Development of a Noninvasive Blood Perfusion Probe

Abstract

Abstract Development of a noninvasive biomedical probe for tissue blood perfusion measurements is described. Simultaneous measurements of the local temperature and heat flux during a thermal cooling event at the surface of the skin is used to determine blood perfusion in the underlying tissue. The probe incorporates a combination heat flux and temperature sensor, which is placed in contact with the tissue and cooled by jets of room temperature air. For safety reasons no electric power or heating is applied to the probe; its low level signals are generated by the small temperature difference produced by air cooling. The small, light-weight probe can be taped to the skin, much like a surface electrode, for repeated measurements. A combination of analytical and experimental results are reported to describe the measurement system. The effect of thermal contact resistance between the probe and tissue is included in the model. Experimental results indicate good heat flux sensitivity and measurement repeatability. Comparison of analytical heat flux predictions and experimental measurements is good. Although not yet fully tested, this non-invasive technique has promise of providing quantitative blood perfusion measurements.