Method and system for detecting electrophysiological changes in pre-cancerous and cancerous tissue

• US 20050203436A1
• Filed: 04/01/2005
• Published: 09/15/2005
• Est. Priority Date: 05/20/2002
• Status: Active Grant

• Current Assignee: Richard J. Davies
• Original Assignee: Richard J. Davies
• Inventors: Davies, Richard J.
• Granted Patent: US 8,280,504 B2
• Time in Patent Office: Days
• US Class Current: 600/547
• CPC Class Codes: A61B 5/0531 Measuring skin impedance
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/2415 Measuring direct current [DC] or slowly varying biopotentials
• CPC Class Codes: A61B 5/4312 Breast evaluation or disorder diagnosis A61B5/0091 takes precedence
• CPC Class Codes: A61B 5/4381 Prostate evaluation or disorder diagnosis
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/6806 Gloves
• CPC Class Codes: A61B 5/6834 using vacuum

Abstract

A method and system are provided for determining a condition of a selected region of epithelial tissue. At least two current-passing electrodes are located in contact with a first surface of the selected region of the tissue. A plurality of measuring electrodes are located in contact with the first surface of the selected region of tissue as well. Electropotential and impedance are measured at one or more locations. An agent may be introduced into the region of tissue to enhance electrophysiological characteristics. The condition of the tissue is determined based on the electropotential and impedance profile at different depths of the epithelium, tissue, or organ, together with an estimate of the functional changes in the epithelium due to altered ion transport and electrophysiological properties of the tissue.

Claims

1. A method for determining a condition of a region of epithelial tissue comprising:

placing at least two current-passing electrodes in contact with or in proximity to a surface of said region;

placing a plurality of measuring electrodes in contact with or in proximity to said surface;

establishing an electrical signal between said current-passing electrodes;

measuring, at one or more of said measuring electrodes, an impedance associated with said signal;

introducing at least one agent into said region;

measuring, at one or more of said measuring electrodes, an impedance associated with said signal following the introduction of said at least one agent; and

determining the condition of said region based on said impedance, following the introduction of said at least one agent.

2. The method of claim 1, wherein placing of the current-passing electrodes includes the step of:

placing a probe in contact with or in proximity to said surface, wherein said current-passing electrodes are situated on said probe.

3. The method of claim 1, wherein placing of the measuring electrodes includes the step of:

placing a probe in contact with or in proximity to said surface, wherein said measuring electrodes are situated on said probe.

4. The method of claim 1, wherein the step of determining the condition of the selected region of tissue includes:

rating the tissue based on one of the following ratings;

normal, at-risk, pre-cancerous, or cancerous.

5. A method for determining a condition of a region of epithelial tissue comprising:

placing at least one current-passing electrode in contact with or in proximity to a surface of said region;

placing a plurality of measuring electrodes in contact with or in proximity to said surface;

establishing an electrical signal between said at least one current-passing electrode and at least one of said measuring electrodes;

measuring, at one or more of said measuring electrodes, an impedance associated with said signal;

introducing at least one agent into said region;

measuring, at one or more of said measuring electrodes, an impedance associated with said signal following the introduction of said at least one agent; and

determining the condition of said region based on said impedance, following the introduction of said at least one agent.

6. The method of claim 5, wherein placing of the current-passing electrodes includes the step of:

placing a probe in contact with or in proximity to said surface, wherein said at least one current-passing electrode is situated on said probe.

7. The method of claim 5, wherein placing of the measuring electrodes includes the step of:

placing a probe in contact with or in proximity to said surface, wherein said measuring electrodes are situated on said probe.

8. The method of claim 5, wherein the step of determining the condition of the selected region of tissue includes:

rating the tissue based on one of the following ratings;

normal, at-risk, pre-cancerous, or cancerous.

9. A method for measuring electrical properties of an epithelium, having a surface, using a combination of DC electrical measurements and impedance spectroscopy, comprising the steps of:

measuring a DC potential at the surface of the epithelium with a first and a second voltage-measuring electrode, wherein said voltage-measuring electrodes are spaced apart from one another and associated with a reference point;

placing a pair of current-passing electrodes in contact with or in proximity to said epithelium;

detecting, via said voltage-measuring electrodes, a resulting electrical signal at different points on said epithelial surface;

applying an electrical signal to said pair of current-passing electrodes at a plurality of frequencies at said different points on said epithelial surface;

monitoring the resulting electrical signal at said voltage-measuring electrodes associated with each of said plurality of frequencies; and

determining the impedance of the epithelium associated with the voltage-measuring electrodes based on each of the plurality of frequencies and the resulting electrical signal associated with each of the plurality of frequencies,

wherein said reference point includes an intravenous electrode or a skin electrode with low skin impedance.

10. The method of claim 9, wherein the applied electrical signal includes low and high frequency sinusoidal alternating currents.

11. The method of claim 10, wherein the sinusoidal alternating currents are applied sequentially.

12. The method of claim 10, wherein the sinusoidal alternating currents are applied in a composite form.

13. The method of claim 9, wherein the resulting electrical signal is a real part of a resulting potential difference measured over a current path across the current-passing electrodes.

14. The method of claim 9, wherein the plurality of frequencies falls within the range of 0.2-6000 Hz.

15. The method of claim 9, wherein the plurality of frequencies falls within the range of 2 to 800 kHz.

16. The method of claim 9, further including the step of:

filtering the resulting electrical signal using a low-pass filter.

17. The method of claim 9, further including the step of:

reducing a DC component of the resulting signal using a band-pass filter.

18. A method for measuring electrical properties of an epithelium, having a surface, using a combination of DC electrical measurements and impedance spectroscopy, comprising the steps of:

measuring a DC potential at the surface of the epithelium with a first and a second voltage-measuring electrodes, wherein the voltage-measuring electrodes are associated with a reference point;

placing at least one current-passing electrode in contact with or in proximity to said epithelium;

detecting, via said voltage-measuring electrodes, a resulting electrical signal at different points on said epithelial surface;

applying an electrical signal to at least one of said current-passing electrodes and at least one of the voltage-measuring electrodes at a plurality of frequencies at said different points on said epithelial surface;

monitoring the resulting electrical signal at said voltage-measuring electrodes associated with each of said plurality of frequencies; and

determining the impedance of said epithelium associated with said voltage-measuring electrodes based on each of said plurality of frequencies and said resulting electrical signal associated with each of said plurality of frequencies.

19. An apparatus for determining the condition of tissue of an epithelium using a combination of surface DC electrical measurements and impedance spectroscopy, the apparatus comprising:

a first pair of spaced electrodes for applying an electrical signal to the epithelium;

a second pair of spaced electrodes for detecting a resulting electrical signal at different points on the epithelium;

a means for applying the electrical signal to the first pair of electrodes at a plurality of frequencies;

a means for measuring the resulting electrical signal at the second pair of electrodes at said plurality of frequencies;

a means for obtaining a measure of the impedance of a part of the epithelium based on the resulting electrical signal; and

a means for obtaining a difference signal representing a change in impedance with frequency,

wherein each electrode of the second pair of electrodes includes an electroconductive medium concentration that differs from the other for estimating the specific ionic conductance of said epithelium.

20. The apparatus of claim 19, further comprising:

one or more additional pairs of electrodes placed at different locations than said first or second pairs of electrodes; and

a means for measuring a resulting electrical signal between said additional pairs of electrodes; and

a means for estimating an impedance for different layers of said epithelium by subtracting the impedance values from two pairs of said electrodes at each frequency.

21. The apparatus of claim 19, wherein each of said second pair of electrodes includes an electroconductive medium (ECM) at a concentration, and each said ECM is at a different concentration for estimating said specific ionic conductance of said epithelium.

22. The apparatus of claim 19, wherein said means for applying said electric signal includes:

a signal generator for producing simultaneously a plurality of low and high frequency constant alternating current signals; and

a connection means for supplying such signals to said first pair of electrodes.

23. The apparatus of claim 19, wherein the means for measuring the resulting electrical signal includes:

at least one adjustable gain voltage amplifier.

24. The apparatus of claim 19, wherein said means for obtaining the difference signal includes a microprocessor computing device.

25. The apparatus of claim 24, wherein said microprocessor computing device includes a low-pass filter.

26. The apparatus of claim 24, wherein said microprocessor computing device includes at least one of a band-pass filter and a high pass filter.

27. A method for determining the condition of a tissue, comprising:

(1) measuring a first DC potential of an area of said tissue using a first electroconductive medium;

(2) measuring a second DC potential of said area of tissue using a second electroconductive medium that differs in its ionic concentration from said first electroconductive medium; and

(3) comparing said first and second measurements to determine the condition of said tissue.

28. A method for determining the condition of a tissue, comprising:

(1) measuring a first DC potential of an area of said tissue using a first electroconductive medium;

(2) administering at least one agent;

(3) measuring a second DC potential of said area of tissue after said step of administering at least one agent; and

(4) comparing said first and second measurements to determine the condition of said tissue.

29. A method for determining the condition of a tissue, comprising:

(1) measuring a first DC potential of an area of said tissue using a first electroconductive medium;

(2) allowing a period of time to pass;

(3) measuring a second DC potential of said area of tissue after said period of time has passed; and

(4) comparing said first and second measurements to determine the condition of said tissue.

30. A method for determining the condition of a tissue, comprising:

(1) measuring a first impedance of an area of said tissue using a first electroconductive medium;

(2) measuring a second impedance of said area of tissue using a second electroconductive medium that differs in its ionic concentration from said first electroconductive medium; and

(3) comparing said first and second measurements to determine the condition of said tissue.

31. A method for determining the condition of a tissue, comprising:

(1) measuring a first impedance of an area of said tissue using a first electroconductive medium;

(2) administering at least one agent;

(3) measuring a second impedance of said area of tissue after said step of administering said at least one agent; and

(4) comparing said first and second measurements to determine the condition of said tissue.

32. A method for determining the condition of a tissue, comprising:

(1) measuring a first impedance of an area of said tissue using a first electroconductive medium;

(2) allowing a period of time to pass;

(3) measuring a second impedance of said area of tissue after said period of time has passed; and

(4) comparing said first and second measurements to determine the condition of said tissue.

33. A method for determining the condition of a tissue, comprising:

(1) measuring a first DC potential and impedance of an area of said tissue using a first electroconductive medium;

(2) measuring a second DC potential and impedance of said area of tissue using a second electroconductive medium that differs in its ionic concentration from said first electroconductive medium; and

(3) comparing said first and second measurements to determine the condition of said tissue.

34. A method for determining the condition of a tissue, comprising:

(1) measuring a first DC potential and impedance of an area of said tissue using a first electroconductive medium;

(2) administering at least one agent;

(3) measuring a second DC potential and impedance of said area of tissue after said step of administering at least one agent; and

(4) comparing said first and second measurements to determine the condition of said tissue.

35. A method for determining the condition of a tissue, comprising:

(1) measuring a first DC potential and impedance of an area of said tissue using a first electroconductive medium;

(2) allowing a period of time to pass;

(3) measuring a second DC potential and impedance of said area of tissue after said period of time has passed; and

(4) comparing said first and second measurements to determine the condition of said tissue.

36. An apparatus for determining the condition of a tissue, comprising:

means for measuring at least one electrical property of an area of said tissue using a first electroconductive medium;

means for measuring said at least one electrical property of said area of tissue using a second electroconductive medium that differs in its ionic concentration from said first electroconductive medium; and

means for comparing said measurements to determine the condition of said tissue.

37. The apparatus of claim 36, wherein said at least one electrical property is DC potential.

38. The apparatus of claim 36, wherein said at least one electrical property is impedance.

39. The apparatus of claim 36, further comprising means for measuring a plurality of electrical properties of said area, wherein said at least one electrical property is DC potential and said at least one electrical property is impedance.

40. An apparatus for determining the condition of a tissue, comprising:

means for measuring at least one electrical property of an area of said tissue using a first electroconductive medium;

at least one agent;

means for measuring said at least one electrical property of said area after said agent is administered; and

means for comparing said measurements to determine the condition of said tissue.

41. The apparatus of claim 40, wherein said at least one electrical property is DC potential.

42. The apparatus of claim 40, wherein said at least one electrical property is impedance.

43. The apparatus of claim 40, further comprising means for measuring a plurality of electrical properties of an area of tissue, wherein said at least one electrical property is DC potential and said at least one electrical property is impedance.

44. An apparatus for determining the condition of a tissue, comprising:

means for making a first measurement of at least one electrical property of an area of said tissue using a first electroconductive medium;

means for making a second measurement of said at least one electrical property of said area at a subsequent time to said first measurement; and

means for comparing said first and second measurements to determine the condition of said tissue.

45. The apparatus of claim 44, wherein said at least one electrical property is DC potential.

46. The apparatus of claim 44, wherein said at least one electrical property is impedance.

47. The apparatus of claim 44, further comprising means for measuring a plurality of electrical properties of said area, wherein said at least one electrical property is DC potential and said at least one electrical property is impedance.