Measuring Cerebral Oxygen Saturation

• US 20080316488A1
• Filed: 05/06/2008
• Published: 12/25/2008
• Est. Priority Date: 06/20/2007
• Status: Active Grant

• Current Assignee: ViOptix, Inc.
• Original Assignee: ViOptix, Inc.
• Inventors: Lash, Robert E., Mao, Jimmy Jian-min
• Granted Patent: US 9,622,694 B2
• Time in Patent Office: Days
• US Class Current: 356/432
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 2562/0242 for varying or adjusting the optical path length in the tissue
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue

Abstract

A device includes source and detector sensors. In a specific implementation, the device has two near detectors, two far detectors, and two sources. The two near detectors are arranged closer to the two sources than the two far detectors. A light-diffusing layer covers the two near detectors. The device may be part of a medical device that is used to monitor or measure oxygen saturation levels in a tissue. In a specific implementation, light is transmitted into the tissue and received by the detectors. An attenuation coefficient is first calculated for a shallow layer of tissue. The attenuation coefficient is then used to calculate an attenuation coefficient for a deep layer of tissue.

Claims

1. A device comprising:

a first source structure;

a first near detector structure;

a first far detector structure; and

a light diffusing layer, wherein the first near detector structure receives a beam of light after the beam of light has been transmitted through a tissue and the light diffusing layer.

2. The device of claim 1 wherein the first source structure, first near detector structure, and first far detector structure are arranged in a line.

3. The device of claim 1 wherein a first distance between the first source structure and the first near detector structure is different from a second distance between the first source structure and first far detector structure.

4. The device of claim 3 wherein the first distance is less than the second distance.

5. The device of claim 3 wherein the first distance is approximately 30 millimeters.

6. The device of claim 3 wherein the second distance is approximately 40 millimeters.

7. The device of claim 1 further comprising:

a second source structure;

a second near detector structure; and

a second far detector structure, wherein the second near detector structure receives the beam of light after the beam of light has been transmitted through the tissue and the light diffusing layer.

8. The device of claim 7 wherein the second source structure, second near detector structure, and second far detector structure are arranged in a line.

9. The device of claim 7 wherein a third distance between the second source structure and the second near detector structure is different from a fourth distance between the second source structure and second far detector structure.

10. The device of claim 9 wherein the third distance is less than the fourth distance.

11. The device of claim 9 wherein the third distance is approximately 30 millimeters.

12. The device of claim 9 wherein the fourth distance is approximately 40 millimeters.

13. The device of claim 1 wherein the light diffusing layer is a semitranslucent film.

14. The device of claim 7 wherein the first near detector structure, the second near detector structure, the first far detector structure, and the second far detector structure comprise photodiodes.

15. The device of claim 7 wherein the first source structure and second source structure comprise optical fiber.

16. A method comprising:

positioning a sensor head to face toward a tissue, wherein the sensor head comprises a first source structure, a second source structure, a far detector arrangement, a near detector arrangement, and a semitranslucent film covering the near detector arrangement;

transmitting light through the first source structure and the second source structure into a tissue;

receiving light transmitted through the tissue and the detector arrangement, the received light including attenuation characteristics; and

processing the received light using a system unit.

17. The method of claim 16 wherein the transmitting light through the first source structure and the second source structure into a tissue, is from the system unit.

18. The method of claim 16 wherein the receiving light transmitted through the tissue and the detector arrangement, the received light including attenuation characteristics, is through photodetectors at the sensor head.

19. The method of claim 16 wherein the attenuation characteristics are at least partially caused by the semitranslucent film.

20. A probe, the probe being adapted for use as a part of a medical device system for measuring oxygen levels in a tissue, the probe comprising:

a sensor pad having a first cavity, a second cavity, and a third cavity, wherein a semitranslucent film is coupled to a bottom surface of the sensor pad and partially overlaps the first cavity; and

a sensor arrangement comprising a plurality photodetectors coupled to the first cavity, a first source structure coupled to the second cavity, and a second source structure coupled to the third cavity.

21. A method comprising:

placing a sensor head on a surface of a tissue to be measured;

transmitting light through a plurality of sources of the sensor head into the tissue;

receiving light transmitted through the tissue at a first plurality of detectors and at a second plurality of detectors, wherein the received light has a first attenuated amount at the first plurality of detectors and a second attenuated amount at the second plurality of detectors;

using the first attenuated amount, calculating a first attenuation coefficient for a shallow tissue region having a depth of at most about X below the surface of the tissue; and

using the second attenuated amount and the first attenuation coefficient, calculating a second attenuation coefficient for a deep tissue region having a depth of at least about Y below the surface of the tissue.

22. The method of claim 21 wherein X is equal to Y.

23. The method of claim 21 wherein X is different from Y

24. The method of claim 21 wherein X is less than Y.

25. The method of claim 21 wherein X and Y are about 12 millimeters.

26. The method of claim 21 wherein the tissue comprises a human scalp, skull, and brain.

27. The method of claim 21 wherein the second attenuated amount is not used in calculating the first attenuation coefficient.

28. The method of claim 21 wherein the calculating the second attenuation coefficient is performed after calculating the first attenuation coefficient.

29. The method of claim 21 wherein the second attenuated amount is greater than the first attenuated amount.

30. The method of claim 21 wherein a near distance from the plurality of sources to the first plurality of detectors is less than a far distance from the plurality of sources to the second plurality of detectors.

31. The method of claim 21 wherein the plurality of sources comprises a first source structure and a second source structure, and the first plurality of detectors comprises a first detector structure and a second detector structure, wherein the first source structure, second source structure, first detector structure, and second detector structure define vertices of a quadrilateral, and

a first side of the quadrilateral between the first source structure and first detector structure is same in length from a second side of the quadrilateral between the second source structure and the second detector structure.

32. The method of claim 21 wherein the plurality of sources comprises a first source structure and a second source structure, and the first plurality of detectors comprises a first detector structure and a second detector structure, wherein the first source structure, second source structure, first detector structure, and second detector structure define vertices of a quadrilateral, and

a first side of the quadrilateral between the first source structure and first detector structure is different in length from a second side of the quadrilateral between the second source structure and the second detector structure.