Abstract: Optical coherence tomography (herein “OCT”) based analyte monitoring systems are disclosed. In one aspect, techniques are disclosed that can identify fluid flow in vivo (e.g., blood flow), which can act as a metric for gauging the extent of blood perfusion in tissue. For instance, if OCT is to be used to estimate the level of an analyte (e.g., glucose) in tissue, a measure of the extent of blood flow can potentially indicate the presence of an analyte correlating region, which would be suitable for analyte level estimation with OCT. Another aspect is related to systems and methods for scanning multiple regions. An optical beam is moved across the surface of the tissue in two distinct manners. The first can be a coarse scan, moving the beam to provide distinct scanning positions on the skin. The second can be a fine scan where the beam is applied for more detailed analysis.

Abstract: Optical coherence tomography (herein “OCT”) based analyte monitoring systems are disclosed. In one aspect, techniques are disclosed that can identify fluid flow in vivo (e.g., blood flow), which can act as a metric for gauging the extent of blood perfusion in tissue. For instance, if OCT is to be used to estimate the level of an analyte (e.g., glucose) in tissue, a measure of the extent of blood flow can potentially indicate the presence of an analyte correlating region, which would be suitable for analyte level estimation with OCT. Another aspect is related to systems and methods for scanning multiple regions. An optical beam is moved across the surface of the tissue in two distinct manners. The first can be a coarse scan, moving the beam to provide distinct scanning positions on the skin. The second can be a fine scan where the beam is applied for more detailed analysis.

Abstract: This invention relates to a method of diagnosing or treating a biological subject, such as a person or animal, comprising the steps of subjecting at least a microsample of the subject's tissue to a physiological perturbation and measuring the response of the microsample to the perturbation using optical coherence tomography (OCT). In an exemplary embodiment, the concentration of glucose in the microsample is perturbed, as by providing the subject with a high glucose drink, and subsequently monitoring at a high sample rate in a microsample by OCT. Pathology, such as diabetes, can be diagnosed by deviation of the concentration vs. time response over several cells (micro-oscillation) from the micro-oscillation in the cells of a healthy subject. Other applications include diagnosing or treating de-hydration and diseases that cause changes in the osmolyte concentrations and thus the osmotic pressure in the cells in tissue.

Abstract: In accordance with the invention, the oxygenation of blood-profused tissue is measured by shining light into the profused tissue and analyzing the light reflected within the tissue. The light is reflected by cell walls in the tissue and is partially absorbed by hemoglobin in the blood. Since the extent of absorption is sensitive to the extent of hemoglobin oxygenation, measurement and processing of the reflected light provides a measure of the oxygenation of the blood. In one embodiment, the method is applied to measure the oxygenation of blood within the tympanic membrane (ear drum).

Abstract: In accordance with the invention, a low coherence interferometer is used to non-invasively monitor the concentration of glucose in blood by shining a light over a surface area of human or animal tissue, continuously scanning the light over a two dimensional area of the surface, collecting the reflected light from within the tissue and constructively interfering this reflected light with light reflected along a reference path to scan the tissue in depth. Since the reflection spectrum is sensitive to glucose concentration at particular wavelengths, measurement and analysis of the reflected light provides a measure of the level of glucose in the blood. The measurement of glucose is taken from multiple depths within blood-profused tissue, and sensitivity is preferably enhanced by the use of multiple wavelengths. Noise or speckle associated with this technique is minimized by continuously scanning the illuminated tissue in area and depth.

Abstract: A system and a method for creating a stable and reproducible interface of an optical sensor system for measuring blood glucose levels in biological tissue include a dual wedge prism sensor attached to a disposable optic that comprises a focusing lens and an optical window. The disposable optic adheres to the skin to allow a patient to take multiple readings or scans at the same location. The disposable optic includes a Petzval surface placed flush against the skin to maintain the focal point of the optical beam on the surface of the skin. Additionally, the integrity of the sensor signal is maximized by varying the rotation rates of the dual wedge prisms over time in relation to the depth scan rate of the sensor. Optimally, a medium may be injected between the disposable and the skin to match the respective refractive indices and optimize the signal collection of the sensor.

Abstract: In accordance with the invention, a low coherence interferometer is used to non-invasively monitor the concentration of glucose in blood by shining a light over a surface area of human or animal tissue, continuously scanning the light over a two dimensional area of the surface, collecting the reflected light from within the tissue and constructively interfering this reflected light with light reflected along a reference path to scan the tissue in depth. Since the reflection spectrum is sensitive to glucose concentration at particular wavelengths, measurement and analysis of the reflected light provides a measure of the level of glucose in the blood. The measurement of glucose is taken from multiple depths within blood-profused tissue, and sensitivity is preferably enhanced by the use of multiple wavelengths. Noise or speckle associated with this technique is minimized by continuously scanning the illuminated tissue in area and depth.

Abstract: A method for noninvasively measuring analytes such as blood glucose levels includes using a non-imaging OCT-based system to scan a two-dimensional area of biological tissue and gather data continuously during the scanning. Structures within the tissue where measured-analyte-induced changes to the OCT data dominate over changes induced by other analytes are identified by focusing on highly localized regions of the data curve produced from the OCT scan which correspond to discontinuities in the OCT data curve. The data from these localized regions then can be related to measured analyte levels.