System for noninvasive determination of alcohol in tissue

Abstract

An apparatus and method for non-invasive determination of attributes of human tissue by quantitative infrared spectroscopy to clinically relevant levels of precision and accuracy. The system includes subsystems optimized to contend with the complexities of the tissue spectrum, high signal- to-noise ratio and photometric accuracy requirements, tissue sampling errors, calibration maintenance problems, and calibration transfer problems. The subsystems include an illumination / modulation subsystem, a tissue sampling subsystem, a calibration maintenance subsystem, an FTIR spectrometer subsystem, a data acquisition subsystem, and a computing subsystem.

Description

FIELD OF THE INVENTION[0001]The present invention generally relates to a quantitative spectroscopy system for measuring the presence or concentration of alcohol, alcohol byproducts, alcohol adducts, or substances of abuse utilizing non-invasive techniques in combination with multivariate analysis.BACKGROUND OF THE INVENTION[0002]Current practice for alcohol measurements is based upon either blood measurements or breath testing. Blood measurements define the gold standard for determining alcohol intoxication levels. However, blood measurements require either a venous or capillary sample and involve significant handling precautions in order to minimize health risks. Once extracted, the blood sample must be properly labeled and transported to a clinical laboratory or other suitable location where a clinical gas chromatograph is typically used to measure the blood alcohol level. Due to the invasiveness of the procedure and the amount of sample handling involved, blood alcohol measuremen...

AI Technical Summary

Benefits of technology

[0018]The subsystems of the non-invasive monitor are highly optimized to provide reproducible and, preferably, uniform radiance of the tissue, low tissue sampling error, depth targeting of the tissue layers that contain the property of interest, efficient collection of diffuse reflectance spectra from the tissue, high optical throughput, high photometric accuracy, large dynamic range, excellent thermal stability, effective calibration maintenance, effective calibration transfer, built-in quality control, and ease-of-use.

Problems solved by technology

The design contends with the complexities of the tissue spectrum, high signal-to-noise ratio and photometric accuracy requirements, tissue sampling errors, calibration maintenance problems, calibration transfer problems plus a host of other issues.

In the 1.0 to 2.5 micron spectral region, the large number of optically active substances that make up the tissue complicate the measurement of any given substance due to the overlapped nature of their absorbance spectra.

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