Optical imaging and oximetry of tissue

• US 7,962,187 B2
• Filed: 03/13/2003
• Issued: 06/14/2011
• Est. Priority Date: 03/13/2002
• Status: Expired due to Fees

• Current Assignee: Tufts University
• Original Assignee: Tufts University
• Inventors: Fantini, Sergio
• Primary Examiner(s): JAWORSKI, FRANCIS J
• Application Number:
  US10/507,336
• Publication Number:
  US 20060106293A1
• Time in Patent Office: 3,015 Days
• Field of Search: 606 40- 49, 606/36, 606/38, 606/710.12, 606 15- 18, 600/424, 600/160, 600/310, 600/407, 600473-476, 600/323, 356/432, 356/436, 372/28, 382/128, 382/131
• US Class Current: 600/310
• CPC Class Codes: A61B 5/0091 for mammography
• CPC Class Codes: A61B 5/4312 Breast evaluation or disorder diagnosis A61B5/0091 takes precedence

Abstract

Systems and methods are disclosed for detecting at least one region of a sample having an absorption level different from a background level of absorption in the sample by obtaining thicknesses of the sample and intensities of light transmitted through the sample at a plurality of locations. The system includes glass plates (10) for compressing the tissue, distance sensors (20, 30), illuminations fibers (40) connected to a light source (70), and collection fibers (50) connected to spectrograph (110). Spatial second derivatives are calculated from products of the thicknesses of the sample and the intensities of the transmitted light for the locations. The data points are compared to detect the region of the sample having an absorption level different from the background level of absorption within the sample. The new systems and method can be used to optically image, detect, and characterize tissue, lesions, such as cancer.

Claims

1. A method of determining whether a tumor in a tissue sample is malignant or benign, the method comprising:

(a) selecting two wavelengths of light to minimize a difference between relative changes in intensity of light transmitted through the tumor for the two wavelengths, wherein the relative changes in intensity of the light for each wavelength are measured relative to a background intensity of light transmitted through the sample;

(b) obtaining measures of background reduced scattering coefficients of the sample at the two wavelengths;

(c) calculating an absolute oxygenation level of the tumor in the sample by using the relative changes in intensity of the light for the two wavelengths and the measures of the background reduced scattering coefficients of the sample for the two wavelengths; and

(d) determining whether the tumor is malignant or benign based on the value of the calculated absolute oxygenation level.

2. The method of claim 1, wherein the tissue sample is selected from the group consisting of breast tissue, brain tissue, and muscle tissue.

3. The method of claim 1, wherein the two wavelengths of light are in the near infrared spectrum.

4. The method of claim 1, wherein the difference between the relative changes in intensity is zero.

5. The method of claim 1, wherein the absolute oxygenation level of the tumor is calculated using a formula

6. The method of claim 1, further comprising, prior to selecting the two wavelengths of light:

(e) illuminating the sample with a plurality of wavelengths of light; and

(f) detecting light transmitted through the sample at a plurality of locations,

wherein the two wavelengths of light are selected from among wavelengths of the light transmitted through the sample.

7. The method of claim 6, further comprising (g) displaying an image of the absolute oxygenation level at the plurality of locations within the tissue sample.

8. The method of claim 1, further comprising (e) storing values of the absolute oxygenation level of the tumor in a computer-readable medium.

9. A method of determining whether a tumor in a tissue sample is malignant or benign, the method comprising:

(a) obtaining thicknesses of the sample and intensities of light transmitted through the sample at a plurality of locations for two wavelengths of light;

(b) calculating spatial second derivatives of products of the sample thicknesses and the intensities of the transmitted light at the locations for the two wavelengths of light;

(c) calculating an oxygenation level of the tumor based on the spatial second derivatives for the two wavelengths of light, the molar extinction coefficients of oxy-hemoglobin for the two the wavelengths of light, the molar extinction coefficients of hemoglobin for the two wavelengths of light, relative changes in intensity of the light for the two wavelengths of light and the measures of the background reduced scattering coefficients of the sample for the two wavelengths of light;

(d) calculating an oxygenation level of non-tumor regions of the tissue sample based on the spatial second derivatives for the two wavelengths of light, the molar extinction coefficients of oxy-hemoglobin for the two wavelengths of light, the molar extinction coefficients of hemoglobin for the two wavelengths of light, relative changes in intensity of the light for the two wavelengths of light, and the measures of the background reduced scattering coefficients of the sample for the two wavelengths of light; and

(e) comparing the oxygenation level of the tumor with the oxygenation level of non-tumor regions of the sample to determine whether the tumor is malignant or benign.

10. The method of claim 9, wherein the tissue sample is selected from the group consisting of breast tissue, brain tissue, and muscle tissue.

11. The method of claim 9, wherein the two wavelengths of light are in the near infrared spectrum.

12. The method of claim 9, wherein the oxygenation level of a region of the sample is calculated using a formula

13. The method of claim 9, further comprising, prior to obtaining the intensities of the transmitted light for two wavelengths:

(f) illuminating the sample with a plurality of wavelengths of light; and

(g) detecting light transmitted through the sample at a plurality of locations,

wherein the two wavelengths of light are selected from among wavelengths of the light transmitted through the sample.

14. The method of claim 9, further comprising (f) displaying an image of oxygenation levels at the plurality of locations within the tissue sample.

15. The method of claim 9, further comprising (f) storing values of oxygenation levels at a plurality of locations within the tissue sample in a computer-readable medium.