Shock wave guide

Abstract

The application discloses an impact wave guide tube, which comprises an outer pipe, a balloon, an IVL optical fiber, an FBG optical fiber, a laser unit and a photoelectric detector, wherein the inner part of the outer pipe is provided with a pipe cavity; the balloon is connected to the distal end side of the outer pipe, and the balloon cavity in the balloon is used for loading inflation medium to form a liquid environment for generating an impact wave; the IVL optical fiber and the FBG optical fiber are arranged in the pipe cavity, and the distal end of the IVL optical fiber and the distal end of the FBG optical fiber are inserted into the balloon; a coating layer is arranged on the distal end surface of the IVL optical fiber; the FBG optical fiber is used for acoustic signal modulation light; the laser unit can emit an IVL light beam and a detection light beam outwardly, the IVL light beam is only coupled to the IVL optical fiber and is transmitted through the coating layer to form an impact wave, and the detection light beam is coupled to the IVL optical fiber and the FBG optical fiber at the same time, part of the detection light beam entering the IVL optical fiber is reflected at the coating layer to form reference light; and the photoelectric detector is used for analyzing the acoustic signal modulation light based on the reference light. The impact wave guide tube can feed back the intravascular condition during IVL treatment to the operator in real time while performing IVL treatment.

Description

Technical Field

[0001] This application relates to the field of vascular interventional therapy devices, and in particular to a shock wave catheter. Background Technology

[0002] Intravascular calcifications and thrombosis are core contributing factors to cardiovascular diseases such as coronary heart disease and peripheral vascular stenosis. In severe cases, they can lead to serious complications such as myocardial infarction and limb necrosis, posing a significant threat to patients' lives and health. Currently, the preferred pretreatment method for complex intravascular calcifications in clinical practice is intravascular lithotripsy (IVL) to break up stubborn calcified plaques in the blood vessels. IVL primarily utilizes a balloon with low pressure adhering to the blood vessel wall. Inside the balloon, a high-voltage electrode or pulsed laser beam generates a shock wave in a liquid environment, which is then used to break up the calcified lesions within the blood vessel.

[0003] Typically, intravascular lithotripsy using only IVL devices relies heavily on the operator's clinical experience. The IVL catheter needs to be inserted based on the location of the calcifications confirmed by previous imaging or other methods to perform lithotripsy at specific points. This can easily lead to incomplete lithotripsy or damage to the normal vessel wall, affecting treatment efficacy and safety. To confirm or monitor the location and fragmentation effect of intravascular calcifications in real time, photoacoustic imaging technology is needed to provide crucial component and functional images before, during, and after treatment.

[0004] However, all existing commercial products and published patents (such as related IVL equipment patents and photoacoustic imaging equipment patents) have obvious technical limitations because IVL and photoacoustic imaging are two separate interventional devices, requiring two separate sets of equipment. Furthermore, at least two interventional procedures are needed to achieve lithotripsy and imaging respectively during clinical operation. Summary of the Invention

[0005] This application provides a shockwave catheter that can provide real-time feedback of environmental information while performing IVL treatment, in order to assist the operator in real-time monitoring of the intravascular condition during IVL treatment.

[0006] According to an embodiment of this application, a shock wave duct is provided, comprising: an outer tube having a cavity inside; a balloon connected to the distal end of the outer tube, the balloon's cavity being used to load an expansion medium flowing through the outer tube to form a liquid environment for shock wave generation; an IVL optical fiber disposed within the cavity along its extension direction, the distal end of the IVL optical fiber extending into the balloon, and a coating layer disposed on the distal end face of the IVL optical fiber; and an FBG optical fiber disposed within the cavity in a direction parallel to the IVL optical fiber. The distal end of the FBG fiber also extends into the balloon, and the FBG fiber can echo the acoustic signal modulation light at the balloon; a laser unit can emit an IVL beam and a probe beam outward, the IVL beam is coupled only to the IVL fiber and transmitted through the coating layer to form a shock wave in the liquid environment, and the probe beam is coupled to both the IVL fiber and the FBG fiber, wherein the portion of the probe beam entering the IVL fiber is reflected at the coating layer to form a reference light; a photodetector is used to analyze the acoustic signal modulation light based on the reference light.

[0007] In some embodiments, the coating layer is configured as a film layer formed by coating Al2O3 or SiO2 onto the distal end face of the IVL optical fiber.

[0008] In some embodiments, the laser unit includes a first laser for emitting the probe beam, a second laser for emitting the IVL beam, a beam splitter, and a dichroic mirror, wherein: the probe beam emitted by the first laser is transmitted through the beam splitter and the dichroic mirror and then enters the IVL fiber and the FBG fiber; the reference light reflected by the coating layer is transmitted through the dichroic mirror and then reflected by the beam splitter to the photodetector; the IVL beam emitted by the second laser is reflected at the dichroic mirror and enters the IVL fiber; the acoustic signal modulation light of the FBG fiber echo is transmitted through the dichroic mirror and then reflected by the beam splitter to the photodetector.

[0009] In some embodiments, the laser unit further includes a verification device, wherein a portion of the probe beam is reflected at the beam splitter to the verification device, and the verification device is used to determine the operating state of the first laser based on the received reflected light.

[0010] In some embodiments, the reference light and the acoustic signal modulation light interfere to form interference light; the laser unit further includes a microlens array, and the reference light, the acoustic signal modulation light and the interference light are subjected to spot trimming by the microlens array before entering the photodetector.

[0011] In some embodiments, the optical path lengths of the FBG fiber and the IVL fiber are set to be equal.

[0012] In some embodiments, the shock waveguide further includes a PA fiber, which is disposed within the cavity along the extension direction of the cavity and extends distally into the balloon; the laser unit is also capable of emitting a pulsed laser beam for photoacoustic imaging, the pulsed laser beam is incident on the PA fiber and propagated distally, and the FBG fiber returns the acoustic signal modulation light and the imaging signal light generated by the pulsed laser beam in time intervals.

[0013] In some embodiments, the pulsed laser beam and the probe beam are emitted continuously and in time-division multiples from the same laser.

[0014] In some embodiments, the shock wave duct further includes a transducer detection unit, which includes a flexible substrate and multiple rows of transducers spaced apart on the flexible substrate. The flexible substrate is capable of being rolled up in the cavity, and in the rolled-up state, the multiple rows of transducers are spaced apart circumferentially along the outer tube.

[0015] In some embodiments, each row of transducers includes at least two ultrasonic transducers with different frequency bands, which are arranged axially along the outer tube in the installed state.

[0016] The technical solutions provided by the embodiments of this application may include the following beneficial effects: After the external tubing and balloon are inserted into the preset position within the blood vessel to be treated, the laser unit emits an IVL beam and a probe beam. Because the distal end face of the IVL fiber has a coating layer, the IVL beam is completely transmitted after entering the IVL fiber and used to generate a shock wave in the liquid environment formed by the fluid within the balloon. The probe beam enters both the IVL fiber and the FBG fiber. A portion of the probe beam entering the IVL fiber is reflected by the coating layer, forming an echo and reference light. The FBG fiber receives the acoustic signal at the balloon and modulates it into acoustic signal modulated light, which then echoes back. The reference light and the acoustic signal modulated light enter a photodetector, which uses the reference light as a reference to analyze the acoustic signal modulated light, thus obtaining relevant signals that reflect the current situation within the blood vessel. This allows for relatively accurate analysis of signal parameters such as temperature, pressure, and shock wave intensity. These signal parameters can be used to assist the operator in real-time monitoring of the IVL treatment within the blood vessel, enabling the operator to truly "monitor" the procedure.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the conduit portion structure of a shock wave duct according to an embodiment of this application; only the portion near the distal end is shown in the figure. Figure 2 This is a schematic diagram of the conduit portion structure of a shock wave duct according to another embodiment of this application, compared to... Figure 1 The diagram shows that a PA fiber has been added to the structure. Figure 3 This is a schematic diagram of the conduit portion structure of a shock wave duct according to another embodiment of this application, compared to... Figure 2 The diagram shows a structure with an added transducer detection unit. Figure 4 yes Figure 3 A schematic diagram of the unfolded structure of the transducer detection unit in the image; Figure 5 This is a partial structural schematic diagram of an IVL optical fiber according to an embodiment of this application; Figure 6 This is a schematic diagram of the optical path principle of a shock waveguide according to an embodiment of this application; Figure 7 This is a schematic diagram of the optical path principle of a shock waveguide according to another embodiment of this application, compared to... Figure 6 The image shows a microlens array added in front of the photodetector; Figure 8 This is a schematic diagram of the probe beam and the IVL beam incident guide tube. Figure 9 This is a schematic diagram illustrating the principle of interference light formed by the light spot modulated by the reference light and sound signal. Figure 10 yes Figure 9 A schematic diagram illustrating the principle of three beams of light being cut and shaped within a microlens array before entering a photodetector.

[0019] Explanation of reference numerals in the attached figures 100. Catheter section; 11. Outer tube; 12. Balloon; 13. IVL fiber; 131. Coating layer; 14. FBG fiber; 15. PA fiber; 16. Transducer detection unit; 161. Flexible substrate; 1610. Bending section; 162. Transducer row; 200. External optical path section; 21. First laser; 22. Beam splitter; 23. Dichroic mirror; 24. Second laser; 25. Photodetector; 26. Microlens array; 27. Verification device. Detailed Implementation

[0020] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The modes described in the following exemplary embodiments do not represent all modes consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0021] It should be understood that the terms "first," "second," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "a" or "one," and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. Unless otherwise stated, the terms "front," "rear," "lower," and / or "upper," and similar terms are for illustrative purposes only and are not limited to a location or spatial orientation. The terms "comprising" or "including," and similar terms, mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects. The terms "connected," "linked," and similar terms are not limited to physical or mechanical connections, and can include electrical connections, whether direct or indirect.

[0022] Typically, treating intravascular calcifications with intravascular lithotripsy (IVL) requires at least two interventions: the first involves the IVL procedure itself, where the operator inserts a catheter into a predetermined location based on pre-operative imaging and other diagnostic information to break up the calcifications; the second intervention uses photoacoustic imaging or similar equipment to confirm the results. In some cases, if the first IVL attempt is unsatisfactory, a second IVL procedure may be performed, taking into account the results of the second intervention and imaging. The entire procedure is lengthy and complex, especially the first IVL attempt, which heavily relies on the operator's experience to determine the location of the shockwave. Integrating detection and lithotripsy is an ideal way to resolve these challenges.

[0023] Generally, there are two main ways to generate shock waves: one is to use high-voltage electrodes applied to a liquid environment to generate a shock wave; the other is to use a powerful laser beam to generate a shock wave in a liquid environment. For the method using high-voltage electrodes, the electromagnetic radiation generated by the high-voltage generating circuit severely interferes with the photoacoustic signal acquisition system. Therefore, even if the photoacoustic imaging components are integrated into the balloon, they cannot acquire signals normally. As for the method using lasers to generate shock waves, since IVL requires a strong pulsed laser beam to produce a sufficiently strong shock wave, the strong pulsed laser beam will generate strong stray light in the liquid environment. The imaging and detection devices are affected by this strong stray light, resulting in significant noise and making it difficult to accurately assist the operator in obtaining information about the current state of the blood vessel.

[0024] Therefore, IVL-related equipment generally falls short of integrating detection and lithotripsy. The shock wave catheter provided in this application, through coating the distal end face of the IVL fiber, enables the coating layer on the IVL fiber to return a reference beam in real time. Since the IVL fiber and FBG fiber are in the same environment, the reference beam and the modulated beam returned from the FBG fiber are affected by essentially the same environmental factors. The photodetector can use the reference beam as a reference to analyze the acoustic signal modulation beam, thereby obtaining relevant signals that reflect the current situation within the blood vessel. This allows for relatively accurate analysis of signal parameters such as temperature, pressure, and shock wave intensity. This method enables the detection of the FBG fiber to be synchronized with the shock wave lithotripsy process, achieving integrated detection and lithotripsy.

[0025] The embodiments of this application will now be described in detail with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments can be combined with each other.

[0026] First refer to Figure 6 As shown, the shock wave catheter in this application is generally divided into a catheter portion 100 and an external optical path portion 200. The distal end of the catheter portion 100 extends into the blood vessel, while the external optical path portion 200 is used to form the probe beam, IVL beam, etc., mentioned below, and to receive signals such as acoustic modulation light, imaging signal light, reference light, and interference light. The photodetector 25, used for signal analysis to obtain environmental information signals at the reaction balloon, is also a functional unit of the external optical path portion 200. It is understood that a complete shock wave catheter may also include a control handle, guidewire, and related components for providing the expansion medium; however, these structures are not discussed in this application and are therefore not described.

[0027] like Figure 1As shown, the shock waveguide in this application includes an outer tube 11, a balloon 12, an IVL fiber 13, an FBG fiber 14, a laser unit, and a photodetector 25. The outer tube 11 has an internal cavity for accommodating the IVL fiber 13, the FBG fiber 14, and a guide wire (not shown), and can also directly or through another internal cavity deliver the expansion medium to the balloon 12. It should be noted that... Figures 1 to 3 The shock wave conduit shown is in the form of a balloon 12. For other types of shock wave conduits, such as forward shock wave conduits that emit shock waves to the distal end of the conduit, the balloon 12 may have other design styles, but in general, the balloon 12 is used to provide the necessary liquid environment for the generation of shock waves.

[0028] The balloon 12 is connected to the distal end of the outer tubing 11. The expansion medium flowing in through the outer tubing 11 can be loaded into the balloon cavity of the balloon 12 to form a liquid environment for shock wave generation. Both IVL fiber 13 and FBG fiber 14 are disposed in the lumen of the outer tubing 11 along the extension direction of the lumen, and their distal ends extend into the balloon cavity of the balloon 12. Specifically, the IVL beam emitted from the distal end face of the IVL fiber 13 can act on the liquid environment in the balloon cavity to generate a shock wave that shatters intravascular calcifications; the FBG fiber 14 is used for acoustic signal modulation light at the echo balloon 12.

[0029] exist Figure 1 Based on the combination Figure 5 As shown, a coating layer 131 is provided on the distal end face of the IVL fiber 13. This coating layer 131 can transmit the IVL beam and reflect the probe beam mentioned later.

[0030] Further integration Figure 6 As shown, the laser unit is used to provide an IVL beam and a probe beam into the catheter section 100. Furthermore, as... Figure 8 As shown, the IVL beam has a smaller spot size and is therefore coupled only to the IVL fiber 13, while the probe beam has a larger spot size and can be coupled to both the IVL fiber 13 and the FBG fiber 14 simultaneously. As mentioned earlier, the coating layer 131 transmits the IVL beam; therefore, the IVL beam exits from the distal end face of the IVL fiber 13 and acts on the liquid environment, forming a shock wave. The portion of the probe beam coupled to the IVL fiber 13 is reflected by the coating layer 131 to form a reference beam.

[0031] The reference light is affected by temperature and stress, while the FBG fiber 14 itself is affected by temperature, stress, and acoustic pressure. The FBG fiber 14 modulates the received acoustic signal into an optical signal, forming an acoustic signal modulated light, which, along with the reference light, can enter the photodetector 25. Since the acoustic signal modulated light echoed from the FBG fiber 14 is affected by essentially the same environmental factors as the reference light, the photodetector can use the reference light as a reference to analyze the acoustic signal modulated light, thereby obtaining relevant signals that can reflect the current situation within the blood vessel. This allows for relatively accurate analysis of signal parameters such as temperature, pressure, and shock wave intensity.

[0032] When the coating layer 131 is damaged by a shock wave or IVL beam, or when the IVL fiber 13 itself is broken or bent, the intensity and spot size of the reference light will inevitably change accordingly. Therefore, the reference light can be used to monitor the coating layer 131 and even the far end of the IVL fiber 13 in real time.

[0033] Furthermore, by modulating the light based on the reference light and acoustic signal, the loss of the IVL fiber 13 due to factors such as temperature and bending during the travel of the intravascular catheter and at the lesion location can be obtained. Based on the loss, the laser parameters of the IVL beam can be corrected.

[0034] In some embodiments, the coating layer 131 is configured as a film formed by coating Al2O3 or SiO2 onto the distal end face of the IVL fiber 13. The coating layer 131 formed by Al2O3 or SiO2 can enhance the transmission of the IVL beam to avoid laser loss affecting the intensity of the shock wave, and also to prevent the high-energy pulse of the IVL beam from causing ablation on the distal end face of the IVL fiber 13.

[0035] For details, please refer to the following: Figure 6 As shown, the laser unit for providing the IVL beam and probe beam to the catheter section 100 is a component of the external optical path section 200, which may include: a first laser 21 for emitting the probe beam, a second laser 24 for emitting the IVL beam, a beam splitter 22, and a dichroic mirror 23. The photodetector 25 is also a device within this optical path section.

[0036] like Figure 6 As shown by the solid arrows, the detection beam emitted by the first laser 21 is transmitted through the beam splitter 22 and the dichroic mirror 23 and then enters the IVL fiber 13 and FBG fiber 14 in the conduit section 100. Meanwhile, the IVL beam emitted by the second laser 24 is reflected at the dichroic mirror 23 and enters the IVL fiber 13. Since devices for connecting the external optical path section 200 and the conduit section 100 may need to be installed, the terms "entering" and "injecting" used here do not necessarily refer to direct entry and direct injection.

[0037] And such Figure 6 As shown by the arrows, the reference light reflected by the coating layer 131 passes through the dichroic mirror 23 and is reflected downwards onto the beam-splitting surface of the beam splitter 22 before entering the photodetector 25. The acoustic signal modulation light echoed from the FBG fiber 14 also enters the photodetector 25 via the same path.

[0038] The IVL beam emitted by the second laser 24 is coupled into the IVL fiber 13 after being reflected by the dichroic mirror 23. Compared with the probe beam, its propagation path is shorter, which helps to avoid the laser intensity of the IVL beam being weakened during propagation.

[0039] Continue to refer to Figure 6 As shown, in some embodiments, the laser unit may also include a verification device 27. A small portion of the detection beam emitted by the first laser 21 is reflected onto the verification device 27 on the beam splitting surface of the beam splitter 22. The verification device 27 can determine the working status of the first laser 21 based on the received reflected light, so as to remind the user to adjust the setting parameters of the first laser 21 in real time or replace it with a new laser.

[0040] refer to Figure 9 and Figure 10 As shown, the reference light and the acoustic signal modulated light interfere to form interference light, and the interference light is as follows: Figure 9 As shown in the shaded area. Combined with... Figure 7 As shown, the laser unit may further include a microlens array 26. The reference light, the acoustic signal modulation light, and the interference light are subjected to spot trimming by the microlens array 26 before entering the photodetector 25, thereby obtaining specific proportions of pure signal light for different beams through spot trimming, which is then analyzed by the photodetector 25.

[0041] In some embodiments, the optical paths of FBG fiber 14 and IVL fiber 13 are set to be equal. In the design, the optical paths of the two fibers can be made equal by physically cutting them into fibers of equal length; or the optical paths of the two fibers can be made equal by appropriate optical path compensation, etc. This application does not limit this.

[0042] refer to Figure 2As shown, in some embodiments, the shock wave catheter may further include a PA fiber 15, which, like the IVL fiber 13 and FBG fiber 14, is disposed within the lumen parallel to the IVL fiber 13 and FBG fiber 14, with its distal end extending into the cavity of the balloon 12. The laser unit is also capable of emitting a pulsed laser beam for photoacoustic imaging, which is propagated distally through the PA fiber 15. Typically, the PA fiber 15 needs to be a side-emitting structure; therefore, the distal surface of the PA fiber 15 is ground at a specific angle or otherwise treated. The pulsed laser beam causes a photoacoustic effect in the tissue within the blood vessel, generating an acoustic signal. This acoustic signal is modulated into imaging signal light, which is then returned to the photodetector 25 in time segments via the FBG fiber 14.

[0043] FBG fiber 14 can only receive and transmit weak light signals (the probe beam is a continuous weak light), and cannot transmit pulsed laser beams used for photoacoustic imaging. The acoustic signal modulated by the echo from FBG fiber 14 can provide some feedback on the intravascular conditions, but cannot form an image. Therefore, Figure 2 In the embodiment shown, the pulsed laser beam is transmitted to the balloon 12 via PA fiber 15, and the excited acoustic signal that can be used for imaging is modulated into imaging signal light by FBG fiber 14 and returned in time intervals with the acoustic signal modulation light.

[0044] In IVL systems, shock waves typically cause localized warming and sustained vibration within the blood vessel. The acoustic signal modulated light returned by the FBG fiber 14 can quantify the impact of environmental factors on the imaging signal light. Based on this, pre-compensation or post-processing of the imaging system can be performed, resulting in more accurate image acquisition.

[0045] Furthermore, such as Figure 6 or Figure 7 As shown, both the pulsed laser beam and the probe beam are emitted continuously and in a time-division manner by the first laser 21. Specifically, after emitting the pulsed laser beam for imaging, the first laser 21 then emits the probe beam, and after external imaging and resolution, it continues to emit the next round of pulsed laser beams. By having the first laser 21 continuously and in a time-division manner emit two types of laser beams, the number of optical devices in the entire external optical path section 200 can be reduced.

[0046] like Figure 3 and Figure 4 As shown, the shock waveguide may also include a transducer detection unit 16, which includes a flexible substrate 161 and multiple rows of transducers 162 spaced apart on the flexible substrate 161.

[0047] The flexible substrate 161 retains its flexibility at the curved portion 1610 between two adjacent transducer rows 162, thus ensuring that the entire transducer detection unit can be placed in the appropriate position within the cavity in a rolled-up state. Figure 3 In the curled state shown, multiple rows of transducers 162 are spaced circumferentially along the outer tube 11. The ultrasonic transducer rows 162 complement the photoacoustic imaging scheme using the PA fiber 15, ultimately resulting in more accurate imaging. Simultaneously, the circumferential spacing of the multiple transducer rows 162 along the outer tube 11 allows signal sources to be located at multiple positions around the outer tube 11, thereby assisting the operator in accurately locating the circumferential position of the signal.

[0048] In some embodiments, each transducer row 162 includes at least two ultrasonic transducers with different frequency bands, which are arranged axially along the outer tube 11 in the installed state. (Reference) Figure 3 and Figure 4 As shown in the figure, there are three transducer rows 162, each of which includes three ultrasonic transducers a, b, and c. By using three or more ultrasonic transducers in the axial direction and selecting ultrasonic transducers with different detection bandwidths, imaging detection with a larger bandwidth can be performed at each position in the circumferential direction.

[0049] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although this application has disclosed preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A shock wave duct, characterized in that, The shock wave duct includes: An outer pipe fitting (11) has a cavity inside; A balloon (12) is connected to the distal end of the outer tube (11), and the cavity of the balloon (12) is used to load an expansion medium flowing in through the outer tube (11) to form a liquid environment for generating shock waves; IVL optical fiber (13), the IVL optical fiber (13) is disposed in the cavity along the extension direction of the cavity, the distal end of the IVL optical fiber (13) extends into the balloon (12), and a coating layer (131) is disposed on the distal end face of the IVL optical fiber (13). FBG optical fiber (14), the FBG optical fiber (14) is disposed in the cavity in a direction parallel to the IVL optical fiber (13), and the distal end of the FBG optical fiber (14) also extends into the balloon (12). The laser unit is capable of emitting an IVL beam and a probe beam. The IVL beam is coupled only to the IVL fiber (13) and transmitted through the coating layer (131) to form a shock wave in the liquid environment. The probe beam is coupled to both the IVL fiber (13) and the FBG fiber (14). A portion of the probe beam entering the IVL fiber (13) is reflected at the coating layer (131) to form a reference light. The FBG fiber (14) is capable of receiving the acoustic signal at the balloon (12) and modulating it into an acoustic signal modulation light. A photodetector (25) is used to analyze the acoustic signal modulated light returned by the FBG fiber (14) based on the reference light.

2. The shock wave duct according to claim 1, characterized in that, The coating layer (131) is configured to be formed by coating Al2O3 or SiO2 onto the distal end face of the IVL optical fiber (13).

3. The shock wave duct according to claim 1, characterized in that, The laser unit includes a first laser (21) for emitting the probe beam, a second laser (24) for emitting the IVL beam, a beam splitter (22), and a dichroic mirror (23), wherein: The detection beam emitted by the first laser (21) is transmitted through the beam splitter (22) and the dichroic mirror (23) and then enters the IVL fiber (13) and the FBG fiber (14). The reference light reflected by the coating layer (131) is transmitted through the dichroic mirror (23) and then reflected by the beam splitter (22) to the photodetector (25). The IVL beam emitted by the second laser (24) is reflected at the dichroic mirror (23) and enters the IVL fiber (13). The acoustic signal modulated light returned by the FBG fiber (14) is transmitted through the dichroic mirror (23) and then reflected by the beam splitter (22) to the photodetector (25).

4. The shock wave duct according to claim 3, characterized in that, The laser unit also includes a verification device (27), a portion of the probe beam is reflected at the beam splitter (22) to the verification device (27), and the verification device (27) is used to determine the working state of the first laser (21) based on the received reflected light.

5. The shock wave duct according to claim 3, characterized in that, The reference light and the acoustic signal modulated light interfere to form interference light; The laser unit also includes a microlens array (26), and the reference light, the acoustic signal modulation light and the interference light are subjected to spot trimming by the microlens array (26) before entering the photodetector (25).

6. The shock wave duct according to claim 5, characterized in that, The optical paths of the FBG fiber (14) and the IVL fiber (13) are set to be of equal length.

7. The shock waveguide according to any one of claims 1-6, characterized in that, The shock wave duct also includes a PA optical fiber (15), which is disposed in the cavity along the extension direction of the cavity and extends distally into the balloon (12). The laser unit can also emit a pulsed laser beam for photoacoustic imaging. The pulsed laser beam is incident on the PA fiber (15) and propagated to the far end. The FBG fiber (14) returns the acoustic signal modulation light and the imaging signal light generated by the pulsed laser beam in time intervals.

8. The shock wave duct according to claim 7, characterized in that, The pulsed laser beam and the detection beam are emitted continuously and in time-division manner from the same laser.

9. The shock wave duct according to claim 7, characterized in that, The shock wave duct also includes a transducer detection unit (16), which includes a flexible substrate (161) and multiple rows of transducers (162) spaced apart on the flexible substrate (161). The flexible substrate (161) can be rolled up in the cavity. In the rolled up state, the multiple rows of transducers (162) are spaced apart along the circumferential direction of the outer tube (11).

10. The shock wave duct according to claim 9, characterized in that, Each of the transducer rows (162) includes at least two ultrasonic transducers with different frequency bands, which are arranged along the axial direction of the outer tube (11) in the installed state.

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