摘要:
Devices and methods for non-invasively measuring at least one parameter of a sample, such as the presence or concentration of an analyte, in a body part wherein the temperature is controlled. The present invention measures light that is reflected, scattered, absorbed, or emitted by the sample from an average sampling depth, dav, that is confined within a temperature controlled region in the tissue. This average sampling depth is preferably less than 2 mm, and more preferably less than 1 mm. Confining the sampling depth into the tissue is achieved by appropriate selection of the separation between the source and the detector and the illumination wavelengths. In another aspect, the invention involves a method and apparatus for non-invasively measuring at least one parameter of a body part with temperature stepping. In another aspect, the invention involves a method and apparatus for non-invasively measuring at least one parameter of a body part with temperature modulation. In another aspect, the invention provides an improved method of measuring at least one parameter of a tissue sample comprising the steps of: (a) lowering the temperature of said tissue sample to a temperature that is lower than the normal physiological temperature of the body; and (b) determining at least one optical property of said tissue sample.
摘要:
A method and apparatus for measuring the concentration of an analyte of interest, e.g. glucose, in blood non-invasively, i.e., without penetrating the skin or obtaining a biological sample from the body of a patient. The method and apparatus uses a plurality of measurement channels with appropriate wavelengths of interest to control variations of signal and to separate the contribution of the analyte of interest from those of interfering compounds. The method and apparatus of this invention can also be adapted to allow a portion of a body part to be engorged with blood to bring about greater accuracy in optical measurements. In the method of this invention, at least two similar, but not identical, measurements are made concurrently. For example, at least two measurements can be made with similar, but not identical, wavelengths of electromagnetic radiation. The two wavelengths should not be overlapping to allow maximum non-identity. By making measurements concurrently, each measurement channel in the system experiences variations as they occur substantially simultaneously in all channels. By selecting one of the channels as a reference channel and by normalizing the optical measurements of the other channels to this reference channel, the variations common to all channels are eliminated. Removing these common variations from the optical measurements by normalization, such as by calculating ratios of the measurement of each of the measuring channels to that of the reference channel, will allow the actual changes of the signal for a specific analyte of interest to be measured.