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 having a predetermined polarization from a radiation source which provides radiation in said particular region of the spectrum, said radiation source being selected and located to provide a polarized illumination to said sample;
collecting radiation which is transmitted from said sample with a detector, said detector being selected and located such that said detector collects only said radiation having said predetermined polarization while excluding depolarized radiation; and
determining said concentration in said sample of said selected substance in response to said collected radiation.
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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.
17 Citations
20 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 having a predetermined polarization from a radiation source which provides radiation in said particular region of the spectrum, said radiation source being selected and located to provide a polarized illumination to said sample; collecting radiation which is transmitted from said sample with a detector, said detector being selected and located such that said detector collects only said radiation having said predetermined polarization while excluding depolarized radiation; and determining said concentration in said sample of said selected substance in response to said collected radiation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification