Liquid Phantom For Calibrating Tissue Oxygen Saturation Measurement

In recent years, the prevalence of peripheral arterial disease (PAD) has increased. This disease is related to arterial occlusion in the heart and brain. Many researches mentioned, measurement of muscle tissue oxygen saturation by near-infrared spectroscopy (NIRS) has a different phenomenon for normal people and patients. In order to quantify the muscle oxygen saturation measured by near-infrared spectroscopy. In this research, we use a in-house made multi-wavelength and two light-detector distances to measure the liquid phantom with adjustable oxygen saturation. LED polarizer wavelength is 740 nm, 808 nm and 850 nm. Two light-detector distances are 32 mm and 40 mm. Liquid phantom using purified red blood cell from pig blood and intralipid to mix the blood cell solution. The liquid phantom simulated lower limbs muscles optical properties. Use yeast and oxygen to change oxygen saturation in the liquid phantom and continuous measurement at the same time. Measurement result show, absorbance at 740 nm and 850 nm will change with oxygen saturation, but absorbance at 808 nm will not. In the other side, between two light-detector distances the trend of change is small. This result is consistent with the absorption spectrum of hemoglobin to calculate a calibration curve for muscle oxygen saturation quantification in a in-house made machine. In the future, it will be embedded in the signal of clinical measurement to help PAD patient's classification. This classification will become one of the indicators for doctor diagnosis.