Detection of the acupuncture points in skin by differential path-length spectroscopy

Abstract

An optical fiber-based diagnostic system was developed to detect the acupuncture points (Bonghan Corpuscle) with small depth in human skin. A split fiber with 600 micrometer diameter was used in contact with the skin to deliver and detect the light to yield backscattered signal, which took information from both small and deep layers. The effect of backscattered signal from deep layer of skin was removed by another single fiber with the same diameter as the split fiber. Both fibers were arranged as close as possible to each other to detect the optical properties of tissue in a very small volume. The optical properties of the acupuncture point and its surrounding tissue in the skin were measured separately in the visible wavelength range (400–700nm), and significant difference was found between them. To control the consistency and reproduction of the experimental conditions of the fiber on the skin, a precise pressure sensor was employed.