Three-dimensional photoacoustic imaging system

Abstract

The utility model discloses a three-dimensional photoacoustic imaging system which is characterized in that a beam expander is arranged in the light beam advancing direction of a laser, the beam expander is provided with a lens set in the light beam advancing direction, the lens set is provided with a diaphragm in the light beam advancing direction, and the diaphragm is provided with a plane mirror in the light beam advancing direction; the plane mirror is provided with a plurality of cambered surface reflector groups along the reflection direction of the light beam, a tissue holding table is arranged in the irradiation direction of the cambered surface reflector groups, a transducer is arranged at the light receiving position of the top of the tissue holding table, and the transducer is electrically connected with an upper computer. According to the invention, the beam expander is optimized to ensure that the diameter of the input parallel light is enlarged, the energy distribution is uniform and concentrated, the excitation efficiency of the photoacoustic signal in the ultrathin sample is enhanced, and the imaging requirement of the ultrathin sample is met. Through the combination of the cambered surface reflector and the plane reflector, the stability of light beam focusing and transmission is improved, and high-resolution and clear image reconstruction can be realized in an ultrathin sample.

Description

Technical Field

[0001] The present application relates to the technical field of photoacoustic imaging, and in particular to a three-dimensional photoacoustic imaging system. Background Art

[0002] Photoacoustic 3D imaging is an advanced imaging technology that combines optical and acoustic properties. This technology uses short-pulse lasers to illuminate the imaging object. The object absorbs light energy and generates ultrasonic waves (i.e., photoacoustic effect). These ultrasonic waves are then received by high-precision ultrasonic sensors and converted into electrical signals. By processing these signals and reconstructing the image, 3D imaging of the internal structure of the object can be achieved. Photoacoustic 3D imaging technology not only provides high-resolution structural information, but also reflects the characteristics at the functional and molecular levels. Therefore, it has broad application prospects in biomedicine, materials science and other fields.

[0003] Existing photoacoustic 3D imaging technology has developed a variety of imaging modes, such as photoacoustic tomography (PAT), photoacoustic microscopy (PAM) and photoacoustic endoscopy (PAE). These technologies have made significant progress in the field of biomedical imaging and are widely used in the diagnosis and research of skin diseases (such as melanoma), musculoskeletal system (such as muscular dystrophy), cardiovascular system (such as atherosclerosis), lymphatic system, nervous system (such as cerebrovascular imaging), endocrine system (such as thyroid disease), reproductive system (such as prostate cancer and breast cancer) and digestive system (such as Crohn's disease). Photoacoustic 3D imaging technology can break through the depth limitation of traditional optical imaging and provide high-contrast and high-resolution images, which is of great value for in-depth observation of the structure and function of tissues and organs.

[0004] However, traditional optical components will cause high energy loss during laser transmission, which limits the effective excitation power of the laser and thus affects the excitation efficiency of photoacoustic signals in ultra-thin samples. Due to insufficient laser energy, weak photoacoustic signals in ultra-thin samples (such as animal and plant tissue sections) may be difficult to be effectively detected and recorded, which in turn affects the sensitivity and resolution of imaging. Existing photoacoustic three-dimensional imaging systems often lack targeted design for ultra-thin samples. Ultra-thin samples such as animal and plant tissue sections have significant differences in optical and acoustic properties from conventional samples, so traditional imaging parameters and methods may not be applicable. This makes it difficult to achieve high-resolution and clear image reconstruction in ultra-thin sample imaging. Utility Model Content

[0005] The embodiment of the present application provides a three-dimensional photoacoustic imaging system to solve the problem that conventional optical elements in the prior art will cause high energy loss during laser transmission, thereby affecting the excitation efficiency of photoacoustic signals in ultra-thin samples. The lack of targeted design for ultra-thin samples makes it difficult to achieve high-resolution and clear image reconstruction in ultra-thin sample imaging.

[0006] On the one hand, an embodiment of the present application provides a three-dimensional photoacoustic imaging system, comprising:

[0007] A laser, a beam expander is arranged along the direction of the laser beam, the beam expander is arranged along the direction of the beam, the lens group is arranged along the direction of the beam, the window plate is arranged along the direction of the beam, the window plate is arranged along the direction of the beam, a plane reflector is arranged along the direction of the beam, and a plurality of arc reflector groups are arranged on the plane reflector along the reflection direction of the beam, the arc reflector group comprises an elastic arc surface, a metal mirror coating, a first mirror adjustment seat, a second mirror adjustment seat, a support seat rotating head and a rotating shaft, the elastic arc surface is adjusted in curvature by the first mirror adjustment seat and the second mirror adjustment seat, the metal mirror coating is fixedly arranged on the elastic arc surface, the elastic arc surface is adjusted in angle and rotation direction by the support seat rotating head and the rotating shaft, a tissue holding table is arranged in the irradiation direction of the arc reflector group, a transducer is arranged at the light receiving position on the top of the tissue holding table, and the transducer is electrically connected to a host computer.

[0008] In a possible implementation, a mirror support seat is also provided on the arc reflector group, and the two opposite sides of the elastic arc surface are respectively connected to the first side and the third side of the two outer ends of the first mirror adjustment seat and the second mirror adjustment seat, and the second side and the fourth side of the two inner ends of the first mirror adjustment seat and the second mirror adjustment seat are respectively rotatably connected to the two opposite sides of the mirror support seat.

[0009] In a possible implementation, the support seat rotating head is fixedly connected to the mirror support seat, one end of the rotating shaft is rotatably set on the support seat rotating head, and the other end of the rotating shaft is connected to the tissue holding table through a universal bracket. Pneumatic telescopic rods are respectively provided on both sides of the support seat rotating head corresponding to the outer end positions of the first mirror adjustment seat and the second mirror adjustment seat, and the other ends of the two pneumatic telescopic rods are respectively rotatably connected to the side midpoints of the outer ends of the first mirror adjustment seat and the second mirror adjustment seat.

[0010] In a possible implementation, a plurality of sheet clips are disposed on the tissue holding platform. The sheet clips are movably disposed on the tissue holding platform via lifting nuts. The sheet clips are also provided with locking nuts.

[0011] In a possible implementation, the lens group includes a plurality of lenses, the plurality of lenses are respectively mounted in threaded sleeves, the distances between the plurality of lenses are controlled by the threaded sleeves, and the plurality of lenses have the same optical path.

[0012] In a possible implementation, the beam expander, the lens group and the window are arranged in the same optical path, and the spacing between the beam expander, the lens group and the window is adjusted by a gear rod. In a possible implementation, the elastic arc surface is connected to the sides of the two outer ends of the first mirror adjustment seat and the second mirror adjustment seat by a buckle or a tongue and groove.

[0013] In a possible implementation, the two pneumatic telescopic rods are respectively controlled by the host computer.

[0014] A three-dimensional photoacoustic imaging system in this application has the following advantages:

[0015] (1) By optimizing the beam expander, the diameter of the input parallel light is enlarged, the energy distribution is uniform and concentrated, and the energy loss is low. This enhances the excitation efficiency of the photoacoustic signal in ultra-thin samples and meets the imaging requirements of ultra-thin samples.

[0016] (2) By combining curved mirrors and flat mirrors, the stability of beam focusing and transmission is improved, and high-resolution and clear image reconstruction can be achieved in ultra-thin samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of the structure of a three-dimensional photoacoustic imaging system provided in an embodiment of the present application;

[0019] Figure 2 A schematic diagram of the structure of a curved reflector group of a three-dimensional photoacoustic imaging system provided in an embodiment of the present application;

[0020] Figure 3 A schematic diagram of the structure of a beam expander for a three-dimensional photoacoustic imaging system provided in an embodiment of the present application;

[0021] Figure 4 A schematic diagram of the transducer structure of a three-dimensional photoacoustic imaging system provided in an embodiment of the present application.

[0022] Explanation of the numbers in the figure: 1. Laser; 2. Beam expander; 21. First convex lens; 22. Second convex lens; 23. Beam expander housing; 3. Lens group; 4. Window piece; 5. Arc reflector group; 51. Elastic arc surface; 52. Mirror support seat; 53. First mirror adjustment seat; 54. Second mirror adjustment seat; 55. First side edge; 56. Third side edge; 57. Second side edge; 58. Fourth side edge; 59. Support seat rotating head; 591. Rotating shaft; 6. Tissue holding table; 7. Plane reflector; 8. Transducer; 81. Transducer support frame; 82. Transducer holding groove; 83. Support frame circular hole; 10. Optical signal; 11. Ultrasonic signal; 12. Photoacoustic common focus. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0024] Figure 1 A schematic diagram of the structure of a three-dimensional photoacoustic imaging system provided in an embodiment of the present application; an embodiment of the present application provides a three-dimensional photoacoustic imaging system, comprising:

[0025] A laser 1, wherein a beam expander 2 is arranged along the beam advancing direction of the laser 1, wherein the beam expander 2 is arranged along the beam advancing direction of the laser 1 with a lens group 3, wherein the lens group 3 is arranged along the beam advancing direction with a window plate 4, wherein the window plate 4 is arranged along the beam advancing direction with a plane reflector 7, wherein the plane reflector 7 is arranged along the reflection direction of the beam with a plurality of arc reflector groups 5, wherein the arc reflector group 5 comprises an elastic arc surface 51, a metal mirror coating, a first mirror adjustment seat 53, a second mirror adjustment seat 54, a support seat rotating head 59 and a rotating shaft 591, wherein the elastic arc surface 51 is adjusted in curvature by the first mirror adjustment seat 53 and the second mirror adjustment seat 54, wherein the metal mirror coating is fixedly arranged on the elastic arc surface 51, wherein the angle and rotation direction of the elastic arc surface 51 are adjusted by the support seat rotating head 59 and the rotating shaft 591, wherein a tissue holding platform 6 is arranged in the irradiation direction of the arc reflector group 5, wherein a transducer 8 is arranged at the light receiving position on the top of the tissue holding platform 6, and wherein the transducer 8 is electrically connected to a host computer;

[0026] The arc reflector assembly 5 is also provided with a mirror support seat 52, two opposite sides of the elastic arc surface 51 are respectively connected to the first side 55 and the third side 56 of the two outer ends of the first mirror adjustment seat 53 and the second mirror adjustment seat 54, and the second side 57 and the fourth side 58 of the two inner ends of the first mirror adjustment seat 53 and the second mirror adjustment seat 54 are respectively rotatably connected to the two opposite sides of the mirror support seat 52;

[0027] The support seat rotating head 59 is fixedly connected to the mirror support seat 52, one end of the rotating shaft 591 is rotatably set on the support seat rotating head 59, and the other end of the rotating shaft 591 is connected to the tissue holding table 6 through a universal bracket, and pneumatic telescopic rods are respectively arranged on both sides of the support seat rotating head 59 corresponding to the outer end positions of the first mirror adjustment seat 53 and the second mirror adjustment seat 54, and the other ends of the two pneumatic telescopic rods are respectively rotatably connected to the side midpoints of the outer ends of the first mirror adjustment seat 53 and the second mirror adjustment seat 54.

[0028] Exemplarily, laser 1 provides a high-energy laser beam, supports bands such as 266nm, and is adapted to the light absorption characteristics of animal and plant tissues. The laser band is optional and can be adjusted according to different samples to meet the imaging requirements of tissue sections. Beam expander 2 is used to expand the diameter of the input parallel light, ensure the uniform distribution of the beam energy, increase the beam coverage, match it with the morphological characteristics of ultra-thin samples, and reduce the damage that may be caused by excessive concentration of laser energy. Lens group 3 focuses the expanded beam to ensure the high-precision scanning capability of the beam. Stable focusing of the light beam in different sample areas is achieved, providing precise point scanning effects for ultra-thin samples; lens group 3 uses an achromatic doublet lens, and its application in the photoacoustic imaging system can not only effectively correct spherical aberration and chromatic aberration, but also improve the optical performance and imaging quality of the system.

[0029] The window 4 is made of materials according to the laser wavelength (e.g., a quartz or sapphire window with high transmittance in the range of 200-350nm is used for a 266nm laser). The window 4 protects the optical system from contamination, while minimizing laser energy loss and ensuring sample excitation efficiency. Figure 2As shown, the arc mirror group 5 can be set in multiple groups according to the detection requirements. The elastic arc surface 51 cooperates with the opening and closing of the first mirror adjustment seat 53 and the second mirror adjustment seat 54 to adjust the curvature and curvature direction of the elastic arc surface 51, thereby achieving the adjustment of the curvature and curvature direction of the metal reflection surface of the arc mirror group 5 (that is, the metal mirror coating arranged on the elastic arc surface 5), and then the support seat rotating head 59 cooperates with the rotating shaft 591 to rotate 360 ​​degrees, and then the universal bracket connected to the tissue holding table 6 controls the overall direction of the entire arc mirror group 5, ensuring that the arc mirror group 5 can achieve light reflection at any angle and ensure that the light energy is maximized and concentrated in the target area. The plane reflector 7 is mainly used to change the direction of the light beam and guide the light beam to the sample area. It is suitable for adjusting the beam path without changing the focusing characteristics of the light beam.

[0030] The surface of the elastic arc surface 51 is provided with a metal mirror coating, which is a layer of metal film, and a variety of materials such as gold, silver, and aluminum can be selected. Among them, the gold film: suitable for the 600-800nm ​​infrared and visible light bands, with high reflectivity, suitable for deep tissue imaging, the silver film: suitable for the 400-2000nm band, widely applicable to ultraviolet to near-infrared imaging needs, and the aluminum film: adapted to the ultraviolet band (100-400nm), with excellent reflective performance, suitable for ultra-thin sample excitation. The transducer 8 is a high-sensitivity ultrasonic detection device, which is used to collect acoustic signals excited by animal and plant slices, improve the signal coverage and acquisition accuracy, especially for the signal acquisition of deep microstructures, such as Figure 4 As shown, the position of the transducer 8 needs to be consistent with the optical path, so as to ensure that the light beam in the photoacoustic imaging can accurately excite the sample, and the transducer 8 can accurately capture the ultrasonic signal 11 reflected from the inside of the sample. The transducer 8 ensures the best signal acquisition effect through the position adjustment of the transducer support 81, and improves the signal coverage and acquisition accuracy according to the sensitivity and frequency response of the transducer 8, especially for the signal acquisition of deep microstructures. In addition, the transducer support 81 is made of PDMS material, which has good flexibility and adaptability, can effectively isolate vibration and provide necessary stability.

[0031] The transducer support frame 81 is used to fix the position of the transducer 8, ensuring the stability and precise alignment of the transducer 8 in the system. The transducer holding groove 82 is used to accommodate the transducer 8 itself, ensuring that the position of the transducer 8 is fixed and reducing the impact caused by vibration or other interference. The circular hole 83 of the support frame is used to insert the adjustment rod to adjust the position of the transducer 8 to ensure that the position of the transducer 8 is consistent with the optical path.

[0032] The tissue holder 6 is used to fix animal and plant tissue slices, supporting ultra-thin samples with a thickness of 1-20 microns, ensuring the stability of the sample during scanning. The adjustable design is suitable for samples of different shapes and provides flexible support for multi-angle scanning.

[0033] The laser 1 emits a high-energy optical signal 10, and the beam diameter is expanded to the required range through the beam expander 2, and further focused by the lens group 3. The uniformity and stability of the beam are optimized at this stage. The beam passes through the curved reflector group 5 to achieve path adjustment and enhance focusing ability, and is finally guided to the sample surface by the plane reflector 7. The entire optical path design ensures that the optical signal is focused on the photoacoustic common focus 12. The sample is excited by the laser in the photoacoustic common focus 12 area to generate an ultrasonic signal 11. The ultrasonic signal is collected by the transducer 8 and converted into an electrical signal for subsequent processing. The imaging processing unit decodes and reconstructs the collected electrical signal in three dimensions to generate a high-resolution image of the internal structure of the sample, providing accurate biological information.

[0034] The position of the transducer 8 is strictly matched with the laser focus to ensure the effective collection of the ultrasonic signal 11. The optimized design of the photoacoustic common focus 12 can be achieved by adjusting the laser wavelength, energy density and curvature of the reflector. The photoacoustic common focus 12 is the core area of ​​signal excitation and collection, and its optimized design ensures the intensity of the photoacoustic effect, the signal-to-noise ratio and the imaging resolution of the system. The plane reflector 7 guides the light beam to the sample surface to ensure that the laser efficiently excites the photoacoustic signal. The sample generates a photoacoustic signal under laser excitation, and the ultrasonic signal 11 is collected by the transducer 8 and converted into an electrical signal. The imaging processing unit converts the signal into three-dimensional reconstruction data to generate a high-resolution three-dimensional image containing biological information.

[0035] like Figure 3 As shown, the beam expander 2 is composed of a convex-convex lens structure, and the diameters of the first convex lens 21 and the second convex lens 22 are 12.7 mm and 25.4 mm respectively. The beam expander 2 is used to expand and focus the light beam to meet the imaging requirements of ultra-thin samples. The laser beam is first expanded by the first convex lens 21 to increase the coverage area and uniformity of the beam; and then the convex surface design of the second convex lens 22 further focuses the beam and adjusts its shape to meet the scanning requirements of different depths. Ensure that the diameter of the input parallel light is enlarged, the energy distribution is uniform and concentrated, and adapt to the imaging requirements of ultra-thin samples.

[0036] The expansion of the light beam is controlled by adjusting the focal length of the first convex lens 21 and the second convex lens 22. The input parallel light beam expands its diameter after passing through the first convex lens 21, and the light beam is evenly expanded under the action of the second convex lens 22, ensuring that the energy distribution of the light beam is uniform and concentrated. The focal length selection of the first convex lens 21 and the second convex lens 22 has a direct impact on the optical performance of the system, so it is necessary to achieve the best effect through precise optical design and adjustment. The focal length of the first convex lens 21 determines the initial degree of light beam expansion. The focal length of the second convex lens 22 is used to further adjust the diameter of the expanded light beam to ensure the uniformity of the light beam and adapt to the requirements of the subsequent system.

[0037] In a possible embodiment, a plurality of sheet clips are arranged on the tissue holding platform 6, and the sheet clips are movably arranged on the tissue holding platform 6 through lifting nuts, and the sheet clips are also provided with locking nuts;

[0038] The lens group 3 includes a plurality of lenses, and the plurality of lenses are respectively installed in threaded sleeves, and the distances between the plurality of lenses are controlled by the threaded sleeves, and the optical paths of the plurality of lenses are the same;

[0039] The beam expander 2 , the lens group 3 and the window sheet 4 are arranged in the same optical path, and the distance between the beam expander 2 , the lens group 3 and the window sheet 4 is adjusted by a gear rod.

[0040] Exemplarily, the film clamp is used to fix the sample slice to be tested. The clip adapts to different sample thicknesses through the lifting nut, and then the height is maintained by the locking nut to ensure the fixation of the sample slice. A section of the top of the lifting nut passes through the through hole of the film clamp and is rotatably connected to the film clamp. The side of the through hole of the clip is also provided with a through hole. The locking nut is screwed on the clip through the through hole. The bottom of the lifting nut is threaded and connected to the tissue holding table 6 through the threaded through hole on the tissue holding table 6. When it is necessary to fix the tissue sample slice, first place the slice on the tissue holding table 6, and then rotate multiple clips to above the sample slice, move the clip down by rotating the lifting nut, let the clip press the sample slice, and then fix the clip on the lifting nut by rotating the locking nut on the side without rotating, so as to keep the sample slice in a fixed state on the tissue holding table 6.

[0041] Each lens of the lens group 3 is placed on a threaded sleeve, and the threaded sleeves are concentrically arranged. The multiple lenses can move forward and backward through the threaded sleeves that are nested with each other while keeping the optical path unchanged.

[0042] The beam expander 2, the lens group 3 and the window piece 4 are arranged in the same optical path. Gears and gear fastening devices are arranged on the sides of the beam expander 2, the lens group 3 and the window piece 4. The distance between the beam expander 2, the lens group 3 and the window piece 4 can be adjusted arbitrarily through the rack and the gear, and then fixed by the gear fastening device. The gear fastening device fixes the gear by friction so that it does not rotate.

[0043] In a possible embodiment, the elastic arc surface 51 is connected to the sides of the two outer ends of the first mirror adjustment seat 53 and the second mirror adjustment seat 54 by means of a buckle or a tongue and groove;

[0044] The two pneumatic telescopic rods are respectively controlled by the host computer.

[0045] Exemplarily, the pneumatic telescopic rod is connected to an air pump, and the air pump valve is controlled by the host computer to control the extension and retraction of the pneumatic telescopic rod, thereby controlling the opening and closing angles of the first mirror adjustment seat 53 and the second mirror adjustment seat 54 on the mirror support seat 52. The two pneumatic telescopic rods are controlled separately by the host computer to ensure that the first mirror adjustment seat 53 and the second mirror adjustment seat 54 can be opened and closed at different angles on the mirror support seat 52.

[0046] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0047] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A three-dimensional photoacoustic imaging system, characterized in that: include: A laser (1), wherein a beam expander (2) is arranged along the advancing direction of a light beam of the laser (1), the beam expander (2) is arranged along the advancing direction of the light beam with a lens group (3), the lens group (3) is arranged along the advancing direction of the light beam with a window sheet (4), the window sheet (4) is arranged along the advancing direction of the light beam with a plane reflector (7), the plane reflector (7) is arranged along the reflection direction of the light beam with a plurality of arc reflector groups (5), the arc reflector groups (5) comprising an elastic arc surface (51), a metal mirror coating, a first mirror adjustment seat (53), and a second mirror adjustment seat ( 54), a support seat rotating head (59) and a rotating shaft (591), the elastic arc surface (51) is adjusted in curvature by means of the first mirror adjustment seat (53) and the second mirror adjustment seat (54), the metal mirror coating is fixedly arranged on the elastic arc surface (51), the elastic arc surface (51) is adjusted in angle and rotation direction by means of the support seat rotating head (59) and the rotating shaft (591), a tissue holding table (6) is arranged in the irradiation direction of the arc reflector group (5), a transducer (8) is arranged at the light receiving position on the top of the tissue holding table (6), and the transducer (8) is electrically connected to a host computer.

2. A three-dimensional photoacoustic imaging system according to claim 1, characterized in that: The arc reflector assembly (5) is further provided with a mirror support seat (52); two opposite sides of the elastic arc surface (51) are respectively connected to the first side edge (55) and the third side edge (56) of the two outer ends of the first mirror adjustment seat (53) and the second mirror adjustment seat (54); and the second side edge (57) and the fourth side edge (58) of the two inner ends of the first mirror adjustment seat (53) and the second mirror adjustment seat (54) are respectively rotatably connected to the two opposite sides of the mirror support seat (52).

3. A three-dimensional photoacoustic imaging system according to claim 2, characterized in that: The support seat rotating head (59) is fixedly connected to the mirror support seat (52), one end of the rotating shaft (591) is rotatably arranged on the support seat rotating head (59), and the other end of the rotating shaft (591) is connected to the tissue holding table (6) via a universal bracket, and pneumatic telescopic rods are respectively arranged on both sides of the support seat rotating head (59) corresponding to the outer end positions of the first mirror adjustment seat (53) and the second mirror adjustment seat (54), and the other ends of the two pneumatic telescopic rods are respectively rotatably connected to the side midpoints of the outer ends of the first mirror adjustment seat (53) and the second mirror adjustment seat (54).

4. A three-dimensional photoacoustic imaging system according to claim 3, characterized in that: A plurality of sheet clips are arranged on the tissue holding platform (6), and the sheet clips are movably arranged on the tissue holding platform (6) via lifting nuts, and locking nuts are also arranged on the sheet clips.

5. The three-dimensional photoacoustic imaging system according to claim 1, characterized in that: The lens group (3) comprises a plurality of lenses, the plurality of lenses are respectively mounted in threaded sleeves, the distances between the plurality of lenses are controlled by the threaded sleeves, and the optical paths of the plurality of lenses are the same.

6. A three-dimensional photoacoustic imaging system according to claim 1, characterized in that: The beam expander (2), the lens group (3) and the window sheet (4) are arranged on the same optical path, and the spacing between the beam expander (2), the lens group (3) and the window sheet (4) is adjusted by a gear rod.

7. A three-dimensional photoacoustic imaging system according to claim 2, characterized in that: The elastic arc surface (51) is connected to the side edges of the two outer ends of the first mirror adjustment seat (53) and the second mirror adjustment seat (54) by means of buckles or tongue and groove.

8. A three-dimensional photoacoustic imaging system according to claim 3, characterized in that: The two pneumatic telescopic rods are respectively controlled by the host computer.

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