Apparatus for monitoring metabolism in body organs

• US 4,380,240 A
• Filed: 08/03/1981
• Issued: 04/19/1983
• Est. Priority Date: 06/28/1977
• Status: Expired due to Fees

• Current Assignee: Duke University
• Original Assignee: Duke University
• Inventors: Overaker, Ronald F., Jobsis, Frans F., Keizer, Johannes H.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US06/289,413
• Time in Patent Office: 624 Days
• Field of Search: 128/633-635, 128/663-665, 128/673, 128/687-689
• US Class Current: 600/344
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0073 by tomography, i.e. reconstruction of 3D images from 2D projections A61B5/0066 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61K 49/0004 Screening or testing of compounds for diagnosis of disorders, assessment of conditions, e.g. renal clearance, gastric emptying, testing for diabetes, allergy, rheuma, pancreas functions

Abstract

A mounting structure secures to a selected portion of the human body, e.g., the head, a limb, or the torso, and incorporates light source and light detecting means adapted for association with spectrophotometric circuitry for in situ, in vivo monitoring of local metabolism in the area of the body where the structure is secured.

Claims

1. In a spectrophotometric reflectance apparatus for measuring in situ, in vivo, non-invasively, atraumatically, harmlessly, rapidly and continuously a local metabolic oxygen dependent activity of a selected portion of the body where such activity bears a measurable relation to an oxygen dependent absorption characteristic of the selected portion for a particular wavelength of light transmitted therethrough having:

(a) circuitry means including;

(i) a plurality of near-infrared light sources located external of the body and having light emissions of different wavelengths in the 700-1300 nanometer spectral range and of an intensity below the level damaging to the body and said selected portion but sufficient to be detectable by a light sensor after transmission through any skin, bone and tissue included in an optical transmission-reflectance path including said selected portion thereof and extending for several centimeters between selected points of light entry and exit laterally spaced several centimeters apart and located on contiguous skin surface areas of the body and after scattering in and deep reflectance from said selected portion 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 selected portion exhibits a selected absorption therefore, the extent of which is dependent upon a specific state of a local metabolic, oxygen dependent activity of said selected portion; and

(ii) means operatively associated with said light sources to produce emissions representing at least one said measuring wavelength and at least one said reference wavelength within said spectral range for transmission along said path to said selected portion and at levels of intensity below that which would be damaging to the body and said selected portion;

(b) first optical cable means providing a bundle of optical fibers with selected fibers connected for receiving, transmitting and directing the output light emissions of said light sources at said measuring and reference wavelengths to a selected light entry point proximate said body and other selected fibers connected for receiving deeply penetrating light emissions reflected directly back from any skin, bone and tissue at or within a few millimeters of said selected point of light entry and coupling such emissions to a processing means;

(c) second optical cable means providing a bundle of optical fibers adapted for receiving deeply penetrating light emissions reflected and scattered to said selected point of light exit from said selected portion of said body and coupling such exiting light emissions to a processing means; and

(d) processing means operatively associated with said circuitry means adapted to produce from the outputs of said first and second optical cable means an 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 said selected body portion as a function of the state of said local metabolic oxygen dependent activity and further adapted to convert said electrical output signal to a signal providing a substantially continuous and rapid measure of said activity;

(e) an improved detachable, body mountable apparatus associated with said circuitry, coupling and processing means comprising;

(i) a flexible, elongated support member adapted to be releasably secured to the body proximate a said selected portion of the body having a selected set of said light entry and exit points, said support member being adapted to provide ambient light shielding over said light entry and exit points and to conform to the curvature and shape of the body at the location thereof;

(ii) a mounting structure secured to said support member and adapted to deform in shape in correspondence with the curvature assumed by said support member when secured to the body;

(iii) a first preformed optical module mounted in said structure and providing a hollow housing enclosing first right angled light guide means formed by a bundle of optical fibers optically coupled to said first optical cable means and having an optical face centered in a slightly tapered outer face of said housing and adapted to be mated in a substantially pressed fit relation with said selected point of light entry utilizing selected fibers of said bundle for entry of light in said wavelengths to be transmitted, deeply reflected and scattered along said path and to said selected portion and other selected fibers for receiving deeply penetrating light emissions reflected directly back from any skin, bone and tissue at or within a few millimeters of said selected point of light entry;

(iv) a second preformed optical module mounted in said mounting structure and providing a second hollow housing enclosing second right angled light guide means formed by a bundle of optical fibers optically coupled to said second optical cable means and having a second optical face centered in a slightly tapered outer face of said second housing and spaced several centimeters away from said first optical face and adapted to be mated in a substantially pressed fit relation with said selected point of light exit for receiving deeply penetrating light emissions reflected and scattered to said selected point of light exit from said selected portion of said body.

2. In an apparatus as claimed in claim 1 wherein each said optical module includes openings in the respective outer faces of the respective housings thereof surrounding the respective optical faces thereof and means communicating said openings to a vacuum source whereby securement of said optical faces to the respective points of light entry and exit is enhanced by a vacuum assisted pull on the skin surrounding said points.

3. In an apparatus as claimed in claim 1 including annular shaped, double-faced, pressure-sensitive adhesive tapes adhered to the respective outer faces of said housings surrounding the respective optical faces and adapted for securement to the skin surrounding said points.

4. In an apparatus as claimed in claim 1 wherein said mounting structure is detachably secured to said support member.

5. An improved detachable, body mountable apparatus for association with spectrophotometric circuitry, coupling and processing means comprising:

(i) a flexible, elongated support member adapted to be releasably secured to the body proximate a said selected portion of the body having a selected set of light entry and exit points, said support member being adapted to provide ambient light shielding over said light entry and exit points and to conform to the curvature and shape of the body at the location thereof;

(ii) a mounting structure secured to said support member and adapted to deform in shape in correspondence with the curvature assumed by said support member when secured to the body;

(iii) a first preformed optical module mounted in said structure and providing a hollow housing enclosing first right angled light guide means formed by a bundle of optical fibers optically coupled to external optical cable means and having a first optical light emitting face positioned in an outer face of said housing having openings therethrough and adapted to be mated in a substantially pressed fit relation with said selected point of light entry utilizing fibers of said bundle for entry of light in selected wavelengths to be transmitted, deeply reflected and scattered along said path and to said selected portion and further enclosing a first light detector means coupled to a processing means and having a first light receiving face positioned in said outer face of said housing for receiving and processing deeply penetrating light emissions reflected directly back from any skin, bone and tissue at or within a few millimeters of said selected point of light entry;

(iv) a second preformed optical module mounted in said mounting structure and providing a second hollow housing enclosing a second light detector means coupled to processing means and having a second light receiving face positioned in an outer face of said second housing and spaced several centimeters away from said first optical face, said outer face of said second housing having openings therethrough and adapted to be mated in a substantially pressed fit relation with said selected point of light exit for receiving and processing deeply penetrating light emissions reflected and scattered to said selected point of light exit from said selected portion of said body; and

(v) means communicating said face openings to a vacuum source whereby securement of said optical faces to the respective points of light entry and exit may be enhanced by a vacuum assisted pull on the skin surrounding said points.