Methods and apparatus for optical imaging

• US 6,519,076 B2
• Filed: 01/10/2002
• Issued: 02/11/2003
• Est. Priority Date: 10/30/1996
• Status: Expired due to Term

• Current Assignee: Provectus Devicetech, Inc.
• Original Assignee: Photogenic Inc.
• Inventors: Wachter, Eric A., Fisher, Walter G.
• Primary Examiner(s): Mack, Ricky
• Assistant Examiner(s): HINDI, OMAR Z
• Application Number:
  US10/045,562
• Publication Number:
  US 20020122236A1
• Time in Patent Office: 397 Days
• Field of Search: 359/278, 359/239, 359/276, 342/27, 342/128, 345/157, 367/100, 250/338.5, 356/437
• US Class Current: 359/326
• CPC Class Codes: A61B 2017/00053 Mapping
• CPC Class Codes: A61B 2017/00057 Light
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61B 2017/00867 shape memory effect for prostheses A61F2210/0014
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0068 Confocal scanning
• CPC Class Codes: A61K 41/008 Two-Photon or Multi-Photon PDT, e.g. with upconverting dyes or photosensitisers
• CPC Class Codes: A61K 49/0017 Fluorescence in vivo
• CPC Class Codes: A61M 25/0041 pre-formed, e.g. specially adapted to fit with the anatomy of body channels urethral catheters A61F2/04
• CPC Class Codes: A61M 25/0133 Tip steering devices
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 2005/0644 Handheld applicators
• CPC Class Codes: A61N 5/062 Photodynamic therapy, i.e. excitation of an agent
• CPC Class Codes: B23K 26/0624 using ultrashort pulses, i.e. pulses of 1ns or less
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B

Abstract

Methods and apparatus directed to using modulation to substantially improve detection limits in optical imaging, and to substantially improve the performance of various optical imaging systems. In an illustrative embodiment, such modulation is achieved using a modulated light source, a modulation frequency reference, a detector, and a demodulator. The modulated light source may comprise a light source emitting an inherently modulated output; alternately, this modulated light source may comprise a separate optical modulator and a continuous wave, modulated, or pulsed light source configured so as to impose a modulation in the output of light source. Methods for imagine using such modulation are also disclosed.

Claims

1. A method for imaging a material, the method comprising the steps of:

encoding light from a light source with a modulation pattern to produce a modulated light;

directing said modulated light onto or into said material, said material emitting a modulated optical signal which is characteristic of the material;

detecting said emitted modulated optical signal from said material and converting said optical signal into a modulated electronic signal which is characteristic of the material; and

demodulating the modulated electronic signal which is characteristic of the material.

2. The method according to claim 1 wherein said light from said light source is encoded with a modulation pattern produced by said light source.

3. The method according to claim 1 wherein said light from said light source is encoded with a modulation pattern synchronous with a modulation frequency reference signal and wherein said modulation frequency reference signal is used in demodulating said modulated electronic signal.

4. The method according to claim 1 wherein said modulation frequency reference signal is produced using a modulation frequency reference.

5. The method according to claim 1 wherein said imaging is for microscopy.

6. The method according to claim 1 wherein said imaging is for medical imaging.

7. The method according to claim 1 further comprising the step of collecting the demodulated electronic signal and forming a multi-dimensional image of said material.

8. The method according to claim 1, wherein said detecting of said emitted modulated optical signal uses detection selected from the group consisting of confocal detection, parafocal detection, monostatic detection, bistatic detection, descanned detection, whole area detection, external detection, and non-optical detection.

9. The method according to claim 1, wherein said encoding and said demodulation are performed simultaneous or substantially simultaneous at two or more modulation frequencies.

10. A method for imaging a material, the method comprising the steps of:

producing a reference frequency signal;

encoding light from a light source with a modulation pattern synchronous with said reference frequency signal to produce a modulated light;

directing said modulated light onto or into said material, said material emitting a modulated optical signal resulting from an interaction of said modulated light and said material;

detecting said emitted modulated optical signal and converting said optical signal into a modulated electronic signal which is characteristic of the material; and

demodulating the modulated electronic signal using said reference frequency signal to produce a demodulated electronic signal which is characteristic of the material.

11. The method according to claim 10 wherein said imaging is for microscopy.

12. The method according to claim 10 wherein said imaging is for medical imaging.

13. The method according to claim 10 further comprising the step of collecting the demodulated electronic signal and forming a multi-dimensional image of said material.

14. The method according to claim 10, wherein said detecting of said emitted modulated optical signal uses detection selected from the group consisting of confocal detection, parafocal detection, monostatic detection, bistatic detection, descanned detection, whole area detection, external detection, and non-optical detection.

15. The method according to claim 10, wherein said encoding and said demodulation are performed simultaneous or substantially simultaneous at two or more modulation frequencies.

16. A method for microscopic imaging, the method comprising the steps of:

producing a reference frequency signal;

encoding light from a light source with a modulation pattern synchronous with said reference frequency signal to produce a modulated light;

directing said modulated light onto or into a material to be imaged, said material emitting a modulated optical signal resulting from an interaction of said modulated light and said material;

detecting said emitted modulated optical signal and converting said optical signal into a modulated electronic signal which is characteristic of the material; and

demodulating the modulated electronic signal using said reference frequency signal to produce a demodulated electronic signal which is characteristic of the material.

17. The method according to claim 16 further comprising the step of collecting the demodulated electronic signal and forming a multi-dimensional image of said material.

18. The method according to claim 16, wherein said detecting of modulated light uses detection selected from the group consisting of confocal detection, parafocal detection, monostatic detection, bistactic detection, descanned detection, whole area detection, external detection, and non-optical detection.

19. The method according to claim 16, wherein said encoding and said demodulation are performed simultaneous or substantially simultaneous at two or more modulation frequencies.