Acetic acid as a signal enhancing contrast agent in fluorescence spectroscopy

• US 6,241,662 B1
• Filed: 10/20/1998
• Issued: 06/05/2001
• Est. Priority Date: 10/20/1997
• Status: Expired due to Term

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Lifespex, Inc.
• Inventors: Agrawal, Anant, Brookner, Carrie, Pitris, Costas, Richards-Kortum, Rebecca, Utzinger, Urs, Mitchell, Michele Follen
• Primary Examiner(s): Lateef, Marvin M.
• Assistant Examiner(s): Lin, Jeoyuh
• Application Number:
  US09/175,232
• Time in Patent Office: 959 Days
• Field of Search: 600/407, 600/310, 600/312, 600/317, 600/473, 600/475, 600/476, 600/477, 356/432, 356/346, 356/349
• US Class Current: 600/310
• CPC Class Codes: A61B 5/0071 by measuring fluorescence emission
• CPC Class Codes: A61B 5/4331 of the cervix A61B5/435 takes precedence
• CPC Class Codes: G01N 1/30 Staining; Impregnating ; Fixation; Dehydration; Multistep processes for preparing samples of tissue, cell or nucleic acid material and the like for analysis
• CPC Class Codes: G01N 2015/1488 Methods for deciding
• CPC Class Codes: G01N 33/52 Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper and including single- and multilayer analytical elements immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72

Abstract

A method for using acetic acid as a signal enhancing contrast agent during fluorescence spectroscopy of normal and neoplastic tissue, particularly epithelium. In one aspect, the invention includes a method of detecting tissue abnormality in a diagnostic tissue sample in a patient, comprising the steps of obtaining a first fluorescence intensity spectrum from the diagnostic tissue sample; thereafter, applying acetic acid to the diagnostic tissue sample in sufficient concentration to alter the response of such diagnostic tissue sample to electromagnetic radiation for at least an effective period of time; during the effective period of time, obtaining a second fluorescence intensity spectrum from the diagnostic tissue sample; determining a parameter indicative of a change between the first and second fluorescence emission intensity spectra; and analyzing the determined parameter to determine a probability that the diagnostic tissue sample is normal or abnormal.

Claims

1. A method of detecting tissue abnormality in a diagnostic tissue sample in a patient, comprising:

(a) obtaining a first fluorescence emission intensity spectrum from the diagnostic tissue sample;

(b) thereafter, applying acetic acid to the diagnostic tissue sample in sufficient concentration to alter the response of such diagnostic tissue sample to excitation electromagnetic radiation, said acetic acid being applied for a selected period of time;

(c) obtaining a second fluorescence emission intensity spectrum from the diagnostic tissue sample during said selected period of time;

(d) determining a parameter indicative of a change between the first and second fluorescence emission intensity spectra, where said parameter is indicative of hemoglobin absorption; and

(e) analyzing the determined parameter to determine a probability that the diagnostic tissue sample is normal or abnormal.

2. The method of claim 1, wherein the step of analyzing the determined parameter to determine a probability that the diagnostic tissue sample is normal or abnormal includes the step of comparing the determined parameter to a threshold value to indicate tissue abnormality in the diagnostic tissue sample if the determined parameter exceeds the threshold value.

8. The method of claims 1 or 3, performed with a cervical tissue sample as the diagnostic tissue sample.

9. The method of claims 1 or 3, wherein the diagnostic tissue sample is in vivo.

3. A method of detecting tissue abnormality, comprising:

(a) illuminating a diagnostic tissue sample with excitation electromagnetic radiation;

(b) detecting a first fluorescence emission intensity spectrum from the diagnostic tissue sample resulting from such illuminating;

(c) thereafter, exposing the diagnostic tissue sample to acetic acid in sufficient concentration to have an effect of detectably altering the response of such diagnostic tissue sample to excitation electromagnetic radiation, where said acetic acid is applied to the tissue sample for a selected period of time;

(d) illuminating the diagnostic tissue sample with excitation electromagnetic radiation during said selected period of time;

(e) detecting a second fluorescence emission intensity spectrum from the diagnostic tissue sample resulting from such further illuminating;

(f) determining a parameter indicative of a change between the first and second fluorescence emission intensity spectra, where said parameter is indicative of hemoglobin absorption; and

(g) comparing the determined parameter to a threshold value to indicate tissue abnormality in the diagnostic tissue sample if the determined parameter exceeds the threshold value.

4. The method of claim 3, wherein the electromagnetic radiation in steps (a) and (d) are essentially identical wavelengths.

5. The method of claim 3, wherein the electromagnetic radiation used in steps (a) and (d) has a wavelength of about 380 nm.

6. The method of claim 3, wherein the electromagnetic radiation used in steps (a) and (d) has a wavelength of about 337 nm.

7. The method of claim 3, wherein the electromagnetic radiation used in steps (a) and (d) has a wavelength of about 460 nm.

10. A method of detecting tissue abnormality in a diagnostic tissue sample in a patient, comprising:

(a) obtaining a first fluorescence emission intensity spectrum from the diagnostic tissue sample;

(b) thereafter, applying acetic acid to the diagnostic tissue sample in sufficient concentration to alter the response of such diagnostic tissue sample to excitation electromagnetic radiation, said acetic acid being applied for a selected period of time;

(c) obtaining a second fluorescence emission intensity spectrum from the diagnostic tissue sample during said selected period of time;

(d) determining a parameter indicative of a change between the first and second fluorescence emission intensity spectra, where said parameter is indicative of red shift; and

(e) analyzing the determined parameter to determine a probability that the diagnostic tissue sample is normal or abnormal.

12. The method of claim 10, wherein the parameter is indicative of a shift in peak emission wavelength.

11. A method of detecting tissue abnormality, comprising:

(a) illuminating a diagnostic tissue sample with excitation electromagnetic radiation;

(b) detecting a first fluorescence emission intensity spectrum from the diagnostic tissue sample resulting from such illuminating;

(c) thereafter, exposing the diagnostic tissue sample to acetic acid in sufficient concentration to have an effect of detectably altering the response of such diagnostic tissue sample to excitation electromagnetic radiation, where said acetic acid is applied to the tissue sample for a selected period of time;

(d) illuminating the diagnostic tissue sample with excitation electromagnetic radiation during said selected period of time;

(e) detecting a second fluorescence emission intensity spectrum from the diagnostic tissue sample resulting from such further illuminating;

(f) determining a parameter indicative of a change between the first and second fluorescence emission intensity spectra, where said parameter is indicative of red shift; and

(g) comparing the determined parameter to a threshold value to indicate tissue abnormality in the diagnostic tissue sample if the determined parameter exceeds the threshold value.

13. The method of claim 11, wherein the parameter is indicative of a shift in peak emission wavelength.