Single-cell label-free photoacoustic flowoxigraphy in vivo

• US 10,433,733 B2
• Filed: 05/06/2016
• Issued: 10/08/2019
• Est. Priority Date: 10/25/2007
• Status: Active Grant

• Current Assignee: Washington University In St Louis
• Original Assignee: Washington University In St Louis
• Inventors: Wang, Lihong, Wang, Lidai, Maslov, Konstantin
• Primary Examiner(s): Cattungal, Sanjay
• Application Number:
  US15/148,685
• Publication Number:
  US 20160249812A1
• Time in Patent Office: 1,250 Days
• Field of Search: 600473-480
• CPC Class Codes: A61B 2090/306 using optical fibres
• 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 5/0068 Confocal scanning
• CPC Class Codes: A61B 5/0082 adapted for particular medical purposes
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/444 Evaluating skin marks, e.g. mole, nevi, tumour, scar
• CPC Class Codes: A61B 5/4848 Monitoring or testing the effects of treatment, e.g. of medication
• CPC Class Codes: A61B 8/485 involving measuring strain or elastic properties
• CPC Class Codes: G01N 21/1702 with opto-acoustic detection, e.g. for gases or analysing solids
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G01N 2291/02872 Pressure
• 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
• CPC Class Codes: G02B 21/0028 specially adapted for specific applications, e.g. for endoscopes, ophthalmoscopes, attachments to conventional microscopes
• CPC Class Codes: G02B 21/008 Details of detection or image processing, including general computer control

Abstract

A method for obtaining a 3-D OR-PAM image of microvasculature within a region of interest of a subject is provided. The method includes: focusing a first light pulse at a first depth beneath a first surface position within the region of interest; receiving a first PA signal in response to the first light pulse; focusing a second light pulse at a second depth beneath the first surface position within the region of interest; receiving a second PA signal in response to the second light pulse; and forming the 3-D OR-PAM image by combining the first PA signal and the second PA signal.

Claims

1. A device for real-time spectral imaging of single moving red blood cells in a subject in vivo, the device comprising:

an isosbestic laser to deliver a series of isosbestic laser pulses at an isosbestic wavelength;

a non-isosbestic laser to deliver a series of non-isosbestic laser pulses at a non-isosbestic wavelength;

an optical fiber to direct the series of isosbestic laser pulses and the series of non-isosbestic laser pulses to an optical assembly;

the optical assembly to focus the series of isosbestic laser pulses and the series of non-isosbestic laser pulses into a beam with a beam cross-sectional diameter of less than 10 μ

m through an optical focus region;

a focused ultrasound transducer to detect acoustic signals generated within the optical focus region in response to the series of isosbestic and non-isosbestic laser pulses, the focused ultrasound transducer comprising an acoustic focus region that is aligned with the optical focus region; and

an acoustically transparent optical reflector to transmit acoustic signals from the acoustic focus region to the focused ultrasound transducer and to reflect the series of isosbestic and non-isosbestic laser pulses from the optical assembly to the optical focus region;

wherein each isosbestic laser pulse is delivered at a pulse separation period of 20 μ

s before or after each adjacent non-isosbestic laser pulse.

2. The device of claim 1, wherein:

the isosbestic wavelength is a wavelength with a hemoglobin absorbance that corresponds to an oxyhemoglobin absorbance;

the isosbestic wavelength is chosen from 532 nm, 548 nm, 568 nm, 587 nm, and 805 nm; and

the non-isosbestic wavelength is any wavelength with the hemoglobin absorbance that does not correspond to the oxyhemoglobin absorbance.

3. The device of claim 2, wherein the isosbestic wavelength is 532 nm and the non-isosbestic wavelength is 560 nm.

4. The device of claim 1, wherein the optical assembly comprises a pair of optical lenses comprising two achromatic doublets with a numerical aperture in water of 0.1.

5. The device of claim 1, wherein the focused ultrasound transducer further comprises a central frequency of at least 10 MHz.

6. The device of claim 5, wherein the central frequency is 50 MHz and the focused ultrasound transducer further comprises an axial spatial resolution of 15 μ

m.

7. The device of claim 5, further comprising a linear scanner to move the optical assembly and the focused ultrasound transducer in a linear scanning pattern.

8. The device of claim 7, wherein the linear scanner is a voice-coil scanner with a scanning rate of at least 100 linear scans per second.

9. The device of claim 1, wherein the acoustically transparent optical reflector comprises a first prism and a second prism, wherein a first face of the first prism and a second face of the second prism are arranged on opposite sides of an aluminum layer forming a planar optical reflector aligned at an angle of 45°

relative to an axis of the optical assembly.

10. A system for real-time spectral imaging of single moving red blood cells in a subject in vivo, the system comprising:

a dual wavelength light source module to produce a series of isosbestic laser pulses and a series of non-isosbestic laser pulses at a non-isosbestic wavelength;

an optical module to direct the series of isosbestic laser pulses and the series of non-isosbestic laser pulses through an optical focus region in a cylindrical beam with a beam cross-sectional diameter of less than 10 μ

m;

an ultrasound detection module to detect acoustic signals generated within the optical focus region in response to the series of isosbestic and non-isosbestic laser pulses, the ultrasound detection module comprising a focused ultrasound transducer, the focused ultrasound transducer comprising an acoustic focus region that is aligned with the optical focus region; and

an acoustically transparent optical reflector to transmit acoustic signals from the acoustic focus region to the focused ultrasound transducer and to reflect the series of isosbestic and non-isosbestic laser pulses from the optical module to the optical focus region;

wherein each isosbestic laser pulse is delivered at a pulse separation period of 20 μ

s before or after each adjacent non-isosbestic laser pulse.

11. The system of claim 10, wherein the dual wavelength light source module comprises an isosbestic laser to produce the series of isosbestic laser pulses and a non-isosbestic laser to produce the series of non-isosbestic laser pulses.

12. The system of claim 10, wherein:

the isosbestic wavelength is a wavelength with a hemoglobin absorbance that corresponds to an oxyhemoglobin absorbance;

the isosbestic wavelength is chosen from 532 nm, 548 nm, 568 nm, 587 nm, and 805 nm; and

the non-isosbestic wavelength is any wavelength with the hemoglobin absorbance that does not correspond to the oxyhemoglobin absorbance.

13. The system of claim 12, wherein the isosbestic wavelength is 532 nm and the non-isosbestic wavelength is 560 nm.

14. The system of claim 10, wherein the optical module comprises an optical fiber operatively connected to the isosbestic laser and the non-isosbestic laser at a first end and operatively connected to a pair of optical lenses comprising two achromatic doublets with a numerical aperture in water of 0.1 at a second end opposite to the first end of the optical fiber.

15. The system of claim 10, wherein the focused ultrasound transducer further comprises a central frequency of 50 MHz.

16. The system of claim 15, further comprising a scanning module to move the optical module and the ultrasound detection module in a linear scanning pattern, wherein the scanning module comprises a voice-coil scanner with a scanning rate of at least 100 linear scans per second.

17. The system of claim 15, wherein the system obtains images of the single moving red blood cells at an axial spatial resolution of 15 μ

m and a lateral spatial resolution of 3.4 μ

m.

18. The system of claim 15, wherein the system simultaneously obtains one or more functional parameters of the single moving red blood cells using a pulse oximetry method, wherein the one or more functional parameters are chosen from:

total hemoglobin concentration, oxygen saturation, gradient of oxygen saturation, flow speed, metabolic rate of oxygen, and any combination thereof.