SYSTEMS AND METHODS FOR PHOTOACOUSTIC OPTHALMOSCOPY

• US 20100245770A1
• Filed: 03/17/2010
• Published: 09/30/2010
• Est. Priority Date: 03/17/2009
• Status: Abandoned Application

• Current Assignee: University of Southern California, UWM Research Foundation, Inc. (University of Wisconsin System)
• Original Assignee: University of Southern California
• Inventors: Zhang, Hao F., Jiao, Shuliang
• Application Number:
  US12/726,182
• Publication Number:
  US 20100245770A1
• Time in Patent Office: Days
• US Class Current: 351/219
• 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 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: A61B 8/10 Eye inspection
• CPC Class Codes: A61B 8/4472 Wireless probes
• CPC Class Codes: G01B 9/0203 With imaging systems
• CPC Class Codes: G01B 9/02044 Imaging in the frequency domain, e.g. by using a spectrometer
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence
• CPC Class Codes: G01N 29/0681 by acoustic microscopy, e.g. scanning acoustic microscopy
• CPC Class Codes: G01N 29/2418 using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046

Abstract

Various embodiments of the present invention include systems and methods for multimodal functional imaging based upon photoacoustic and laser optical scanning microscopy. In particular, at least one embodiment of the present invention utilizes a contact lens in combination with an ultrasound transducer for purposes of acquiring photoacoustic microscopy data. Traditionally divergent imaging modalities such as confocal scanning laser opthalmoscopy and photoacoustic microscopy are combined within a single laser system. Functional imaging of biological samples can be utilized for various medical and biological purposes.

Claims

1. An ophthalmic imaging system comprising:

a laser capable of generating a laser beam for irradiating a biological sample;

an optical coherence tomography (OCT) apparatus capable of generating an OCT probing light beam;

a dual-axis scanner for scanning both the laser beam and OCT probing light beam;

an optical apparatus for delivering the laser beam and OCT probing light beam to the biological sample; and

an ultrasonic transducer for measuring laser induced ultrasonic waves in the biological sample.

2. The system according to claim 1, wherein the laser system includes a tunable pulse laser.

3. The system according to claim 1, and further comprising a processor for generating an image based at least in part upon the optical absorption contrast of the biological sample.

4. The system according to claim 1, wherein the OCT apparatus includes a broadband light source, a fiber coupler, and a spectrometer for detecting interference signals within a spectral domain.

5. The system according to claim 1, wherein the spectral-domain OCT apparatus is fiber-based.

6. The system according to claim 1, and further comprising a photodiode for recording the energy of each laser beam for use in compensating laser pulse energy instability.

7. The system according to claim 1, wherein the dual-axis scanner is an x-y galvanometer scanner or a polygon mirror scanner.

8. The system according to claim 1, wherein the optical system is capable of producing an optical tuning range from about 300 nm to about 1300 nm.

9. The system according to claim 4, and further comprising a processor for processing imaging data.

10. The system according to claim 7, wherein the ultrasonic detector is selected from the group consisting of a single stationary detector, an array of detectors, and a contact lens integrated with an ultrasonic detector.

11. The system according to claim 9, wherein the processor includes a time based controller capable of synchronizing laser triggering, optical scanning and data acquisition.

12. The system according to claim 11, wherein the time based controller is capable of dynamically registering the timing of laser triggering and photoacoustic data acquisition, galvanometer scanning and OCT data acquisition.

13. The system according to claim 12, and further comprising a GUI for displaying a functional and anatomical image of the biological sample based at least in part upon the detected photoacoustic waves.

14. The system according to claim 12, and further comprising a processor having executable code capable of detecting the boundaries of different anatomical layers.

15. A method of imaging a biological sample comprising:

generating a laser beam capable of irradiating a region of interest on a biological sample, the laser beam generated from a tunable laser system;

merging the laser beam with an optical coherence tomographic probing light to form a merged beam;

scanning the merged beam using a dual-axis optical scanner capable of two-dimensional raster scanning;

recording photoacoustic waves generated by the irradiated retinal region;

recording light reflected off of the biological sample;

controlling the recording and scanning within a single time base; and

generating an ophthalmic image based at least in part upon scanning the merged beam and recording photoacoustic waves and reflected light.

16. The method according to claim 15, wherein the biological sample is selected from the group consisting of an eye, retina and anterior segment of an eye.

17. The method according to claim 15, wherein the image includes retinal vessel morphology.

18. The method according to claim 15, wherein merging the laser beam with an optical coherence tomography probing light is performed by a dichrotic mirror.

19. The method according to claim 15, and further comprising synchronizing the timing of laser triggering and photoacoustic data acquisition, optical scanning and OCT data acquisition.

20. The method according to claim 15, and further comprising three-dimensionally registering OCT and photoacoustic images.

21. The method according to claim 15, wherein generating the ophthalmic image includes a three dimensional OCT image and photoacoustic vessel morphology.

22. The method according to claim 17, and further comprising measuring the selective absorption of incident photons by hemoglobin and generating an sO₂ level in retinal vessels.

23. The method according to claim 15, and further comprising generating an HbR value based at least in part upon processing the photoacoustic signals.

24. The method according to claim 21, and further comprising noninvasively measuring the retinal blood hemoglobin oxygen saturation.

25. The method according to claim 20, and further comprising generating an HbO₂ value based at least in part upon processing the photoacoustic signals.

26. A method of ophthalmic imaging comprising:

irradiating a retinal region of interest with a laser beam generated from a tunable laser;

scanning the retinal region of interest using a dual-axis galvanometer capable of two-dimensional raster scanning;

merging the laser beam with an OCT probing light to form a merged beam;

recording photoacoustic waves generated by the irradiated retinal region;

controlling the recording and scanning within a single time base; and

generating an ophthalmic image based at least in part upon the recording and scanning steps.

27. An OCT-guided laser scanning photoacoustic microscope comprising:

a tunable laser capable of irradiating a biological sample with a laser beam;

a dual-axis galvanometer for raster scanning the laser beam;

a fiber-based spectral-domain optical coherence tomography (OCT) system capable of generating an OCT probing light beam, the OCT system having a spectrometer for detecting interference signals within a spectral domain;

an optical delivery system for merging the laser beam and OCT probing light beam and delivering a merged beam to the biological sample;

an ultrasound transducer integrated within a contact lens for detecting photoacoustic waves generated by the irradiated biological sample; and

a GUI for displaying a image of the biological sample based at least in part upon the photoacoustic waves and spectrometer detected signals.