Low coherence interferometry for detecting and characterizing plaques
First Claim
1. A method for diagnosing a human condition from a characteristic of tissue in a biological sample, the method comprising:
- directing broadband light by means of a sensing light path at the biological sample at a first depth defined by effective light path lengths of said sensing light path and a reference light path;
receiving said broadband light reflected from the biological sample by means of said sensing light path;
directing said broadband light by means of said reference light path at a reflecting device;
receiving said broadband light reflected from said reflecting device by means of said reference light path;
modulating at about a distance of a center wavelength said broadband light an effective light path length of at least one of said reference light path and said sensing light path with respect to said first depth;
detecting said broadband light resulting from said broadband light reflected from said first depth in the biological sample and said broadband light reflected from said reflecting device, to generate a first signal indicative of an interference of said broadband light reflected from said first depth in the biological sample and said broadband light reflected from said reflecting device, wherein said first signal is a product of a cosine function;
determining a first phase component that is an argument of the cosine function of the first signal;
changing said effective light path lengths of at least one of said reference light path and said sensing light path to define a second depth;
modulating at about a distance of said center wavelength of said broadband light an effective light path length of at least one of said reference light path and said sensing light path with respect to said second depth;
detecting said broadband light resulting from said broadband light reflected from said second depth in the biological sample and said broadband light reflected front said reflecting device, to generate a second signal indicative of an interference of said broadband light reflected from said second depth in the biological sample and said broadband light reflected from said reflecting device, wherein said second signal is a product cosine function;
determining a second phase component that is an argument of the cosine function of the second signal;
determining a characteristic of the biological sample from said first phase component and said second phase component; and
diagnosing a human condition from the characteristic.
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Accused Products
Abstract
A method for determining a characteristic of tissue in a biological sample comprising: directing light at the biological sample at a first depth and receiving that light reflected from the biological; directing the light at a reflecting device and receiving that light reflected from the reflecting device. The method also includes: interfering the light reflected from the biological sample and the light reflected from the reflecting device; detecting light resulting from the interfering; and determining a first phase associated with the light resulting from the interfering based on the first depth. The method further includes: varying an effective light path length to define a second depth; determining a second phase associated with the light resulting from the interfering based on the second depth; and determining the characteristic of the biological sample from the first phase and the second phase.
376 Citations
49 Claims
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1. A method for diagnosing a human condition from a characteristic of tissue in a biological sample, the method comprising:
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directing broadband light by means of a sensing light path at the biological sample at a first depth defined by effective light path lengths of said sensing light path and a reference light path; receiving said broadband light reflected from the biological sample by means of said sensing light path; directing said broadband light by means of said reference light path at a reflecting device; receiving said broadband light reflected from said reflecting device by means of said reference light path; modulating at about a distance of a center wavelength said broadband light an effective light path length of at least one of said reference light path and said sensing light path with respect to said first depth; detecting said broadband light resulting from said broadband light reflected from said first depth in the biological sample and said broadband light reflected from said reflecting device, to generate a first signal indicative of an interference of said broadband light reflected from said first depth in the biological sample and said broadband light reflected from said reflecting device, wherein said first signal is a product of a cosine function; determining a first phase component that is an argument of the cosine function of the first signal; changing said effective light path lengths of at least one of said reference light path and said sensing light path to define a second depth; modulating at about a distance of said center wavelength of said broadband light an effective light path length of at least one of said reference light path and said sensing light path with respect to said second depth; detecting said broadband light resulting from said broadband light reflected from said second depth in the biological sample and said broadband light reflected front said reflecting device, to generate a second signal indicative of an interference of said broadband light reflected from said second depth in the biological sample and said broadband light reflected from said reflecting device, wherein said second signal is a product cosine function; determining a second phase component that is an argument of the cosine function of the second signal; determining a characteristic of the biological sample from said first phase component and said second phase component; and diagnosing a human condition from the characteristic. - 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)
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24. A system for determining a characteristic of tissue in a biological sample, the system comprising:
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a broadband light source for providing a broadband light; a sensing light path receptive to said broadband light from said broadband light source, said sensing light path configured to direct said broadband light at the biological sample and to receive said broadband light reflected from the biological sample; a reflecting device; a reference light path receptive to said broadband light from said broadband light source, said reference light path configured to direct said broadband light at said reflecting device and to receive said broadband light reflected from said reflecting device; a modulator associated with at least one of said reference light path and said sensing light path, said modulator for modulating at about a distance of a center wavelength of said broadband light an effective light path length of said at least one of said reference light path and said sensing light path; a detector receptive to said broadband light resulting from said broadband light reflected from the biological sample and said broadband light reflected from said reflecting device, said detector generating signals indicative of an interference of said broadband light reflected from the biological sample and said broadband light reflected from said reflecting device, which said signals are product of cosine functions; means for changing an effective light path length of at least one of said reference light path and said sensing light path; and a processor configured to;
(1) determine a first phase component that is an argument of the corresponding cosine function of said signal indicative of said interference of said broadband light reflected from a first depth in the biological sample and said broadband light reflected from said reflecting device based, said first depth defined by said effective light path length of said sensing light path and said effective light path length of said reference light path, (2) determine a second phase component that is an argument of the corresponding cosine function of said signal indicative of said interference of said broadband light reflected from a second depth in the biological sample and said broadband light reflected from said reflecting device based, said second depth defined by said effective light path length of at least one of said sensing light path and said reference light path having been changed, and (3) determine a characteristic of the biological sample from said first phase component and said second phase component. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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Specification