Method for measuring concentration of substance in blood

• Main Author: Yamakawa, Koichi
• Format: Patent
• Language: English
• Published: 16.08.2022
• Subjects: BASIC ELECTRIC ELEMENTS; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; DEVICES USING STIMULATED EMISSION; DIAGNOSIS; ELECTRICITY; FREQUENCY-CHANGING; HUMAN NECESSITIES; HYGIENE; IDENTIFICATION; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MEDICAL OR VETERINARY SCIENCE; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; SURGERY; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; TESTING

The concentration of substance in blood is measured non-invasively, with high accuracy and with simple configuration. Laser light generated by a light source is locally irradiated on the body epithelium of a subject, and the resulting diffused reflected light is detected by a light detector. The laser light has a wavelength of 9.26 μm. The laser light is generated by converting and amplifying pulsed excitation light from an excitation light source to a long wavelength. A plate-shaped window that is transparent to mid-infrared light is brought in close contact with the body epithelium. The glucose concentration in interstitial fluid can be calculated using normalized light intensity calculated from a signal ratio of signals from a monitoring light detector and the light detector.