Method and apparatus for noninvasive measurement of carotenoids and related chemical substances in biological tissue
First Claim
1. A method for noninvasively determining the presence or risk of a malignancy disease in biological tissue, comprising the steps of:
- obtaining a light sourse which generates light at a wavelength that produces a Raman tenoids to be detected;
directing light from the light sourse onto biological tissue for which carotenoid levels are to be measured, the light having an intensity which does not cause destruction of the tissue and does not substantially alter carotenoid levels in the tissue;
collecting light scattered from the tissue, the scattered light including elastically and inelastically scattered light, the inelastically scattered light producing a Raman signal corresponding to carotenoid in the tissue;
filtering out the elastically scattered light; and
quantifying the intensity of the Raman signal, wherein a substantial difference between the intensity of the Raman signal and the intensity of Raman scattering from adjkacent normal biological tissue indicates the presence or risk of a malignancy disease.
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Accused Products
Abstract
A method and apparatus are provided for the determination of levels of carotenoids and similar chemical compounds in biological tissue such as living skin. The method and apparatus provide a noninvasive, rapid, accurate, and safe determination of carotenoid levels which in turn can provide diagnostic information regarding cancer risk, or can be a marker for conditions where carotenoids or other antioxidant compounds may provide diagnostic information. Such early diagnostic information allows for the possibility of preventative intervention. The method and apparatus utilize the technique of resonance Raman spectroscopy to measure the levels of carotenoids and similar substances in tissue. In this technique, laser light is directed upon the area of tissue which is of interest. A small fraction of the scattered light is scattered inelastically, producing the carotenoid Raman signal which is at a different frequency than the incident laser light, and the Raman signal is collected, filtered, and measured. The resulting Raman signal can be analyzed such that the background fluorescence signal is subtracted and the results displayed and compared with known calibration standards.
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Citations
32 Claims
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1. A method for noninvasively determining the presence or risk of a malignancy disease in biological tissue, comprising the steps of:
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obtaining a light sourse which generates light at a wavelength that produces a Raman tenoids to be detected;
directing light from the light sourse onto biological tissue for which carotenoid levels are to be measured, the light having an intensity which does not cause destruction of the tissue and does not substantially alter carotenoid levels in the tissue;
collecting light scattered from the tissue, the scattered light including elastically and inelastically scattered light, the inelastically scattered light producing a Raman signal corresponding to carotenoid in the tissue;
filtering out the elastically scattered light; and
quantifying the intensity of the Raman signal, wherein a substantial difference between the intensity of the Raman signal and the intensity of Raman scattering from adjkacent normal biological tissue indicates the presence or risk of a malignancy disease. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for noninvasively determining the antioxidant status in skin tissue, comprising the steps of:
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obtaining a light source which generates light at a wavelength that produces a Raman response with a wavelength shift for carotenoids to be detected in skin tissue;
directing light from the light source onto skin tissue for which carotenoid levels are to be measured, the light having an intensity which does not cause destruction of the tissue and does not substantially alter carotenoid levels in the tissue;
collecting light scattered from the tissue, the scattered light including elastically and inelastically scattered light, the inelastically scattered light producing a Raman signal corresponding to carotenoids in the tissue;
filtering out the elastically scattered light; and
quantifying the intensity of the Raman signal in order to assess the antioxidant status of the tissue. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method for noninvasive measurement of carotenoids in skin tissue, comprising the steps of:
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obtaining a light source which generates light at a wavelength that produces a Raman response with a wavelength shift for carotenoids to be detected;
directing light from the light source onto skin tissue for which carotenoid levels are to be measured, the light having an intensity which does not cause destruction of the skin tissue and does not substantially alter carotenoid levels in the skin tissue;
collecting light scattered from the skin tissue, the scattered light including elastically and inelastically scattered light, the inelastically scattered light producing a Raman signal corresponding to carotenoids in the skin tissue;
filtering out the elastically scattered light;
quantifying the intensity of the Raman signal; and
subtracting a background fluorescence signal of the skin tissue from the Raman signal of the carotenoids being detected. - View Dependent Claims (17, 18, 19, 20, 21)
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22. An apparatus for noninvasive measurement of carotenoids and related chemical substances in biological tissue, comprising:
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a laser light source that generates light at a wavelength giving a Raman response with a wavelength shift for carotenoids being detected;
a light delivery and collection module for directing light onto biological tissue and collecting scattered light from the tissue such that the light does not damage the tissue or substantially alter the carotenoid levels in the tissue, the light delivery and collection module comprising;
a first lens for collimating laser light;
a first narrow bandwidth filter in optical communication with the first lens;
first and second dichroic beam splitters in optical communication with the first narrow bandwidth filter;
a second lens adapted to direct a beam of laser light from the second dichroic beam splitter to tissue and collect scattered light from the tissue;
a second narrow bandwidth filter in optical communication with the second lens; and
a third lens in optical communication with the second narrow bandwidth filter;
a spectrally selective system for selecting Raman shifted light from the collected scattered light;
detection means for scanning and measuring the Raman shifted light at frequencies characteristic of carotenoids; and
quantifying means for determining Raman signal intensity for the carotenoids being detected. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification