Abstract: A spectroscopic method and system for examination of biological tissue includes multiple input ports optically connected to at least one light source, multiple detection ports optically connected to at least one detector, a radiation pattern controller coupled to the light source and detector, and a processor. The multiple input ports are arranged to introduce light at input locations into biological tissue and the multiple detection ports are arranged to collect light from detection locations of the biological tissue. The radiation pattern controller is constructed to control patterns of light introduced from the multiple input ports and constructed to control detection of light migrating to the multiple detection ports. The processor is operatively connected to the radiation pattern controller and connected to receive detector signals from the detector, and is constructed to examine a tissue region based on the introduced and detected light patterns.

Abstract: A spectroscopic system for quantifying in vivo concentration of an absorptive pigment in biological tissue includes an oscillator for generating a first carrier waveform of a first frequency on the order of 108 Hz, a light source for generating light of a selected wavelengths modulated by the carrier waveform, and a detector for detecting radiation that has migrated over photon migration paths in the tissue from an input port to a detection port spaced several centimeters apart. The wavelength is sensitive to concentration of an absorptive pigment present in the tissue. A phase detector compares the detected radiation with the introduced radiation and determines therefrom the phase shift of the detected radiation. A processor quantifies the concentration of the absorptive pigment by calculating a value of the absorption coefficient.

Abstract: A spectroscopic system for quantifying in vivo concentration of an absorptive pigment in biological tissue includes an oscillator for generating a first carrier waveform of a first frequency on the order of 108 Hz, a light source for generating light of at least two selected wavelengths modulated by the carrier waveform, and a detector for detecting radiation that has migrated over photon migration paths in the tissue from an input port to a detection port spaced several centimeters apart. At least one of the wavelengths is sensitive to concentration of an absorptive pigment present in the tissue, while the tissue exhibits similar scattering properties at the two wavelengths. A phase detector compares, at each wavelength, the detected radiation with the introduced radiation and determines therefrom the phase shift of the detected radiation at each wavelength.

Abstract: Methods and apparatus using the principles of time-resolved spectroscopy are disclosed. The present invention employs incident light pulses of sufficiently short duration to permit the rate of the rise and decay of such pulses to be measured. Consequently, the rate of decay, u, permits a determination of the concentration of an absorptive pigment, such as hemoglobin. The present invention also allows the precise path length the photons travel to be determined. Using this path length information and by measuring changes in optical density using known continuous light (CW) spectrophotometry systems, the methods and apparatus disclosed allow changes in the concentration of an absorptive pigment to be correctly be measured. From these data, the oxygenation state of a tissue region, such as the brain, can be accurately determined in real time.

Abstract: The present invention provides in various embodiments novel, wearable systems for determining the metabolic condition of an aerobically stressed portion of tissue such as the muscle tissue of an exercising person. Generally, the systems comprise lightweight rugged detectors, worn adjacent the tissue being monitored. The system of the present invention thus minimizes any performance impairment. In preferred systems a wearable power pack and a wearable display means are provided for displaying information indicative of the aerobic metabolic condition of the region being monitored. In a preferred embodiment intended for use while running or engaged in similar athletic activities, the display is worn on the wrist and displays information from a leg-mounted detector. In another embodiment, intended to provide information to coaches, a telemetry system is employed to transmit a signal carrying the data from the detector to a remote location, for processing and display.

Abstract: Optical methods and systems for in vivo, non-invasive examination of biological tissue include at least one light source constructed to emit light of a visible or infra-red wavelength for introduction into an examined tissue volume from at least one input port, and at least one detector constructed to detect light of the visible or infra-red wavelength that has migrated in the examined tissue volume from at least one input port to at least one detection port. The optical systems also include an optical array, a radiation controller, and a processor. The optical array includes the input and detection ports located in a selected geometrical pattern providing several average photon migration pathlengths in the examined tissue volume. Each arrangement of least one input port and at least one detection port provides one of the average pathlengths, wherein the average pathlength is characteristic of the tissue between one input port and one detection port.

Abstract: For in vivo examination using a spectrophotometer that generates optical radiation and characterizes biological tissue by detecting photons that have migrated in the tissue, an array of optical fibers that transmit radiation between the spectrophotometer and biological tissue, the fibers including distal ends freely protruding from a support in the manner of bristles from a hairbrush, forming an array of optical ports to couple photons to a contiguous tissue region or to collect photons from the tissue region, the optical fibers including proximal ends arranged to optically couple the radiation with the spectrophotometer.

Abstract: Systems are shown that utilize differential measurement of radiation that has migrated through migration paths between two source-detector pairs placed on the head in a manner that each path is localized in a portion of one hemisphere of the brain. Various spectrophotometer systems are also shown for in vivo examination of tissue of a human by measuring changes in electromagnetic radiation scattered and absorbed in a migration path in the tissue. Generally, the spectrophotometer systems comprise a light source for introducing the radiation into the tissue, a detector for detecting radiation that has migrated in the tissue, a processor for processing signals of the detected radiation to create processed data, and a system for determining physiological or pathophysiological changes in the tissue of interest such as bleeding or tumor.

Abstract: Imaging tumors using diffuse light. An imaging system includes a source of diffuse light for generating oscillatory diffuse photon density waves to illuminate an object, a detector for detecting diffuse photon density waves interacting with the object, and a computer interfaced with the detector for processing data corresponding to the photon density waves detected to determine at least a position of the object. In one embodiment, the turbid medium and the object have associated therewith at least one diffusion coefficient and the diffuse photon density waves which illuminate the object refract around the object as a result of their interaction with it, thereby producing a distorted wavefront that allows the computer to construct an image of the object. In another embodiment, a fluorescent object produces re-radiated diffuse photon density waves which allow the object to be imaged.

Abstract: A method of breast tissue examination using time-resolved spectroscopy includes the following steps. A support that includes an input port and an output port separated by a selected distance is positioned relative to the examined breast. Locations of the input and output ports are selected to examine a tissue region of the breast. Light pulses of a selected wavelength and duration less than a nanosecond are introduced into the breast tissue at the input port and detected over time at the detection port. Signals corresponding to photons of detected modified pulses are accumulated over time. Values of a scattering coefficient or an absorption coefficient of the examined breast tissue are calculated based on the shape of the modified pulses. The examined breast tissue is characterized based on the values of the scattering coefficient or the absorption coefficient. Absorbing or fluorescing contrast agents may be introduced into the examined tissue.

Abstract: The present invention utilizes differential measurement of radiation that migrated into two migration paths between two source-detector pairs placed on the head in a manner that each path is localized in a portion of one hemisphere of the brain. The present invention also provides various embodiments of spectrophotometer systems for in vivo examination of tissue of a human by measuring changes in electromagnetic radiation scattered and absorbed in a migration path in the tissue. Generally, the spectrophotometer systems comprise a light source for introducing the radiation into the tissue, a detector for detecting radiation that has migrated in the tissue, a processor for processing signals of the detected radiation to create processed data, and a system for determining physiological or pathophysiological changes in the tissue of interest. The present invention also provides for determining the metabolic condition of an aerobically stressed portion of tissue such as the muscle tissue of an exercising person.

Abstract: An optical system for in vivo, non-invasive imaging of tissue change including an optical module, a spectrophotometer, and a processor. The optical module includes an array of input ports and detection ports located in a selected geometrical pattern to provide a multiplicity of arrayed source-detector pairs engaged directly with the subject. The spectrophotometer includes at least one light source constructed to introduce electromagnetic radiation of visible or infra-red wavelength into the examined tissue successively at the input ports, wherein the wavelength is sensitive to a constituent of the imaged tissue, and at least one detector constructed to detect, at the detection ports, radiation of the selected wavelength that has migrated in the tissue from respective input ports.

Abstract: Methods and systems are described that examine a subject positioned between an input port and detection ports of a spectroscopic system applied to the subject. At least one source of a visible or infrared wavelength is provided that introduces electromagnetic radiation into the subject. The detection ports are optically connected to a detector circuit constructed to provide a detection signal of known sensitivity. The input and detection locations and the sensitivity define a null plane in the tissue. Radiation is introduced into the subject at the input port and the radiation that migrates through the tissue is detected at the detection ports. The detector circuit provides a first detection signal corresponding to a first detected radiation and a second detection signal corresponding to a second detected radiation. The first detection signal is subtracted from the second detection signal to obtain processed data.

Abstract: A method and system for examination of a subject positioned between input and detection ports of the spectroscopic system applied to the subject. The systems shown include at lease one light source for introducing at one or multiple input ports, electromagnetic non-ionizing radiation of a known time-varying pattern of photon density of a wavelength selected to be scattered and absorbed while migrating in the subject, radiation pattern control means for achieving a directional pattern of emitted resulting radiation that possesses substantial gradient of photon density, at least one detector for detecting the radiation that has migrated in the subject at one or multiple detection ports. The systems also include processing means for processing the detected radiation and creating sets of data, and evaluation means for examining the subject using the data sets. The emitted directional radiation pattern utilizes its gradient of photon density to detect a hidden object while scanning across the examined subject.

Abstract: The invention features an optical probe for non-invasive monitoring of neural activity. The optical probe includes a light source constructed to introduce electromagnetic radiation of a visible or infra-red wavelength into biological tissue at an input port; and a detector constructed to detect, at a detection port, radiation of the selected wavelength that has migrated in the biological tissue from the input port. The optical probe also includes a processor, receiving signals of the detected radiation, constructed and arranged to determine neural activity of the tissue by measuring scattering or absorptive properties of the tissue. The neural activity detected by the optical probe includes redistribution of K.sup.+, Na.sup.+ and H.sub.2 O, which may occur upon death, during hypoxia, ischemia, or other physiological process.

Abstract: A scheme for monitoring one or more solutes in a biological system comprising the steps of: delivering light into a biological system containing one or more solutes, the light having a wavelength selected to be in a range wherein at least one of the one or more solutes is substantially non-absorbing; detecting at least first and second portions of the delivered light, the first portion having traveled through the biological system along one or more paths characterized by a first average path length, and the second portion having traveled through the biological system along one or more paths characterized by a second average path length that is greater than the first average path length; and comparing the first and second portions of the delivered light to monitor a concentration of one or more of the solutes in the biological system.

Abstract: One preferred embodiment utilizes differential measurement of radiation that migrated in two migration paths between two source (100) detector (110) pairs placed on the head in a manner that each path is localized in a portion of one hemisphere. The present invention also provides in various embodiments of spectrophotometer systems for in vivo examination of a tissue of a human by measuring changes in electromagnetic radiation scattered and absorbed in a migration path in the tissue. Generally, the spectrophotometer systems comprise a light source for introducing the radiation into the tissue, a detector for detecting radiation that has migrated in the tissue, processing means for processing signals of the detected radiation to create processed data, and evaluation means for determining physiological or pathophysiological changes in the tissue of interest.

Abstract: Methods and systems are described that examine a subject positioned between input and detection ports of a spectroscopic system applied to the subject. At least one least source is provided that introduces at one or multiple input ports electromagnetic non-ionizing radiation into the subject of a visible or infrared wavelength selected to be scattered and absorbed while migrating in the tissue. A detection port is optically connected to a detector; the detector being connected to a detector circuit. For each input port first and second radiation intensities are selected to be introduced to the tissue; the selected radiation intensities defining a null plane in the tissue. The detection port is positioned relative to a selected detection location of the examined tissue corresponding to the null plane. Radiation of the first intensity is introduced into the subject, at the first input port and the first radiation that has migrated in the examined tissue is detected.

Abstract: A method and system for examination of a subject positioned between input and detection ports of the spectroscopic system applied to the subject. The systems shown include at least one light source for introducing at one or multiple input ports, electromagnetic non-ionizing radiation of a known time-varying pattern of photon density of a wavelength selected to be scattered and absorbed while migrating in the subject, radiation pattern control means for achieving a directional pattern of emitted resulting radiation that possesses substantial gradient of photon density, at least one detector for detecting the radiation that has migrated in the subject at one or multiple detection ports. The systems also include processing means for processing the detected radiation and creating sets of data, and evaluation means for examining the subject using the data sets. The emitted directional radiation pattern utilizes its gradient of photon density to detect a hidden object while scanning across the examined subject.

Abstract: An optical coupler for in vivo examination of biological tissue includes an optical input port positionable on or near the examined tissue, a first light guide optically coupled to the optical input port and constructed to transmit optical radiation of a visible or infra-red wavelength from a source to the optical input port. The optical coupler also includes an optical detection port, positionable on or near the examined tissue, constructed and arranged to receive radiation that has migrated in the examined tissue from the input port. Connected to the detection port is a detector light guide, constructed to transmit radiation from the detection port to an optical detector. Disposed at least partially around the examined tissue and the input and detection ports is optical medium arranged to couple the radiation to the tissue, limit escape of photons, or account for photons that escaped from the tissue. The optical coupler also enables a precise relative geometry of input and detection ports.