초록 ▼

A spectrophotometric method, apparatus and reflectance technique is directed to non-invasive, harmless, continuous, atraumatic, in vivo, in situ monitoring of metabolism in a body organ utilizing measuring and reference wavelengths within the near infrared region, i.e., 700-1300 nm. Monitoring of ox

A spectrophotometric method, apparatus and reflectance technique is directed to non-invasive, harmless, continuous, atraumatic, in vivo, in situ monitoring of metabolism in a body organ utilizing measuring and reference wavelengths within the near infrared region, i.e., 700-1300 nm. Monitoring of oxidative metabolism is accomplished by monitoring oxygen sufficiency in an organ, normally an internal vital organ, e.g., the brain or heart, of a living human or animal body. Advantage is taken of the critical characteristic of cellular enzyme cytochrome a, a3 within the optical path and within the radiated portion of the selected organ from which the light so reflected for absorbing the selected measuring wavelength and for light of this measuring wavelength, as well as at least one reference wavelength within the same defined infrared region and at a low, non-hazardous level of intensity to travel to the organ, be reflected and be detectable at a point spaced from the point of entry and at the end of a relatively long path, e.g., of several centimeters length, which may include substantial content of bone as well as soft tissue. The method corrects for skin blood flow effects, variations in laser diode output and variations in metabolic and circulatory parameters during measuring.

대표청구항 ▼

A spectrophotometric reflectance method for measuring local metabolism of a body organ such as the brain, in situ, in vivo, non-invasively, atraumatically, harmlessly, rapidly and continuously, said method comprising the steps: (a) locating and fixing the body in a position appropriate to the measur

A spectrophotometric reflectance method for measuring local metabolism of a body organ such as the brain, in situ, in vivo, non-invasively, atraumatically, harmlessly, rapidly and continuously, said method comprising the steps: (a) locating and fixing the body in a position appropriate to the measuring operation; (b) selecting an optical transmission-reflectance path including said organ and extending for several centimeters between points of light entry and exit said points of light entry and exit being laterally spaced several centimeters apart and positioned on contiguous skin surface areas of the body; (c) establishing a plurality of near-infrared light sources located external of the body and having light emissions of different wavelengths in the 700 to 1300 nanometer spectral range and of an intensity below the level damaging to the body and said organ but sufficient to be detectable by a light sensor after transmission through any skin, bone and tissue included in said path and scattering in and reflectance from said organ along said path, said emissions including at least one measuring wavelength and at least one reference wavelength within said spectral range, each said measuring wavelength being selected such that said organ exhibits a selective absorption therefor, the extent of which is dependent upon a specific state of metabolic activity of said organ; (d) directing said light emissions at said measuring and reference wavelengths sequentially at said point of entry to be transmitted, reflected and scattered along said path and to said organ and receiving the light emissions reflected directly back from said skin, bone and tissue at or within a few millimeters of said point of entry as well as the light emissions reflected and scattered from said organ at a point several centimeters away from said point of entry and light sensor and circuit means adapted to produce and electrical output signal corrected for changes in blood volume of said skin, bone and tissue during the measuring cycle and representing the difference in absorption of said measuring and reference wavelengths by the organ as a function of the state of said metabolic activity; and (e) converting said electrical output signal to a signal providing a substantially continuous and rapid measure of said activity.