Arthroscopic device integrating optical-photoacoustic multimodal imaging and imaging method thereof

Abstract

The present invention discloses an arthroscopic device integrating optical-photoacoustic multimodal imaging and an imaging method thereof, the arthroscopic device includes a light source and an optical path system, a control and data acquisition system, an arthroscopic probe, and the imaging method steps are as follows: pulsed excitation light enters the arthroscopic probe from the optical path system through an adjustable focus collimator; polarized light modulation is realized by a hollow servo motor and a λ / 2 plate combination; different wavelengths of pulsed light are realized in common through a dichroic plate; white light and pulsed light are realized in common through a spectroscope; pulsed light is used to quickly scan tissues using a MEMS mirror; echo signals are collected by a micro-transducer; and photoacoustic, photoacoustic polarization, and photoacoustic elastic image reconstruction are completed by a computer; optical signals are collected by the CCD of the arthroscopic probe for optical image reconstruction. The imaging method of the present invention realizes optical, photoacoustic, photoacoustic polarization, and photoacoustic elastic imaging through an integrated arthroscopic probe, and can be used for anisotropy and biomechanical detection of microvessels, cartilage, and ligaments in the joint cavity.

Description

Technical Field

[0001] The present invention belongs to the field of arthroscopic imaging, and in particular relates to an arthroscopic device integrating optical-photoacoustic multimodal imaging and an imaging method thereof. Background Art

[0002] Osteoarthritis (OA) is the most common joint disease in the world today, affecting millions of people worldwide. These joint diseases cause abnormal remodeling of normal joint structures, leading to joint degeneration, a condition that affects approximately 10-12% of the adult population worldwide. Osteoarthritis (OA) can cause permanent joint damage, leading to chronic pain, reduced range of motion, and significantly reduces the patient's quality of life, which also leads to an increased socioeconomic burden.

[0003] For osteoarthritis (OA), timely prediction of joint structure progression and disease plays an important role. It is very important to take appropriate treatment measures. Timely diagnosis and treatment are conducive to improving quality of life and early mortality. In addition, with the implementation of active targeted treatment strategies, osteoarthritis (OA) symptoms can often be significantly improved, so the progress of treatment needs to be monitored frequently.

[0004] Although the clinical diagnostic criteria for osteoarthritis (OA) do not include imaging evidence, plain X-rays are often used clinically to assess the progression of OA, but the imaging capabilities of cartilage and synovium are poor. Although computed tomography (CT) has strong imaging capabilities for bone structures, it is expensive to use and there is ionizing radiation. Although ultrasound can sensitively identify changes in soft tissue and superficial bones and has the advantage of non-invasive vascular assessment, it has poor penetration into deep structures within joints. Magnetic resonance imaging (MRI) can provide more information than the above detection methods, does not have ionizing radiation, and has excellent anatomical resolution, but the examination time is longer and may not be used for some special patients.

[0005] Arthroscopy is a minimally invasive diagnostic and therapeutic method used to observe and treat diseases inside joints. By inserting a tiny tube (arthroscopy) into the joint, doctors can directly observe the internal structures of the joint, such as cartilage, tendons, ligaments, etc. This technique is widely used to examine and treat the knee, shoulder, ankle and elbow joints.

[0006] Traditional arthroscopy technology mainly relies on white light optical imaging systems, which can provide intuitive images of the inside of the joint, but have limitations in resolution and contrast. Especially when identifying early pathological changes (such as minor soft tissue injuries), white light imaging often fails to provide sufficient details.

[0007] Photoacoustic imaging is an emerging biomedical imaging technology that combines optical and acoustic principles. It uses laser to illuminate tissues and then relies on the ultrasound signal generated by the tissue absorbing the laser to construct an image that can reflect the distribution of light absorption differences within the tissue. Photoacoustic imaging can obtain images of blood vessel distribution within the joint cavity, which is used to determine the progression of osteoarthritis.

[0008] Polarized photoacoustic imaging technology is based on photoacoustic imaging. It can identify changes in the anisotropy of tissues such as cartilage and ligaments by analyzing the intensity of tissue absorption of polarized light vectors at different angles.

[0009] Photoacoustic elasticity technology is based on photoacoustic imaging. It measures elastic parameters by using the time and phase characteristics of the photoacoustic point source response through thermoelastic expansion and damping effects. It can identify changes in the mechanical properties of tissues such as cartilage and ligaments.

[0010] Currently, the commonly used arthroscopy is a white light arthroscopy that mainly relies on white light optical imaging. Traditional white light imaging technology mainly provides morphological information of tissues, but cannot provide direct information on the biochemical and molecular characteristics of tissues. This limitation is determined by the working principle of white light imaging technology. It mainly relies on the reflection and refraction of light to form images, and these processes do not involve the detection of changes in the biochemical composition or molecular structure of tissues. Therefore, an arthroscopic device integrating optical-photoacoustic multimodal imaging is invented, in which the photoacoustic imaging technology combines the characteristics of high resolution of optical imaging and deep depth of acoustic imaging, and can image the distribution of blood vessels in the joint cavity, which is used to judge the progression of osteoarthritis; and on the basis of photoacoustic imaging, polarized photoacoustic and photoacoustic elastic imaging are combined to characterize the anisotropy and biomechanical differences of structures such as cartilage and ligaments in the joint cavity, which can be used for early diagnosis of osteoarthritis and preoperative and postoperative imaging evaluation.

[0011] The patent publication number is CN111387947A, and the patent name is "Multimodal microendoscopic imaging device and method", which discloses a multimodal microendoscopic imaging device that combines three imaging methods: confocal, photoacoustic, and ultrasonic, and has two modes: forward scanning and side scanning. However, the imaging mode does not have polarized photoacoustic and photoacoustic elasticity, and lacks the ability to identify pathological changes in major joint tissues such as cartilage and ligaments.

[0012] The invention patent with the patent publication number CN115480376B is titled "A high-definition ultra-wide-angle arthroscopic imaging system", which introduces a high-definition ultra-wide-angle arthroscopic imaging system with high resolution, large field of view and small distortion. Although the traditional optical imaging arthroscopy has improved the joint resolution and observation angle, it still has the shortcomings of the traditional optical arthroscopy, which can only extract the changes in the surface morphology of the tissue, and cannot perform imaging at the level of tissue pathological changes. Summary of the invention

[0013] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide an arthroscopic device integrating optical-photoacoustic multimodal imaging. The device can realize imaging in four modes: optical, photoacoustic, polarized photoacoustic, and photoacoustic elastic. The target area can be optically imaged to obtain tissue surface morphological information. At the same time, photoacoustic imaging can be performed to obtain the blood vessel distribution image in the joint cavity. Polarized photoacoustic and photoacoustic elastic imaging can characterize the anisotropy and biomechanical differences of structures such as cartilage and ligaments in the joint cavity. It can be used for early diagnosis of osteoarthritis and preoperative and postoperative imaging evaluation, providing a multi-parameter data detection device and method for the field of medical imaging.

[0014] In order to achieve the above object, the present invention adopts the following technical solutions:

[0015] An arthroscopic device integrating optical-photoacoustic multimodal imaging, the arthroscopy comprising a control and data acquisition system, a light source and optical path system, and an arthroscopic probe.

[0016] The control and data acquisition system includes an FPGA development board, a signal amplifier, an acquisition card, and a computer; the FPGA development board is used as a control module to generate timing pulses to control the coordinated operation of various systems. After the pulse laser is incident on the tissue surface, the tissue surface is stimulated to generate ultrasonic waves, which are received by the micro-transducer in the arthroscopic probe. After the signal is amplified by the signal amplifier, it enters the acquisition card, and finally the acquisition card transmits the raw data to the computer.

[0017] The light source and optical path system include a pulse laser, a first optical fiber coupler, a single-mode optical fiber, a first adjustable focus collimator, a second optical fiber coupler, a polarization-maintaining optical fiber, a second adjustable focus collimator, and a white light source. The control end of the white light source and the pulse laser is connected to the FPGA development board of the control and data acquisition system to control the light source output. The pulse lasers with wavelengths of 532nm and 1550nm are respectively connected to the optical path system through the first optical fiber coupler and the second optical fiber coupler, and then enter the arthroscopic probe through the single-mode optical fiber and the polarization-maintaining optical fiber, the first adjustable focus collimator and the second adjustable focus collimator.

[0018] The arthroscopic probe comprises a charge coupled device, a beam splitter, a MEMS mirror, a pulse fiber interface, a hollow servo motor, a λ / 2 plate, a dichroic plate, a focusing lens, a cold light source interface, a rod mirror group, an arthroscopic housing, a lens group, a light-transmitting reflective mirror, a micro transducer and a light-guiding optical fiber. A 532nm pulse laser enters the arthroscopic probe through the pulse fiber interface, is vertically incident and passes through the dichroic plate. A 1550nm pulse laser enters the arthroscopic probe through the pulse fiber interface, passes through the hollow servo motor and the λ / 2 plate. The rotation of the hollow servo motor realizes the modulation of polarized light. The 1550nm pulse laser is reflected by the dichroic plate and combined with the 532nm pulse laser, and the combined light is incident on the surface of the MEMS mirror. After the reflection, the scanning light is focused by the focusing lens, passes through the beam splitter and is incident on the rod mirror group, is transmitted inside the rod lens, passes through the lens group and the light-transmitting reflective mirror, and finally is incident on the tissue surface. The white light source is used to illuminate the tissue through the light-guiding optical fiber on the side wall of the arthroscopic probe, and the optical signal is received by the charge-coupled device after being reflected by the beam splitter. As a preferred technical solution, the effective focal length of the first adjustable focus collimator is 7.5mm, and the wavelength range of the anti-reflection film is 350nm-700nm, and the effective focal length of the second adjustable focus collimator is 7.5mm, and the wavelength range of the anti-reflection film is 1050nm-1700nm. The addition of the first and second adjustable focus collimators realizes the confocal of lasers of different wavelengths.

[0019] As a preferred technical solution, the hollow servo motor has an inner diameter of 4 mm and a rotation speed range of 0.5-2000 rpm. The addition of the hollow servo motor realizes the rotation of the λ / 2 plate, thereby changing the polarization state of light.

[0020] As a preferred technical solution, the cutoff wavelength of the short-wave dichroic film is 950nm, the transmission rate of 532nm wavelength laser is 85-95%, and the reflectivity of 1550nm wavelength laser is 90-99%. The addition of the dichroic film realizes the common path of pulsed light of different wavelengths.

[0021] As a preferred technical solution, the spectroscope has a white light transmittance of 50%, a 532nm wavelength laser reflectivity of 50%, and a 1550nm wavelength laser reflectivity of 80-90%. The addition of the spectroscope enables white light and laser to share the same path.

[0022] As a preferred technical solution, the MEMS mirror has a scanning angle of 5-20° and a response frequency of 2.5-5KHz. The scanning range and scanning speed can be changed by changing the frequency of the driving signal. The addition of the MEMS mirror can achieve rapid scanning of the imaging area.

[0023] As a preferred technical solution, the pulse laser is one of a semiconductor laser, a solid laser, a dye laser or a gas laser, and the output pulse laser has a wavelength range of 400nm~2000nm and a pulse width of 3ns~30ns.

[0024] As a preferred technical solution, the signal amplifier has an amplification gain of 50dB to 60dB.

[0025] Another object of the present invention is to provide a method for imaging using the above-mentioned imaging device, by which white light images, photoacoustic images, polarized photoacoustic images, and photoacoustic elastic images of the imaging area can be obtained.

[0026] In order to achieve the above second purpose, the present invention adopts the following technical solutions:

[0027] The present invention provides a method for utilizing an arthroscopic device integrating optical-photoacoustic multimodal imaging, comprising the following steps:

[0028] a. System triggering: The control and data acquisition system generates a trigger signal to control the pulsed lasers of 532nm and 1550nm wavelengths to generate pulsed light, and controls the illumination light source at the same time. The pulsed lasers of different wavelengths enter the fiber coupler respectively, and enter the arthroscopic probe through the first and second adjustable focus collimators. The 1550nm wavelength laser is modulated by the electro-optic polarization modulator and then combined with the 532nm wavelength laser through the dichroic film. The combined light finally reaches the surface of the tissue to be imaged through the focusing lens and the beam splitter, and the illumination light irradiates the surface of the tissue to be imaged through the optical fiber;

[0029] b. Data acquisition: The photoacoustic signal excited by the pulsed laser is reflected by the light-transmitting reflective mirror and received by the ultrasonic transducer on the side wall of the arthroscope, and then converted into an electrical signal. The signal enters the signal amplifier through the coaxial cable, and the amplified electrical signal is collected by the acquisition card and sent to the computer; the optical signal passes through multiple groups of lenses and a spectroscope and enters the charge-coupled device. The charge-coupled device converts the incident light signal into a charge output, and the electrical signal enters the computer through the data line;

[0030] c. Image processing: The computer uses the collected data for the reconstruction of optical, photoacoustic, polarized photoacoustic, and photoacoustic elastic images. Reconstruction of photoacoustic images: The maximum projection image of the blood vessels is reconstructed through the maximum projection algorithm using the ultrasonic waves (photoacoustic signals) generated by the instantaneous thermal expansion of hemoglobin to absorb the 532 nm wavelength laser. Reconstruction of photoacoustic polarization images: The anisotropic absorption difference of the tissue sample is obtained by modulating the lasers of different polarization states through the combination of the hollow servo motor and the λ / 2 plate, thereby reconstructing the quantitative anisotropic image of the tissue sample. Reconstruction of photoacoustic elastic images: By measuring the time required for the surface vibration displacement of the tissue sample to go from zero to the maximum value, the elastic modulus of the tissue sample can be calculated, and its quantitative elastic image can be reconstructed.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. The present invention realizes an arthroscopic device integrating optical-photoacoustic multimodal imaging and its imaging method, which can perform real-time high-resolution multi-parameter imaging, and obtain white light images, photoacoustic images, polarized photoacoustic images, and photoacoustic elastic images of the imaging area. Among them, the photoacoustic imaging technology combines the characteristics of high resolution of optical imaging and deep depth of acoustic imaging, and can image the distribution of blood vessels in the joint cavity, which is used to judge the progress of osteoarthritis; and on the basis of photoacoustic imaging, the combination of polarized photoacoustic and photoacoustic elastic imaging can characterize the anisotropy and biomechanical differences of structures such as cartilage and ligaments in the joint cavity, which can be used for early diagnosis of osteoarthritis and preoperative and postoperative imaging evaluation.

[0033] 2. The present invention realizes the confocal common optical path of 532nm and 1550nm wavelength lasers. By adding an adjustable focus collimator, the two wavelength lasers can be confocal. The addition of a dichroic filter allows 532nm and 1550nm wavelength lasers to share the same optical path. Since the wavelengths of these two lasers are quite different, the dichroic filter with an appropriate cutoff frequency can effectively realize the beam combination of dual-wavelength lasers.

[0034] 3. The present invention uses a MEMS mirror to achieve rapid scanning of photoacoustic signals, which significantly improves the flexibility and controllability of the system compared to the traditional motor scanning method. The miniaturized design of the MEMS mirror makes the arthroscopy more flexible in operation and can accurately control the emission direction of the laser, thereby improving the clarity and contrast of the imaging. This feature helps to speed up data acquisition and realize real-time imaging of photoacoustic multimodality.

[0035] 4. The present invention realizes efficient modulation of polarized light by combining a hollow servo motor with a λ / 2 plate. By controlling the rotation of the hollow servo motor with an FPGA development board in the control system, the rotation angle of the λ / 2 plate can be precisely adjusted, thereby more effectively controlling the polarization state of light and improving the quality of polarized photoacoustic imaging.

[0036] 5. The internal lens structure design of the arthroscopic probe of the present invention allows the diameter of the device to be adjusted to adapt to joints at different locations. By adjusting the focal position of the photoacoustic system, the working distance of the multimodal imaging system can be changed. In addition, adjusting the number of multiple lens groups can also achieve changes in the system working distance, thereby meeting the requirements of multimodal imaging at different depths of the joint, which meets the requirements of practical clinical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments:

[0038] Figure 1 The present invention is a schematic diagram of the structure of an arthroscopic device integrating optical-photoacoustic multimodal imaging.

[0039] Figure 2 The present invention is a schematic diagram of an arthroscopic imaging device integrating optical-photoacoustic multimodal imaging.

[0040] Figure 3 The present invention is a schematic diagram of the probe structure of an arthroscopic device integrating optical-photoacoustic multimodal imaging.

[0041] Explanation of the accompanying drawings: 1. Control and data acquisition system; 2. Light source and optical path system; 3. Arthroscopy; 4. Tissue surface; 5. FPGA development board; 6. Pulsed laser; 7. First fiber coupler; 8. Single-mode optical fiber; 9. First adjustable-focus collimator; 10. Second fiber coupler; 11. Polarization-maintaining optical fiber; 12. Second adjustable-focus collimator; 13. White light source; 14. Arthroscopy probe; 15. Signal amplifier; 16. Acquisition card; 17. Computer; 18. Charge-coupled device; 19. Spectroscope; 20. MEMS mirror; 21. Pulsed optical fiber interface; 22. Hollow servo motor; 23. λ / 2 plate; 24. Dichroic plate; 25. Focusing lens; 26. Cold light source entrance; 27. Rod mirror group; 28. Arthroscopy housing; 29. ​​Lens group; 30. Transparent acoustic reflector; 31. Micro transducer; 32. Light-guiding optical fiber. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0043] like Figure 2 As shown, this embodiment discloses an arthroscopic device integrating optical-photoacoustic multimodal imaging and an imaging method thereof of the present invention, including a control and data acquisition system, a light source and optical path system, and an arthroscopic probe.

[0044] The control and data acquisition system 1 includes an FPGA development board 5, a signal amplifier 15, an acquisition card 16, and a computer 17; the FPGA development board 5 is used as a control module to generate timing pulses to control the coordinated operation of various systems. After the pulse laser is incident on the tissue surface 4, the tissue surface is stimulated to generate ultrasonic waves, which are received by the micro transducer 31 in the arthroscopic probe. After the signal is amplified by the signal amplifier 15, it enters the acquisition card 16, and finally the acquisition card transmits the raw data to the computer 17.

[0045] Furthermore, in the light source and optical path system 2, a pulse laser 6, a first fiber coupler 7, a single-mode optical fiber 8, a first adjustable focus collimator 9, a second fiber coupler 10, a polarization-maintaining optical fiber 11, a second adjustable focus collimator 12, and a white light source 13 are included. The control end of the white light source 13 and the pulse laser 6 is connected to the FPGA development board 5 of the control and data acquisition system to control the light source output. The pulse lasers with wavelengths of 532nm and 1550nm are respectively connected to the optical path system through the first fiber coupler 7 and the second fiber coupler 10, and then enter the arthroscopic probe 14 through the single-mode optical fiber 8 and the polarization-maintaining optical fiber 11, the first adjustable focus collimator 9 and the second adjustable focus collimator 12.

[0046] Furthermore, the arthroscopic probe 14 includes a charge coupled device 18, a beam splitter 19, a MEMS mirror 20, a pulse fiber interface 21, a hollow servo motor 22, a λ / 2 plate 23, a dichroic plate 24, a focusing lens 25, a cold light source interface 26, a rod mirror group 27, an arthroscopic housing 28, a lens group 29, a light-transmitting reflective mirror 30, a micro transducer 31, and a light-guiding fiber 32. The 532nm pulse laser enters the arthroscopic probe through the pulse fiber interface 21, is vertically incident, and passes through the dichroic plate 24. The 1550nm pulse laser enters the arthroscopic probe through the pulse fiber interface 21, and passes through the hollow servo motor 22 and the λ / 2 plate 23. The rotation of the hollow servo motor realizes the modulation of polarized light. The 1550nm pulse laser is reflected by the dichroic plate 24 and combined with the 532nm pulse laser. The combined light is incident on the surface of the MEMS mirror 20. The reflected scanning light is focused by the focusing lens 25, passes through the beam splitter 19, and is incident on the rod lens group 27. It is transmitted inside the rod lens, passes through the lens group 29 and the light-transmitting reflective mirror 30, and finally incident on the tissue surface. The white light source 13 illuminates the tissue through the light-guiding fiber 32 on the side wall of the arthroscopic probe. The optical signal is reflected by the beam splitter 19 and received by the charge coupled device 18.

[0047] In this embodiment, the effective focal length of the first adjustable focus collimator is 7.5mm, and the wavelength range of the anti-reflection film is 350nm-700nm. The effective focal length of the second adjustable focus collimator is 7.5mm, and the wavelength range of the anti-reflection film is 1050nm-1700nm. The addition of the first and second adjustable focus collimators realizes confocalization of lasers of different wavelengths.

[0048] In this embodiment, the hollow servo motor has an inner diameter of 4 mm and a rotation speed range of 1000 rpm. The addition of the hollow servo motor realizes the rotation of the λ / 2 plate, thereby changing the polarization state of the light.

[0049] In this implementation case, the cutoff wavelength of the short-wave dichroic filter is 950nm, the transmission rate of 532nm wavelength laser is 85-95%, and the reflectivity of 1550nm wavelength laser is 95%. The addition of the dichroic filter realizes the common path of pulsed light of different wavelengths.

[0050] In this implementation case, the spectrometer has a white light transmittance of 50%, a 532nm wavelength laser reflectivity of 50%, and a 1550nm wavelength laser reflectivity of 85%. The addition of the spectrometer enables white light and laser to share the same path.

[0051] In this implementation case, the MEMS mirror has a scanning angle of 10° and a response frequency of 2.5KHz. The scanning range and scanning speed can be changed by changing the frequency of the driving signal. The addition of the MEMS mirror can achieve rapid scanning of the imaging area.

[0052] In this embodiment, the pulse laser is a semiconductor laser, and the output pulse laser wavelengths are 532nm and 1550nm, respectively, and the pulse width is 10ns.

[0053] In this implementation case, the signal amplifier gain is 60dB.

[0054] In this embodiment, the arthroscopic shell is a metal shell that is resistant to high temperature and high pressure disinfection and has biocompatibility. The working distance is 10 cm and the diameter of the arthroscopic lens is 4 mm.

[0055] In order to achieve the above second purpose, the present invention adopts the following technical solutions:

[0056] The present invention provides a method for utilizing an arthroscopic device integrating optical-photoacoustic multimodal imaging, comprising the following steps:

[0057] a. System triggering: The control and data acquisition system generates a trigger signal to control the pulsed lasers of 532nm and 1550nm wavelengths to generate pulsed light, and controls the illumination light source at the same time. The pulsed lasers of different wavelengths enter the fiber coupler respectively, and enter the arthroscopic probe through the first and second adjustable focus collimators. The 1550nm wavelength laser is modulated by the electro-optic polarization modulator and then combined with the 532nm wavelength laser through the dichroic film. The combined light finally reaches the surface of the tissue to be imaged through the focusing lens and the beam splitter, and the illumination light irradiates the surface of the tissue to be imaged through the optical fiber;

[0058] b. Data acquisition: The photoacoustic signal excited by the pulsed laser is reflected by the light-transmitting reflective mirror and received by the ultrasonic transducer on the side wall of the arthroscope, and then converted into an electrical signal. The signal enters the signal amplifier through the coaxial cable, and the amplified electrical signal is collected by the acquisition card and sent to the computer; the optical signal passes through multiple groups of lenses and a spectroscope and enters the charge-coupled device. The charge-coupled device converts the incident light signal into a charge output, and the electrical signal enters the computer through the data line;

[0059] c. Image processing: The computer uses the collected data for the reconstruction of optical, photoacoustic, polarized photoacoustic, and photoacoustic elastic images. Reconstruction of photoacoustic images: The maximum projection image of the blood vessels is reconstructed through the maximum projection algorithm using the ultrasonic waves (photoacoustic signals) generated by the instantaneous thermal expansion of hemoglobin to absorb the 532 nm wavelength laser. Reconstruction of photoacoustic polarization images: The anisotropic absorption difference of the tissue sample is obtained by modulating the lasers of different polarization states through the combination of the hollow servo motor and the λ / 2 plate, thereby reconstructing the quantitative anisotropic image of the tissue sample. Reconstruction of photoacoustic elastic images: By measuring the time required for the surface vibration displacement of the tissue sample to go from zero to the maximum value, the elastic modulus of the tissue sample can be calculated, and its quantitative elastic image can be reconstructed.

[0060] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An arthroscopic device integrating optical-photoacoustic multimodal imaging, the arthroscopy comprising a control and data acquisition system, a light source and optical path system, and an arthroscopic probe; The control and data acquisition system includes an FPGA development board, a signal amplifier, an acquisition card, and a computer; the FPGA development board is used as a control module to generate timing pulses to control the coordinated operation of various systems. After the pulse laser is incident on the tissue surface, the tissue surface is stimulated to generate ultrasonic waves, which are received by the micro-transducer in the arthroscopic probe. After the signal is amplified by the signal amplifier, it enters the acquisition card, and finally the acquisition card transmits the original data to the computer; The light source and optical path system include a pulse laser, a first optical fiber coupler, a single-mode optical fiber, a first adjustable focus collimator, a second optical fiber coupler, a polarization-maintaining optical fiber, a second adjustable focus collimator, and a white light source. The control end of the white light source and the pulse laser is connected to the FPGA development board of the control and data acquisition system to control the light source to output pulse lasers with wavelengths of 532nm and 1550nm, respectively, through the first optical fiber coupler and the second optical fiber coupler to access the optical path system, and then through the single-mode optical fiber and the polarization-maintaining optical fiber, through the first adjustable focus collimator and the second adjustable focus collimator to enter the arthroscopic probe; The pulse laser is one of a semiconductor laser, a solid laser, a dye laser or a gas laser, and the output pulse laser has a wavelength range of 400nm to 2000nm and a pulse width of 3ns to 30ns; The effective focal length of the first adjustable focus collimator is 7.5 mm, and the wavelength range of the anti-reflection film is 350 nm-700 nm. The effective focal length of the second adjustable focus collimator is 7.5 mm, and the wavelength range of the anti-reflection film is 1050 nm-1700 nm. The addition of the first and second adjustable focus collimators realizes the confocal of lasers of different wavelengths. The arthroscopic probe comprises a charge coupled element, a beam splitter, a MEMS mirror, a pulse fiber interface, a hollow servo motor, a λ / 2 plate, a dichroic plate, a focusing lens, a cold light source interface, a rod mirror group, an arthroscopic housing, a lens group, a light-transmitting reflective mirror, a micro-transducer and a light-guiding optical fiber. A 532nm pulse laser enters the arthroscopic probe through the pulse fiber interface, is vertically incident and passes through the dichroic plate. A 1550nm pulse laser enters the arthroscopic probe through the pulse fiber interface, passes through the hollow servo motor and the λ / 2 plate, and the rotation of the hollow servo motor realizes the modulation of polarized light. The 1550nm pulse laser is combined with the 532nm pulse laser after being reflected by the dichroic plate, and the combined light is incident on the surface of the MEMS mirror. After reflection, the scanning light is focused by the focusing lens, passes through the beam splitter and then is incident on the rod mirror group, is transmitted inside the rod lens, passes through the lens group and the light-transmitting reflective mirror, and finally is incident on the tissue surface. The white light source illuminates the tissue through the light-guiding optical fiber on the side wall of the arthroscopic probe, and the optical signal is received by the charge coupled element after being reflected by the beam splitter. The cut-off wavelength of the dichroic film is 950nm, the transmittance of 532nm wavelength laser is 85-95%, and the reflectivity of 1550nm wavelength laser is 90-99%. The addition of the dichroic film realizes the co-path of pulsed light of different wavelengths.

2. An arthroscopic device integrating optical-photoacoustic multimodal imaging according to claim 1, characterized in that: The hollow servo motor has an inner diameter of 4 mm and a rotation speed range of 0.5-2000 rpm. The addition of the hollow servo motor enables the rotation of the λ / 2 plate, thereby changing the polarization state of light.

3. The arthroscopic device integrating optical-photoacoustic multimodal imaging according to claim 1, characterized in that: The spectroscope has a white light transmission rate of 50%, a 532nm wavelength laser reflectivity of 50%, and a 1550nm wavelength laser reflectivity of 80-90%. The addition of the spectroscope enables white light and laser to share the same path.

4. The arthroscopic device integrating optical-photoacoustic multimodal imaging according to claim 1, characterized in that: The MEMS mirror has a scanning angle of 5-20° and a response frequency of 2.5-5KHz. The scanning range and scanning speed can be changed by changing the frequency of the driving signal. The addition of the MEMS mirror can achieve rapid scanning of the imaging area.

5. The arthroscopic device integrating optical-photoacoustic multimodal imaging according to claim 1, characterized in that: The signal amplifier has an amplification gain of 50dB to 60dB.

6. An imaging method using an arthroscopic device integrating optical-photoacoustic multimodal imaging according to any one of claims 1 to 5, characterized in that: The steps include: a. System triggering: The control and data acquisition system generates a trigger signal to control the pulsed lasers of 532nm and 1550nm wavelengths to generate pulsed light, and controls the illumination light source at the same time. The pulsed lasers of different wavelengths enter the fiber coupler respectively, and enter the arthroscopic probe through the first and second adjustable focus collimators. The 1550nm wavelength laser is modulated by the electro-optic polarization modulator and then combined with the 532nm wavelength laser through the dichroic film. The combined light finally reaches the surface of the tissue to be imaged through the focusing lens and the beam splitter, and the illumination light irradiates the surface of the tissue to be imaged through the optical fiber; b. Data acquisition: The photoacoustic signal excited by the pulsed laser is reflected by the light-transmitting reflective mirror and received by the ultrasonic transducer on the side wall of the arthroscope, and then converted into an electrical signal. The signal enters the signal amplifier through the coaxial cable, and the amplified electrical signal is collected by the acquisition card and sent to the computer; the optical signal passes through multiple groups of lenses and a spectroscope and enters the charge-coupled device. The charge-coupled device converts the incident light signal into a charge output, and the electrical signal enters the computer through the data line; c. Image processing: The computer uses the collected data for the reconstruction of optical, photoacoustic, polarized photoacoustic, and photoacoustic elastic images. Reconstruction of photoacoustic images: The photoacoustic signal generated by the absorption of 532 nm wavelength laser by hemoglobin and the instantaneous thermal expansion is used to reconstruct the maximum projection image of the blood vessels through the maximum projection algorithm; Reconstruction of photoacoustic polarization images: The anisotropic absorption difference of the tissue sample is obtained by modulating the laser light of different polarization states through the combination of the hollow servo motor and the λ / 2 plate, so as to reconstruct the quantitative anisotropic image of the tissue sample; Reconstruction of photoacoustic elastic images: By measuring the time required for the surface vibration displacement of the tissue sample to go from zero to the maximum value, the elastic modulus of the tissue sample is calculated, and its quantitative elastic image is reconstructed.

Images