Methods of minimizing scattering and improving tissue sampling in non-invasive testing and imaging
First Claim
1. A method of measuring the concentration in a sample of a selected substance which absorbs radiation in a particular region of the spectrum, said sample further containing a plurality of sites which scatter radiation in said particular region, said method comprising the steps of:
- illuminating said sample with radiation from a radiation source which provides radiation in said particular region of the spectrum, said radiation source being selected and located to provide illumination of said sample;
collecting radiation which is transmitted from said sample with a detector, said detector being selected and located such that said detector collects radiation only from a limited solid angle, said radiation being collected from an area having a diameter or width at least comparable in size to the thickness of said sample; and
determining concentration of said selected substance from said detected radiation;
whereby the ratio of directly transmitted radiation to diffusely scattered radiation collected by said detector from said sample is higher than if said method is not used.
2 Assignments
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Accused Products
Abstract
An improved method and apparatus for use in optical testing of concentration in samples has been developed. The apparatus restricts the solid angle of illumination and the solid angle of detection to eliminate a high proportion of the scattered radiation while allowing the ballistic radiation and the snake-like radiation to be transmitted. In samples which contain multiple scattering centers, this allows less correction for variations in effective pathlength and allows easier calibration of the apparatus. The use of polarized radiation as a means of minimizing scattered radiation in the sample is also disclosed.
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Citations
50 Claims
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1. A method of measuring the concentration in a sample of a selected substance which absorbs radiation in a particular region of the spectrum, said sample further containing a plurality of sites which scatter radiation in said particular region, said method comprising the steps of:
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illuminating said sample with radiation from a radiation source which provides radiation in said particular region of the spectrum, said radiation source being selected and located to provide illumination of said sample; collecting radiation which is transmitted from said sample with a detector, said detector being selected and located such that said detector collects radiation only from a limited solid angle, said radiation being collected from an area having a diameter or width at least comparable in size to the thickness of said sample; and determining concentration of said selected substance from said detected radiation; whereby the ratio of directly transmitted radiation to diffusely scattered radiation collected by said detector from said sample is higher than if said method is not used. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A device for measuring the concentration in a sample of a selected substance which absorbs radiation in a particular region of the spectrum, said sample also containing a plurality of sites which scatter radiation in said particular region, said device comprising:
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a radiation source for illuminating said sample with radiation from said particular region of the spectrum; and a detector for collecting radiation which is transmitted by said sample, said detector being selected and located such that said detector collects radiation only from a limited solid angle with an area having a diameter or width at least comparable in size to the thickness of said sample; whereby the ratio of radiation collected by said detector which is directly transmitted by said sample to that scattered by said sample is higher than if said device is not used. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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49. A method of measuring the concentration in a tissue of a selected substance which absorbs radiation in a particular region of the spectrum, said tissue containing a plurality of sites which scatter radiation in said particular region, said method comprising the steps of:
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illuminating said tissue with radiation from a radiation source which provides radiation in said particular region of the spectrum, said radiation source being selected and located to provide illumination of said tissue; and collecting radiation which is transmitted from said tissue with a detector, said detector being selected and located such that said detector collects radiation only from an area having a diameter or width at least comparable in size to the thickness.
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50. A device for measuring the concentration in a tissue of a selected substance which absorbs radiation in a particular region of the spectrum, said tissue containing a plurality of sites which scatter radiation in said particular region, said device comprising:
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a radiation source for illuminating said tissue with radiation from said particular region of the spectrum, said radiation source being selected and located to provide illumination of said tissue; and a detector for collecting radiation which is transmitted by said tissue, said detector being selected and located such that said detector collects radiation only from an area having a diameter or width at least comparable in size to the thickness of said tissue.
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Specification