Polarized light scattering spectroscopy of tissue

• US 6,404,497 B1
• Filed: 01/25/1999
• Issued: 06/11/2002
• Est. Priority Date: 01/25/1999
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Dasari, Ramanchandra R., Backman, Vadim, Feld, Michael S., Itzkan, Irving, Gurjar, Rajan, Perelman, Lev
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): STAFIRA, MICHAEL PATRICK
• Application Number:
  US09/237,153
• Time in Patent Office: 1,233 Days
• Field of Search: 356/369, 356/367, 356/364, 356/342, 250/578.1, 250/216, 600/178, 600/180, 600/181, 600/473, 600/476, 600/310, 600/477, 600/478, 600/314, 600/342
• US Class Current: 356/369
• 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

Abstract

The present invention relates to the use of polarized light to measure properties of tissue. More particularly, polarized light can be used to detect dysplasia in tissue as the polarization of backscattered light from such tissues is preserved while the contribution of diffusely scattered light from underlying tissues can be removed. A fiber optic system for delivery and collection of light can be used to measure tissues within the human body.

Claims

1. A method of detecting dysplasia comprising:

directing polarized light having a plurality of wavelengths onto tissue, the tissue including a first epithelial layer having a region of interest and an underlying tissue layer;

detecting polarized backscattered light returning from the region of interest, the backscattered light having a component that is periodic as a function of wavelength; and

determining whether tissue in the region of interest is normal or includes epithelial dysplasia with the detected periodic component of the backscattered light.

2. The method of claim 1 further comprising determining a size of tissue cells within the region of interest.

3. The method of claim 1 further comprising removing a nonpolarized component of the light returning from the tissue.

4. The method of claim 1 further comprising providing a fiber optic probe and delivering the polarized light onto the tissue with the probe.

5. The method of claim 1 further comprising detecting the polarized backscattered light and forming a spectrum with the detected light, the spectrum including wavelengths in the range of 300 nm to 1200 nm.

6. A method of measuring tissue comprising:

directing polarized light having a plurality of wavelengths onto tissue with a fiber optic probe;

detecting polarized backscattered light returning from the tissue including a component that is periodic as a function of wavelength;

determining a characteristic of the tissue with the detected periodic component of light.

7. The method of claim 6 further comprising determining a size of tissue cells within the tissue.

8. The method of claim 6 further comprising removing a nonpolarized component of the light returning from the tissue.

9. The method of claim 6 further comprising collecting the returning light with the fiber optic probe.

10. The method of claim 6 further comprising detecting the polarized backscattered light and forming a spectrum with the detected light, the spectrum including wavelengths in the range of 300 nm to 1200 nm.

11. The method of claim 6 further comprising measuring a plurality of polarization components in the returning light.

12. The method of claim 6 further comprising providing a plurality of polarization filters at the distal end of the probe.

13. The method of claim 6 further comprising providing a broadband light source that is optically coupled to the fiber optic probe.

14. The method of claim 6 further comprising a spectrometer optically coupled to the fiber optic probe.

15. The method of claim 6 further comprising inserting the probe through an endoscopic channel.