustic-based portable device with a wearable frame for continuous, noninvasive measuring the deep blood core temperature measurement is presented in this work. The development of the temperature detection module, i.e., laser and ultrasound transducer, and the integrated processing unit are detailed. In-vivo animal experiments and human trials both validate the system’s functionality and accuracy. Experiments on small animals show the feasibility of this system in locating the target vessels ($5-10 \mathrm{~mm}$) and noninvasively extracting the core temperature value. The Bland-Altman analysis of the field trials data suggests a good measurement agreement (95% accuracy within a deviation of $0.5^{\circ} \mathrm{C}$) with the tympanic reference results.