Development of a Hybrid Microwave-Optical Thermoregulation Monitor for the Muscle
This paper presents the latest development of the hybrid microwave-optical thermoregulation monitor for the muscle. It is capable of warming the muscle and measuring the subsequent blood volume changes, using a novel microwave applicator with integrated optical probes. The challenge is to measure the thermoregulation response in deep tissue while minimizing any effect from the skin layer. We have introduced a skin cooling device, an additional integrated optical Laser Doppler flow monitoring probe and a temperature sensor to measure skin blood flow and temperature, respectively. The result shows that skin cooling is essential to minimize skin flow changes during microwave warming. The hybrid probe was placed on a human thigh to measure oxy/deoxy/total haemoglobin concentration changes (ΔHbO2/ΔHHb/ΔHbT), skin flux and temperature upon microwave warming. Without skin cooling, the skin temperature was elevated by 4 °C and both ΔHbO2/ΔHbT and skin flux increased, showing microwave warming occurring in both the skin and muscle. With skin cooling, the skin temperature was kept relatively constant. While ΔHbO2/ΔHbT increased, the skin flux was relatively stable, showing a preferential microwave warming in the muscle, rather than the skin.
KeywordsNear infrared spectroscopy Thermoregulation Microwave applicator Muscle Laser Doppler flowmetry
This work was partly funded by EPSRC (Grant Code EP/G005036/1). We would also like to thank Sonny Gunadi and Nick Everdell for building the NIRS monitor.
- 6.Gebuhr P, Jorgensen JP, Vollmer-Larsen B et al (1989) Estimation of amputation level with a laser Doppler flowmeter. J Bone Joint Surg 71-B(3):514–517Google Scholar