Non-contact optical coherence elastography endoscope device and use method

Abstract

The invention discloses a non-contact optical coherence elastography endoscope device and a use method. A millimeter-level ultrasonic excitation probe and a laser detection probe device are integrated; a millimeter-level air coupling ultrasonic transducer is adopted to realize lossless and non-contact excitation of sample tissues; the three-dimensional structure and vibration information of the sample are detected and acquired by adopting a high-speed near-infrared swept-frequency laser; an ultrasonic probe and a laser probe device are integrated and packaged by adopting a 3D printing method, so that different application objects can be adapted; according to the non-contact optical coherence elastography endoscope method and device, an off-axis parabolic mirror is adopted to achieve confocal of ultrasonic pulses and excitation detection light beams, non-contact direct excitation and imaging can be achieved through an air medium, use of various coupling agents is avoided, and the non-contact optical coherence elastography endoscope device has the advantages of being simple in structure and easy to machine and integrate a system.

Description

Technical Field

[0001] The present invention belongs to the technical field of biophotonics elastic imaging, and specifically relates to a non-contact optical coherence elastic imaging endoscope device and a use method thereof. Background Art

[0002] The occurrence, development and clinical treatment of many clinical diseases are accompanied by changes in the biomechanical properties of biological tissues, such as shear modulus, Young's modulus and other parameters. For example, atherosclerosis, esophageal cancer, respiratory syndrome, etc., will cause the corresponding human blood vessels, esophagus and respiratory tract tissues to harden or soften. Clinical studies have found that changes in the biomechanical properties of human tissues often occur in the early stages of the disease before causing changes in tissue structure. Therefore, changes in the biomechanical properties of human tissues can be used as biomarkers for many clinical diseases, and their detection and quantification can provide scientific basis and technical support for the diagnosis, treatment and prevention of many clinical diseases.

[0003] At present, clinical imaging methods for in vivo elasticity detection include magnetic resonance elastography and ultrasound elastography. However, due to the technical limitations of millimeter or sub-millimeter resolution, it is impossible to achieve micrometer-level high-resolution quantitative detection of elastic parameters for tissues such as cardiovascular tissue, esophageal tissue, and respiratory tract. In addition, there are some in vitro detection methods, mainly represented by uniaxial tensile testing, which calculates the Young's modulus by recording the stress-strain relationship of the tissue. This method can only be used for in vitro sample tissues or slices, and cannot meet the conditions for clinical in vivo detection.

[0004] Photoelastic imaging is an elasticity detection method based on optical means, including Brillouin scattering elastic imaging, laser speckle elastic imaging, and optical coherence elastic imaging. Among them, optical coherence elastic imaging based on mechanical waves has developed into the photoelastic imaging technology with the most potential for clinical multidisciplinary applications due to its advantages such as non-destructive, non-contact, high resolution, high signal-to-noise ratio, and fast three-dimensional imaging, and has now undergone preliminary clinical application transformation. However, at present, optical coherence elastic imaging technology is mainly used for detection and imaging of exposed tissues such as eye tissue, skin tissue, and oral tissue. In addition, existing optical coherence elastic imaging technology often uses large-sized water-coupled ultrasonic transducers or contact probes to mechanically excite sample tissues. Not only because the use of coupling agents can cause physiological rejection, but also because the system design is not convenient for clinical examination and experimental operation, and it cannot be applied to tissues such as arteries, esophagus, and respiratory tract. Summary of the invention

[0005] The purpose of the present invention is to provide a non-contact optical coherence elastic imaging endoscope device and a method of use, so as to solve the technical problems that the traditional optical coherence elastic imaging technology requires the use of a coupling agent excitation method and cannot be applied to endoelastic imaging of tissues such as arteries, esophagus, and respiratory tract due to size problems.

[0006] To achieve the above object, the present invention provides the following technical solution: a non-contact optical coherence elastic imaging endoscope device, comprising:

[0007] A non-contact ultrasonic excitation and optical detection integrated probe, the non-contact ultrasonic excitation and optical detection integrated probe comprises an air-coupled ultrasonic transducer, a collimating optical fiber, an off-axis parabolic reflector and a polymer resin encapsulation shell, and is used for lossless excitation and optical detection of a sample; the diameter of the air-coupled ultrasonic transducer is not greater than 2.5 mm, and the center frequency is not less than 250 kHz; the collimating optical fiber is a single-mode optical fiber and a collimator is integrated at the transmitting end to generate a collimated light beam; the off-axis parabolic reflector has a focal length greater than 7 mm and is used to focus ultrasonic pulses and detection beams; the polymer resin encapsulation shell is used to integrally encapsulate the air-coupled ultrasonic transducer, the collimating optical fiber and the off-axis parabolic reflector, the polymer resin encapsulation shell is designed by 3D printing, a window is opened at the exit end of the off-axis parabolic reflector, and the overall outer diameter of the polymer resin encapsulation shell does not exceed 4 mm;

[0008] A high-speed frequency sweeping laser has a sweeping speed of 100 kHz, a central wavelength of 1310 nm, a bandwidth of 100 nm, and synchronous output of a trigger clock and a sampling clock.

[0009] Preferably, it also includes: an endoscope probe connector, an endoscope probe micro-rotation motor, a programmable electric translation stage, and a flexible steel fiber endoscope connecting line, which are used to realize rotational scanning of the probe and radial scanning of the sample to be tested.

[0010] Preferably, it also includes: an optical isolator and a 2×2 99:1 fiber coupler to divide the incident light of the high-speed frequency sweeping laser into two beams that enter the sample light path and the reference light path respectively, wherein the sample light path has 99% and the reference light path has 1%.

[0011] Preferably, it also includes: an electric fiber optic delay line and a photoelectric balanced detector. The electric fiber optic delay line electrically adjusts the reference arm optical path according to the different samples to be tested to meet the interference matching conditions of the sample light and the reference light; the photoelectric balanced detector can detect and receive the interference return light of the sample light and the reference light, with a bandwidth of 2.0 GHz.

[0012] Preferably, it also includes: a timing control unit, an endoscopic probe and an air-coupled ultrasonic transducer driving module and a computer, wherein the timing control unit outputs a clock for sampling the photoelectric balance detector and a trigger clock for driving the air-coupled ultrasonic transducer by recording the trigger clock and sampling clock of the high-speed sweep laser; the endoscopic probe and the air-coupled ultrasonic transducer driving module have a 4-channel signal output function, wherein channel 1 is used to output the driving signal of the micro-rotating motor of the endoscopic probe, channel 2 is used to output the driving signal of the programmable electric translation stage, channel 3 is used to output the driving signal of the air-coupled ultrasonic transducer, and channel 4 is used to output the sampling monitoring signal; the computer is used for system signal processing and image reconstruction.

[0013] Preferably, the air-coupled ultrasonic transducer adopts a planar emission type composite material chip, and the emission end face matching layer material is designed with a multilayer dielectric material to match the acoustic impedance difference between the chip material and the air medium. The output ultrasonic pulse forms a focus after being reflected by the off-axis parabolic reflector, and the focal spot diameter of the focus is 1 mm.

[0014] Preferably, a collimating device is integrated at the output end of the collimating optical fiber to ensure that the output light is collimated and output to the off-axis parabolic reflector to form a focus after reflection.

[0015] Preferably, the off-axis parabolic reflector reflects and focuses the ultrasonic pulse and the incident light beam simultaneously, forming a confocal effect of the optical focus and the acoustic focus, so as to achieve synchronous ultrasonic excitation and optical detection.

[0016] A method for using a non-contact optical coherence elastic imaging endoscope device, using the non-contact optical coherence elastic imaging endoscope device, the specific steps include the following:

[0017] S1. Using the MB four-dimensional scanning algorithm, in each imaging section, the endoscope probe micro-rotating motor completes 200 optical scans at each sampling point, a total of 2ms M scan; during the 51st to 70th optical scan, the timing control unit and the endoscope probe and air-coupled ultrasonic transducer driving module output signals to drive the air-coupled ultrasonic transducer to generate ultrasonic pulses, excite the sample to generate mechanical vibration, and the excitation time is a total of 200us; after completing the M scan at the sampling point, the endoscope probe micro-rotating motor controls the probe to rotate to the next sampling point, and then repeats the new M scan, thereby completing the M scan within a 360° range, which is a complete MB scan;

[0018] S2. The non-contact ultrasonic excitation and optical detection integrated probe is moved to the next cross-sectional position by a programmable electric translation stage, and a new MB scan is repeated, thereby achieving a four-dimensional scan;

[0019] S3. The elastic properties of the sample are imaged pixel by pixel along the depth direction using a depth-resolved elastic imaging algorithm. The propagation velocity of the corresponding mechanical wave is calculated at each imaging depth. The elastic parameters such as shear modulus and Young's modulus are further calculated from the wave velocity, and then three-dimensional elastic mapping is performed on the detection area.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention proposes a non-contact optical coherence elastic imaging endoscope system method and device. The endoscope adopts a non-contact ultrasonic excitation and optical detection integrated probe, including an air-coupled ultrasonic transducer with a diameter of less than 2.5 mm and a center frequency of more than 250 kHz to generate non-focused ultrasonic pulses, thereby achieving non-destructive non-contact excitation of sample tissues. It does not require any coupling agent and can work only through the air medium. It can be perfectly suitable for non-contact excitation of different diseases in clinical practice, and has the beneficial effect of being suitable for elastic imaging detection of tissues such as arteries, esophagus and respiratory tract.

[0022] The sample light is collimated by using collimating optical fiber, and the collimating device with a central wavelength of 1310nm is independently designed and integrated with the single-mode optical fiber and placed inside the probe, which has the beneficial effects of easy integration and simple structure. The off-axis parabolic reflector is used to achieve synchronous focusing of the ultrasonic pulse and the collimated detection beam, and the focus is naturally formed outside the probe with a focal length of 7mm; the off-axis parabolic reflector can design the corresponding optical parameters according to the actual sample characteristics, and has the beneficial effect of being able to adapt to different ultrasonic pulses and detection beams.

[0023] 3D printing technology is adopted, and the outer shell is packaged with polymer resin material. Windows are set at the output ends of the ultrasonic pulse and the detection beam. The overall outer diameter does not exceed 4mm, which has the beneficial effects of facilitating overall fixed packaging and being simple and convenient.

[0024] A near-infrared swept laser with a sweep speed of 100kHz and a central wavelength of 1310nm is used. A single A-line scan time is only 10us. Combined with an air-coupled ultrasonic transducer, it has the beneficial effect of achieving fully non-contact ultrasonic excitation and optical detection.

[0025] The MB four-dimensional space-time scanning algorithm is used to obtain the vibration signal and mechanical wave propagation process excited by the ultrasonic transducer in the sample. The specific data matrix size is (1000, 100, 1024, 200). The entire MB scanning process lasts for 2 seconds, and the four-dimensional space-time data acquisition time does not exceed 240 seconds. The scanning results can not only present the three-dimensional structure of the sample, but also dynamically reconstruct the mechanical wave propagation process in the sample.

[0026] The elastic properties of the sample are imaged pixel by pixel along the depth direction using a depth-resolved elastic imaging algorithm. The propagation velocity of the corresponding mechanical wave is calculated at each imaging depth. The elastic parameters such as shear modulus and Young's modulus are further calculated from the mechanical wave velocity, and then three-dimensional elastic mapping is performed on the detection area. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the non-contact optical coherence elastic imaging endoscope device of the present invention.

[0028] Figure 2 Schematic diagram of the probe of the non-contact optical coherence elastic imaging endoscope device of the present invention.

[0029] Figure numerals: 01-high-speed frequency sweeping laser, 02-optical isolator, 03-2×2 99:1 optical fiber coupler, 04-endoscopic probe connector, 05-endoscopic probe micro-rotation motor, 06-programmable electric translation stage, 07-flexible steel fiber endoscope connecting line, 08-non-contact ultrasonic excitation and optical detection integrated probe, 09-sample to be tested, 10-electric optical fiber delay line, 11-photoelectric balance detector, 12-timing control unit, 13-endoscopic probe and air-coupled ultrasonic transducer drive module, 14-computer, 15-collimating optical fiber, 16-air-coupled ultrasonic transducer, 17-off-axis parabolic reflector, 18-polymer resin packaging shell, 19-focus. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the solution method of the present invention, the present invention is further described in detail below with reference to specific embodiments in conjunction with the accompanying drawings. However, this method is not limited to a specific example and can be applied to similar situations.

[0031] Example 1

[0032] See also Figure 1 and Figure 2A non-contact optical coherence elastic imaging endoscope device, comprising: a non-contact ultrasonic excitation and optical detection integrated probe 08 and a high-speed sweeping laser 01, wherein the high-speed sweeping laser 01 has a scanning speed of 100kHz, a central wavelength of 1310nm, a bandwidth of 100nm, and synchronously outputs a trigger clock and a sampling clock, and the non-contact ultrasonic excitation and optical detection integrated probe 08 comprises an air-coupled ultrasonic transducer 16, a collimating optical fiber 15, an off-axis parabolic reflector 17 and a polymer resin packaging shell 18, which are used for lossless excitation and optical detection of samples; the diameter of the air-coupled ultrasonic transducer 16 is not greater than 2.5mm, and the central frequency is not less than 250kHz; the collimating optical fiber 15 is a single-mode optical fiber and a collimator is integrated at the transmitting end to generate a collimated light beam; the focal length of the off-axis parabolic reflector 17 is greater than 7mm, and is used to focus ultrasonic pulses and detection beams; the polymer resin packaging shell 18 is used to integrally encapsulate the air-coupled ultrasonic transducer 16, and the collimating optical fiber 15 is used to focus ultrasonic pulses and detection beams; the polymer resin packaging shell 18 is used to integrally encapsulate the air-coupled ultrasonic transducer 16, and the collimating optical fiber 15 is used to focus ultrasonic pulses and detection beams. The acoustic transducer 16, the collimating optical fiber 15 and the off-axis parabolic reflector 17, the polymer resin packaging shell 18 is designed by 3D printing, a window is opened at the output end of the off-axis parabolic reflector 17, and the overall outer diameter of the polymer resin packaging shell 18 does not exceed 4mm; the output end of the collimating optical fiber 15 integrates a collimating device to ensure that the output light is collimated and output to the off-axis parabolic reflector 17, and a focus 19 is formed after reflection. The air-coupled ultrasonic transducer 16 adopts a planar emission type composite material chip, and the emission end surface matching layer material is designed with a multilayer dielectric material to match the acoustic impedance difference between the chip material and the air medium. The output ultrasonic pulse is reflected by the off-axis parabolic reflector 17 to form a focus 19, and the focal spot diameter of the focus 19 is 1mm. The off-axis parabolic reflector 17 reflects and focuses the ultrasonic pulse and the incident light beam at the same time to form a confocal effect of the optical focus and the acoustic focus, so as to realize the simultaneous ultrasonic excitation and optical detection.

[0033] Furthermore, it also includes an optical isolator 02, a 2×2 99:1 optical fiber coupler 03, an endoscope probe connector 04, an endoscope probe micro-rotation motor 05, a programmable electric translation stage 06, and a flexible steel fiber endoscope connecting line 07, which are used to realize rotational scanning of the probe and radial scanning of the sample to be tested 09. The 2×2 99:1 optical fiber coupler 03 divides the incident light of the high-speed scanning laser 01 into two beams that enter the sample light path and the reference light path respectively, wherein the sample light path accounts for 99% and the reference light path accounts for 1%.

[0034] Furthermore, it also includes an electric fiber delay line 10, a photoelectric balance detector 11, a timing control unit 12, an endoscope probe and an air-coupled ultrasonic transducer drive module 13 and a computer 14. The electric fiber delay line 10 electrically adjusts the reference arm optical path according to the different samples to be tested to meet the interference matching conditions of the sample light and the reference light; the photoelectric balance detector 11 can detect and receive the interference return light of the sample light and the reference light, with a bandwidth of 2.0GHz; the timing control unit 12 outputs the clock for sampling the photoelectric balance detector 11 and the trigger clock for driving the air-coupled ultrasonic transducer 16 by recording the trigger clock and sampling clock of the high-speed sweep laser 01; the endoscope probe and the air-coupled ultrasonic transducer drive module 13 have a 4-channel signal output function, wherein channel 1 is used to output the drive signal of the endoscope probe micro-rotation motor 05, channel 2 is used to output the drive signal of the programmable electric displacement stage 06, channel 3 is used to output the drive signal of the air-coupled ultrasonic transducer 16, and channel 4 is used to output the sampling monitoring signal; the computer 14 is used for system signal processing and image reconstruction.

[0035] The working process is as follows: the high-speed frequency sweeping laser 01 emits a near-infrared laser with a central wavelength of 1310nm and a bandwidth of 100nm. After passing through the optical isolator 02, it is divided into two beams by the 2×2 99:1 optical fiber coupler 03, of which 99% of the light is incident on the sample optical path and 1% of the light is incident on the reference optical path; the light entering the sample optical path reaches the non-contact ultrasonic excitation and optical detection integrated probe 08, and after being expanded by the collimating optical fiber 15, it is incident on the off-axis parabolic reflector 17 for reflection and focusing to the sample to be tested area, and its back-emitted and scattered light returns to the 2×2 99:1 optical fiber coupler 03 along the original optical path; the light entering the reference optical path is incident on the electric optical fiber delay line 10 to realize the optical path scanning of the reference optical path, and its back-reflected light returns to the 2×2 99:1 optical fiber coupler 03 along the original optical path. The sample light and the reference light interfere with each other in the 2×299:1 fiber coupler 03. The interference signal is converted into digital signals by the built-in data acquisition card of the computer 14 after the photoelectric conversion by the photoelectric balance detector 11. The sampling clock is generated by the timing control unit 12, including the wavelength trigger clock and the wave number sampling clock.

[0036] Example 2

[0037] See also Figure 1 and Figure 2 The specific steps of the method for using the non-contact optical coherence elastic imaging endoscope device provided by the present invention are as follows:

[0038] S1. The non-contact ultrasonic excitation and optical detection integrated probe 08 adopts the MB four-dimensional scanning algorithm, repeats 200 A-line scans at each sampling point to complete an M scan, and completes 1024 samples at each sampling point in the depth direction; that is, at each imaging section, the endoscope probe micro-rotating motor 05 completes 200 optical scans at each sampling point, a total of 2ms of M scan; after the M scan is completed at the sampling point, the endoscope probe micro-rotating motor 05 controls the probe to rotate to the next sampling point, and then repeats a new M scan, thereby completing a total of 1000 sampling points within a 360° range M scan, which is a complete MB scan; during the 51st to 70th optical scans, the timing control unit 12 and the endoscope probe and air-coupled ultrasonic transducer driving module 13 output signals to drive the air-coupled ultrasonic transducer 16 to generate ultrasonic pulses, excite the sample to generate mechanical vibration, and the excitation time is a total of 200us;

[0039] S2. The non-contact ultrasonic excitation and optical detection integrated probe 08 is moved to the next cross-sectional position by the programmable electric translation stage 06, and a new MB scan is repeated to achieve four-dimensional scanning. Data of 100 sampling sections are collected in the radial direction, thereby completing a four-dimensional space-time scan, and the data matrix is ​​(1000, 100, 1024, 200);

[0040] S3. The elastic parameters of the samples to be tested are calculated by combining multiple mechanical wave models. First, different mechanical wave models are selected and constructed according to the different structural characteristics of the samples. The mechanical wave velocity at each position in the depth direction is calculated pixel by pixel using a depth resolution algorithm. The tomographic calculation results of the mechanical wave propagation velocity at different depths are obtained. The elastic parameters such as the shear modulus and Young's modulus at different depths of the sample are then calculated based on the mechanical wave velocity, and three-dimensional mapping of the elastic modulus of the sample is achieved.

[0041] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by those skilled in the art within the essential scope of the present invention shall also fall within the protection scope of the present invention. The present invention does not elaborate on some of the known technologies of those skilled in the art.

Claims

1. A non-contact optical coherence elastography endoscope device, characterized in that: include: A non-contact ultrasonic excitation and optical detection integrated probe (08), the non-contact ultrasonic excitation and optical detection integrated probe (08) comprising an air-coupled ultrasonic transducer (16), a collimating optical fiber (15), an off-axis parabolic reflector (17) and a polymer resin packaging shell (18), for non-destructive excitation and optical detection of a sample; the diameter of the air-coupled ultrasonic transducer (16) is not greater than 2.5 mm, and the center frequency is not less than 250 kHz; the collimating optical fiber (15) is a single-mode optical fiber and the transmitting end is integrated with a collimating The device is used to generate a collimated light beam; the off-axis parabolic reflector (17) has a focal length greater than 7 mm and is used to focus the ultrasonic pulse and the detection light beam; the polymer resin packaging shell (18) is used to integrally package the air-coupled ultrasonic transducer (16), the collimating optical fiber (15) and the off-axis parabolic reflector (17); the polymer resin packaging shell (18) is designed by 3D printing, a window is opened at the exit end of the off-axis parabolic reflector (17), and the overall outer diameter of the polymer resin packaging shell (18) does not exceed 4 mm; A high-speed frequency sweeping laser (01) has a sweeping speed of 100 kHz, a central wavelength of 1310 nm, a bandwidth of 100 nm, and synchronous output of a trigger clock and a sampling clock.

2. A non-contact optical coherence elastography endoscope device according to claim 1, characterized in that: Also includes: An endoscope probe connector (04), an endoscope probe micro-rotation motor (05), a programmable electric displacement stage (06), and a flexible steel fiber endoscope connecting line (07) are used to realize rotational scanning of the probe and radial scanning of a sample to be tested (09).

3. The non-contact optical coherence elastography endoscope device according to claim 1, characterized in that: Also includes: An optical isolator (02) and a 2×2 99:1 optical fiber coupler (03) divide the incident light of the high-speed frequency sweeping laser (01) into two beams, which enter the sample light path and the reference light path respectively, wherein the sample light path accounts for 99% and the reference light path accounts for 1%.

4. The non-contact optical coherence elastography endoscope device according to claim 2, characterized in that: Also includes: An electric optical fiber delay line (10) and a photoelectric balanced detector (11), wherein the electric optical fiber delay line (10) electrically adjusts the optical path of a reference arm according to the difference of a sample (09) to be tested to meet the interference matching condition of the sample light and the reference light; and the photoelectric balanced detector (11) can detect and receive the interference return light of the sample light and the reference light, with a bandwidth of 2.0 GHz.

5. The non-contact optical coherence elastography endoscope device according to claim 4, characterized in that: Also includes: A timing control unit (12), an endoscope probe and an air-coupled ultrasonic transducer driving module (13) and a computer (14), wherein the timing control unit (12) outputs a clock for sampling the photoelectric balance detector (11) and a trigger clock for driving the air-coupled ultrasonic transducer (16) by recording the trigger clock and sampling clock of the high-speed frequency sweeping laser (01); the endoscope probe and the air-coupled ultrasonic transducer driving module (13) have a 4-channel signal output function, wherein channel 1 is used to output the driving signal of the endoscope probe micro-rotating motor (05), channel 2 is used to output the driving signal of the programmable electric displacement stage (06), channel 3 is used to output the driving signal of the air-coupled ultrasonic transducer (16), and channel 4 is used to output the sampling monitoring signal; the computer (14) is used for system signal processing and image reconstruction.

6. The non-contact optical coherence elastography endoscope device according to claim 1, characterized in that: The air-coupled ultrasonic transducer (16) adopts a planar emission composite material chip, and the emission end surface matching layer material adopts a multi-layer dielectric material design to match the acoustic impedance difference between the chip material and the air medium. The output ultrasonic pulse is reflected by the off-axis parabolic reflector (17) to form a focus (19), and the focal spot diameter of the focus (19) is 1 mm.

7. The non-contact optical coherence elastography endoscope device according to claim 1, characterized in that: The output end of the collimating optical fiber (15) is integrated with a collimating device to ensure that the output light is collimated and output to the off-axis parabolic reflector (17) to form a focus (19) after reflection.

8. The non-contact optical coherence elastography endoscope device according to claim 1, characterized in that: The off-axis parabolic reflector (17) reflects and focuses the ultrasonic pulse and the incident light beam simultaneously, forming a confocal effect of an optical focus and an acoustic focus, so as to achieve synchronous ultrasonic excitation and optical detection.

9. A method for using a non-contact optical coherence elastic imaging endoscope device, characterized in that: Using the non-contact optical coherence elastic imaging endoscope device according to any one of claims 1 to 8, the specific steps include the following: S1. Using the MB four-dimensional scanning algorithm, in each imaging section, the endoscope probe micro-rotating motor (05) completes 200 optical scans at each sampling point, a total of 2ms of M scanning; during the 51st to 70th optical scan, the timing control unit (12) and the endoscope probe and air-coupled ultrasonic transducer driving module (13) output signals to drive the air-coupled ultrasonic transducer (16) to generate ultrasonic pulses, excite the sample to generate mechanical vibration, and the excitation time is a total of 200us; after completing the M scan at the sampling point, the endoscope probe micro-rotating motor (05) controls the probe to rotate to the next sampling point, and then repeats a new M scan, thereby completing the M scan within a range of 360°, which is a complete MB scan; S2. The non-contact ultrasonic excitation and optical detection integrated probe (08) is moved to the next cross-sectional position by a programmable electric translation stage (06), and a new MB scan is repeated, thereby achieving a four-dimensional scan; S3. The elastic properties of the sample are imaged pixel by pixel along the depth direction using a depth-resolved elastic imaging algorithm. The propagation velocity of the corresponding mechanical wave is calculated at each imaging depth. The elastic parameters such as shear modulus and Young's modulus are further calculated from the wave velocity, and then three-dimensional elastic mapping is performed on the detection area.

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