Photoacoustic capsule endoscope and imaging method

Abstract

The invention discloses a photoacoustic capsule endoscope and an imaging method. The photoacoustic capsule endoscope comprises a light path folding assembly, an optical collimation focusing assembly, a miniaturized internal scanning assembly, a port connecting assembly and a multi-angle imaging probe. The multi-angle imaging probe can be rapidly and conveniently replaced through the port connecting assembly so as to adapt to different types of in-vivo cavities or cavity walls of esophagus, rectum, cervix uteri and the like. By designing the internal structure of the imaging probe and introducing a novel device, the device can achieve the miniaturized size with the diameter of 5 mm and the hard length of 15 mm, the requirement for in-vivo high-degree-of-freedom rapid lossless imaging is met, the detectable area and the imaging depth are enlarged, the influence of motion artifacts and image distortion is avoided, the clinical use cost is reduced, and the application prospect is wide. And multi-angle full-space endoscopic imaging is realized.

Description

Technical Field

[0001] The present invention belongs to the field of medical equipment and methods, and in particular relates to a photoacoustic capsule endoscope and an imaging method. Background Art

[0002] Capsule endoscopic imaging technology is a clinical endoscopic imaging technology that has gradually emerged in recent years. Different from traditional endoscopic imaging technology, capsule endoscope has the characteristics of small size, high freedom of movement, and wide imaging range. Although it is widely used in clinical gastrointestinal endoscopic imaging, it is limited by the characteristics of white light endoscopic imaging and can only observe the surface structure information of the cavity, but cannot obtain deep structure and function information.

[0003] As an emerging non-invasive and non-ionizing imaging technology, photoacoustic imaging can simultaneously achieve high-resolution imaging of deep biological tissues through optical scanning and ultrasonic detection. In order to combine photoacoustic microscopy with capsule endoscopy imaging technology, it is necessary to solve the problem of how to reduce the volume of the imaging probe, reduce the image misalignment and distortion during movement, and achieve the coupling between the probe port and tissue for different types of cavities in the body. In order to solve the above problems, Ntziachristos of the Technical University of Munich in Germany designed a photoacoustic endoscope with a diameter of 16 mm. By using unfocused light, the change in the distance between the imaging port and the tissue can be reduced. The effect of changes in the image quality on the image quality; Guan Baiou of Jinan University has developed a photoacoustic endoscope based on a fiber-optic ultrasound detector. The diameter of the photoacoustic endoscope has been reduced by miniaturizing the fiber-optic ultrasound detector, and its axial hard length is 105 mm. All of the above methods use a fixed light beam and a point-focused ultrasonic transducer. To complete the scanning imaging of the pulsed laser, it is necessary to rotate the entire probe and continuously pull the probe back mechanically, which inevitably causes the loss of imaging field of view and produces artifacts due to movement, greatly affecting the imaging quality. The fiber-optic ultrasonic detector can only shorten the lateral diameter of the photoacoustic capsule endoscope, but cannot shorten its axial hard length, so that the photoacoustic capsule endoscope cannot achieve high-degree-of-freedom imaging inside the cavity, limiting the imaging range and imaging cavity type. At the same time, the use of non-focused light will significantly reduce the imaging resolution, and high-sensitivity diagnosis of early diseases cannot be achieved.

[0004] The present invention aims to provide a new photoacoustic capsule endoscope and imaging method. The capsule endoscope as a whole can reach a diameter of 5 mm and a hard length of 15 mm, and can realize high-degree-of-freedom imaging in narrow cavities. The miniaturized internal scanning component can realize the imaging process without any relative movement between the imaging probe and the imaged tissue, so that full-space high-resolution photoacoustic microscopic images of different types of cavities can be obtained. Summary of the invention

[0005] 1. Technical issues to be resolved The problems to be solved by the present invention include: in existing photoacoustic endoscopy systems, external rotation and mechanical pullback driven by a stepper motor are usually used to achieve full-space imaging, but since the external rotation motor and mechanical pullback cannot be synchronized with the imaging process, motion artifacts will be caused; the existing technology generally uses an imaging probe with only one specific imaging port angle, and since photoacoustic coupling requires the imaging probe port to fit the tissue surface, it is impossible to simultaneously achieve imaging of multiple types of cavities in the body such as the intestine, uterus and throat; the existing technology is limited by the size of the internal components of the imaging probe and cannot effectively reduce the overall volume of the probe.

[0006] In view of the problems of large imaging probe size, single application scenario and misalignment and distortion of in vivo imaging in existing photoacoustic endoscopy technology, the present invention provides a photoacoustic capsule endoscope and imaging method that combines MEMS scanning micromirrors for fast and high-resolution scanning, miniaturized imaging devices, conveniently replaceable installation components and replaceable multi-angle imaging probes, while achieving high-degree-of-freedom full-space imaging of multiple types of cavities, and obtaining distortion-free high-resolution photoacoustic images.

[0007] (II) Technical solution In order to solve the technical problem, the present invention provides a photoacoustic capsule endoscope and an imaging method, and the specific technical solution is as follows.

[0008] A photoacoustic capsule endoscope comprises a capsule shell, a capsule base, and an optical fiber component, an optical path folding component, an optical modulation component, a miniaturized internal scanning component, a port connection component, and a multi-angle imaging probe located at the front end, which are arranged in sequence from the rear end to the front end inside the capsule shell; The optical fiber assembly is located at the rear end of the capsule shell and is used to emit laser light; The optical path folding component is located at the front end of the optical fiber component and is used to spatially fold the laser emitted from the optical fiber; The optical modulation component is located at the front end of the optical path folding component, and includes a collimating lens and a focusing lens placed in sequence from the rear end to the front end; The miniaturized internal scanning component is located at the front end of the optical modulation component, and includes a MEMS scanning micromirror lens and a flexible PCB connected thereto, wherein the MEMS scanning micromirror lens package is connected to the flexible PCB; The multi-angle imaging probe assembly is located at the front end of the photoacoustic capsule endoscope, and includes a set of detachable and replaceable imaging probes, which can be installed with an oblique imaging probe, a direct imaging probe or a side-view imaging probe as needed to detect the cavity to be tested; The port connection component is located between the miniaturized internal scanning component and the multi-angle imaging probe component, and includes a mechanical fixing component and a magnetic fixing component placed in parallel; The capsule base is located at the bottom of the capsule shell and is used to fix various component units inside the capsule shell.

[0009] Preferably, the capsule base fixes the various component units inside the capsule shell in the following manner: the optical fiber is fixed by inserting into a ring-shaped hollow fixture at the rear end of the capsule base, the optical path folding component is fixed by inserting into a conical interlocking groove arranged on the capsule base, the optical modulation component is fixed by a semicircular slide arranged on the capsule base, and the MEMS scanning micromirror is fixed by a groove body and a back substrate base arranged on the capsule base.

[0010] Preferably, the optical path folding component includes three identical aluminum-coated mirrors, the first reflector and the second reflector are connected at a first bonding point at an angle of 135°, the second reflector and the third reflector are connected at a second bonding point at an angle of 45°, the third reflector and the first reflector are connected at a third bonding point at an angle of 45°, the first reflector and the second reflector are placed in an azimuth relationship of 180° staggered with each other in the xy plane, the second reflector and the third reflector are placed in an azimuth relationship of 180° staggered with each other in the yz plane, and the first reflector and the third reflector are placed in an azimuth relationship of 180° staggered with each other in the xz plane, so that the incident pulse nanosecond laser is reflected by the first reflector and then enters the surface of the second reflector, and then reflects from it and enters the surface of the third reflector, and then is emitted parallel to the y-axis.

[0011] Preferably, the collimating lens of the optical modulation component is an aspherical mirror, the laser incident side is a flat surface, the laser exit side is a convex surface, and its focal plane is located at the optical fiber port; the focusing lens is a plano-convex lens, the laser incident side is a flat surface, the laser exit side is a convex surface, and the collimated nanosecond laser passes through the focusing lens plane and is focused and emitted by the convex surface, and its focus is located at the imaging port.

[0012] Preferably, the MEMS scanning micromirror lens of the miniaturized internal scanning component is electrically connected to the flexible PCB by means of gold wire bonding; a high-transmittance glass sheet is bonded to the first pin and the second pin on the surface of the MEMS scanning micromirror, and the MEMS scanning micromirror is connected to the FR4 epoxy glass fiber board at the end of the flexible PCB by ultraviolet photosensitive adhesive; an analog voltage signal is input into the first pin and the second pin of the MEMS scanning micromirror through the internal circuit of the flexible PCB by the third pin and the fourth pin, so that the analog voltage signal can control the MEMS scanning micromirror lens to perform two-dimensional plane scanning.

[0013] Preferably, the strabismus imaging probe in the multi-angle imaging probe includes: a fourth reflector, a first probe base; a first light-transmitting component, a first light-transmitting anti-sound component, a first patch ultrasonic transducer, and a first light-transmitting and sound-transmitting film; the fourth reflector is located at the rear end of the strabismus imaging probe, with an angle of 30° with the horizontal direction, and is bonded to the square groove of the first probe base; the first light-transmitting component is located at the front end of the fourth reflector, with an angle of 60° with the horizontal direction, and is bonded to the circular groove of the first probe base; the first light-transmitting and anti-sound component is located at the front end of the first light-transmitting component, with an angle of 75° with the horizontal direction, and is bonded to the protrusion of the first probe base; the first light-transmitting and sound-transmitting film is bonded to the front end of the strabismus imaging probe; the first patch ultrasonic transducer is located in the square groove of the first probe base; the strabismus imaging probe is connected to the capsule base through the mechanical fixing and magnetic fixing components.

[0014] Preferably, the direct-view imaging probe in the multi-angle imaging probe includes: a fifth reflector, a second probe base; a second light-transmitting component, a second light-transmitting anti-sound component, a second patch ultrasonic transducer, and a second light-transmitting and sound-transmitting film; the fifth reflector is located at the rear end of the direct-view imaging probe, with an angle of 45° to the horizontal direction, and is bonded to the square groove of the second probe base; the second light-transmitting component is located at the front end of the fifth reflector, with an angle of 90° to the horizontal direction, and is bonded to the circular groove of the second probe base; the second light-transmitting and anti-sound component is located at the front end of the second light-transmitting component, with an angle of 45° to the horizontal direction, and is bonded to the protrusion of the second probe base; the second light-transmitting and sound-transmitting film is bonded to the front end of the direct-view imaging probe; the second patch ultrasonic transducer is located in the square groove of the second probe base; the direct-view imaging probe is connected to the capsule base through the mechanical fixing and magnetic fixing components.

[0015] Preferably, the side-view imaging probe in the multi-angle imaging probe comprises: a sixth reflector, a third probe base; a third light-transmitting component, a seventh reflector, a third light-transmitting anti-sound component, a third patch ultrasonic transducer, and a third light-transmitting and sound-transmitting film; the sixth reflector is located at the rear end of the side-view imaging probe, with an angle of 45° with the horizontal direction, and is bonded in the square groove of the third probe base; the seventh reflector is located at the front end of the sixth reflector, with an angle of 135° with the horizontal direction, and is bonded in the square groove of the third probe base; the third light-transmitting component is located on the side of the seventh reflector, is placed parallel to the horizontal direction, and is bonded in the circular groove of the third probe base; the third light-transmitting and anti-sound component is located on the side of the third light-transmitting component, with an angle of 45° with the horizontal direction, and is bonded to the protrusion of the third probe base; the third light-transmitting and sound-transmitting film is bonded to the front end of the side-view imaging probe; the third patch ultrasonic transducer is located in the square groove of the third probe base; the side-view imaging probe is connected to the capsule base through the mechanical fixing and magnetic fixing components.

[0016] Preferably, the mechanical fixing component in the port connection component includes: a first gasket, a first sealing ring, an inserted cylindrical carrier, a first cylindrical hole, a second sealing ring, a second gasket, a screw, a second cylindrical hole, and an internal thread; the first cylindrical hole is located at the bottom end of the middle part of the multi-angle imaging probe, and a slot is provided at the bottom thereof, and the gasket is inserted into the bottom of the first cylindrical hole and is engaged with the slot; the first sealing ring is placed between the inserted cylindrical carrier and the first cylindrical hole; the second cylindrical hole is located at the bottom end of the outer side of the multi-angle imaging probe, and the inner wall thereof is provided with the internal thread and a slot is provided at the bottom, and the second gasket is inserted into the bottom of the second cylindrical hole and its protrusion is engaged with the slot; the second sealing ring is placed between the screw and the second cylindrical hole; the external thread of the screw cooperates with the internal thread and is screwed into the second cylindrical hole; so that the inserted cylindrical carrier is fixed between the second gasket and the side wall of the multi-angle imaging probe.

[0017] Preferably, the magnetic fixing component in the port connection component includes: a first magnet, a second magnet, a third sealing ring, a third cylindrical hole, a fourth cylindrical hole, a third magnet, a fourth magnet, a fourth sealing ring, a fifth cylindrical hole, and a sixth cylindrical hole; the first magnet is embedded in the third cylindrical hole at the inner bottom end of the multi-angle imaging probe, the second magnet is embedded in the fourth cylindrical hole on the inner side of the capsule base, and the third sealing ring is placed between the first magnet and the third cylindrical hole; the first magnet is bonded to the third cylindrical hole, and the second magnet is bonded to the fourth cylindrical hole on the inner side of the capsule base; the third magnet is embedded in the fifth cylindrical hole at the inner bottom end of the multi-angle imaging probe, the third magnet is embedded in the sixth cylindrical hole on the inner side of the capsule base, and the fourth sealing ring is placed between the fourth magnet and the fifth cylindrical hole; the third magnet is bonded to the fifth cylindrical hole; the third magnet is bonded to the fourth cylindrical hole on the inner side of the capsule base.

[0018] The present invention also discloses a photoacoustic capsule endoscope imaging method, which uses the above-mentioned photoacoustic capsule endoscope to obtain endoscopic microscopic images of cavity structures including the human esophagus, stomach, uterus, vagina, and intestines, and the specific steps are as follows: Step S1, selecting a required multi-angle imaging probe based on the target imaging cavity, and detachably connecting and fixing the probe to the capsule base; Step S2, injecting ultrasonic coupling liquid into the multi-angle imaging probe through the imaging port, and sealing the multi-angle imaging probe port with a first light-transmitting and sound-transmitting film; Step S3, injecting ultrasound coupling liquid into the cavity to be imaged, and extending the photoacoustic capsule endoscope into the cavity to be imaged; Step S4, the nanosecond pulse laser emits nanosecond pulse laser, and completes a two-dimensional plane scan of the imaging port surface under the control of the MEMS scanning micromirror; Step S5, controlling the multi-angle imaging probe to perform translation and three-dimensional rotation in the region of interest, acquiring imaging data of a specific position in the cavity, and reconstructing the image based on the acquired data to achieve high-degree-of-freedom full-space imaging.

[0019] Preferably, in step S1, when the multi-angle imaging probe is disassembled, the screws are first unscrewed, the first magnet and the second magnet are separated, and the third magnet and the fourth magnet are separated, so that the imaging probe can be disassembled; when replacing the imaging probe, the first magnet and the second magnet are first connected, the third magnet and the fourth magnet are connected, and then the screws are tightened to achieve the installation of the imaging probe.

[0020] (III) Beneficial effects Compared with the prior art, the present invention has significantly positive technical effects, and its beneficial effects are at least reflected in the following aspects.

[0021] (1) The present invention greatly reduces the overall diameter and hard length of the endoscope by designing the internal structure of the photoacoustic capsule endoscope and innovatively introducing independently designed optical folding components and miniaturized internal scanning components. Photoacoustic endoscopic imaging requires that the imaging port and the imaging area fit tightly together so that the imaging area is within the focal plane of the pulsed laser to obtain a high-resolution image. Therefore, in order to achieve full-space high-resolution imaging in the human body cavity, the imaging port must be able to rotate 360° in a relatively narrow cavity. Compared with the existing photoacoustic endoscope with a hard length of more than 30 mm, the present invention finally achieved a diameter of 5 mm and a hard length of 15 mm, achieving high-degree-of-freedom imaging inside a narrow cavity.

[0022] (2) The present invention can simultaneously realize multi-cavity multi-angle endoscopic imaging by innovatively proposing a multi-angle imaging probe and a conveniently detachable and replaceable port connection method. Compared with the imaging probe that only includes one angle in the prior art, it is impossible to keep the imaging port and the imaging area in the cavity of different diameters and shapes, which greatly affects the resolution and field of view of the image obtained, thereby limiting the application of photoacoustic endoscopes in clinical practice. The present invention uses only one capsule endoscope body, and can integrate three different angle imaging probes through the port connection component. The installation and replacement of the multi-angle imaging probe can be achieved through simple operations, so that it can cover various human cavities at the ports of tubular cavities represented by the digestive tract and rectum, spherical cavities represented by the uterus and stomach, and cervix and throat. In addition, the detachable and replaceable port connection method makes it possible to easily replace the imaging port in clinical applications, prevent cross-infection during the diagnosis process, and reduce the cost of use and the consumption of disposable medical resources.

[0023] (3) The present invention proposes a new MEMS scanning micromirror packaging method, which greatly reduces the volume of a single scanning component, so that the internal scanning function can still be realized in a smaller space. Compared with the prior art that only rotates a fixed focused light externally, since the rotation of the fixed light can only form a scanning line, a mechanical pullback action must be used to form a two-dimensional image. This process will introduce motion artifacts and image distortion. In the present invention, the MEMS scanning micromirror is driven by an analog voltage signal to perform fast two-dimensional scanning, which can achieve 12 Hz real-time video frame rate imaging, avoiding the process that may cause motion artifacts during the imaging process, thereby greatly improving the image quality of endoscopic microscopic imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the photoacoustic capsule endoscope and the direct-view imaging probe, the oblique-view imaging probe and the side-view imaging probe of the present invention.

[0025] Figure 2 Schematic diagram of the internal structure of the photoacoustic capsule endoscope.

[0026] Figure 3 Schematic diagram of the optical path folding component.

[0027] Figure 4 Schematic diagram of MEMS scanning micromirror and its packaging method.

[0028] Figure 5 Schematic diagram of the capsule shell.

[0029] Figure 6 Schematic diagram of the multi-angle imaging probe.

[0030] Figure 7 It is a schematic diagram of the structure of the mechanical fixing component and the magnetic fixing component.

[0031] Figure 8 It is a schematic diagram of the imaging planes corresponding to the direct-view imaging probe, the oblique-view imaging probe and the side-view imaging probe in the multi-angle imaging probe.

[0032] The reference numerals and corresponding names in the figure are: 1-1 optical fiber, 1-2 capsule base, 1-3 annular hollow fixture, 1-4 optical fiber assembly, 1-5 optical path folding assembly, 1-5-1 first reflector, 1-5-2 second reflector, 1-5-3 third reflector, 1-6 collimating lens, 1-7 focusing lens, 1-8 flexible PCB, 1-9 MEMS scanning micromirror, 1-9-1 third pin, 1-9-2 FR4 epoxy glass fiber board, 1-9-3 fourth pin, 1-9-4 MEMS scanning micromirror lens, 1-9-5 first pin, 1-9-6 second pin, 1-10 capsule shell, 1-10-1 second square slot, 1-10-2 circular slot, 1-10-3 first square slot, 2-1 first magnet, 2-2 second magnet, 2-3 inserted cylindrical carrier, 2-4 third magnet, 2-5 fourth magnet, 2-6 First sealing ring, 2-7 First gasket, 2-8 Third sealing ring, 2-9 Fourth sealing ring, 2-10 Second gasket, 2-11 Second sealing ring, 2-12 Screw, 2-13 Internal thread, 2-14 Second cylindrical hole, 2-15 Fifth cylindrical hole, 2-16 First cylindrical hole, 2-17 Third cylindrical hole, 2-18 Fourth cylindrical hole, 2-19 Sixth cylindrical hole, 3 Oblique imaging probe, 3-1 Fourth reflector, 3-2 First probe base, 3-3 First light-transmitting component, 3-4 First light-transmitting anti-sound component, 3-5 First patch ultrasonic transducer, 3-6 First light-transmitting and sound-transmitting film, 4 Direct imaging probe, 4-1 Fifth reflector, 4-2 Second probe base, 4-3 Second light-transmitting component, 4-4 Second light-transmitting and anti-sound component, 4-5 Second patch ultrasonic transducer, 4-6 Second light-transmitting and sound-transmitting film, 5 Side imaging probe, 5-1 The sixth reflector, 5-2 the third probe base, 5-3 the third light-transmitting component, 5-4 the seventh reflector, 5-5 the third light-transmitting and sound-transmitting film, 5-6 the third light-transmitting and sound-reflecting component, 5-7 the third patch ultrasonic transducer, 6-1 the vertical plane, 6-2 the oblique viewing plane, 6-3 the horizontal plane. DETAILED DESCRIPTION

[0033] In order to solve the technical problem, the present invention provides a photoacoustic capsule endoscope and an imaging method. The technical solution of the present invention is further described below by means of specific implementation methods in conjunction with the accompanying drawings of the specification.

[0034] The present invention provides a photoacoustic capsule endoscope, specifically, as Figure 1-2 As shown, the device includes a capsule base (1-2), an optical fiber component (1-4), an optical path folding component (1-5), an optical modulation component, a miniaturized internal scanning component, a multi-angle imaging probe component, a port connection component, and a capsule shell (1-10).

[0035] like Figure 2 As shown, the capsule base (1-2) fixes the optical fiber component (1-4), the optical path folding component (1-5), the optical modulation component, and the miniaturized internal scanning component at corresponding positions by means of arranging a groove body and a backing.

[0036] like Figure 2 As shown, the optical fiber assembly (1-4) is located in the annular hollow fixture (1-3) and connected to the optical fiber (1-1).

[0037] like Figure 2 As shown, the optical modulation component includes a collimating lens (1-6) and a focusing lens (1-7) which are arranged in sequence from the rear end to the front end.

[0038] like Figure 2 As shown, the miniaturized internal scanning component includes a MEMS scanning micromirror (1-9) and a flexible PCB (1-8) connected thereto.

[0039] like Figure 2 As shown, the port connection component includes a mechanical fixing component and a magnetic fixing component placed in parallel.

[0040] Figure 3-Figure 7 The optical path folding component (1-5), the miniaturized internal scanning component, the capsule shell (1-10), the multi-angle imaging probe and the port connection component are displayed separately.

[0041] like Figure 3 As shown, the optical path folding component (1-5) comprises three identical aluminum-coated reflectors. The first reflector (1-5-1) and the second reflector (1-5-2) are connected at a first bonding point (1-5-7) at an angle of 135°, the second reflector (1-5-2) and the third reflector (1-5-3) are connected at a second bonding point (1-5-8) at an angle of 45°, and the third reflector (1-5-3) and the first reflector (1-5-1) are connected at a third bonding point (1-5-6) at an angle of 45°, so that the incident pulse nanosecond laser (1-5-4) is first reflected by the first reflector (1-5-1), and the reflected light (1-5-5) is then incident on the surface of the second reflector (1-5-2), enters the third reflector (1-5-3) after being reflected by the second reflector (1-5-2), and finally is emitted in parallel along the y-axis direction. The optical path folding component shortens the length of the optical path in the horizontal direction without affecting the diameter of the photoacoustic capsule endoscope, thereby shortening the hard length of the photoacoustic capsule endoscope.

[0042] like Figure 4As shown, the MEMS scanning micromirror (1-9) in the miniaturized internal scanning component is electrically connected to the flexible PCB (1-8) by means of gold wire bonding; the first pin (1-9-5) for controlling the two-dimensional translation of the MEMS scanning micromirror lens (1-9-4) is connected to the third pin (1-9-1) on the flexible PCB (1-8), and the second pin (1-9-6) for controlling the spatial rotation of the MEMS scanning micromirror lens (1-9-4) is connected to the fourth pin (1-9-3) on the flexible PCB (1-8). A high-transmittance glass sheet is bonded to the pin surface of the MEMS scanning micromirror lens (1-9-4), and the MEMS scanning micromirror (1-9) is connected to the FR4 epoxy glass fiber board (1-9-2) at the end of the flexible PCB (1-8) by means of ultraviolet photosensitive adhesive. The polyimide film is bonded to the inner circuit surface of the flexible PCB (1-8). The analog voltage signal output by external control is input into the control pin of the MEMS scanning micromirror lens (1-9-4) through the line inside the flexible PCB (1-8), thereby controlling it to perform two-dimensional plane scanning.

[0043] like Figure 5 As shown, the capsule shell (1-10) includes a circular slot (1-10-2) embedded in the hollow fixture (1-3), a first square slot (1-10-3) embedded in the flexible PCB (1-8), and a second square slot (1-10-1) embedded in the patch ultrasonic transducer signal line; like Figure 6 As shown, the multi-angle imaging probe comprises an oblique imaging probe (3), a direct imaging probe (4) and a side-view imaging probe (5); the oblique imaging probe (3) in the multi-angle imaging probe comprises: a fourth reflector (3-1), a first probe base (3-2); a first light-transmitting component (3-3), a first light-transmitting anti-sound component (3-4), a first patch ultrasonic transducer (3-5), and a first light-transmitting and sound-transmitting film (3-6); the direct imaging probe (4) in the multi-angle imaging probe comprises: a fifth reflector (4-1) , a second probe base (4-2); a second light-transmitting component (4-3), a second light-transmitting anti-sound component (4-4), a second patch ultrasonic transducer (4-5), and a second light-transmitting and sound-transmitting film (4-6); the side-view imaging probe (5) in the multi-angle imaging probe comprises: a sixth reflector (5-1), a third probe base (5-2); a third light-transmitting component (5-3), a seventh reflector (5-4), a third light-transmitting and anti-sound component (5-6), a third patch ultrasonic transducer (5-7), and a third light-transmitting and sound-transmitting film (5-5).

[0044] Photoacoustic capsule endoscopic imaging is achieved in the following way.

[0045] like Figure 2As shown, the nanosecond pulse laser emitted by the optical fiber (1-1) passes through the optical fiber component (1-4) and enters the optical path folding component (1-5) to perform three-dimensional optical path folding. After being optically modulated by the collimating lens (1-6) and the focusing lens (1-7), the laser is emitted into the MEMS scanning micromirror (1-9) and enters the interior of the multi-angle imaging probe after being reflected by the MEMS scanning micromirror. The analog voltage signal is input into the MEMS scanning micromirror (1-9) controller through the flexible PCB (1-8) to perform two-dimensional plane scanning.

[0046] like Figure 6 As shown, in the squint imaging probe (3) in the multi-angle imaging probe, the focused light controlled by the MEMS scanning micromirror (1-9) is reflected by the fourth reflector (3-1) placed at an angle of 60° to the horizontal direction, enters the ultrasonic coupling liquid inside the squint imaging probe (3) through the first light-transmitting component (3-3) perpendicular to the main optical axis of the reflected light, and then passes through the first light-transmitting anti-sound component (3-4) at an angle of 75° to the horizontal direction to reach the straight imaging port for two-dimensional plane scanning. The ultrasonic wave generated by the interaction between the nanosecond pulse laser and the biological tissue passes through the first light-transmitting anti-sound film (3-6) and is reflected by the first light-transmitting anti-sound component (3-4), and then propagates vertically to the surface of the first patch ultrasonic transducer (3-5) inside the squint imaging probe (3). The ultrasonic signal is stored in a computer after being amplified and filtered, and the photoacoustic image of the imaging area is obtained by image reconstruction.

[0047] like Figure 6 As shown, in the direct-view imaging probe (4) in the multi-angle imaging probe, the focused light controlled by the MEMS scanning micromirror (1-9) is reflected by the fifth reflector (4-1) placed at an angle of 45° to the horizontal direction, enters the ultrasonic coupling liquid inside the direct-view imaging probe (4) through the second light-transmitting component (4-3) perpendicular to the main optical axis of the reflected light, and then passes through the second light-transmitting anti-sound component (4-4) at an angle of 90° to the horizontal direction to reach the straight imaging port for two-dimensional plane scanning. The ultrasonic wave generated by the interaction between the nanosecond pulse laser and the biological tissue passes through the second light-transmitting anti-sound film (4-6) and is reflected by the second light-transmitting anti-sound component (4-4), and then propagates vertically to the surface of the second patch ultrasonic transducer (4-5) inside the direct-view imaging probe (4). The ultrasonic signal is stored in a computer after being amplified and filtered, and the photoacoustic image of the imaging area is obtained by image reconstruction.

[0048] like Figure 6As shown, in the side-view imaging probe (5) in the multi-angle imaging probe, the focused light controlled by the MEMS scanning micromirror (1-9) is reflected by the sixth reflector (5-1) placed at an angle of 45° to the horizontal direction, and then reflected by the seventh reflector (5-4) placed at an angle of 135° to the horizontal direction, and enters the ultrasonic coupling liquid inside the side-view imaging probe (5) through the third light-transmitting component (5-3) perpendicular to the main optical axis of the reflected light, and then passes through the third light-transmitting anti-sound component (5-6) at an angle of 45° to the horizontal direction to reach the straight imaging port for two-dimensional plane scanning. The ultrasonic wave generated by the interaction between the nanosecond pulse laser and the biological tissue passes through the third light-transmitting anti-sound film (5-5) and is reflected by the third light-transmitting anti-sound component (5-6), and then propagates vertically to the surface of the third patch ultrasonic transducer (5-7) inside the side-view imaging probe (5). The ultrasonic signal is stored in a computer after being amplified and filtered, and a photoacoustic image of the imaging area is obtained through image reconstruction.

[0049] The installation of the multi-angle imaging probe is achieved in the following manner.

[0050] like Figure 7 As shown, the selected imaging port is connected to the capsule base (1-2) through a port connection assembly, the first magnet (2-1) and the second magnet (2-2) are respectively bonded to the third cylindrical hole (2-17) and the fourth cylindrical hole (2-18), and the third sealing ring (2-8) is embedded in the inner wall of the third cylindrical hole (2-17); the third magnet (2-4) and the fourth magnet (2-5) are respectively bonded to the fifth cylindrical hole (2-15) and the sixth cylindrical hole (2-19), and the fourth sealing ring (2-9) is embedded in the inner wall of the fifth cylindrical hole (2-15); the first gasket (2-7) is placed at the bottom of the first cylindrical hole (2-16). The first sealing ring (2-6) is placed on the inner wall of the first cylindrical hole (2-16), and the inserted cylindrical carrier (2-3) is inserted into the first cylindrical hole; the second gasket is placed on the bottom of the second cylindrical hole (2-14), and its protruding portion is engaged with the slot, and the second sealing ring (2-11) is placed on the inner wall of the second cylindrical hole (2-14), and the screw (2-12) is matched with the internal thread (2-13), and the screw (2-12) is screwed into the second cylindrical hole (2-14), and the mechanical fixing component and the magnetic fixing component work together to achieve complete connection and fixation between the multi-angle imaging probe and the capsule base (1-2).

[0051] like Figure 7As shown, the multi-angle imaging probe can be disassembled in the following manner: first, the screw (2-12) is screwed out, the first magnet (2-1) and the second magnet (2-2) are separated, and the third magnet (2-4) and the fourth magnet (2-5) are separated, and the imaging probe can be disassembled.

[0052] The oblique imaging probe 3, the direct imaging probe 4 and the side imaging probe 5 in the multi-angle imaging probe correspond to imaging surfaces at different angles.

[0053] like Figure 8 As shown in (a), the direct-view imaging probe 4 corresponds to the imaging area corresponding to the horizontal plane (6-3), and the imaging port can be fitted with the imaging surface; the nanosecond pulse laser emitted by the direct-view imaging probe (4) is focused on the horizontal plane (6-3), and two-dimensional plane scanning is performed through the miniaturized internal scanning component.

[0054] like Figure 8 As shown in (b), the oblique imaging probe 3 corresponds to the imaging area corresponding to the oblique plane (6-2). Figure 8 The angle ϴ1 shown in (b) is 30°, and the imaging port can be fitted with the imaging surface; the nanosecond pulse laser emitted by the oblique imaging probe (3) is focused on the oblique plane (6-2), and two-dimensional plane scanning is performed through the miniaturized internal scanning component.

[0055] like Figure 8 As shown in (c), the side-view imaging probe 5 corresponds to the imaging area corresponding to the vertical plane (6-1). Figure 8 ϴ2 shown in (c) is 90°, and the imaging port can be aligned with the imaging surface; the nanosecond pulse laser emitted by the side-view imaging probe (5) is focused on the vertical plane (6-1), and two-dimensional plane scanning is performed through the miniaturized internal scanning component.

[0056] The specific implementation cases described in this application are merely examples of the main ideas of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims.

Claims

1. A photoacoustic capsule endoscope, characterized in that: It comprises a capsule shell (1-10), a capsule base (1-2), and an optical fiber component (1-4), an optical path folding component (1-5), an optical modulation component, a miniaturized internal scanning component, a port connection component, and a multi-angle imaging probe located at the front end, which are arranged inside the capsule shell in sequence from the rear end to the front end; The optical fiber assembly (1-4) is located at the rear end of the capsule shell and is used to emit laser light; The optical path folding component (1-5) is located at the front end of the optical fiber component and is used to spatially fold the laser emitted from the optical fiber; The optical modulation component is located at the front end of the optical path folding component, and comprises a collimating lens (1-6) and a focusing lens (1-7) which are arranged in sequence from the rear end to the front end; The miniaturized internal scanning component is located at the front end of the optical modulation component, and comprises a MEMS scanning micromirror lens (1-9-4) and a flexible PCB (1-8) connected thereto, wherein the MEMS scanning micromirror lens (1-9-4) is packaged and connected to the flexible PCB (1-8); The multi-angle imaging probe assembly is located at the front end of the photoacoustic capsule endoscope and includes a set of detachable and replaceable imaging probes, and an oblique imaging probe (3), a direct imaging probe (4) or a side-view imaging probe (5) can be installed as required to detect the cavity to be tested; The port connection component is located between the miniaturized internal scanning component and the multi-angle imaging probe component, and includes a mechanical fixing component and a magnetic fixing component placed in parallel; The capsule base (1-2) is located at the bottom of the capsule shell and is used to fix various component units inside the capsule shell.

2. The photoacoustic capsule endoscope according to claim 1, characterized in that: The capsule base (1-2) fixes the various component units inside the capsule shell in the following manner: the optical fiber (1-1) is fixed by inserting into a ring-shaped hollow fixer (1-3) at the rear end of the capsule base (1-2); the optical path folding component (1-5) is fixed by inserting into a conical fitting groove arranged on the capsule base (1-2); the optical modulation component is fixed by a semicircular slideway arranged on the capsule base (1-2); and the MEMS scanning micromirror (1-9) is fixed by a groove body and a backing substrate seat arranged on the capsule base (1-2).

3. The photoacoustic capsule endoscope according to claim 1, characterized in that: The optical path folding component (1-5) comprises three identical aluminum-coated reflectors, wherein the first reflector (1-5-1) and the second reflector (1-5-2) are connected at a first bonding point (1-5-7) at an angle of 135°, the second reflector (1-5-2) and the third reflector (1-5-3) are connected at a second bonding point (1-5-8) at an angle of 45°, the third reflector (1-5-3) and the first reflector (1-5-1) are connected at a third bonding point (1-5-6) at an angle of 45°, and the first reflector (1-5-1) and the second reflector (1-5-2) are connected at a first bonding point (1-5-7) at an angle of 135°. The second reflector (1-5-2) and the third reflector (1-5-3) are placed in an azimuth relationship of 180° staggered with each other in the xy plane, the second reflector (1-5-2) and the third reflector (1-5-3) are placed in an azimuth relationship of 180° staggered with each other in the yz plane, and the first reflector (1-5-1) and the third reflector (1-5-3) are placed in an azimuth relationship of 180° staggered with each other in the xz plane, so that the incident pulse nanosecond laser (1-5-4) is reflected by the first reflector (1-5-1) and then enters the surface of the second reflector (1-5-2), and then enters the surface of the third reflector (1-5-3) after being reflected by it, and then is emitted parallel to the y axis.

4. The photoacoustic capsule endoscope according to claim 1, characterized in that: The collimating lens (1-6) of the optical modulation component enables the laser to be collimated and emitted, and the focusing lens (1-7) enables the collimated laser to be focused at the imaging port.

5. The photoacoustic capsule endoscope according to claim 1, characterized in that: The MEMS scanning micromirror lens (1-9-4) of the miniaturized internal scanning component is electrically connected to the flexible PCB (1-8) by means of gold wire bonding; a high-transmittance glass sheet is bonded to the surface of the MEMS scanning micromirror (1-9), and the MEMS scanning micromirror (1-9) is bonded to an FR4 epoxy glass fiber board (1-9-2); an analog voltage signal controls the MEMS scanning micromirror lens (1-9-4) to perform two-dimensional plane scanning via an internal circuit of the flexible PCB (1-8).

6. The photoacoustic capsule endoscope according to claim 1, characterized in that: The strabismus imaging probe (3) in the multi-angle imaging probe comprises: a fourth reflector (3-1), a first probe base (3-2); a first light-transmitting component (3-3), a first light-transmitting anti-sound component (3-4), a first patch ultrasonic transducer (3-5), and a first light-transmitting and sound-transmitting film (3-6); the fourth reflector (3-1) is located at the rear end of the strabismus imaging probe (3), with an angle of 30° with the horizontal direction, and is bonded in a square groove of the first probe base (3-2); the first light-transmitting component (3-3) is located at the front end of the fourth reflector (3-1), with an angle of 6° with the horizontal direction. The first light-transmitting and sound-reflecting component (3-4) is located at the front end of the first light-transmitting component (3-3), with an angle of 75° with the horizontal direction, and is bonded to the protruding part of the first probe base (3-2); the first light-transmitting and sound-transmitting film (3-6) is bonded to the front end of the strabismus imaging probe (3); the first patch ultrasonic transducer (3-5) is located in the square groove of the first probe base (3-2); the strabismus imaging probe (3) is connected to the capsule base (1-2) via the mechanical fixing and magnetic fixing components.

7. The photoacoustic capsule endoscope according to claim 1, characterized in that: The direct-view imaging probe (4) in the multi-angle imaging probe comprises: a fifth reflector (4-1), a second probe base (4-2); a second light-transmitting component (4-3), a second light-transmitting anti-sound component (4-4), a second patch ultrasonic transducer (4-5), and a second light-transmitting and sound-transmitting film (4-6); the fifth reflector (4-1) is located at the rear end of the direct-view imaging probe (4), with an angle of 45° with the horizontal direction, and is bonded into a square groove of the second probe base (4-2); the second light-transmitting component (4-3) is located at the front end of the fifth reflector (4-1), with an angle of 9° with the horizontal direction. The second light-transmitting and sound-reflecting component (4-4) is located at the front end of the second light-transmitting component (4-3), with an angle of 45° with the horizontal direction, and is bonded to the protruding part of the second probe base (4-2); the second light-transmitting and sound-transmitting film (4-6) is bonded to the front end of the direct-view imaging probe (4); the second patch ultrasonic transducer (4-5) is located in the square groove of the second probe base (4-2); and the direct-view imaging probe (4) is connected to the capsule base (1-2) via the mechanical fixing and magnetic fixing components.

8. The photoacoustic capsule endoscope according to claim 1, characterized in that: The side-view imaging probe (5) in the multi-angle imaging probe comprises: a sixth reflector (5-1), a third probe base (5-2); a third light-transmitting component (5-3), a seventh reflector (5-4), a third light-transmitting anti-sound component (5-6), a third patch ultrasonic transducer (5-7), and a third light-transmitting and sound-transmitting film (5-5); the sixth reflector (5-1) is located at the rear end of the side-view imaging probe (5), with an angle of 45° to the horizontal direction, and is bonded into a square groove of the third probe base (5-2); the seventh reflector (5-4) is located at the front end of the sixth reflector (5-1), with an angle of 135° to the horizontal direction, and is bonded into a square groove of the third probe base (5-2); The third light-transmitting component (5-3) is located on the side of the seventh reflector (5-4), is placed parallel to the horizontal direction, and is bonded to the circular groove of the third probe base (5-2); the third light-transmitting anti-sound component (5-6) is located on the side of the third light-transmitting component (5-3), is at an angle of 45° to the horizontal direction, and is bonded to the protruding part of the third probe base (5-2); the third light-transmitting and sound-transmitting film (5-5) is bonded to the front end of the side-view imaging probe (5); the third patch ultrasonic transducer (5-7) is located in the square groove of the third probe base (5-2); and the side-view imaging probe (5) is connected to the capsule base (1-2) via the mechanical fixing and magnetic fixing components.

9. The photoacoustic capsule endoscope according to claim 1, characterized in that: The mechanical fixing component in the port connection component comprises: a first gasket (2-7), a first sealing ring (2-6), an inserted cylindrical carrier (2-3), a first cylindrical hole (2-16), a second sealing ring (2-11), a second gasket (2-10), a screw (2-12), a second cylindrical hole (2-14), and an internal thread (2-13); the first cylindrical hole (2-16) is located at the bottom end of the middle part of the multi-angle imaging probe, and a slot is provided at the bottom of the first cylindrical hole (2-16); the first gasket (2-7) is inserted into the bottom of the first cylindrical hole (2-16) and is engaged with the slot; the first sealing ring (2-6) is placed between the inserted cylindrical carrier (2-3) and the first cylindrical hole (2-16); the second cylindrical hole (2-14) is provided at the bottom end of the outer side of the multi-angle imaging probe, and the inner wall of the second cylindrical hole (2-14) is provided with the internal thread (2-13) and a slot is provided at the bottom. The second gasket (2-10) is placed at the bottom of the second cylindrical hole (2-14) so ​​that its protruding portion is engaged with the slot; the second sealing ring (2-11) is placed between the screw (2-12) and the second cylindrical hole (2-14); the external thread of the screw (2-12) cooperates with the internal thread (2-13) and is screwed into the second cylindrical hole (2-14); so that the inserted cylindrical carrier (2-3) is fixed between the second gasket (2-10) and the side wall of the multi-angle imaging probe.

10. The photoacoustic capsule endoscope according to claim 1, characterized in that: The magnetic fixing component in the port connection component comprises: a first magnet (2-1), a second magnet (2-2), a third sealing ring (2-8), a third cylindrical hole (2-17), a fourth cylindrical hole (2-18), a third magnet (2-4), a fourth magnet (2-5), a fourth sealing ring (2-9), a fifth cylindrical hole (2-15), and a sixth cylindrical hole (2-19); the first magnet (2-1) is embedded in the third cylindrical hole (2-17) at the bottom end of the inner side of the multi-angle imaging probe, the second magnet (2-2) is embedded in the fourth cylindrical hole (2-18) on the inner side of the capsule base (1-2), and the third sealing ring (2-8) is placed between the first magnet (2-1) and the third cylindrical hole (2-17); the A magnet (2-1) is bonded to the third cylindrical hole (2-17); the second magnet (2-2) is bonded to the fourth cylindrical hole (2-18) on the inner side of the capsule base (1-2); the third magnet (2-4) is embedded in the fifth cylindrical hole (2-15) at the inner bottom end of the multi-angle imaging probe; the third magnet (2-4) is embedded in the sixth cylindrical hole (2-19) on the inner side of the capsule base (1-2); the fourth sealing ring (2-9) is placed between the fourth magnet (2-5) and the fifth cylindrical hole (2-15); the third magnet (2-4) is bonded to the fifth cylindrical hole (2-15); and the third magnet (2-4) is bonded to the fourth cylindrical hole (2-18) on the inner side of the capsule base (1-2).

11. A photoacoustic capsule endoscopy imaging method, characterized in that: The endoscopic microscopic image of the cavity structure including the human esophagus, stomach, uterus, vagina, and intestines is obtained by using the photoacoustic capsule endoscope as described in any one of claims 1 to 10, and the specific steps are as follows: Step S1, selecting a required multi-angle imaging probe based on the target imaging cavity, and detachably connecting and fixing the probe to the capsule base (1-2); Step S2, injecting ultrasonic coupling liquid into the multi-angle imaging probe through the imaging port, and sealing the multi-angle imaging probe port with a first light-transmitting and sound-transmitting film (3-6); Step S3, injecting ultrasound coupling liquid into the cavity to be imaged, and extending the photoacoustic capsule endoscope into the cavity to be imaged; Step S4, the nanosecond pulse laser emits nanosecond pulse laser, and completes two-dimensional plane scanning of the imaging port surface under the control of the MEMS scanning micromirror (1-9); Step S5, controlling the multi-angle imaging probe to perform translation and three-dimensional rotation in the region of interest, acquiring imaging data of a specific position in the cavity, and reconstructing the image based on the acquired data to achieve high-degree-of-freedom full-space imaging.

12. The photoacoustic capsule endoscopy imaging method according to claim 11, characterized in that: In step S1, when the multi-angle imaging probe is disassembled, the screw (2-12) is first screwed out, the first magnet (2-1) and the second magnet (2-2) are separated, and the third magnet (2-4) and the fourth magnet (2-5) are separated, so that the imaging probe can be disassembled; when the imaging probe is replaced, the first magnet (2-1) and the second magnet (2-2) are first connected, the third magnet (2-4) and the fourth magnet (2-5) are connected, and then the screw (2-12) is first tightened, so that the imaging probe can be installed.

Images