Substance Concentration Analysis Methods and Apparatuses

Abstract

A substance concentration analysis method includes calculating a difference for the particular time between a first measured amount of mid-infrared (MIR) radiation absorbed by or emitted from a body in a first wavelength and a second measured amount of MIR radiation absorbed by or emitted from the body in a second wavelength, calculating a quotient including a dividend based on the difference divided by a divisor based on a dT/dt value, and calculating the concentration of the substance in the body based on a correlation with the quotient.

What is claimed is: 
     
         1 . A substance concentration analysis method comprises:
 calculating a dT/dt value for a particular time for a temperature derivative with respect to time (dT/dt) of a function for a measured surface temperature (T) of a body that varies with time (t);   calculating a difference for the particular time between a first measured amount of mid-infrared (MIR) radiation absorbed by or emitted from a body in a first wavelength and a second measured amount of MIR radiation absorbed by or emitted from the body in a second wavelength;   calculating a quotient including a dividend based on the difference divided by a divisor based on the dT/dt value; and   calculating the concentration of the substance in the body based on a correlation with the quotient and outputting the concentration to a user.   
     
     
         2 . The method of  claim 1 , wherein the quotient is correlated with glucose concentration. 
     
     
         3 . The method of  claim 1 , wherein the divisor is a value of a function of dT/dt (f(dT/dt)) that yields a fraction of the substance concentration between 0 and 1 that emits or absorbs photons when taken out of Boltzmann equilibrium at the dT/dt value. 
     
     
         4 . The method of  claim 1 , wherein the calculation of the quotient comprising calculating a slope value for a series of (x,y) values in which x values are the divisor and y values are the dividend measured over time while the surface exhibits the dT/dt. 
     
     
         5 . The method of  claim 1 , further including:
 measuring the first measured amount of MIR radiation absorbed by or emitted from the body in the first wavelength at the particular time;   measuring the second measured amount of MIR radiation absorbed by or emitted from the body in the second wavelength at the particular time; and   measuring the measured surface temperature at the particular time.   
     
     
         6 . The method of  claim 5 , wherein the substance has an effect on MIR emission or absorption in the first wavelength and has no or negligible effect on MIR emission or absorption in the second wavelength. 
     
     
         7 . The method of  claim 6 , wherein measuring the first measured amount, the second measured amount, and the measured surface temperature occur during a positive dT/dt (an upward sloping temperature change). 
     
     
         8 . The method of  claim 7 , further comprising:
 normalizing the first measured amount and the second measured amount to black body calibration;   measuring an ambient temperature at the particular time; and   correcting the quotient for ambient temperature effects on a measurement apparatus for the ambient temperature.   
     
     
         9 . The method of  claim 1 , wherein calculating the dT/dt value for the particular time comprises:
 measuring the measured surface temperature at each of a plurality of different times including the particular time;   curve-fitting the corresponding plurality of measured surface temperatures to obtain the function for temperature (T) of the surface of the body that varies with time (t), including the particular time;   differentiating the function for temperature (T) to obtain the temperature derivative with respect to time (dT/dt); and   calculating the dT/dt value by evaluating the dT/dt for the particular time.   
     
     
         10 . The method of  claim 1 , further comprising generating a correlation of the substance concentration with the quotient by:
 for each of a plurality of different times, calculating the dT/dt value and calculating the difference;   statistically smoothing the plurality of differences for the corresponding plurality of dT/dt values to correct the plurality of differences;   providing a function of dT/dt (f(dT/dt)) that yields a fraction of the substance concentration between 0 and 1 that emits or absorbs photons when taken out of Boltzmann equilibrium;   for each of the plurality of different times, calculating a f(dT/dt) value by evaluating the f(dT/dt) for the respective dT/dt value and calculating the quotient with the corresponding f(dT/dt) value as the divisor; and   correlating the concentration of the substance in the body with the plurality of quotients.   
     
     
         11 . A substance concentration analysis method comprising:
 inducing a change in a temperature (T) of a surface of a body over time (t) by heating or cooling with an element according to a signal received by the element, then allowing temperature recovery of the surface and yielding a function for temperature (T) that varies with time (t) during the temperature recovery so as to exhibit a temperature derivative with respect to time (dT/dt);   measuring the temperature (T) of the surface of the body over time (t) during the temperature recovery and calculating the dT/dt;   measuring mid-infrared (MIR) radiation absorbed by or emitted from the body during the temperature recovery while the surface of the body exhibits the dT/dt;   calculating a measured value based on the MIR radiation measurement and on the dT/dt; and   calculating the concentration of the substance in the body based on a correlation with the measured value.   
     
     
         12 . The method of  claim 11 , further comprising calculating a dT/dt value for the time the MIR radiation is measured. 
     
     
         13 . The method of  claim 11 , wherein the allowing temperature recovery of the surface occurs without the heating or cooling of the element. 
     
     
         14 . The method of  claim 11 , wherein the measured value is correlated with glucose concentration. 
     
     
         15 . The method of  claim 11 , wherein measuring MIR radiation comprises:
 measuring MIR radiation during a positive dT/dt (an upward sloping temperature change), the measuring occurring within a first wavelength band in which the substance has an effect on MIR emission; and   measuring reference MIR radiation at the temperature during the positive dT/dt, the measuring occurring within a second wavelength band in which the substance has no or negligible effect on MIR emission.   
     
     
         16 . A substance concentration analysis apparatus comprises:
 a housing;   at least one MIR detector attached to the housing;   a ring-shaped heating and/or cooling element attached to the housing;   a controller configured to control the MIR detector and the ring-shaped heating and/or cooling element; and   a transmission window structure in direct thermal communication with the ring-shaped heating and/or cooling element and attached to the housing such that a line of sight of the MIR detector passes through the transmission window structure.   
     
     
         17 . The apparatus of  claim 16 , wherein the transmission window structure exhibits a thermal conductivity greater than 1,000 Watts/meter-Kelvin 
     
     
         18 . The apparatus of  claim 16 , further comprising a wireless transmitter, the apparatus being configured to send a warning output to a remote device via the wireless transmitter to display a warning, the remote device including a mobile telephone and the warning output indicating that the remote device is to contact an emergency service.