Scanning optical fiber, phototherapy device and phototherapy system

Abstract

A scanning optical fiber (1) comprises an optical fiber (3) and a protruding member (5) that is provided in a tip region (3c) of the optical fiber (3) and that has a larger outer diameter than the optical fiber (3). The protruding member (5) generates a force in the radial direction of the optical fiber (3) in response to the flow of a fluid (C) in the longitudinal direction of the optical fiber (3) toward a tip (3a) of the optical fiber (3).

Description

Scanning optical fiber, phototherapy device, phototherapy system, and phototherapy method

[0001] The present invention relates to a scanning optical fiber, a phototherapy device, a phototherapy system, and a phototherapy method.

[0002] Conventionally, lithotripsy has been known in which stones formed in the kidneys or the like are fragmented by laser light (see, for example, Non-Patent Document 1 and Patent Document 1). In order to fragment stones efficiently, it is preferable to irradiate the stones with the laser light while scanning it.

[0003] Non-Patent Document 1 and Patent Document 1 disclose vibration mechanisms that vibrate the tip of an optical fiber to scan with laser light. The vibration mechanism in Non-Patent Document 1 uses a magnetic bead fixed to the optical fiber and a solenoid near the optical fiber, and vibrates the tip of the optical fiber by magnetic force. The vibration mechanism in Patent Document 1 uses a plate-shaped operating member placed near the optical fiber, and vibrates the tip of the optical fiber by the contraction of a bubble generated at the tip of the optical fiber by laser light.

[0004] Layton A. Hall, and 2 others, “Thulium fiber laser stone dusting using an automated, vibrating optical fiber,” Proceedings SPIE 10852, Therapeutics and Diagnostics in Urology 2019, February 26, 2019.

[0005] International Publication No. 2022 / 190259

[0006] The vibration mechanism of Non-Patent Document 1 requires a drive power source and is therefore large in size. The vibration mechanism of Patent Document 1 requires specific laser light conditions to control the timing of bubble generation. However, it is desirable that the laser light conditions, such as pulse waveform and frequency, can be changed depending on the size and type of stone.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a scanning optical fiber, a phototherapy device, a phototherapy system, and a phototherapy method that can be miniaturized and that allow the conditions of laser light to be set arbitrarily.

[0008] One aspect of the present invention is a scanning optical fiber comprising an optical fiber and a protruding member provided in a tip region of the optical fiber and having an outer diameter larger than the outer diameter of the optical fiber, wherein the protruding member receives a fluid flow in the longitudinal direction of the optical fiber toward the tip of the optical fiber and generates a radial force on the optical fiber.

[0009] Another aspect of the present invention is a phototherapy device comprising a medical tube having a channel, an optical fiber inserted into the channel, and a protruding member provided in a tip region of the optical fiber and having an outer diameter larger than the outer diameter of the optical fiber, wherein the protruding member receives a fluid flow in the longitudinal direction of the optical fiber toward the tip of the optical fiber and generates a radial force on the optical fiber.

[0010] Another aspect of the present invention is a phototherapy system comprising: a medical tube having a channel; an optical fiber inserted into the channel; a protruding member provided in a tip region of the optical fiber and having an outer diameter larger than that of the optical fiber; a fluid supply source that supplies fluid to the channel; and a laser light source that supplies laser light to the optical fiber, wherein the protruding member receives a flow of fluid in the longitudinal direction of the optical fiber toward the tip of the optical fiber, thereby generating a radial force on the optical fiber.

[0011] Another aspect of the present invention is a phototherapy method comprising irradiating a subject with laser light from a tip of an optical fiber and vibrating the tip of the optical fiber, wherein the vibrating comprises generating a fluid flow in the longitudinal direction of the optical fiber toward the tip of the optical fiber, and a protruding member provided in the tip region of the optical fiber receives the fluid flow and generates a radial force on the optical fiber.

[0012] According to the present invention, it is possible to achieve miniaturization and to arbitrarily set the conditions for the laser light.

[0013] 1 is an overall configuration diagram of a phototherapy system according to one embodiment of the present invention; FIG. 2 is a partial side view of a scanning optical fiber according to one embodiment; FIG. 3 is a diagram showing an example of laser light conditions; FIG. 4 is a diagram showing another example of laser light conditions; FIG. 5 is a diagram showing laser light conditions in the case of a conventional scanning optical fiber in which the optical fiber is vibrated by bubble contraction; FIG. 6 is a flowchart of a phototherapy method according to one embodiment of the present invention; FIG. 7 is a diagram showing a scanning optical fiber during treatment of a stone; FIG. 8 is a diagram showing a conventional scanning optical fiber during treatment of a stone; FIG. 9 is a cross-sectional view of a wing-shaped acting member; FIG. 10 is a diagram explaining the action of the acting member of FIG. 6; FIG. 11 is a partial side view of a scanning optical fiber having a cylindrical or rotating acting member; FIG. 12 is a diagram showing an example cross-section of the acting member of FIG. 13; FIG. 14 is a diagram showing another example cross-section of the acting member of FIG. 14; FIG. 15 is a diagram showing another example cross-section of the acting member of FIG. 15; FIG. 16 is a diagram showing another example cross-section of the acting member of FIG. 16; FIG. 17 is a diagram showing another example cross-section of the acting member of FIG. 17;

[0014] A scanning optical fiber, a phototherapy device, a phototherapy system, and a phototherapy method according to an embodiment of the present invention will be described below with reference to the drawings. As shown in Fig. 1, the phototherapy system 100 according to this embodiment is a lithotripsy system that uses laser light L to fragment a calculus, which is a treatment target A. The phototherapy system 100 includes a phototherapy device 10, a laser light source 20, a fluid supply source 30, and a control unit 40.

[0015] The phototherapy device 10 includes a scanning optical fiber 1 and a medical tube 2. The medical tube 2 is an endoscope having a long, flexible insertion section 2a. Images of the inside of a body B acquired by the endoscope 2 may be displayed on a display section 50. The endoscope 2 has a channel 2b that passes through the insertion section 2a in the longitudinal direction, and the channel 2b has an outlet 2c at its tip that opens on the distal end surface of the endoscope 2. The channel 2b of the endoscope 2 is for the irrigation fluid C and the optical fiber 3, and also serves as a passage for inserting other treatment tools.

[0016] The scanning optical fiber 1 includes an optical fiber 3, a fiber holding part 4, and an action member (protruding member) 5. The optical fiber 3 has a tip 3a that emits laser light L and a base end 3b that is connected to a laser light source 20. The optical fiber 3 has an outer diameter that is smaller than the inner diameter of the channel 2b, and can be inserted into the channel 2b.

[0017] The fiber holding unit 4 holds a portion of the optical fiber 3 at a position spaced apart from the tip 3a in the longitudinal direction, and fixes the portion of the optical fiber 3 so as not to move radially within the channel 2b. For example, the fiber holding unit 4 is a cylindrical member attached to the side surface of the portion of the optical fiber 3, and has an outer diameter slightly smaller than the inner diameter of the channel 2b.

[0018] The cantilever-shaped tip region 3c protruding from the tip surface of the holding portion 4 of the optical fiber 3 is a vibration region that vibrates in the radial direction. The vibration region 3c vibrates in the radial direction with the portion held by the holding portion 4 as a fulcrum, thereby scanning the laser light L emitted from the tip 3a. The fiber holding portion 4 has a shape that allows the perfusion fluid C to pass through it in the longitudinal direction, and has, for example, a flow path extending in the longitudinal direction.

[0019] The action member 5 is fixed to a side surface of a part of the vibration region 3c between the tip 3a and the fiber holding part 4. The tip of the action member 5 is arranged at a position spaced apart from the tip 3a toward the base end, and the base end of the action member 5 is arranged at a position spaced apart from the tip of the fiber holding part 4 toward the tip end.

[0020] The action member 5 has an outer diameter larger than the outer diameter of the optical fiber 3 and protrudes radially from the side surface of the optical fiber 3. The maximum outer diameter of the action member 5 is equal to or smaller than the inner diameter of the channel 2b, and the action member 5 can pass through the channel 2b together with the optical fiber 3. The outer diameter of the action member 5 is the dimension of the action member 5 in a direction perpendicular to the longitudinal axis 3d of the optical fiber 3. In one example, the inner diameter of the channel 2b is 1.2 mm, and the maximum outer diameter of the action member 5 is equal to or smaller than 1.2 mm.

[0021] As shown in FIG. 2 , the perfusion fluid C passing through the channel 2b from the proximal end to the distal end forms a flow near the outlet 2c toward the distal end 3a that is parallel or substantially parallel to the longitudinal direction of the optical fiber 3. The action member 5 is positioned to block the flow of perfusion fluid C and receives the flow of perfusion fluid C to generate a radial force F in the optical fiber 3 (see FIGS. 7 and 8 ). Specifically, the action member 5 deflects the flow of perfusion fluid C in the radial direction, thereby generating a lift force F perpendicular to the direction of the flow of perfusion fluid C. The vibration region 3c, which is deflected and displaced radially in response to the lift force F, generates a radial restoring force G that attempts to return to a linear shape (see FIG. 7 ). The action member 5 generates a lift force F such that the direction of the resultant force of the lift force F and the restoring force G periodically reverses, thereby vibrating the vibration region 3c. The specific configuration of the action member 5 will be described in detail later.

[0022] To prevent interference between the action member 5 and the inner surface of the channel 2b, it is preferable that at least a portion of the action member 5 is disposed outside the outlet 2c, and it is more preferable that the entire action member 5 is disposed outside the outlet 2c. The preferred protruding length of the optical fiber 3 from the tip of the endoscope 2 to the tip 3a is 2 to 20 mm. Therefore, it is preferable that the base end of the action member 5 is disposed at a position 2 to 20 mm from the tip 3a.

[0023] The laser light source 20 is, for example, a laser oscillator, and is optically connected to the proximal end 3b of the optical fiber 3. In response to operation of the foot switch 20a, the laser light source 20 outputs pulsed laser light L for treating the subject A. The laser light L is, for example, infrared light.

[0024] The fluid supply source 30 is fluidly connected to the proximal end of the channel 2b and supplies the channel 2b with an irrigation fluid C, such as physiological saline. For example, the fluid supply source 30 includes a bag containing the irrigation fluid C and a tube connecting the bag to the channel 2b, and supplies the irrigation fluid C to the channel 2b by natural dripping from the bag.

[0025] In order for the working member 5 to stably generate the lifting force F, it is desirable that the perfusion fluid C form a uniform flow near the outlet 2c. Therefore, the fluid supply source 30 supplies the perfusion fluid C at a constant flow rate (e.g., 20 ml / min). The magnitude of the lifting force F generated by the working member 5 depends on the flow rate of the perfusion fluid C. To make the magnitude of the lifting force F adjustable, the fluid supply source 30 may be able to change the flow rate of the perfusion fluid C, and may, for example, have a pump that can control the flow rate. The fluid supply source 30 may also change the flow rate of the perfusion fluid C over time in synchronization with the vibration of the optical fiber 3.

[0026] The control unit 40 controls the conditions of the laser light L output by the laser light source 20. 3A and 3B show examples of the laser light L. The conditions include, for example, the pulse waveform, the number n of pulses in one pulse group, the repetition frequency f, the interval T between the pulse groups, and the like.

[0027] Next, a phototherapy method using the scanning optical fiber 1, the phototherapy device 10, and the phototherapy system 100 will be described. As shown in Fig. 4, the phototherapy method includes step S1 of placing the endoscope 2 inside the body B, step S2 of preparing the optical fiber 3 to which the action member 5 is attached, step S3 of inserting the optical fiber 3 to which the action member 5 is attached into the channel 2b of the endoscope 2, step S4 of irradiating the target A with laser light L, and step S5 of vibrating the tip 3a of the optical fiber 3.

[0028] An operator such as a surgeon inserts the endoscope 2, for example, through the urethra into a kidney (step S1). Next, the operator attaches the holding part 4 and the working member 5 to the side of the optical fiber 3, for example, by passing the optical fiber 3 through through holes provided in the holding part 4 and the working member 5 (step S2). The optical fiber 3 to which the holding part 4 and the working member 5 are already attached may be provided to the operator.

[0029] Next, the operator inserts the optical fiber 3 to which the holding part 4 and the action member 5 are attached into the channel 2b, and places the tip 3a of the optical fiber 3 and the action member 5 outside the channel 2b through the outlet 2c, and places the holding part 4 inside the channel 2b (step S3). Next, the operator depresses the foot switch 20a to start outputting the laser light L from the laser light source 20 (step S4). The laser light L is irradiated from the tip 3a of the optical fiber 3 onto the target A, and the stone, which is the target A, is fragmented.

[0030] Step S5 is performed in parallel with step S4. In step S5, the operator supplies perfusion fluid C from the fluid supply source 30 to the channel 2b, thereby generating a flow of perfusion fluid C around the vibration region 3c in the longitudinal direction of the vibration region 3c toward the tip 3a near the outlet 2c (step S5). This flow of perfusion fluid C collides with the operating member 5, generating a lift force F, which vibrates the vibration region 3c. As a result, the laser light L scans the stone A and irradiates a wide area of ​​the stone A. This improves the efficiency of treatment using the laser light L, for example, the efficiency of fragmenting the stone A. In step S5, the perfusion fluid C improves the visual field of the endoscope 2 caused by fragments of the stone A, thereby providing a clear field of view and suppressing the temperature rise within the kidney due to the laser light L.

[0031] In this way, during the treatment of stone A, perfusion fluid C is supplied into body B through channel 2b to improve poor visibility and suppress its rise within the kidney. According to this embodiment, the energy of the flow of perfusion fluid C is converted by working member 5 into a lifting force F in the radial direction of optical fiber 3, and optical fiber 3 vibrates due to the lifting force F. In other words, the flow of perfusion fluid C is used as a driving source for the vibration. Therefore, a driving source such as a power supply is not required, and a compact device 10 and system 100 can be realized.

[0032] Furthermore, when a vibration mechanism that generates an electromagnetic field is used as in Non-Patent Document 1, the electromagnetic field can affect the quality of the endoscopic image. The scanning optical fiber 1 of this embodiment does not require an electromagnetic field, and therefore can obtain a good endoscopic image.

[0033] Furthermore, since the vibration of the optical fiber 3 due to the lifting force F does not depend on the conditions of the laser light L, the conditions of the laser light can be set arbitrarily. Therefore, as shown in FIGS. 3A and 3B, laser light L can be used under conditions according to the size, type, etc. of the target A, thereby further improving the therapeutic effect of the target A. When vibrating the tip 3a by utilizing the contraction of the bubble formed at the tip 3a by the laser light L, as in Patent Document 1, it is necessary to use laser light L under specific conditions. For example, as shown in FIG. 3C, the number of pulses n, the repetition frequency f, and the interval T are limited to predetermined ranges. Therefore, it is difficult to adjust the conditions of the laser light L according to the target A.

[0034] Furthermore, according to this embodiment, the action member 5 is disposed closer to the base end than the tip 3a, and the scanning optical fiber 1 does not have any structure near the tip 3a. Therefore, as shown in Fig. 5A, it is possible to prevent the action member 5 from interfering with the stone A, which would otherwise interfere with the scanning of the laser light L. In the case of a plate-shaped action member 105 that applies the contraction force of the bubble E to the tip 3a, as in Patent Document 1, the action member 105 may interfere with the stone A, which would otherwise interfere with the scanning of the laser light L (see Fig. 5B).

[0035] Next, specific examples of the action member 5 will be described. FIGS. 6 and 7 show plate-shaped action members 5, while FIGS. 8 to 9G show cylindrical or rotatable action members 5. The action member 5 in FIG. 6 has a first surface 51 and a second surface 52 that face each other in the thickness direction and are disposed at an angle relative to the longitudinal axis 3d of the optical fiber 3. The cross section of the action member 5 along the longitudinal axis 3d is wing-shaped. The wing-shaped shape generates lift due to the difference in pressure between the first surface 51 and the second surface 52, and is generally a streamlined shape with a pointed trailing edge 5b and a rounded leading edge 5c. The chord 5a of the action member 5 is inclined at an angle θ relative to the longitudinal axis 3d and forms an elevation angle α with the direction of the flow of the perfusion fluid C. When the vibration region 3c is disposed in an initial position without deflection, the elevation angle α is equal to the angle θ.

[0036] The plate-shaped acting member 5 may have a cross section of other shapes as long as it can obtain the lift F of the magnitude necessary for vibration of the vibration region 3c. For example, the acting member 5 may be a flat plate that is inclined with respect to the longitudinal axis 3d and deflects the flow of the perfusion fluid C. By deflecting the flow of the perfusion fluid C, the flat acting member 5 receives a reaction force from the flow and generates a lift force F due to the reaction force.

[0037] 7 illustrates the vibration of the vibrating region 3c due to the lifting force F and the restoring force G of the optical fiber 3. When the vibrating region 3c is positioned at its initial position, the flow of perfusion fluid C causes the acting member 5 to generate a lifting force F (t = t1). At the initial position, the restoring force G of the vibrating region 3c is zero, and the vibrating region 3c is displaced radially while bending in response to the lifting force F. As the vibrating region 3c is displaced from its initial position, a restoring force G opposite to the lifting force F is generated. As the displacement increases, the restoring force G increases. Furthermore, as the displacement increases, the elevation angle α decreases, thereby decreasing the lifting force F. Therefore, the direction of the resultant force of the lifting force F and the restoring force G reverses, and the vibrating region 3c is subsequently displaced in the opposite direction toward its initial position (t = t2).

[0038] In the process of displacement in the opposite direction toward the initial position, the lift force F increases and the restoring force G decreases. Therefore, the direction of the resultant force is reversed again. When the vibration region 3c is displaced in the opposite direction from the initial position, the direction of the restoring force G is the same as the direction of the lift force F (t = t3). As the displacement increases, the restoring force G increases. Also, as the displacement increases, the angle of elevation α increases, thereby increasing the lift force F. Therefore, the vibration region 3c continues to displace toward the initial position.

[0039] In this way, the wing-shaped acting member 5 always generates lift F in the same direction, and the magnitude of the lift F changes with the angle of attack α. In addition, the direction of the restoring force G changes periodically. Therefore, the direction of the resultant force periodically reverses, causing the vibration region 3c to vibrate. The lift F generated by the acting member 5 depends on the angle θ and the camber β. The camber β is the distance between the chord 5a and the center line 5d. The angle θ and the camber β are designed to achieve the above-mentioned vibration.

[0040] The cylindrical or rotating action member 5 in FIG. 8 is plane-symmetrical with respect to a plane including the longitudinal axis 3d, and generates Karman vortices K at the tip side of the action member 5. The Karman vortices K are a row of multiple vortices, and the rotation directions of the vortices alternately reverse. Therefore, the action member 5 alternately generates a lift force F1 and a lift force F2 opposite to the lift force F1, thereby vibrating the vibration region 3c. In the case of a cylindrical action member 5, the tip 3a vibrates one-dimensionally in the radial direction. In the case of a rotating action member 5, the tip 3a vibrates two-dimensionally within a radial plane. To be able to pass through the channel 2b, the maximum outer diameter of the action member 5 is equal to or smaller than the inner diameter of the channel 2b (e.g., 1.2 mm).

[0041] The cylinder has a height perpendicular to the longitudinal axis 3d and a pair of bottom surfaces disposed on both sides of the longitudinal axis 3d. Figures 9A to 9G show examples of cross-sectional shapes perpendicular to the bottom surface or the height, where the height is the direction perpendicular to the paper surface. As shown in Figures 9A to 9G, the shape of the bottom surface or the cross-sectional shape may be circular, bullet-shaped, triangular, square, trapezoidal, rectangular with its short side aligned with the longitudinal axis 3d, or substantially T-shaped. The shapes of the bottom surface and the cross-sectional shape may be other polygons or other shapes that are line-symmetric with respect to the longitudinal axis 3d, as long as they can generate Karman vortices K.

[0042] The rotating body is a solid body obtained by rotating a plane figure that is line-symmetrical with respect to the longitudinal axis 3d, as shown in Figures 9A to 9G, around the longitudinal axis 3d, and is symmetrical with respect to the longitudinal axis 3d. For example, the operating member 5 of the rotating body is a sphere (Figure 9A). As described above, the operating member 5 of the rotating body vibrates the tip 3a two-dimensionally, which is advantageous in that it allows the laser light L to be irradiated over a wider area.

[0043] The cross-sectional shapes of the cylinder and rotor may be obtained by flipping the planar shapes shown in Figures 9A to 9G horizontally. That is, the flow direction of the perfusion fluid C relative to the working member 5 may be either a left-to-right direction D1 or a right-to-left direction D2. As is well known, cylinders and rotors generate Karman vortices when the Reynolds number is within a predetermined range, and the Reynolds number depends on the flow velocity and the dimensions of the cylinder or rotor. Therefore, the dimensions of the working member 5 are designed so that Karman vortices are generated at a desired flow velocity of the perfusion fluid C.

[0044] For a cylindrical acting member 5, the vibration direction of the vibration region 3c depends on the height of the acting member 5. Regarding a cylindrical acting member 5, when the height is sufficiently large (for example, the height is larger than the diameter of the bottom surface), the vibration direction is parallel to the bottom surface (the vertical direction in FIG. 9A ). On the other hand, as the height decreases, the shape of the acting member 5 approaches a disk. When the height is sufficiently small (for example, the height is approximately 1 / 10 of the diameter of the bottom surface), the vibration direction is the height direction (the direction perpendicular to the paper surface in FIG. 9A ). Thus, as the height decreases and the acting member 5 approaches a plate shape, the vibration direction approaches the height direction. Similarly, for acting members 5 having bottom surfaces of other shapes, the vibration direction also depends on the height.

[0045] In the above embodiment, the medical tube is the endoscope 2, but the medical tube may be any long medical device having a channel 2b, such as a catheter. In the above embodiment, the fiber holding unit 4 is attached to the side of the optical fiber 3, but instead, the fiber holding unit 4 may be provided on the inner surface of the channel 2b.

[0046] In the above embodiment, the scanning optical fiber 1 is inserted into the body B through the channel 2b of the medical tube. Alternatively, the scanning optical fiber 1 may be inserted into the body B independently of the medical tube. In this case, the outer diameter of the action member 5 may be larger than the inner diameter of the channel 2b. Furthermore, any means may be used to generate a flow of perfusion fluid C necessary for generating lift F around the vibration region 3c.

[0047] While the above describes the embodiments and their modifications of the present invention, the present invention is not limited to these and can be modified as appropriate without departing from the spirit and scope of the present invention. For example, the phototherapy device 10 and the phototherapy system 100 can be applied to any treatment that irradiates the subject A with light, not limited to stone fragmentation, and are particularly suitable for treatment performed while supplying a liquid or gas. The fluid supplied to the channel 2b by the fluid supply source 30 can be appropriately selected depending on the type of treatment. In other words, the fluid supply source 30 may supply other liquids or gases to the channel 2b. Furthermore, the scanning optical fiber 1 can be used not only for treatment but also for other applications involving laser light scanning.

[0048] REFERENCE SIGNS LIST 1 Scanning optical fiber 2 Endoscope (medical tube) 3 Optical fiber 3c Vibration region (tip region) 3d Longitudinal axis 5 Working member (protruding member) 10 Phototherapy device 20 Laser light source 30 Fluid supply source 100 Phototherapy system A Subject C Perfusion fluid (fluid) F, F1, F2 Lifting force L Laser light

Claims

1. An optical fiber; a protruding member provided at a tip region of the optical fiber and having an outer diameter larger than an outer diameter of the optical fiber; The protruding member receives a fluid flow in the longitudinal direction of the optical fiber toward the tip of the optical fiber, thereby generating a force in the radial direction of the optical fiber.

2. The scanning optical fiber according to claim 1 , wherein the protruding member is a plate-shaped member inclined with respect to the longitudinal axis of the optical fiber.

3. The scanning optical fiber of claim 2 , wherein the protruding member has a wing-shaped cross section.

4. the protruding member is a column or a rotating body, the columnar body has a height in a direction perpendicular to the longitudinal axis of the optical fiber and is plane-symmetric with respect to a plane including the longitudinal axis, The scanning optical fiber of claim 1 , wherein the body of revolution is symmetric about the longitudinal axis.

5. The scanning optical fiber of claim 4 , wherein the protruding member has a circular, polygonal, or bullet-shaped cross section that is axisymmetric about the longitudinal axis.

6. The scanning optical fiber of claim 1 , wherein the protruding member has an outer diameter equal to or smaller than an inner diameter of a channel in a medical tube into which the scanning optical fiber is inserted.

7. a medical tube having a channel; an optical fiber inserted into the channel; a protruding member provided at a tip region of the optical fiber and having an outer diameter larger than an outer diameter of the optical fiber; The optical therapy device, wherein the protruding member receives a fluid flow in the longitudinal direction of the optical fiber toward the tip of the optical fiber, and generates a force in the radial direction of the optical fiber.

8. The phototherapy device of claim 7 , wherein the outer diameter of the protruding member is equal to or smaller than the inner diameter of the channel.

9. The phototherapy device of claim 7 , wherein the medical tube is an endoscope.

10. a medical tube having a channel; an optical fiber inserted into the channel; a protruding member provided at a tip region of the optical fiber and having an outer diameter larger than an outer diameter of the optical fiber; a fluid supply source for supplying fluid to the channel; a laser light source that supplies laser light to the optical fiber, The protruding member receives a fluid flow in the longitudinal direction of the optical fiber toward the tip of the optical fiber, thereby generating a radial force on the optical fiber.

11. The phototherapy system of claim 10 , wherein the protruding member is a plate-shaped member inclined with respect to the longitudinal axis of the optical fiber.

12. The phototherapy system of claim 11 , wherein the protruding member has an airfoil-shaped cross section.

13. the protruding member is a column or a rotating body, the columnar body has a height in a direction perpendicular to the longitudinal axis of the optical fiber and is plane-symmetric with respect to a plane including the longitudinal axis, The phototherapy system of claim 10 , wherein the body of revolution is symmetrical about the longitudinal axis.

14. 14. The phototherapy system of claim 13, wherein the protruding member has a circular, polygonal, or bullet-shaped cross section that is symmetrical about the longitudinal axis.

15. The phototherapy system of claim 10 , wherein the protruding member has an outer diameter equal to or smaller than an inner diameter of a channel of a medical tube into which the optical fiber is inserted.

16. Irradiating a laser beam from the tip of the optical fiber onto the target; and vibrating the tip of the optical fiber; The vibrating step includes generating a fluid flow in the longitudinal direction of the optical fiber toward the tip of the optical fiber, and a protruding member provided in the tip region of the optical fiber receives the fluid flow and generates a radial force on the optical fiber.

17. The phototherapy system of claim 16, wherein the protruding member is a plate-shaped member that is inclined with respect to the longitudinal axis of the optical fiber.

18. 18. The phototherapy system of claim 17, wherein the protruding member has an airfoil-shaped cross section.

19. the protruding member is a column or a rotating body, the columnar body has a height in a direction perpendicular to the longitudinal axis of the optical fiber and is plane-symmetric with respect to a plane including the longitudinal axis, 17. The phototherapy system of claim 16, wherein the body of revolution is symmetrical about the longitudinal axis.

20. 20. The phototherapy system of claim 19, wherein the protruding member has a circular, polygonal, or bullet-shaped cross section that is symmetrical about the longitudinal axis.

21. 17. The phototherapy system of claim 16, wherein the protruding member has an outer diameter equal to or smaller than an inner diameter of a channel of a medical tube into which the optical fiber is inserted.