Method and apparatus for optical measurement of bilirubin in tissue
First Claim
1. A method for the transcutaneous determination of bilirubin concentration in tissue, comprising:
- illuminating said tissue with light;
detecting a frequency spectrum of light reflected from said tissue;
calculating, from a first portion of said spectrum, a first parameter indicative of a maturity of said tissue;
calculating, from a second portion of said spectrum, a second parameter indicative of an amount of melanin in said tissue;
calculating, form a third portion of said spectrum, a third parameter indicative of a blood content of said tissue;
calculating, from a fourth portion of said spectrum, a fourth parameter indicative of an uncorrected bilirubin concentration in said tissue; and
calculating a connected bilirubin concentration in said tissue as a function of said first, second, third and fourth parameters.
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Abstract
A method and apparatus for the determination of bilirubin concentration in tissue such as skin, particularly neonatal skin. Light reflected from the skin under test is analyzed to determine bilirubin concentration in the skin, corrected for maturity-dependent optical properties of the skin, the amount of melanin in the skin and the amount of blood in the skin. Reflected red to infrared light is used to determine maturity-dependent optical properties, reflected red light is used to determine melanin content, and reflected yellow-orange light is used to determine the amount of blood in the skin. Then, these quantities are used, in combination with reflected blue light, to calculate cutaneous bilirubin concentration.
317 Citations
13 Claims
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1. A method for the transcutaneous determination of bilirubin concentration in tissue, comprising:
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illuminating said tissue with light; detecting a frequency spectrum of light reflected from said tissue; calculating, from a first portion of said spectrum, a first parameter indicative of a maturity of said tissue; calculating, from a second portion of said spectrum, a second parameter indicative of an amount of melanin in said tissue; calculating, form a third portion of said spectrum, a third parameter indicative of a blood content of said tissue; calculating, from a fourth portion of said spectrum, a fourth parameter indicative of an uncorrected bilirubin concentration in said tissue; and calculating a connected bilirubin concentration in said tissue as a function of said first, second, third and fourth parameters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An apparatus for detecting a concentration of bilirubin in tissue, comprising:
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a light source adapted to direct light onto tissue under test; a light detector, adapted to detect a spectrum of light reflected form said tissue; and a computer means, connected to said light source and light detector, for calculating a first parameter indicative of a maturity of said tissue form a magnitude of a first portion of said spectrum, for calculating a second parameter indicative of an amount of melanin in said tissue from a second portion of said spectrum, for calculating a third parameter indicative of a blood content of said tissue from a third portion of said spectrum, for calculating a fourth parameter indicative of a raw bilirubin concentration form a fourth portion of said spectrum, and for calculating bilirubin concentration in said tissue as a function of said first, second, third and fourth parameters.
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Specification