Laser endoscope for spectroscopic imaging

• US 5,318,024 A
• Filed: 12/16/1991
• Issued: 06/07/1994
• Est. Priority Date: 03/22/1985
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Feld, Michael S., Kittrell, Carter, Cothren, Robert M. Jr.
• Primary Examiner(s): HINDENBURG, MAX F
• Application Number:
  US07/808,001
• Time in Patent Office: 904 Days
• Field of Search: 128/634, 128/664, 128/665, 356/73, 356/375
• US Class Current: 600/478
• CPC Class Codes: A61B 1/00096 Optical elements
• CPC Class Codes: A61B 18/20 using laser
• CPC Class Codes: A61B 18/245 for removing obstructions in blood vessels or calculi
• CPC Class Codes: A61B 2018/00636 Sensing and controlling the application of energy
• CPC Class Codes: A61B 2018/2238 with means for selectively laterally deflecting the tip of the fibre
• CPC Class Codes: A61B 5/0071 by measuring fluorescence emission
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/0648 comprising lenses
• CPC Class Codes: B23K 26/0665 by beam condensation on the workpiece, e.g. for focusing
• CPC Class Codes: B23K 26/067 Dividing the beam into multiple beams, e.g. multifocusing
• CPC Class Codes: G01N 2021/4747 Concentric bundles
• CPC Class Codes: G02B 6/04 formed by bundles of fibres G02B6/24 takes precedence
• CPC Class Codes: G02B 6/14 Mode converters
• CPC Class Codes: G02B 6/241 Light guide terminations
• CPC Class Codes: G02B 6/3502 involving direct waveguide displacement, e.g. cantilever type waveguide displacement involving waveguide bending, or displacing an interposed waveguide between stationary waveguides
• CPC Class Codes: G02B 6/3504 Rotating, tilting or pivoting the waveguides, or with the waveguides describing a curved path rotary joint G02B6/3628
• CPC Class Codes: G02B 6/3508 Lateral or transverse displacement of the whole waveguides, e.g. by varying the distance between opposed waveguide ends, or by mutual lateral displacement of opposed waveguide ends
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/3516 : the reflective optical element moving along the beam path, e.g. controllable diffractive effects using multiple micromirrors within the beam
• CPC Class Codes: G02B 6/353 : the optical element being a shutter, baffle, beam dump or opaque element absorbers on light guide termination G02B6/243
• CPC Class Codes: G02B 6/3548 : 1xN switch, i.e. one input and a selectable single output of N possible outputs
• CPC Class Codes: G02B 6/3588 : of the processed beams, i.e. controlling during switching of orientation, alignment, or beam propagation properties such as intensity, size or shape
• CPC Class Codes: G02B 6/3598 : Switching means directly located between an optoelectronic element and waveguides, including direct displacement of either the element or the waveguide, e.g. optical pulse generation based on changing the optical properties of the medium G02F1/00; optical pulse generation in optical transmitters H04B10/508; optical pulse generation by controlling laser operation H01S3/00
• CPC Class Codes: G02B 6/4296 : coupling with sources of high radiant energy, e.g. high power lasers, high temperature light sources

Abstract

A laser endoscope is disclosed for generating a spectrally resolved spatial image of tissue. Fiber optics positioned within an optically shielded endoscope are used to deliver laser radiation to tissue to be imaged. Radiation returning through the fiber optics from the tissue is spectrally resolved and used to generate an image of tissue that can assist in diagnosis and treatment.

Claims

1. A method for generating a spectrally resolved spatial image of tissue comprising:

positioning an endoscope containing a plurality of optical fibers within a body lumen, the endoscope having an optical shield positioned between distal ends of the fibers and the tissue;

coupling laser radiation to a waveguide extending through or adjacent to the endoscope to illuminate tissue within the lumen with the radiation;

separating light returned by the tissue through the optical shield and transmitted along the endoscope fibers into different wavelengths with a spectral analyzer;

processing the separated light received by the detector with a computer such that the spectrally resolved light provides a displayable spatial image of the illuminated tissue.

2. The method of claim 1 wherein the optical fibers are arranged within the endoscope in a fiber bundle.

3. The method of claim 1 wherein said spectral analyzer comprises a diffraction grating.

4. A method of obtaining spectrally resolved spatial images comprising the steps of:

positioning the distal end of an endoscope in proximity with tissue to be imaged;

passing light through optical fibers within the endoscope onto the surface of the tissue;

collecting inelastically scattered light returned from said tissue and delivering it to a spectral analyzer with said optical fibers such that the scattered light is spectrally dispersed and impinges on a detector array; and

processing signals from said detector array in a computer to generate a spectrally resolved spatial image of said tissue.

5. A spectrally resolved imaging system comprising:

an endoscope containing a plurality of optical fibers;

a light source coupled to the fiber bundle to irradiate tissue positioned adjacent a distal end of the endoscope such that inelastically scattered radiation returning from the tissue in response to the irradiation from the source is transmitted through the endoscope;

a spectral analyzer that receives the inelastically scattered light returned by the tissue which is transmitted from the proximal end of the endoscope such that the light emitted by each portion of tissue is spectrally resolved;

a detector to receive the spectrally resolved light; and

a data processor that processes the spectral information received by the detector for each portion of tissue to form a spectrally resolved spatial image of the tissue.

6. The spectrally resolved imaging system of claim 5 wherein the detector comprises a detector array such that each wavelength of light falls on a single detector element of the array.

7. The spectrally resolved imaging system of claim 5 wherein the spectral analyzer comprises a plurality of filer elements.

8. The spectrally resolved imaging system of claim 5 wherein the spectral analyzer comprises a diffraction grating.

9. The spectrally resolved imaging system of claim 5 wherein the detector comprises an array of photodiodes.

10. A method of imaging tissue comprising;

positioning a distal end of an endoscope adjacent to the tissue;

transmitting laser radiation along optical fibers within the endoscope;

irradiating the tissue with the laser radiation projected from the distal end of the endoscope;

collecting radiation returned from the tissue resulting form the irradiation thereof with the optical fibers such that the collected radiation is projected from the proximal end of the endoscope;

spectrally resolving the radiation projected from the proximal end of the endoscope;

forming a spectrally resolved spatial image of the tissue from the resolved radiation.

11. The method of imaging tissue to claim 10 further comprising spectrally resolving the radiation transmitted from the tissue with a diffraction grating.

12. The method of imaging tissue of claim 10 further comprising detecting the spectrally resolved radiation such that each wavelength of the radiation transmitted from the tissue by the fibers is directed onto a different portion of a detector array.

13. The method of imaging tissue of claim 10 wherein said spectrally resolving step further comprises directing the projected radiation a plurality of filters.

14. The method imaging tissue of claim 10 further comprising detecting the spectrally resolved radiation to produce an imaging signal and processing the imaging signal to form the spectrally resolved spatial image.