SYSTEMS AND METHODS FOR MEASURING OXYGENATION

• US 20160007892A1
• Filed: 07/08/2015
• Published: 01/14/2016
• Est. Priority Date: 04/11/2007
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: ESENALIEV, Rinat, PROUGH, Donald S., PETROV, Yuriy, PETROV, Irene, SAADE, George, OLSON, Gayle L.
• Granted Patent: US 10,307,088 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2562/0271 Thermal or temperature sensors
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/1464 specially adapted for foetal tissue
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: A61B 5/6875 Uterus
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence

Abstract

Optoacoustic diagnostic systems, devices, and methods are described. A system may comprise a console unit and a handheld probe. The console unit comprises a controller, a processor, a photodiode array, an acoustic processing subsystem, and a cooling subsystem. The probe directs light signals from the photodiode array to patient tissue. The light signals each have different wavelengths selected based on the physiological parameter of interest. The probe further comprises an acoustic transducer that receives acoustic signals generated in response to the directed light signals. The probe may comprise a finger-held working end that can be directed to the skull of a fetus within the uterus during labor. The probe can then accurately determine blood oxygenation of the fetus to determine if a caesarian section is necessary.

Claims

1. A method for optoacoustically determining oxygenation of a subject, the method comprising:

emitting a first light having a first wavelength to tissue of the subject;

emitting a second light having a second wavelength to the tissue, the second wavelength being different from the first wavelength;

emitting a third light having a third wavelength to the tissue, the third wavelength being different from the first and second wavelengths;

detecting acoustic pressure generated by the tissue in response to the first, second, and third emitted lights; and

determining oxygenation in response to the detected acoustic pressure.

2. The method of claim 1, wherein the first wavelength is in a range from 790 to 820 nm.

3. The method of claim 2, wherein the first wavelength is 805 nm.

4. The method of claim 1, wherein the second or third wavelength is in a range from 685 nm to 715 nm, 715 nm to 745 nm, 745 nm to 775 nm, or 845 nm to 875 nm.

5. The method of claim 4, wherein the second or third wavelength is 700 nm, 730 nm, 760 nm, or 860 nm.

6. The method of claim 1, wherein the first, second, and third lights are emitted from a common light source.

7. The method of claim 6, wherein the common light source is configured to rapidly switch between emitting the first light with the first wavelength, the second light with the second wavelength, and the third light with the third wavelength.

8. The method of claim 6, wherein the first, second, and third lights are emitted to the tissue from a common optical fiber.

9. The method of claim 1, wherein one or more of the first, second, or third lights have an energy level of at least 0.5 microjoules.

10. The method of claim 1, wherein determining oxygenation in response to the detected acoustic pressure comprises determining oxygenation in response to a first difference in detected acoustic pressure in response to the first emitted light and in response to the second emitted light and a second difference in detected acoustic pressure in response to the first emitted light and in response to the third emitted light.

11. The method of claim 10, wherein determining oxygenation comprises determining oxygenation in response to an average of oxygenation determined in response to the first difference and oxygenation determined in response to the second difference.

12. The method of claim 1, wherein one or more of the emitted first, second, or third light has a pulse width of at least 150 ns.

13. The method of claim 1, wherein one or more of the emitted first, second, or third light has a repetition rate of 10 to 2000 Hz.

14. The method of claim 1, wherein the first wavelength has substantially equal absorption between oxyhemoglobin and deoxyhemoglobin.

15. The method of claim 1, wherein the second and third wavelengths have absorption differences between oxyhemoglobin and deoxyhemoglobin.

16. A system for optoacoustically determining oxygenation of a subject, the system comprising:

a light source configured to emit to tissue a first light having a first wavelength, a second light having a second wavelength different from the second wavelength, and a third light having a third wavelength different from the first and second wavelengths;

an acoustic transducer configured to detect acoustic pressure generated by the tissue in response to the first, second and third emitted lights; and

a processor configured to determine oxygenation in response to the detected acoustic pressure.

17. The system of claim 16, wherein the light source comprises an array of laser diodes or light emitting diodes.

18. The system of claim 17, wherein the array of laser diodes or light emitting diodes comprises a first laser diode configured to emit the first light, a second laser diode configured to emit the second light, and a third laser diode configured to emit the third light.

19. The system of claim 16, wherein the first wavelength is in a range from 790 to 820 nm.

20. The system of claim 19, wherein the first wavelength is 805 nm.

21. The system of claim 16, wherein the second or third wavelength is in a range from 685 nm to 715 nm, 715 nm to 745 nm, 745 nm to 775 nm, or 845 nm to 875 nm.

22. The system of claim 21, wherein the second or third wavelength is 700 nm, 730 nm, 760 nm, or 860 nm.

23. The system of claim 16, further comprising a controller configured to rapidly switch the light source between emitting the first light with the first wavelength, the second light with the second wavelength, and the third light with the third wavelength.

24. The system of claim 16, further comprising a common optical fiber coupled to the light source and through which the first, second, and third lights are transmitted.

25. The system of claim 16, wherein one or more of the first, second, or third lights have an energy level of at least 0.5 microjoules.

26. The system of claim 16, wherein the processor is configured to determine oxygenation in response to a first difference in detected acoustic pressure in response to the first emitted light and in response to the second emitted light and a second difference in detected acoustic pressure in response to the first emitted light and in response to the third emitted light.

27. The system of claim 26, wherein the processor is configured to determine oxygenation in response to an average of oxygenation determined in response to the first difference and oxygenation determined in response to the second difference.

28. The system of claim 16, wherein the light source is configured to emit the first, second, or third light with a pulse width of at least 150 ns.

29. The system of claim 16, wherein the light source is configured to emit the first, second, or third light with a repetition rate of 10 to 2000 Hz.

30. The system of claim 16, wherein the first wavelength has substantially equal absorption between oxyhemoglobin and deoxyhemoglobin.

31. The system of claim 16, wherein the second and third wavelengths have absorption differences between oxyhemoglobin and deoxyhemoglobin.

32. The system of claim 16, further comprising a display configured to display the determined oxygenation.