Method and apparatus for performing optical measurements of a material

• US 20070052965A1
• Filed: 02/16/2006
• Published: 03/08/2007
• Est. Priority Date: 10/07/2002
• Status: Active Grant

• Current Assignee: Intellectual Discovery Co., Ltd.
• Original Assignee: IntelliDx, Inc.
• Inventors: Pesach, Benny, Bitton, Gabriel, Nagar, Ron
• Granted Patent: US 7,646,484 B2
• Time in Patent Office: Days
• US Class Current: 356/432
• CPC Class Codes: G01N 2021/6491 Measuring fluorescence and transmission; Correcting inner filter effect
• CPC Class Codes: G01N 21/1702 with opto-acoustic detection, e.g. for gases or analysing solids
• CPC Class Codes: G01N 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427
• CPC Class Codes: G01N 21/64 Fluorescence; Phosphorescence

Abstract

A method of determining an optical parameter or function thereof for a liquid, the method comprising: flowing the liquid through a flow cell; transmitting a pulse of light into the liquid in the flow cell; generating a signal responsive to energy that the material emits responsive to a portion of the light from the light pulse that is absorbed by the liquid; and using the signal to determine the optical parameter or function thereof.

Claims

1. A method of determining an optical parameter or function thereof for a liquid, the method comprising:

flowing the liquid through a flow cell;

transmitting a pulse of light into the liquid in the flow cell;

generating a signal responsive to energy that the material emits responsive to a portion of the light from the light pulse that is absorbed by the liquid; and

using the signal to determine the optical parameter or function thereof.

2. A method according to claim 1 wherein transmitting the light into the flow cell comprises transmitting the light in a direction along which the internal cross-section of the flow cell has a dimension that is greater than an absorption length of the light in the liquid.

3. A method according to claim 2 wherein the liquid is blood.

4. A method according to claim 3 wherein the dimension is greater than two absorption lengths of the light in the blood.

5. A method according to claim 3 wherein the dimension is greater than five times the absorption length.

6. A method according to claim 3 wherein the dimension is greater than ten times the absorption length.

7. A method according to claim 1 wherein the energy that the liquid emits is acoustic energy generated by a photoacoustic effect.

8. A method according to claim 1 wherein the energy that the liquid emits is thermal energy.

9. A method according to claim 1 wherein the liquid is blood.

10. A method according to claim 7 wherein the liquid is blood.

11. A method according to claim 8 wherein the liquid is blood.

12. A method according to claim 1 and comprising generating a signal responsive to light from the light pulse that is scattered by the material and using the signal to determine the optical parameter or function thereof.

39. A method according to claim 1 and comprising:

receiving light scattered by the liquid from the light pulse;

generating a signal responsive to the received scattered light;

providing a model that relates the received scattered light to a distance that the light travels in the material;

assuming a value for the distance; and

determining the optical parameter or function thereof responsive to the signal, the model and the assumed value.

40. A method according to claim 39 wherein the optical parameter comprises an absorption coefficient for the light.

13. Apparatus for determining an optical parameter or function thereof for a liquid, the apparatus comprising:

a flow cell through which the liquid flows the flow cell having a cross-section dimension greater than an absorption length in the liquid for light for which the optical parameter or function thereof is determined;

a light source that transmits a pulse of light into the liquid in the flow cell along the cross-section dimension;

a detector that receives energy emitted by the material responsive to light from the light pulse that is absorbed by the material and generates a signal responsive to the received energy; and

a processor that receives the signal and uses it to determine the optical parameter or function thereof.

14. Apparatus according to claim 13 wherein the dimension is greater than two absorption lengths of the light in the blood.

15. Apparatus according to claim 13 wherein the dimension is greater than five times the absorption length.

16. Apparatus according to claim 13 wherein the dimension is greater than ten times the absorption length.

17. Apparatus according to claim 13 wherein the energy that the liquid emits is acoustic energy generated by a photoacoustic effect.

18. Apparatus according to claim 13 wherein the energy that the liquid emits is thermal energy.

19. Apparatus according to claim 13 wherein the liquid is blood.

20. Apparatus according to claim 17 wherein the liquid is blood.

21. Apparatus according to claim 18 wherein the liquid is blood.

22. Apparatus according to claim 13 and comprising a detector that receives light from the light pulse that is scattered by the material and generates a signal responsive thereto;

23. Apparatus according to claim 22 wherein the processor receives the signal responsive to the scattered light and uses the signal to determine the optical parameter or function thereof.

24. Apparatus for determining an optical parameter or function thereof for a liquid, the apparatus comprising:

a flow cell through which the liquid flows;

a light source that transmits a pulse of light into the liquid in the flow cell that generates photoacoustic waves in the liquid;

a detector that receives energy from the photoacoustic waves and generates a signal responsive to the received energy; and

a processor that receives the signal and uses it to determine the optical parameter or function thereof.

25. A method of determining an optical parameter or function thereof for a material, the method comprising:

transmitting a pulse of light into the material;

receiving energy that the material emits responsive to a portion of the light from the light pulse that is absorbed by the material;

generating a signal responsive to the received energy;

providing a model that relates the received energy to a distance that the light travels in the material;

assuming a value for the distance; and

determining the optical parameter or function thereof responsive to the first signal, the model and the assumed value.

26. A method according to claim 25 wherein the assumed distance is substantially greater than an absorption length of the light in the material.

27. A method according to claim 26 wherein the assumed distance is infinite.

28. A method according to claim 25 wherein the material is strongly absorbing at a wavelength that characterizes the light.

29. A method according to claim 25 wherein the material is a liquid.

30. A method according to claim 29 wherein the liquid is blood.

31. A method according to claim 30 wherein transmitting the light into the blood comprises containing the blood in a receptacle having an internal dimension along a direction in which the light pulse is introduced into the blood that is greater than an absorption length of the light in the blood.

32. A method according to claim 31 wherein the internal dimension is greater than two absorption lengths of the light in the blood.

33. A method according to claim 31 wherein the internal dimension is greater than five times the absorption length.

34. A method according to claim 31 wherein the internal dimension is greater than ten times the absorption length.

35. A method according to claim 31 wherein the receptacle is a flow cell and the blood is flowing through the flow cell.

36. A method according to claim 31 wherein the energy that the material emits comprises a pulse of acoustic energy generated in the material by a photoacoustic effect and generating the first signal comprises sensing the acoustic energy and generating the first signal responsive thereto.

37. A method according to claim 31 wherein the energy that the material emits comprises thermal energy and generating the first signal comprises sensing the thermal energy and generating the first signal responsive thereto.

38. A method according to claim 31 wherein the energy that the material emits comprises optical energy luminesced by the material and generating the first signal comprises sensing the luminesced light and generating the first signal responsive thereto.