Method for non-invasive analysis of a substance concentration within a body

Abstract

Embodiments of the present methods measure a concentration of a substance, such as glucose, in a body. The described embodiments change the temperature of the surface of a body from a first temperature to a second temperature, then change the temperature of the surface of the body from the second temperature back to the first temperature, and measure a first amount of infrared (“IR”) radiation absorbed or emitted from the surface of the body in a first wavelength band, and a second amount of IR radiation absorbed or emitted from the surface of the body in a second wavelength band at predetermined time intervals during the time period that the temperature of the surface of the body changes from the second temperature back to the first temperature. The described embodiments also measure a temperature at the surface of the body and an ambient temperature. A normalized ratio parameter is calculated from the four measurements, and the concentration of the substance in the body is determined by correlating the normalized ration parameter with the body surface temperature and the ambient temperature.

1 . A method for non-invasive measurement of a concentration of a substance in a body, comprising the steps of:
 changing a temperature of a surface of a body from a first temperature to a second temperature;   changing the temperature of the surface of the body from the second temperature to the first temperature;   measuring a first amount of infrared radiation absorbed or emitted from a body in a first wavelength band at predetermined time intervals during the change of the surface of the body from the second temperature to the first temperature;   measuring a second amount of infrared radiation absorbed or emitted from a body in a second wavelength band at predetermined time intervals during the change of the surface of the body from the second temperature to the first temperature;   measuring a temperature at the surface of the body;   measuring an ambient temperature;   calculating a normalized ratio parameter based on the first amount, the second amount, the body surface temperature and the ambient temperature; and   determining the concentration of the substance in the body by correlating the normalized ratio parameter with the body surface temperature and the ambient temperature.   
     
     
         2 . The method of  claim 1 , wherein the first wavelength band is a wavelength band or bands in which the substance emits and absorbs infrared radiation, and the second wavelength band is the entire spectrum in which the body emits and absorbs infrared radiation in the far infrared spectrum. 
     
     
         3 . The method of  claim 1 , wherein the first wavelength band is a wavelength band or bands in which the substance emits and absorbs infrared radiation, and the second wavelength band is the entire spectrum in which the substance has no or negligible emission and absorption of infrared radiation. 
     
     
         4 . The method of  claim 1 , wherein the normalized ratio parameter is the average ratio selected from the group consisting of at least one of the ratio of the first amount normalized against a black body to the second amount normalized against a black body at each time interval, and a logarithm of the ratio of the first amount normalized against a black body to the second amount normalized against a black body at each time interval. 
     
     
         5 . The method of  claim 1 , wherein the substance is glucose. 
     
     
         6 . The method of  claim 1 , wherein the body is a human body. 
     
     
         7 . The method of  claim 1 , wherein the concentration of the substance in the body is determined using an empirically deprived lookup table. 
     
     
         8 . The method of  claim 1  wherein the first wavelength range comprises about 8.5μ to about 10.0μ and the second wavelength range comprises about 10.5μ to about 15.0μ. 
     
     
         9 . The method of  claim 8  wherein the second wavelength range comprises about 7.0μ to about 15.0μ. 
     
     
         10 . The method of  claim 1  wherein the step of changing the temperature of the surface of the body from the second temperature to the first temperature is at a predetermined rate. 
     
     
         11 . A method of noninvasively measuring a concentration of a substance in a body using an apparatus including a detector and an optical system, the method comprising the steps of:
 changing a temperature of a surface of a body from a first temperature to a second temperature;   changing the temperature of the surface of the body from the second temperature to the first temperature;   detecting an infrared radiation value emitted by the body in a wavelength band including at least one wavelength characteristic of the substance at predetermined time intervals during the change of the surface of the body from the second temperature to the first temperature; and   detecting an infrared radiation value emitted by the body in a wavelength band including at least one wavelength characteristic of the substance at predetermined time intervals during the change of the surface of the body from the second temperature to the first temperature.   
     
     
         12 . The method of  claim 11 , further comprising the step of measuring the ambient temperature. 
     
     
         13 . The method of  claim 12 , further comprising the step of measuring the temperature of the body. 
     
     
         14 . The method of  claim 11 , furthering comprising the step of limiting the wavelength band of the detected infrared radiation value. 
     
     
         15 . The method of  claim 14 , further comprising the step of limiting the wavelength range of the detected infrared radiation value to a first wavelength band including at least one wavelength characteristic of the substance to provide a first detected radiation value, and limiting the wavelength range of the detected infrared radiation value to a second wavelength band wherein wavelengths characteristic of the substance are minimized to provide a second detected radiation value. 
     
     
         16 . The method of  claim 15 , wherein the first wavelength band comprises about 8.5μ to about 10.0μ and the second wavelength band comprises about 10.5μ to about 15.0μ. 
     
     
         17 . The method of  claim 16  wherein the second wavelength range comprises about 7.0μ to about 15.0μ. 
     
     
         18 . The method of  claim 11  wherein the step of changing the temperature of the surface of the body from the second temperature to the first temperature is at a predetermined rate.