SELF-EMISSION NONINVASIVE INFRARED SPECTROPHOTOMETER WITH TEMPERATURE COMPENSATION

摘要

This invention is a method and apparatus for monitoring glucose, ethyl alcohol, and other blood constituents in a noninvasive manner. Long wavelength infrared energy emitted by the person as heat is monitored and the infrared absorption of particular constituents in the blood is measured (114) at characteristic infrared absorption wavelengths (110) for those constituents. The measurements are preferably synchronized (124) with systole and diastole of the cardiac cycle so that the signal contribution caused by veins and tissues may be cancelled when a ratio of the detected signals is taken. If no synchronization is provided, the spectrophotometer may measure the arterial, venous, and tissue constituent concentrations simultaneously. The internal "blackbody" energy level of an infrared emissions source such as a vascularized appendage is measured (300) and used to compensate temperature dependent effects in the concentration calculation. The internal energy level ratio is ratioed to the actual measured energy.