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, said sensing light path having an effective light path length;
receiving said broadband light reflected from the biological sample by means of said sensing light path;
directing said broadband light by means of a reference light path at a reference reflecting device, said reference light path having an effective light path length;
receiving said broadband light reflected from said reference reflecting device by means of said reference light path;
directing said broadband light reflected from the biological sample and reflected from said reference reflecting device at a first reflecting device by means of a first light path and at a second reflecting device by means of a second light path, said first and second light paths having corresponding effective light path lengths;
combining said broadband light reflected from said first reflecting device and reflected from said second reflecting device;
modulating said effective light path lengths of said first and second light paths to minimize a difference to within about two coherence lengths of said broadband light, said difference corresponding to the effective light path lengths of said reference light path and said sensing light path;
detecting said broadband light resulting from broadband light reflected from said first depth in the biological sample and said broadband light reflected from said reference reflecting device, to generate a 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 reference reflecting device;
determining a first phase from said signal indicative of said interference of said broadband light reflected from said first depth in the biological sample and said broadband light reflected from said reference reflecting device;
changing the effective light path length of at least one of said reference light path and said sensing light path to define a 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 from said reference reflecting device, to generate a 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 reference reflecting device;
determining a second phase from said signal indicative of said interference of said broadband light reflected from said second depth in the biological sample and said broadband light reflected from said reference reflecting device;
determining the characteristic of the biological sample from said first phase and said second phase; and
diagnosing a human condition from the characteristic.
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Abstract
A method and system for determining a characteristic of a biological sample including directing light at the biological sample and receiving that light; directing the light at a reference reflecting device and receiving that light; adjusting an effective light path length to facilitate an interference of the light reflected from the biological sample corresponding to a first depth and the light reflected from the reference reflecting device; and detecting the broadband light resulting from the interference, to provide an interference signal. The method also includes: determining a first phase associated with the interference signal corresponding to the first depth; varying the effective light path length to define a second depth; determining a second phase associated with the interference signal corresponding to the second depth; and determining the characteristic of the biological sample from the phases.
411 Citations
70 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, said sensing light path having an effective light path length; receiving said broadband light reflected from the biological sample by means of said sensing light path; directing said broadband light by means of a reference light path at a reference reflecting device, said reference light path having an effective light path length; receiving said broadband light reflected from said reference reflecting device by means of said reference light path; directing said broadband light reflected from the biological sample and reflected from said reference reflecting device at a first reflecting device by means of a first light path and at a second reflecting device by means of a second light path, said first and second light paths having corresponding effective light path lengths; combining said broadband light reflected from said first reflecting device and reflected from said second reflecting device; modulating said effective light path lengths of said first and second light paths to minimize a difference to within about two coherence lengths of said broadband light, said difference corresponding to the effective light path lengths of said reference light path and said sensing light path; detecting said broadband light resulting from broadband light reflected from said first depth in the biological sample and said broadband light reflected from said reference reflecting device, to generate a 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 reference reflecting device; determining a first phase from said signal indicative of said interference of said broadband light reflected from said first depth in the biological sample and said broadband light reflected from said reference reflecting device; changing the effective light path length of at least one of said reference light path and said sensing light path to define a 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 from said reference reflecting device, to generate a 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 reference reflecting device; determining a second phase from said signal indicative of said interference of said broadband light reflected from said second depth in the biological sample and said broadband light reflected from said reference reflecting device; determining the characteristic of the biological sample from said first phase and said second phase; 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, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. 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 reference 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 reference reflecting device and to receive said broadband light reflected from said reflecting device; a first Light path receptive to said broadband light reflected from the biological sample and reflected from said reference reflecting device, said first light path configured to direct said broadband light reflected from the biological sample and reflected from said reference reflecting device at a first reflecting device; a second light path receptive to said broadband light reflected from the biological sample and reflected from said reference reflecting device, said second light path configured to direct said broadband light reflected from the biological sample and reflected from said reference reflecting device at a second reflecting device, said first and second light paths having corresponding effective light path lengths; and means for modifying said effective light path lengths of said first and second light paths to minimize a difference to within about two coherence lengths of said broadband light, said difference corresponding to the effective light path lengths 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 reference reflecting device, to generate signals indicative of an interference of said broadband light reflected from the biological sample and said broadband light reflected from said reference reflecting device; means for changing an effective light path length of at least one of said reference light path and said sensing light path to define a second depth; and a processor configured to;
(1) determine a first phase from 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 reference reflecting device, 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 from 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 reference reflecting device, said second depth defined by said effective light path length of at least one of said sensing light path and a reference light path having been changed; and
(3) determine the characteristic of the biological sample from said first phase and said second phase. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
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Specification