Light irradiation medical device

Abstract

To provide a light irradiation medical device that can contribute to the efficiency of procedures.SOLUTION: A light irradiation medical device 1 includes a shaft 10 having a distal end and a proximal end in a longitudinal axis direction x, and having a lumen 11 extending in the longitudinal axis direction x, an optical fiber 20 disposed in the lumen 11, a cylindrical member 40 disposed in the lumen 11 that covers part of a distal part of the optical fiber 20, and a coil member 50 disposed more on a proximal side than the cylindrical member 40 of the lumen 11, in which a wire 52 is spirally wound so as to surround the optical fiber 20. The optical fiber 20 extends in the longitudinal axis direction x in a predetermined section of the distal part, and includes a light diffusion part 21 for diffusing light outward in a radial direction of the shaft 10. The cylindrical member 40 covers part of the light diffusion part 21. The coil member 50 can move in the longitudinal axis direction x with respect to the optical fiber 20. The maximum outer diameter of the cylindrical member 40 is larger than the maximum outer diameter of the coil member 50.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a light irradiation medical device for irradiating light onto tissues such as cancer cells in a body lumen such as a blood vessel or a digestive tract.

Background Art

[0002] In photodynamic therapy (PDT), a photosensitizer is administered into the body by intravenous injection or intraperitoneal administration, the photosensitizer is accumulated in target tissues such as cancer cells, and the photosensitizer is excited by irradiating light of a specific wavelength. When the excited photosensitizer returns to the ground state, energy conversion occurs to generate reactive oxygen species. By attacking the target tissue with the reactive oxygen species, the target tissue can be removed. In ablation using laser light, the target tissue is irradiated with laser light and cauterized. Devices for performing such light irradiation have been proposed.

[0003] Patent Document 1 discloses a method of illuminating a patient's tissue using a light diffusing optical fiber. It is also disclosed that the desired length of the light diffusing optical fiber is exposed to perform a medical treatment by sliding a sheath distally or proximally along the length of the light diffusing optical fiber.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the optical fiber as described in Patent Document 1, the length of the exposed portion can be adjusted, but unevenness may occur in the light emission intensity distribution in the circumferential direction of the device. For this reason, in order to irradiate the entire target tissue, it is necessary to repeatedly perform light injection and position adjustment of the light emission site, which may cause the procedure to take a long time and impose a burden on the patient and the operator. Therefore, an object of the present invention is to provide a light irradiation medical device that contributes to the efficiency of the procedure.

Means for Solving the Problems

[0006] One embodiment of the light irradiation medical device of the present invention that can achieve the above object has a shaft having a distal end and a proximal end in the longitudinal axis direction and having a lumen extending in the longitudinal axis direction, an optical fiber disposed in the lumen of the shaft, a cylindrical member disposed in the lumen of the shaft and covering a part of the distal portion of the optical fiber, and a coil member disposed on the proximal side of the cylindrical member in the lumen of the shaft and having a wire wound around the optical fiber in a helical shape. The optical fiber has a light diffusion portion that extends in the longitudinal axis direction in a predetermined section of its distal portion and emits light outward in the radial direction of the shaft. The cylindrical member covers a part of the light diffusion portion. The coil member is movable in the longitudinal axis direction with respect to the optical fiber, and the gist lies in that the maximum outer diameter of the cylindrical member is larger than the maximum outer diameter of the coil member. According to the above light irradiation medical device, in the portion of the light diffusion portion covered by the cylindrical member, the light emitted from the light diffusion portion is reflected by the inner surface of the cylindrical member, so that the reflected light is easily diffused in various directions from the exposed portion, which is the portion of the light diffusion portion not covered by the cylindrical member. As a result, the light emission intensity distribution of the exposed portion in the circumferential direction of the shaft is likely to be uniformized. Thereby, the number of irradiations of the target tissue such as a tumor and the number of position adjustments of the exposed portion with respect to the target tissue can be reduced, so that the efficiency of the procedure can be achieved. Further, since the coil member is movable in the longitudinal axis direction with respect to the optical fiber, it is possible to adjust the length of the exposed portion in the longitudinal axis direction according to the shape of the target tissue. Furthermore, since the maximum outer diameter of the cylindrical member is larger than the maximum outer diameter of the coil member, the movement operation of the coil member with respect to the optical fiber becomes easy.

[0007] In the above-described light irradiation medical device, the coil member may be movable to a position distal to the proximal end of the light diffusing portion. When the coil member is moved to the most distal side, the distal end of the coil member may be located proximal to the proximal end of the cylindrical member. When the coil member is moved to the most proximal side, the distal end of the coil member may be located proximal to the proximal end of the light diffusing portion. The minimum inner diameter of the coil member may be larger than the minimum inner diameter of the cylindrical member. In the longitudinal axis direction, the coil member may be longer than the cylindrical member. The coil member may have a second pitch portion having a pitch that is not more than twice the wire diameter of the wire.

[0008] In the above-described light irradiation medical device, the cylindrical member may have a first coil portion in which a wire is wound in a helical shape so as to surround the light diffusing portion. The cylindrical member may have a second coil portion in which a wire is wound in a helical shape so as to surround the light diffusing portion within the lumen of the first coil portion. The wire diameter of the wire of the first coil portion may be larger than the wire diameter of the wire of the second coil portion.

[0009] In the above-described light irradiation medical device, the optical fiber has a core extending in the longitudinal axis direction, and the optical fiber has a first section having a first cladding disposed on the outer periphery of the core, and the optical fiber has a second section located distal to the first section and having a second cladding disposed on the outer periphery of the core and having a surface roughness of the outer peripheral surface larger than that of the first cladding at the light diffusing portion. The optical fiber has a core extending in the longitudinal axis direction, and the optical fiber has a first section having a first cladding disposed on the outer periphery of the core, and the optical fiber may have a third section located distal to the first section and having no cladding at the light diffusing portion.

Advantages of the Invention

[0010] According to the above-described light irradiation medical device, in the portion of the light diffusing portion covered by the cylindrical member, the light emitted from the light diffusing portion is reflected by the inner surface of the cylindrical member, so that the reflected light is likely to be diffused in various directions from the exposed portion which is the portion of the light diffusing portion not covered by the cylindrical member. As a result, the light emission intensity distribution of the exposed portion in the circumferential direction of the shaft is likely to be uniformized. Thereby, the number of irradiations of the target tissue such as a tumor and the number of times of adjusting the position of the exposed portion with respect to the target tissue can be reduced, and thus the efficiency of the procedure can be improved. Further, since the coil member is movable in the longitudinal axis direction with respect to the optical fiber, it is possible to adjust the length of the exposed portion in the longitudinal axis direction according to the shape of the target tissue. Furthermore, since the maximum outer diameter of the cylindrical member is larger than the maximum outer diameter of the coil member, the movement operation of the coil member with respect to the optical fiber becomes easier.

Brief Description of the Drawings

[0011]

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Mode for Carrying Out the Invention

[0012] Hereinafter, the present invention will be described more specifically based on the following embodiments. However, the present invention is not limited by the following embodiments, and it is of course possible to appropriately modify and implement it within the range that can conform to the gist of the foregoing and following descriptions, and all of them are included in the technical scope of the present invention. In each drawing, for the sake of convenience, hatching, reference numerals of members, etc. may be omitted, but in such cases, reference shall be made to the specification and other drawings. Also, the dimensions of various members in the drawings may differ from the actual dimensions because priority is given to facilitating the understanding of the features of the present invention.

[0013] One embodiment of the light irradiation medical device of the present invention has a shaft having a distal end and a proximal end in the longitudinal axis direction and having a lumen extending in the longitudinal axis direction, an optical fiber disposed in the lumen of the shaft, a cylindrical member disposed in the lumen of the shaft and covering a part of the distal portion of the optical fiber, and a coil member disposed on the proximal side of the cylindrical member in the lumen of the shaft and having a wire wound in a helical shape so as to surround the optical fiber. The optical fiber has a light diffusion portion extending in the longitudinal axis direction in a predetermined section of its distal portion and emitting light outward in the radial direction of the shaft. The cylindrical member covers a part of the light diffusion portion. The coil member is movable in the longitudinal axis direction with respect to the optical fiber, and the gist lies in that the maximum outer diameter of the cylindrical member is larger than the maximum outer diameter of the coil member. According to the above light irradiation medical device, in the portion of the light diffusion portion covered by the cylindrical member, the light emitted from the light diffusion portion is reflected by the inner surface of the cylindrical member, so that the reflected light is easily diffused in various directions from the exposed portion which is the portion of the light diffusion portion not covered by the cylindrical member. As a result, the light emission intensity distribution of the exposed portion in the circumferential direction of the shaft is likely to be uniformized. Thereby, the number of irradiations to the target tissue such as a tumor and the number of times of adjusting the position of the exposed portion with respect to the target tissue can be reduced, so that the efficiency of the procedure can be improved. Further, since the coil member is movable in the longitudinal axis direction with respect to the optical fiber, it is possible to adjust the length of the exposed portion in the longitudinal axis direction according to the shape of the target tissue. Furthermore, since the maximum outer diameter of the cylindrical member is larger than the maximum outer diameter of the coil member, the movement operation of the coil member with respect to the optical fiber becomes easy.

[0014] The light irradiation medical device is used to irradiate a treatment site, which is a target tissue such as cancer cells, with light of a specific wavelength in a body lumen such as a blood vessel or the digestive tract in PDT or photoablation. The light irradiation medical device may be delivered to the treatment site alone or may be used together with a delivery catheter or an endoscope. In the treatment using an endoscope, the light irradiation medical device is disposed in the body through the forceps channel of the endoscope and delivered to the treatment site.

[0015] Referring to FIGS. 1 to 12, the basic configuration of the device will be described. FIG. 1 is a cross-sectional view (partial side view) of a light irradiation medical device according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view (partial side view) of the distal side of the light irradiation medical device shown in FIG. 1. FIG. 3 is a cross-sectional view (partial side view) showing a state in which the coil member is moved to the distal side in the light irradiation medical device shown in FIG. 2. FIG. 4 is an end face view of a cut portion at the IV-IV line of the light irradiation medical device shown in FIG. 2. FIG. 5 is an end face view of a cut portion of the cylindrical member shown in FIG. 2. FIGS. 6 to 9 are cross-sectional views (partial side views) showing still other modified examples of the light irradiation medical device shown in FIG. 2. FIG. 10 is an enlarged cross-sectional view of the distal side of the optical fiber shown in FIG. 2. FIGS. 11 to 12 are cross-sectional views showing modified examples of the optical fiber shown in FIG. 10. The light irradiation medical device 1 has a shaft 10, an optical fiber 20, a cylindrical member 40, and a coil member 50. Hereinafter, the light irradiation medical device may be simply referred to as the device. In order to easily understand the positional relationship between the optical fiber 20 and the cylindrical member 40, the shaft 10 is omitted in FIGS. 10 to 12.

[0016] In this specification, the distal side of the device 1 refers to the distal end side in the longitudinal axis direction x of the shaft 10 and points to the treatment target side. The proximal side of the device 1 refers to the proximal end side in the longitudinal axis direction x of the shaft 10 and points to the user's hand side. When each member is bisected in the longitudinal axis direction x of the shaft 10, the proximal side may be referred to as the proximal portion, and the distal side may be referred to as the distal portion. In the radial direction of the device 1, the inner side refers to the direction toward the central axis c extending in the longitudinal axis direction x of the shaft 10, and the outer side refers to the radial direction opposite to the inner side.

[0017] The shaft 10 has a longitudinal axis direction x, a radial direction, and a circumferential direction p. As shown in FIG. 1, the shaft 10 has a distal end and a proximal end in the longitudinal axis direction x and has a lumen 11 extending in the longitudinal axis direction x. The shaft 10 may have only one lumen 11 or may have a plurality of lumens. The shaft 10 has a cylindrical shape for arranging the optical fiber 20, the cylindrical member 40, and the coil member 50 in its lumen 11. Preferably, the shaft 10 has a cylindrical shape with only one lumen 11. Since the shaft 10 is inserted into the body, it preferably has flexibility. The shaft 10 has an inner circumferential surface 12 and an outer circumferential surface 13.

[0018] The shaft 10 is a hollow body formed by arranging one or a plurality of wire rods in a predetermined pattern; a body in which at least one of the inner surface or the outer surface of the hollow body is coated with resin; a resin tube; or a combination thereof, for example, those connected in the longitudinal axis direction. Examples of the hollow body in which the wire rods are arranged in a predetermined pattern include a cylindrical body having a mesh structure formed by simply crossing or braiding the wire rods, and a coil in which the wire rods are wound. The wire rod may be one or a plurality of single wires or one or a plurality of stranded wires. The resin tube can be manufactured, for example, by extrusion molding. When the shaft 10 is a resin tube, the shaft 10 can be composed of a single layer or a plurality of layers. A part of the shaft 10 in the longitudinal axis direction x or the circumferential direction p may be composed of a single layer and the other part may be composed of a plurality of layers.

[0019] The shaft 10 can be made of, for example, synthetic resins such as polyolefin resins (e.g., polyethylene and polypropylene), polyamide resins (e.g., nylon), polyester resins (e.g., PET), aromatic polyether ketone resins (e.g., PEEK), polyether polyamide resins, polyurethane resins, polyimide resins, fluorine resins (e.g., PTFE, PFA, ETFE), etc., or metals such as stainless steel, carbon steel, nickel-titanium alloys, etc. These can be used alone or in combination of two or more. It is preferable that at least the portion of the shaft 10 overlapping with the light diffusing portion 21 is made of a resin having light transmissibility. At least the portion of the shaft 10 overlapping with the light diffusing portion 21 may be made of a transparent resin.

[0020] As shown in FIG. 1, a tip chip 15 may be attached to the distal end of the shaft 10. Damage to the biological tissue by the distal end portion of the shaft 10 can be avoided. Examples of the shape of the tip chip 15 include a cylindrical shape, an oblong cylindrical shape, a hemispherical shape, an oblong spherical shape, a frustum of a pyramid shape, a frustum of a cone shape, an oblong frustum of a cone shape, a rounded frustum of a cone shape, or a combination thereof.

[0021] In FIG. 1, the proximal portion of the shaft 10 is connected to the handle 60. By the operator gripping the handle 60, the operation of the device 1 becomes easier. The handle 60 extends, for example, in the longitudinal axis direction x. The handle 60 can be composed of one or a plurality of members. In FIG. 1, the handle 60 has a hollow portion 61 extending in the longitudinal axis direction x. The handle 60 may have, for example, a cylindrical shape. In FIG. 1, the shaft 10 and the optical fiber 20 are inserted into the hollow portion 61.

[0022] The constituent material of the handle 60 is not particularly limited, and for example, polyolefin resins such as polypropylene (PP) and polyethylene (PE), polyester resins such as polyethylene terephthalate (PET), synthetic resins such as polycarbonate resin, ABS resin, and polyurethane resin can be used.

[0023] The optical fiber 20 is a transmission path that transmits an optical signal to the target tissue. As shown in FIGS. 1 to 2, the optical fiber 20 is disposed in the inner cavity 11 of the shaft 10. The optical fiber 20 has an optical diffusion portion 21 that extends in the longitudinal axis direction x in a predetermined section of its distal portion and emits light outward in the radial direction of the shaft 10. The optical diffusion portion 21 functions as a light-emitting area. The optical diffusion portion 21 is arranged to extend in the longitudinal axis direction x and the circumferential direction p of the shaft 10. The optical diffusion portion 21 has an outer peripheral surface 23. The outer peripheral surface 23 of the optical diffusion portion 21 faces the inner peripheral surface 12 side of the shaft 10. In FIG. 1, the proximal end portion of the optical fiber 20 extends proximally from the handle 60. The proximal end portion of the optical fiber 20 is connected to a light source such as a semiconductor laser.

[0024] Through the endoscope, the device 1 is inserted to a position where the target tissue is in the body cavity. At this time, the target tissue is arranged to be located radially outward of the outer peripheral surface 13 of the shaft 10. The light emitted from the optical diffusion portion 21 reaches the target tissue around the device 1 by passing through at least the portion of the shaft 10 that overlaps with the optical diffusion portion 21.

[0025] It is sufficient that light is emitted from the optical diffusion portion 21 at least outward in the radial direction of the shaft 10. Preferably, light is emitted from the optical diffusion portion 21 outward in the radial direction of the shaft 10 over the entire circumferential direction p of the shaft 10. Further, light may be emitted from the optical diffusion portion 21 in the distal direction of the shaft 10, that is, forward. However, preferably, the device 1 does not include one in which light is emitted from the optical diffusion portion 21 only in the distal direction of the shaft 10.

[0026] As shown in FIGS. 1 to 2, a part of the light diffusing portion 21 is covered by the cylindrical member 40. In this specification, when the cylindrical member 40 is removed from the optical fiber 20, the portion where light is emitted at least outward in the radial direction is referred to as the light diffusing portion 21. In a state where the cylindrical member 40 covers a part of the light diffusing portion 21, at least one of the distal end and the proximal end of the light diffusing portion 21 may be hidden by the cylindrical member 40 and not visible, and it may be difficult to grasp the positions of the distal end and the proximal end of the light diffusing portion 21. Therefore, the identification of the positions of the distal end and the proximal end of the light diffusing portion 21 shall be performed with the cylindrical member 40 removed from the optical fiber 20.

[0027] In this specification, the portion of the light diffusing portion 21 that is not covered by the cylindrical member 40 and is exposed on the side of the shaft 10 is referred to as the exposed portion 22. In the radial direction of the shaft 10, it is preferable that there is no other member between the exposed portion 22 and the shaft 10, but any member that does not block the light emitted from the exposed portion 22 may be arranged.

[0028] The light diffusing portion 21 is not a separate diffusing member (for example, a diffusing plate or a prism) from the optical fiber 20, but is a part that constitutes a part of the optical fiber 20. The optical fiber 20 has a core and a cladding. The cladding is arranged on the outer periphery of the core and covers a part of the core outward in the radial direction. The light diffusing portion 21 is preferably composed of any one of (i) a mode in which only the core is arranged, (ii) a mode in which the core and the cladding are arranged, or (iii) a mode in which a part has only the core arranged and the other part has the core and the cladding arranged. A protective coating material may be arranged outside the cladding in the radial direction, but it is preferable that no member other than the core and the cladding is arranged in the light diffusing portion 21.

[0029] The materials constituting the core and the cladding are not particularly limited, and glasses such as plastic, quartz glass, and fluoride glass can be used.

[0030] In at least the portion of the shaft 10 that overlaps with the light diffusing portion 21, light diffusing materials such as inorganic particles such as titanium oxide, barium sulfate, and calcium carbonate, and organic particles such as crosslinked acrylic particles and crosslinked styrene particles can be added to the resin constituting the shaft 10. The light emitted from the light diffusing portion 21 is more likely to be diffused by the shaft 10.

[0031] The light diffusing portion 21 is preferably arranged on the most distal side of the optical fiber 20. This makes it easier to form the light diffusing portion 21 and can also enhance the flexibility at the distal end of the optical fiber 20.

[0032] In the longitudinal axis direction x, the length of the light diffusing portion 21 may be set to a length that is 1 / 50 or more, 1 / 45 or more, 1 / 30 or more of the total length of the optical fiber 20. By setting the length in this way, it becomes easier to irradiate the entire target tissue in one irradiation. Also, in the longitudinal axis direction x, the length of the light diffusing portion 21 may be set to a length that is 1 / 20 or less, 1 / 25 or less, 1 / 30 or less of the total length of the optical fiber 20. By setting the length in this way, irradiation of non-target tissues can be prevented.

[0033] The light diffusing portion 21 may be arranged only in a part of the circumferential direction p of the shaft 10, but as shown in FIG. 4, the light diffusing portion 21 is preferably arranged in the entire circumferential direction p of the shaft 10. Since a wide range in the circumferential direction p can be irradiated at once, the efficiency of the procedure can be improved.

[0034] A configuration example of the optical fiber 20 will be described with reference to FIGS. 10 to 12. In FIGS. 10 to 12, the optical fiber 20 has a core 25 extending in the longitudinal axis direction x, and the optical fiber 20 has a first section 31 having a first cladding 26 arranged on the outer periphery of the core 25. In the first section 31, since light is likely to be totally reflected at the boundary between the core 25 and the first cladding 26, in the first section 31, the light is propagated to the distal side of the optical fiber 20 while being confined within the core 25.

[0035] In the first section 31, it is preferable that one core 25 is arranged within one first cladding 26. In the first section 31, the optical fiber can be described as a single-core optical fiber.

[0036] To prevent an increase in the profile of the optical fiber 20, in the first section 31, the first cladding 26 may be located at the outermost radial position of the optical fiber 20. That is, other members such as a coating material may not be arranged in the first section 31.

[0037] Although not shown, a coating material may be arranged on the outer periphery of the first cladding 26 in the first section 31 of the optical fiber 20. It becomes possible to protect the outside of the first section 31, and it is also possible to suppress light leakage and emission to the outside in the first section 31. The coating material may be a coating layer arranged on the outer peripheral surface of the first cladding 26, or may be a sheath that encloses the first cladding 26. The coating material can be composed of a resin such as an ultraviolet curable resin.

[0038] In FIG. 10, the optical fiber 20 has a second cladding 27 that is arranged on the outer periphery of the core 25 in the light diffusing portion 21 and has a larger surface roughness of the outer peripheral surface than the first cladding 26, and has a second section 32 located on the distal side from the first section 31. By increasing the surface roughness of the cladding in the second section 32 compared to the first section 31, part of the light is propagated to the distal side of the optical fiber 20 while being confined within the core 25, and the remaining light leaks out from the second cladding 27 and is emitted radially outward. In addition, it is preferable that light is not emitted radially outward in the first section 31, or the amount of light leakage is smaller than that in the second section 32.

[0039] Similar to the first section 31, in the second section 32, it is preferable that one core 25 is arranged within one second cladding 27. The first cladding 26 in the first section 31 and the second cladding 27 in the second section 32 may be integrally formed, or the optical fiber for the first section 31 and the optical fiber for the second section 32 may be joined in the longitudinal axis direction x.

[0040] In the second section 32, it is preferable that the second cladding 27 is located at the outermost position in the radial direction of the optical fiber 20. That is, in the second section 32, it is preferable that no member other than the core 25 and the second cladding 27 (for example, a coating material) is arranged. With this configuration, light can be emitted outward in the radial direction of the shaft 10 from the second section 32.

[0041] The surface roughness of the outer peripheral surface of the second cladding 27 in the second section 32 is greater than the surface roughness of the outer peripheral surface of the first cladding 26 in the first section 31. Here, the surface roughness is the arithmetic mean roughness Ra between the reference lengths of the roughness curve in the longitudinal axis direction of the outer peripheral surface of the optical fiber 20. The reference length may be set according to the magnification of the laser microscope used, for example, 200 μm. The above arithmetic mean roughness Ra corresponds to the arithmetic mean roughness Ra defined in JIS B 0601 (2001) and is measured according to JIS B 0633 (2001). For the measurement, a measuring instrument defined in JIS B 0651 (2001) (for example, a laser microscope VK-X3000 manufactured by Keyence Corporation) is used.

[0042] It is preferable that the average value of the surface roughness of the outer peripheral surface of the second cladding 27 in the second section 32 is greater than the average value of the surface roughness of the outer peripheral surface of the first cladding 26 in the first section 31. In the first section 31, light is easily confined in the core 25, and in the second section 32, light is easily emitted outward in the radial direction from the second cladding 27. As a result, the light emission intensity distribution of the light diffusion part 21 is easily made uniform in the longitudinal axis direction x. The average value of the surface roughness is the average value of the surface roughness values of 10 or more measurement points set side by side in the longitudinal axis direction x in the section to be measured (for example, the first section 31).

[0043] As shown in FIG. 10, when the second section 32 is bisected into a distal portion 323 and a proximal portion 324 in the longitudinal axis direction x, it is preferable that the average value of the surface roughness of the outer peripheral surface of the second cladding 27 in the proximal portion 324 is smaller than the average value of the surface roughness of the outer peripheral surface of the second cladding 27 in the distal portion 323. With this configuration, in the proximal portion 324, the effect of confining light in the core 25 is enhanced more than in the distal portion 323, and in the distal portion 323, light is more likely to be emitted radially outward from the second cladding 27. Therefore, the light emission intensity distribution of the second section 32 in the longitudinal axis direction x is likely to be uniformized.

[0044] As can be understood from FIGS. 1 and 10, it is preferable that the second section 32 is shorter than the first section 31 in the longitudinal axis direction x. This makes it easier to form the light diffusing portion 21 and can also enhance the flexibility at the distal end of the optical fiber 20. The length of the second section 32 in the longitudinal axis direction x can be set to 1 / 20 or less, 1 / 25 or less, or 1 / 30 or less of the length of the first section 31. Also, the length of the second section 32 in the longitudinal axis direction x may be set to 1 / 50 or more, 1 / 45 or more, or 1 / 30 or more of the length of the first section 31.

[0045] As can be understood from FIG. 10, it is preferable that the average thickness of the second cladding 27 of the second section 32 is smaller than the average thickness of the first cladding 26 of the first section 31. By adjusting the thickness of the cladding in this way, light is more likely to be confined in the core 25 in the first section 31, and light is more likely to be emitted radially outward from the second cladding 27 in the second section 32. Here, the thickness of the cladding can be measured using a laser microscope VK-X3000 manufactured by Keyence Corporation.

[0046] As shown in FIGS. 11 to 12, when the optical fiber 20 has the first section 31, the optical fiber 20 may have a third section 33 in the light diffusing portion 21 where there is no cladding and which is located on the distal side of the first section 31. Since there is no cladding in the third section 33, light from the core 25 is emitted radially outward.

[0047] In the third section 33, it is preferable that the cladding does not exist in at least a part of the circumferential direction of the core 25, and it is more preferable that the cladding does not exist in the entire circumferential direction of the core 25.

[0048] In the third section 33, it is preferable that the core 25 is located at the outermost position in the radial direction among the optical fibers 20. However, it is preferable that at least a part of the third section 33 is covered by the cylindrical member 40. That is, in the third section 33, it is preferable that not only the cladding but also all members other than the core 25 and the cylindrical member 40 (for example, the coating material) are not arranged.

[0049] In the longitudinal axis direction x, the outer diameter of the core 25 in the third section 33 may be a constant value, or the outer diameter of the core 25 may be different values depending on the position in the longitudinal axis direction x.

[0050] As shown in FIGS. 11 to 12, in the longitudinal axis direction x, it is preferable that the distal end of the third section 33 is at the same position as the distal end of the core 25. This makes it easier to form the third section 33 and can also enhance the flexibility at the distal end portion of the optical fiber 20.

[0051] The surface roughness of the outer peripheral surface of the core 25 in the third section 33 is preferably larger than the surface roughness of the outer peripheral surface of the first cladding 26 in the first section 31. In the first section 31, light is more easily confined in the core 25, and in the third section 33, light is more easily emitted radially outward from the core 25.

[0052] It is preferable that at least one of the second section 32 and the third section 33 is arranged in the light diffusing portion 21, and both the second section 32 and the third section 33 may be arranged. As shown in FIG. 11, it is preferable that the second section 32 and the third section 33 are arranged in order from the proximal side to the distal side in the light diffusing portion 21. With this configuration, the emission intensity distribution of the light diffusing portion 21 in the longitudinal axis direction x is likely to be uniformized. To enhance this effect, it is preferable that the first section 31, the second section 32, and the third section 33 are adjacent to each other in the longitudinal axis direction x.

[0053] When the optical fiber 20 has the second section 32 and the third section 33, as shown in FIG. 11, it is preferable that the third section 33 is shorter than the second section 32 in the longitudinal axis direction x. With this configuration, it becomes easier to make the emission intensity distribution of the entire exposed portion 22 in the longitudinal axis direction x uniform. Note that an aspect in which the second section 32 is shorter than the third section 33 in the longitudinal axis direction x is also acceptable.

[0054] In the longitudinal axis direction x, the length of the third section 33 is preferably 20% or less of the total length of the second section 32 and the third section 33, more preferably 18% or less, and even more preferably 15% or less. Also, in the longitudinal axis direction x, the length of the third section 33 may be 5% or more, 8% or more, or 10% or more of the total length of the second section 32 and the third section 33. With this configuration, it becomes easier to make the emission intensity distribution of the exposed portion 22 in the longitudinal axis direction x uniform.

[0055] It is preferable that the average value of the surface roughness of the outer peripheral surface of the second cladding 27 of the second section 32 is smaller than the average value of the surface roughness of the outer peripheral surface of the core 25 of the third section 33. With this configuration, it becomes easier to make the emission intensity distribution in the longitudinal axis direction x uniform in each of the second section 32 and the third section 33.

[0056] As shown in FIG. 10, the optical fiber 20 may have only the second section 32 in the light diffusing portion 21. That is, the optical fiber 20 may not have the third section 33 in the light diffusing portion 21. Even with a configuration having only the second section 32, it is possible to make the emission intensity distribution of the exposed portion 22 in the longitudinal axis direction x uniform. Since the core 25 is not exposed, it also has the effect of preventing damage to the optical fiber 20 due to bending of the apparatus 1 during the procedure.

[0057] When the optical fiber 20 has only the second section 32 in the light diffusing portion 21, it is preferable that the distal end of the second section 32 is at the same position as the distal end of the core 25 in the longitudinal axis direction x.

[0058] As shown in Fig. 12, the optical fiber 20 may have only the third section 33 in the light diffusing section 21. That is, the optical fiber 20 may not have the second section 32 in the light diffusing section 21. Even with a configuration having only the third section 33, the emission intensity distribution of the exposed portion 22 in the longitudinal axis direction x can be made uniform.

[0059] The second section 32 and the third section 33 can be formed by peeling the cladding by etching or polishing. In order to adjust the surface roughness of the second section 32 or the third section 33, irregularities may be arranged on the outer peripheral surface of the second cladding 27 or the outer peripheral surface of the core 25 of the third section 33. The irregularities can be formed by mechanically or chemically roughening the surface of the second cladding 27 or the core 25 of the third section 33. Examples of the method for roughening the surface include an etching process, a blasting process, a scribing needle, a wire brush, or a method using sandpaper.

[0060] It is sufficient that the first light ray for treatment is emitted from the light diffusing section 21. The first light ray is preferably laser light having a wavelength suitable for phototherapy such as PDT or PIT, which irradiates the body tissue. In addition to the first light ray, a second light ray for targeting may be emitted. The second light ray is a light ray emitted to grasp the treatment site before the emission of the first light ray, and preferably has a lower radiant energy than the first light ray.

[0061] As shown in FIGS. 1 and 2, the cylindrical member 40 is disposed in the inner cavity 11 of the shaft 10 and covers a part of the distal portion of the optical fiber 20. Specifically, the cylindrical member 40 covers a part of the light diffusing portion 21. According to the apparatus 1, in the portion of the light diffusing portion 21 covered by the cylindrical member 40, the light emitted from the light diffusing portion 21 is reflected by the inner surface of the cylindrical member 40, so that the reflected light is easily diffused in various directions from the exposed portion 22 which is the portion of the light diffusing portion 21 not covered by the cylindrical member 40. As a result, the light emission intensity distribution of the exposed portion 22 in the circumferential direction p of the shaft 10 is likely to be uniformized. Thereby, the number of irradiations of the target tissue such as a tumor and the number of times of adjusting the position of the exposed portion 22 with respect to the target tissue can be reduced, and thus the efficiency of the procedure can be improved. In FIG. 2, an example of the state where the light traveling from the proximal side to the distal side is directly emitted from the exposed portion 22 and the state where the light is emitted from the exposed portion 22 after being reflected by the cylindrical member 40 are shown by thick arrows.

[0062] The cylindrical member 40 covers only a part of the light diffusing portion 21 and does not cover the whole of the light diffusing portion 21. That is, an exposed portion 22 is always formed in the light diffusing portion 21.

[0063] The cylindrical member 40 is formed to extend in the longitudinal axis direction x of the shaft 10. Among the cylindrical member 40, the direction parallel to the longitudinal axis direction x of the shaft 10 is referred to as the axial direction of the cylindrical member 40. As shown in FIG. 4, the cylindrical member 40 has an inner peripheral surface 43 and an outer peripheral surface 44. The inner peripheral surface 43 extends in the circumferential direction p of the shaft 10 and faces the outer peripheral surface 23 side of the optical fiber 20. The outer peripheral surface 44 extends in the circumferential direction p of the shaft 10 and faces the inner peripheral surface 12 side of the shaft 10. The light emitted from the light diffusing portion 21 is preferably reflected at least by the inner peripheral surface 43 of the cylindrical member 40.

[0064] As shown in FIGS. 2, 5 to 8, the cylindrical member 40 may have a shape in which the distal end 401 side is closed and the proximal end 402 side is open. In that case, the cylindrical member 40 has an outer end face 45 on the distal end 401 side and an inner end face 46 on the distal end 401 side. This shape can also be described as a bottomed cylindrical shape with the closed portion on the distal end 401 side as the bottom. The outer end face 45 on the distal end 401 side is a visible surface when the cylindrical member 40 is viewed from the distal side toward the proximal side. The inner end face 46 on the distal end 401 side corresponds to the inner bottom surface of the bottomed cylindrical shape. With this configuration, not only the inner peripheral surface 43 of the cylindrical member 40 but also the inner end face 46 on the distal end 401 side can reflect light, so that the reflected light is likely to be diffused in various directions from the exposed portion 22. As shown in FIG. 9, the cylindrical member 40 may be a cylindrical shape in which both the distal end 401 side and the proximal end 402 side are open.

[0065] The inner peripheral surface 43 may be composed of only a curved surface portion, only a flat surface portion, or a combination of a curved surface portion and a flat surface portion. In order to easily diffuse the light reflected by the inner peripheral surface 43 in multiple directions, it is preferable that the inner peripheral surface 43 has a curved surface portion. The inner end face 46 may be composed of only a flat surface portion, only a curved surface portion, or a combination of a curved surface portion and a flat surface portion.

[0066] The cylindrical member 40 preferably has one lumen. The shape of the cylindrical member 40 is not particularly limited, and it may be a cylindrical shape, an oval cylindrical shape, or a polygonal cylindrical shape. The axial length of the cylindrical member 40 may be larger or smaller than the maximum outer diameter of the cylindrical member 40.

[0067] As shown in FIGS. 2, 4 to 6, the cylindrical member 40 preferably has a first coil portion 41a in which the wire 42a is wound in a spiral shape so as to go around the light diffusing portion 21. In the portion of the light diffusing portion 21 covered by the first coil portion 41a, the light emitted from the light diffusing portion 21 is reflected by the inner surface of the coil portion 41, so that the reflected light is likely to be diffused in various directions from the exposed portion 22 of the light diffusing portion 21 not covered by the cylindrical member 40. The configuration of the first coil portion 41a will be described later.

[0068] The cylindrical member 40 does not necessarily have a coil shape in which a wire is wound, and may be a cylindrical body such as a resin tube or a metal pipe as shown in FIG. 8.

[0069] In order to enhance the effect of reflecting light by the inner peripheral surface 43 of the cylindrical member 40, it is preferable that the light emitted from the light diffusing portion 21 does not pass through the cylindrical member 40 outward in the radial direction of the shaft 10.

[0070] In the longitudinal axis direction x, it is preferable that the distal end 401 of the cylindrical member 40 is at the same position as the distal end of the light diffusing portion 21 or is located on the distal side of the distal end of the light diffusing portion 21.

[0071] The light diffusing portion 21 has a longitudinal axis direction, and the longitudinal axis direction of the light diffusing portion 21 is parallel to the longitudinal axis direction x of the shaft 10. As shown in FIG. 2, it is preferable that the proximal end 402 of the cylindrical member 40 is located on the distal side of the midpoint 211 in the longitudinal axis direction of the light diffusing portion 21. Since the exposed portion 22 can be formed long in the longitudinal axis direction of the light diffusing portion 21, a wide range in the longitudinal axis direction can be irradiated at once.

[0072] The cylindrical member 40 is preferably disposed at a position including the distal end of the light diffusing portion 21. It is preferable that the cylindrical member 40 is not located on the proximal side of the midpoint 211 in the longitudinal axis direction of the light diffusing portion 21.

[0073] In the longitudinal axis direction x, it is preferable that the entire cylindrical member 40 is disposed in the inner cavity 11 of the shaft 10.

[0074] In the longitudinal axis direction x, the length of the cylindrical member 40 can be set to be 1 / 2 or less, 1 / 3 or less, 1 / 4 or less of the length of the exposed portion 22. Also, in the longitudinal axis direction x, the length of the cylindrical member 40 may be set to be 1 / 20 or more, 1 / 18 or more, 1 / 15 or more of the length of the exposed portion 22.

[0075] In the longitudinal axis direction x of the shaft 10, the outer diameter of the cylindrical member 40 may be constant, or the outer diameter of the cylindrical member 40 may vary depending on the position in the longitudinal axis direction x. For example, when the cylindrical member 40 is bisected into a distal portion and a proximal portion in the longitudinal axis direction x, the average outer diameter of the distal portion of the cylindrical member 40 may be larger than the average outer diameter of the proximal portion of the cylindrical member 40.

[0076] The cylindrical member 40 is preferably made of a material having a higher reflectivity than the shaft 10. With this configuration, the reflected light is likely to be diffused on the inner surface of the cylindrical member 40. Here, the reflectivity refers to the reflectivity of the light emitted from the light diffusing portion 21, and the unit is %. The reflectivity can be measured using an Ocean Photonics reflectivity measurement system OP-RF-VIS-GT50.

[0077] The cylindrical member 40 is preferably made of metal. For example, it may be a radiation-impermeable metal such as gold, silver, platinum, palladium, tungsten, tantalum, iridium, and alloys thereof, or a superelastic alloy such as stainless steel or Ni-Ti alloy.

[0078] The cylindrical member 40 may have a cylindrical member body and a reflective layer disposed on the inner surface of the cylindrical member body. Regardless of the material of the cylindrical member body, the reflective layer can reflect the light from the light diffusing portion 21. For example, a coil body around which a resin wire is wound or a resin tube may be the cylindrical member body. The reflective layer may be disposed by applying a coating agent containing a reflective material to the inner surface of the cylindrical member body, or may be disposed by attaching a reflective material to the inner surface of the cylindrical member body by methods such as vapor deposition, sputtering, electroplating, or chemical plating. Note that the reflective layer may be a metal thin film. Examples of the reflective material include aluminum, gold, silver, copper, tin, titanium dioxide, tantalum pentoxide, aluminum oxide, silicon dioxide, magnesium fluoride, or combinations thereof. When the cylindrical member 40 has a reflective layer, any of the materials mentioned as the constituent materials of the shaft 10 can be used for the cylindrical member body.

[0079] By heating and deforming the distal end 401 side of the cylindrical member 40, a cylindrical member 40 with the distal end 401 side closed as shown in FIG. 5 can be obtained. Further, a cylindrical coil having one lumen and a metal member different from the cylindrical coil are prepared, and the metal member is heated and welded so as to close the opening on the distal side of the cylindrical coil, whereby a cylindrical member 40 with the distal end 401 side closed can also be obtained.

[0080] The inner peripheral surface 43 of the cylindrical member 40 may be provided with irregularities. By roughening the surface of the inner peripheral surface 43 to form fine irregularities on the order of micrometers or nanometers, the reflected light is likely to be diffused in multiple directions.

[0081] The concavo-convex structure of the inner peripheral surface 43 of the cylindrical member 40 can be formed by etching, blasting, scribing needles, wire brushes, or sandpaper to roughen the inner peripheral surface 43 of the cylindrical member 40.

[0082] In the longitudinal axis direction x of the shaft 10, the irregularities may be arranged only on a part of the cylindrical member 40, or the irregularities may be arranged on the entire cylindrical member 40. Also, in the circumferential direction of the shaft 10, the irregularities may be arranged only on a part of the cylindrical member 40, or the irregularities may be arranged on the entire cylindrical member 40.

[0083] As shown in FIG. 9, it is preferable that a reflective material 17 that reflects the light from the light diffusing portion 21 is arranged on the distal end 401 side of the cylindrical member 40. The reflective material 17 is, for example, a mirror arranged such that the reflective surface faces the proximal side. With this configuration, light can be reflected not only by the inner peripheral surface of the cylindrical member 40 but also by the reflective material 17, so that the reflected light is likely to be diffused in various directions.

[0084] The surface of the reflective material 17 is preferably composed of aluminum, gold, silver, copper, tin, titanium dioxide, tantalum pentoxide, aluminum oxide, silicon dioxide, or magnesium fluoride.

[0085] As shown in FIG. 9, the reflector 17 is preferably disposed on the distal side of the cylindrical member 40. Although not shown, the reflector 17 may be disposed at the most distal side of the inner cavity of the cylindrical member 40. When the distal end 401 side of the cylindrical member 40 is closed, the inner end face 46 of the cylindrical member 40 and the distal end face of the reflector 17 may be in contact with each other.

[0086] When the optical fiber 20 has the second section 32, as shown in FIG. 10, the cylindrical member 40 preferably covers a part of the second section 32, and more preferably covers a part of the distal portion of the second section 32. The light emitted radially outward from the light diffusing portion 21 can be reflected by the portion of the second section 32 covered by the cylindrical member 40. Note that the cylindrical member 40 preferably does not cover the entire second section 32.

[0087] As shown in FIGS. 11 to 12, when the optical fiber 20 has the third section 33, the cylindrical member 40 preferably covers at least a part of the third section 33. The light emitted radially outward from the light diffusing portion 21 can be reflected by the portion of the third section 33 covered by the cylindrical member 40. In the longitudinal axis direction x, as shown in FIG. 12, the cylindrical member 40 may cover only a part of the third section 33. In that case, the cylindrical member 40 preferably covers a part of the distal portion of the third section 33. Also, in the longitudinal axis direction x, as shown in FIG. 11, the cylindrical member 40 may cover the entire third section 33.

[0088] When the optical fiber 20 has the second section 32 and the third section 33, the proximal end 402 of the cylindrical member 40 may be located on the distal side of the distal end of the second section 32. In this way, the cylindrical member 40 may be disposed only on the third section 33 and may not be disposed on the second section 32.

[0089] When the optical fiber 20 has the second section 32 and the third section 33, the proximal end 402 of the cylindrical member 40 may be located on the proximal side of the distal end of the second section 32. In this way, the cylindrical member 40 may be disposed on a part of the second section 32 and at least a part of the third section 33.

[0090] The configuration of the first coil part 41a will be described in detail below. The wire 42a that constitutes the first coil part 41a may be composed of a single linear member from the tip to the base end, or the wire 42a may be composed of a plurality of linear members connected to each other in the longitudinal axis direction thereof.

[0091] The shape of the cross-section perpendicular to the longitudinal axis direction of the wire 42a may be circular, oval, polygonal, or a combination thereof. The oval shape shall include elliptical, egg-shaped, and rounded rectangular shapes. The same shall apply in other descriptions in this specification.

[0092] The shape of the cross-section perpendicular to the longitudinal axis direction of the wire 42a is preferably circular or oval. With such a cross-sectional shape, as shown in FIG. 5, in the cross-section along the longitudinal axis direction x of the shaft 10, a plurality of convex portions 491 are arranged in the longitudinal axis direction x on the inner peripheral surface 43 of the cylindrical member 40. As a result, it is preferable that a concave portion 492 is arranged between the two convex portions 491. Due to the convex portions 491 and concave portions 492 on the inner peripheral surface 43, the reflected light is likely to be diffused in multiple directions.

[0093] The wire diameter (thickness) of the wire 42a and the number of turns of the wire 42a are not particularly limited. In FIGS. 1 to 2, an example in which the first coil part 41a is wound in a single layer is shown, but it may be wound in multiple layers, or a combination of single-layer winding and multi-layer winding may be used. The axial length of the first coil part 41a may be larger or smaller than the maximum outer diameter of the first coil part 41a.

[0094] The pitch P of the first coil part 41a 1 is not particularly limited and may be constant in the axial direction or may vary depending on the axial position. The pitch P 1 is, as shown in FIG. 1, the distance between the central axes of two adjacent wires 42a that form the first coil part 41a in the axial direction.

[0095] In the first coil portion 41a, a gap may be formed between adjacent wire rods 42a in the axial direction, but it is preferable that the gap between adjacent wire rods 42a is not too large. This is because if too much light leaks from the gap between adjacent wire rods 42a, the light emission intensity at the exposed portion 22 may decrease. Therefore, it is preferable that the first coil portion 41a has a first pitch portion 48 having a pitch of not more than twice the wire diameter of the wire rod 42a.

[0096] As shown in FIG. 1, in the first pitch portion 48, the first coil portion 41a may have the same pitch as the wire diameter of the wire rod 42a. Such a coil is generally referred to as a closely wound coil. In a closely wound coil, there is no gap between two adjacent wire rods 42a, and it is preferable because light is less likely to leak from the first coil portion 41a.

[0097] When the wire diameter of the wire rod 42a changes in the longitudinal axis direction (for example, when there is a thick diameter portion and a thin diameter portion having a smaller wire diameter than the thick diameter portion), in the first pitch portion 48, the cylindrical member 40 may have a pitch smaller than the wire diameter of the wire rod 42a.

[0098] In the first pitch portion 48, the first coil portion 41a may have a pitch of 1.1 times or more the wire diameter of the wire rod 42a, and may have a pitch of 1.2 times or more. Also, in the first pitch portion 48, the first coil portion 41a may have a pitch of 1.9 times or less the wire diameter of the wire rod 42a, and may have a pitch of 1.8 times or less. By setting the pitch in this way, it is possible to suppress light leakage from the first coil portion 41a, which is preferable.

[0099] The first pitch portion 48 may constitute only a part of the axial direction of the first coil portion 41a. Also, as shown in FIG. 1, the first pitch portion 48 may constitute the entire axial direction of the first coil portion 41a.

[0100] It is preferable that the first coil portion 41a constitutes only a part of the axial direction of the cylindrical member 40. For example, when the cylindrical member 40 has a body portion having a shape extending in the circumferential direction of the shaft 10 and a bottom portion located more distally than the body portion, it is preferable that the body portion is the first coil portion 41a.

[0101] As shown in FIG. 7, it is preferable that the cylindrical member 40 has a second coil portion 41b in which a wire 42b is wound in a spiral shape so as to go around the light diffusing portion 21 in the inner cavity of the first coil portion 41a. Due to the presence of the second coil portion 41b, the inner cavity of the first coil portion 41a can be narrowed. As a result, the position of the cylindrical member 40 with respect to the optical fiber 20 becomes less likely to shift, and the position of the distal end of the exposed portion 22 is fixed, so that the irradiation position can be stabilized. In the embodiment of FIG. 7, it can also be said that the second coil portion 41b functions as a spacer.

[0102] As shown in FIG. 7, it is preferable that the wire diameter of the wire 42a of the first coil portion 41a is larger than the wire diameter of the wire 42b of the second coil portion 41b. By setting the thickness of the wire in this way, the second coil portion 41b becomes less likely to shift in the longitudinal axis direction x with respect to the first coil portion 41a, so that the position of the distal end of the exposed portion 22 can be fixed.

[0103] It is preferable that the inner peripheral surface of the second coil portion 41b is in contact with the light diffusing portion 21, and the inner peripheral surface of the first coil portion 41a is in contact with the outer peripheral surface of the second coil portion 41b. By arranging the first coil portion 41a and the second coil portion 41b in this way, the position of the cylindrical member 40 with respect to the optical fiber 20 becomes less likely to shift, and the position of the distal end of the exposed portion 22 is easily fixed.

[0104] As shown in FIG. 7, the first coil portion 41a may have a shape in which its distal end side is closed and its proximal end side is open, and the second coil portion 41b may have a shape in which both its distal end side and proximal end side are open.

[0105] Although not shown, the first coil portion 41a has a shape in which the distal end side and the proximal end side are each open, and the second coil portion 41b may have a shape in which its distal end side is closed and its proximal end side is open. In that case, the inner end face on the distal end side of the second coil portion 41b will contact the distal end face of the light diffusing portion 21.

[0106] The shape of the cross section perpendicular to the longitudinal axis direction of the wire 42a of the first coil portion 41a and the shape of the cross section perpendicular to the longitudinal axis direction of the wire 42b of the second coil portion 41b may be similar to each other or different from each other. FIG. 7 shows an example in which the shapes of the cross sections perpendicular to the longitudinal axis directions of the wires 42a and 42b are both circular.

[0107] As shown in FIGS. 1 to 2, the coil member 50 is disposed closer to the proximal side than the cylindrical member 40 in the inner cavity 11 of the shaft 10, and the wire 52 is wound in a spiral so as to surround the optical fiber 20. By covering the optical fiber 20 with the coil member 50 in this way, the torque on the proximal side is more likely to be transmitted to the distal side, and the operability of the device 1 can be improved. Since the coil member 50 is movable in the longitudinal axis direction x with respect to the optical fiber 20, it is possible to adjust the length of the exposed portion 22 in the longitudinal axis direction x according to the shape of the target tissue. For example, in the aspect of FIG. 3 compared to FIG. 2, the distal end of the coil member 50 is located on the distal side, so the length of the exposed portion 22 is shorter. By changing the position of the coil member 50 with respect to the light diffusing portion 21 in this way, the length of the exposed portion 22 in the longitudinal axis direction x can be adjusted. Furthermore, since the maximum outer diameter of the cylindrical member 40 is larger than the maximum outer diameter of the coil member 50, the movement operation of the coil member 50 with respect to the optical fiber 20 becomes easier.

[0108] The coil member 50 is formed to extend in the longitudinal axis direction x of the shaft 10. Among the coil member 50, the direction parallel to the longitudinal axis direction x of the shaft 10 is referred to as the axial direction of the coil member 50. As shown in FIG. 2, the coil member 50 has an inner peripheral surface 53 and an outer peripheral surface 54. The inner peripheral surface 53 extends in the circumferential direction p of the shaft 10 and faces the outer peripheral surface 23 side of the optical fiber 20. The outer peripheral surface 54 extends in the circumferential direction p of the shaft 10 and faces the inner peripheral surface 12 side of the shaft 10.

[0109] As shown in FIG. 1, it is preferable that the coil member 50 has a shape in which the distal end 501 side and the proximal end 502 side are each open. Thereby, the movement operation of the coil member 50 in the longitudinal axis direction x becomes easier.

[0110] In FIG. 1, the proximal portion of the coil member 50 is connected to the operation portion 65. When the operation portion 65 is moved distally with respect to the handle 60 from the state of FIG. 2, the coil member 50 is moved so that the distal end 501 of the coil member 50 approaches the proximal end 402 of the cylindrical member 40 as shown in FIG. 3. As a result, the length of the exposed portion 22 in the longitudinal axis direction x can be made shorter than that in the state of FIG. 2. Further, when the operation portion 65 is moved proximally with respect to the handle 60 from the state of FIG. 3, the coil member 50 is moved so that the distal end 501 of the coil member 50 moves away from the proximal end 402 of the cylindrical member 40 as shown in FIG. 2. As a result, the length of the exposed portion 22 in the longitudinal axis direction x can be made longer than that in the state of FIG. 3.

[0111] In FIG. 1, an example is given of a mode in which the coil member 50 is moved in the longitudinal axis direction x with respect to the optical fiber 20 by sliding the operation portion 65 with respect to the handle 60, but the mode is not limited to this. For example, the coil member may be moved in the longitudinal axis direction x with respect to the optical fiber by rotating the operation portion 65 with respect to the handle 60. For example, the handle 60 and the operation portion 65 may have a rack and pinion mechanism.

[0112] The coil member 50 may be directly fixed to the operation portion 65, or may be indirectly fixed via another member. The fixing method of the coil member 50 and the operation portion 65 is not particularly limited, and examples thereof include methods such as welding, soldering, caulking such as crimping, adhesion by an adhesive, physical fixing such as engagement, connection, binding, ligation, etc., or combinations thereof. FIG. 1 shows an example in which the proximal portion of the coil member 50 is directly fixed to the operation portion 65.

[0113] The operation portion 65 only needs to include a portion that the operator grips, pinches, or hooks a finger, etc., and its shape is not particularly limited.

[0114] The constituent material of the operation portion 65 is not particularly limited, and for example, polyolefin resins such as polypropylene (PP) and polyethylene (PE), polyester resins such as polyethylene terephthalate (PET), polycarbonate resin, ABS resin, synthetic resins such as polyurethane resin can be used.

[0115] In order to make the coil member 50 movable in the longitudinal axis direction x with respect to the optical fiber 20, the coil member 50 is not fixed to the optical fiber 20. Further, the outer peripheral surface of the optical fiber 20 is preferably arranged apart from the inner peripheral surface 53 of the coil member 50. In addition, when the device 1 is inserted in a curved shape in the body cavity, when the coil member 50 is moved distally or proximally with respect to the optical fiber 20, it is allowed that a part of the inner peripheral surface of the coil member 50 contacts the outer peripheral surface of the optical fiber 20.

[0116] As shown in FIG. 3, it is preferable that the coil member 50 is movable to a position more distal than the proximal end of the light diffusing portion 21. By setting the movement range of the coil member 50 in this way, the length of the exposed portion 22 in the longitudinal axis direction x can be adjusted according to the stop position of the distal end 501 of the coil member 50.

[0117] The coil member 50 is preferably movable to a position proximal to the midpoint 211 in the longitudinal axis direction of the light diffusing portion 21. With this configuration, the length of the exposed portion 22 in the longitudinal axis direction can be ensured. Note that the coil member 50 preferably does not move to a position distal to the midpoint 211 in the longitudinal axis direction of the light diffusing portion 21.

[0118] As shown in FIG. 3, when the coil member 50 is moved to the most distal position, it is preferable that the distal end 501 of the coil member 50 is located proximal to the proximal end 402 of the cylindrical member 40. By moving the coil member 50 in this way, the exposed portion 22 can be adjusted to be the shortest. When the coil member 50 is moved to the most distal position, it is preferable that the coil member 50 covers a part of the light diffusing portion 21. With this configuration, the leakage of light from the proximal end portion of the light diffusing portion 21 can be blocked by the coil member 50.

[0119] When the coil member 50 is moved to the most distal position, it is preferable that the distal end 501 of the coil member 50 is located proximal to the midpoint 211 in the longitudinal axis direction of the light diffusing portion 21. With this configuration, the length of the exposed portion 22 in the longitudinal axis direction can be ensured. That is, it is preferable that the distal end of the coil member 50 does not move to a position distal to the midpoint 211 in the longitudinal axis direction of the light diffusing portion 21.

[0120] As shown in FIG. 2, when the coil member 50 is moved to the most proximal position, it is preferable that the distal end 501 of the coil member 50 is located proximal to the proximal end of the light diffusing portion 21. By defining the movement range of the coil member 50 in this way, the exposed portion 22 can be adjusted to be the longest. Also, by positioning the distal end 501 of the coil member 50 proximal to the proximal end of the light diffusing portion 21, the amount of light from the light diffusing portion 21 irradiated onto the inner surface of the coil member 50 can be reduced, and heat generation can be prevented. This is particularly beneficial when an increase in the irradiation time or the number of irradiations is required.

[0121] It is preferable that the distal end 501 of the coil member 50 is movable from a position proximal to the proximal end of the light diffusing portion 21 to a position distal to the proximal end of the light diffusing portion 21. By positioning the distal end 501 distal to the proximal end of the light diffusing portion 21, the length of the exposed portion 22 can be adjusted, and by positioning the distal end 501 proximal to the proximal end of the light diffusing portion 21, heat generation can be prevented. By configuring the coil member 50 to be movable within the above range, the position relationship between the distal end 501 of the coil member 50 and the proximal end of the light diffusing portion 21 in the longitudinal axis direction x, that is, the arrangement of the coil member 50, can be changed according to the desired purpose.

[0122] When the coil member 50 is moved to the most proximal side, the distal end 501 of the coil member 50 may be located distal to the proximal end of the light diffusing portion 21. By defining the movement range of the coil member 50 in this way, even when the exposed portion 22 is the shortest, the light leakage from the proximal end portion of the light diffusing portion 21 can be blocked by the coil member 50.

[0123] As shown in FIG. 7, it is preferable that the minimum inner diameter of the coil member 50 is larger than the minimum inner diameter of the cylindrical member 40. When the coil member 50 is slid, the inner peripheral surface of the coil member 50 is less likely to contact the outer peripheral surface of the optical fiber 20, so that the movement operation of the coil member 50 becomes easier.

[0124] It is preferable that a part of the light diffusing portion 21 is not covered by the cylindrical member 40 and the coil member 50 regardless of the position of the coil member 50 in the longitudinal axis direction x. That is, it is preferable that the proximal end 402 of the cylindrical member 40 and the distal end 501 of the coil member 50 are arranged apart from each other in the longitudinal axis direction x. By arranging the cylindrical member 40 and the coil member 50 in this way, the exposed portion 22 is formed, and thus it becomes possible to emit light outward in the radial direction from the exposed portion 22.

[0125] When the coil member 50 overlaps so as to cover a part of the light diffusing portion 21 in the longitudinal axis direction x, the light emitted from the light diffusing portion 21 is preferably reflected by the inner peripheral surface of the portion of the coil member 50 that covers the light diffusing portion 21. The reflected light is likely to be diffused in various directions from the exposed portion 22 of the light diffusing portion 21 that is not covered by the coil member 50.

[0126] The inner peripheral surface 53 of the coil member 50 may be composed of only a curved surface portion, may be composed of only a flat surface portion, or may be composed of a combination of a curved surface portion and a flat surface portion. In order to easily diffuse the light reflected by the inner peripheral surface 53 in multiple directions, it is preferable that the inner peripheral surface 53 has a curved surface portion.

[0127] In order to enhance the effect of reflecting light by the inner surface of the coil member 50, it is preferable that the light emitted from the light diffusing portion 21 does not pass through the coil member 50 toward the outside in the radial direction of the shaft 10.

[0128] As shown in FIG. 1, in the longitudinal axis direction x, it is preferable that the coil member 50 is longer than the cylindrical member 40. Since the coil member 50 can cover a wide range in the longitudinal axis direction x of the optical fiber, the torque transmission performance can be enhanced.

[0129] The portion of the coil member 50 that covers the light diffusing portion 21 is preferably composed of a material having a higher reflectivity than the shaft 10. With this configuration, the reflected light is likely to be diffused on the inner surface of the coil member 50. Here, the reflectivity refers to the reflectivity of the light emitted from the light diffusing portion 21, and the unit is %. The reflectivity of the coil member 50 can be measured in the same manner as the cylindrical member 40.

[0130] The coil member 50 is preferably composed of a metal. For example, it may be a radiation-impermeable metal such as gold, silver, platinum, palladium, tungsten, tantalum, iridium, and their alloys, or a superelastic alloy such as stainless steel or Ni-Ti alloy.

[0131] A part of the coil member 50 may be made of resin. The coil member 50 may have a coil member body and a reflective layer disposed on the inner surface of the coil member body. Regardless of the material of the coil member body, the reflective layer can reflect the light from the light diffusing portion 21. For example, a coil body wound with a resin wire or a resin tube may be the coil member body. The reflective layer may be disposed by applying a coating agent containing a reflective material on the inner surface of the coil member body, or may be disposed by attaching the reflective material to the inner surface of the coil member body by methods such as vapor deposition, sputtering, electroplating, and chemical plating. Note that the reflective layer may be a metal thin film. As the reflective material, those mentioned in the description of the cylindrical member 40 can be used. When the coil member 50 has a reflective layer, at least one of the materials mentioned as the constituent materials of the shaft 10 can be used for the coil member body.

[0132] The wire 52 constituting the coil member 50 has a tip and a base end in the longitudinal axis direction thereof. The wire 52 may be composed of a single linear member from the tip to the base end, or the wire 52 may be composed of a plurality of linear members connected to each other in the longitudinal axis direction thereof.

[0133] The shape of the cross section perpendicular to the longitudinal axis direction of the wire 52 may be circular, oval, polygonal, or a combination thereof. The oval shape shall include an elliptical shape, an egg shape, and a rounded rectangular shape. The same shall apply in other descriptions of this specification.

[0134] The shape of the cross section perpendicular to the longitudinal axis direction of the wire 52 is preferably circular or oval. With such a cross-sectional shape, similar to the cylindrical member 40, in the cross section along the longitudinal axis direction x of the shaft 10, a plurality of convex portions are arranged in the longitudinal axis direction x on the inner peripheral surface 53 of the coil member 50, and a concave portion is arranged between two convex portions. Due to the convex and concave portions of the inner peripheral surface 53, the reflected light is likely to be diffused in multiple directions on the proximal side of the light diffusing portion 21.

[0135] The wire diameter (thickness) of the wire 52 that constitutes the coil member 50 and the number of turns of the wire 52 are not particularly limited. The axial length of the coil member 50 may be larger or smaller than the maximum outer diameter of the coil member 50.

[0136] The pitch P of the coil member 50 2 is not particularly limited and may be constant in the axial direction or may vary depending on the axial position. The pitch P 2 is, as shown in FIG. 1, the distance between the central axes of two adjacent wires 52 that form the coil member 50 in the axial direction.

[0137] A gap may be formed between adjacent wires 52 of the coil member 50 in the axial direction. However, in order to facilitate the transmission of the proximal torque to the distal side, as shown in FIG. 1, it is preferable that the coil member 50 has a second pitch portion 58 having a pitch of 2 times or less the wire diameter of the wire 52. In the second pitch portion 58, the coil member 50 may have the same pitch as the wire diameter of the wire 52. That is, there may be no gap between two adjacent wires 52. When the wire diameter of the wire 52 changes in the longitudinal axis direction (for example, when there is a thick diameter portion and a thin diameter portion with a smaller wire diameter than the thick diameter portion), in the second pitch portion 58, the coil member 50 may have a pitch smaller than the wire diameter of the wire 52.

[0138] In the second pitch portion 58, the coil member 50 may have a pitch of 1.1 times or more the wire diameter of the wire 52, and may have a pitch of 1.2 times or more. Also, in the second pitch portion 58, the coil member 50 may have a pitch of 1.9 times or less the wire diameter of the wire 52, and may have a pitch of 1.8 times or less. By setting the pitch in this way, the proximal torque can be easily transmitted to the distal side, and light leakage from the coil member 50 can also be suppressed.

[0139] The second pitch portion 58 may constitute only a part of the axial direction of the coil member 50. Also, as shown in FIG. 1, the second pitch portion 58 may constitute the entire axial direction of the coil member 50.

[0140] The coil member 50 may be a single-layer wound coil, a multi-layer wound coil, or a combination thereof. For example, FIG. 1 shows an example in which the coil member 50 is a single-layer wound coil. By configuring in this way, when the coil member 50 covers a part of the proximal portion of the light diffusing portion 21, the reflected light is likely to be diffused in multiple directions on the inner peripheral surface 53 of the coil member 50.

[0141] As shown in FIGS. 1 to 2, it is preferable that the first coil portion 41a of the cylindrical member 40 is wound in a single layer, and the coil member 50 is also wound in a single layer over the entire longitudinal axis direction x. This is preferable in terms of manufacturing because it facilitates the formation of the cylindrical member 40 and the coil member 50. Also, on the inner peripheral surface 43 of the cylindrical member 40, the reflected light is likely to be diffused in multiple directions. Further, when the coil member 50 covers a part of the light diffusing portion 21, the reflected light is also likely to be diffused in multiple directions on the inner peripheral surface 53 of the coil member 50.

[0142] As shown in FIG. 6, the first coil portion 41a of the cylindrical member 40 may be wound in a single layer, and the coil member 50 may have a third coil portion 51a wound in multiple layers. Due to the single-layer wound first coil portion 41a, the reflected light is likely to be diffused in multiple directions on the inner peripheral surface of the cylindrical member 40. Also, due to the multi-layer wound third coil portion 51a, the proximal torque is likely to be transmitted to the distal side, and the operability of the device 1 can be improved.

[0143] The first coil portion 41a is preferably composed of a radiation-impermeable material. Since the first coil portion 41a can be used as a radiation-impermeable marker, it becomes easier for the operator to grasp the position on the distal side of the light diffusing portion 21. Since the third coil portion 51a is preferably arranged to extend over a wide range in the axial direction, configuring it from a radiation-impermeable material rather makes it difficult to grasp the position of the light diffusing portion 21. For this reason, the third coil portion 51a is preferably composed of a material that allows radiation to pass through more easily than the first coil portion 41a.

[0144] The first coil portion 41a is preferably made of, for example, gold, silver, platinum, palladium, tungsten, tantalum, iridium, or an alloy thereof. The third coil portion 51a is preferably made of a metal such as stainless steel, carbon steel, or a nickel-titanium alloy.

[0145] In FIG. 6, the coil member 50 has a third coil portion 51a wound in multiple layers and a fourth coil portion 51b located on the distal side of the third coil portion 51a and wound in a single layer. In this configuration, when the coil member 50 is moved to the most distal side, it is preferable that the fourth coil portion 51b covers a part of the light diffusing portion 21. In the third coil portion 51a, the wire 52b is wound around the optical fiber 20 in a helical shape with three layers. In the fourth coil portion 51b, the wire 52a is wound around the optical fiber 20 in a helical shape with one layer. By providing the third coil portion 51a in this way, the torque on the proximal side is more likely to be transmitted to the distal side, and the operability of the device 1 can be improved. In addition, by providing the fourth coil portion 51b, a function different from that of the third coil portion 51a can be imparted to the fourth coil portion 51b. For example, the fourth coil portion 51b can be used as a radiation-impermeable marker. Alternatively, when the fourth coil portion 51b covers a part of the light diffusing portion 21, the reflected light is likely to be diffused in multiple directions by the inner peripheral surface 53 of the coil member 50.

[0146] In the longitudinal axis direction x, the third coil portion 51a is preferably longer than the fourth coil portion 51b. With this configuration, the torque on the proximal side is more likely to be transmitted to the distal side, and the operability of the device 1 can be improved.

[0147] Although not shown, in the coil member 50, the third coil portion 51a wound in multiple layers may be located on the distal side of the fourth coil portion 51b wound in a single layer.

[0148] As shown in FIG. 6, it is preferable that the fourth coil portion 51b covers a part of the light diffusing portion 21 and the third coil portion 51a is located closer to the proximal side than the light diffusing portion 21. Specifically, it is preferable that the distal end of the fourth coil portion 51b is located more distally than the proximal end of the light diffusing portion 21, and the proximal end of the fourth coil portion 51b is located more proximally than the proximal end of the light diffusing portion 21. With this configuration, it becomes easier to impart both functions of reflection of light from the light diffusing portion 21 and good transmission of torque to the fourth coil portion 51b.

[0149] The fourth coil portion 51b is preferably made of a radiation-impermeable material through which radiation is less likely to pass than the third coil portion 51a. Thereby, since the fourth coil portion 51b can be used as a radiation-impermeable marker, it becomes easier for the operator to grasp the position on the proximal side of the light diffusing portion 21.

[0150] The fourth coil portion 51b is preferably composed of, for example, gold, silver, platinum, palladium, tungsten, tantalum, iridium, or an alloy thereof. The fourth coil portion 51b may be made of the same material as the third coil portion 51a, but is preferably made of a different material. Each layer of the third coil portion 51a may be made of different materials, but is preferably made of the same material. The fourth coil portion 51b may be made of a different material from the first coil portion 41a, but is preferably made of the same material.

[0151] The cylindrical member 40 is preferably fixed to the light diffusing portion 21. As shown in FIG. 2, it is more preferable that the cylindrical member 40 is fixed to the outer peripheral surface 23 of the light diffusing portion 21. Further, as can be understood from FIGS. 2 and 5, it is even more preferable that the inner peripheral surface 43 of the cylindrical member 40 is fixed to the outer peripheral surface 23 of the light diffusing portion 21. Since the position of the proximal end 402 of the cylindrical member 40 in the longitudinal axis direction x is fixed so as not to shift with respect to the light diffusing portion 21 even when the device 1 is inserted into the body, the irradiation position can be stabilized. Even when the cylindrical member 40 is fixed to the outer peripheral surface 23 of the light diffusing portion 21, it is preferable that the cylindrical member 40 also bends following the bending of the device 1.

[0152] The fixation of the cylindrical member 40 and the light diffusing portion 21 includes methods such as adhering the cylindrical member 40 and the light diffusing portion 21, and caulking the cylindrical member 40 to fix the cylindrical member 40 to the light diffusing portion 21.

[0153] When fixing the cylindrical member 40 to the light diffusing portion 21, it is preferable that the cylindrical member 40 is in contact with the outer peripheral surface 23 of the light diffusing portion 21, and it is more preferable that the inner peripheral surface 43 of the cylindrical member 40 is in contact with the outer peripheral surface 23 of the light diffusing portion 21. This can prevent an increase in the profile of the optical fiber 20 to which the cylindrical member 40 is attached and make it easier for light to be reflected by the cylindrical member 40.

[0154] When the light diffusing portion 21 is arranged at the farthest position of the optical fiber 20, as shown in FIG. 2, the light diffusing portion 21 has a distal end face 212. In that case, it is preferable that the distal end face 212 of the light diffusing portion 21 is not fixed to the cylindrical member 40. By making the distal end face 212 non-fixed in this way, even when the device 1 passes through a bent portion in the body, the distal end side of the cylindrical member 40 does not protrude and can easily follow the bending of the shaft 10. As a result, the risk of damage to the optical fiber 20 can be reduced, and the light emission intensity distribution of the exposed portion 22 in the circumferential direction p of the shaft 10 is also likely to be uniformized. Note that the distal end face 212 of the light diffusing portion 21 only needs to be fixed so as not to move relative to the cylindrical member 40, and it is acceptable for the distal end face 212 of the light diffusing portion 21 to be in contact with the cylindrical member 40 as shown in FIG. 2.

[0155] The distal end face 212 of the light diffusing portion 21 preferably has a planar shape perpendicular to the longitudinal axis direction of the optical fiber 20 as shown in FIG. 2, but it may also have a planar shape inclined with respect to the longitudinal axis direction of the optical fiber 20, or may have a curved surface shape.

[0156] As shown in FIG. 2, it is preferable that the outer peripheral surface 44 of the cylindrical member 40 is in contact with the inner peripheral surface 12 of the shaft 10. Thereby, the position of the cylindrical member 40 with respect to the shaft 10 is less likely to shift and the position of the exposed portion 22 is fixed, so that the irradiation position can be stabilized. Note that the cylindrical member 40 only needs to be inserted into the inner cavity 11 of the shaft 10, and the outer peripheral surface 44 of the cylindrical member 40 does not have to be fixed to the inner peripheral surface 12 of the shaft 10.

[0157] When the cylindrical member 40 covers a part of the second section 32, the cylindrical member 40 may be in contact with the outer peripheral surface of the second cladding 27 of the second section 32. Further, when the cylindrical member 40 covers at least a part of the third section 33, the cylindrical member 40 may be in contact with the outer peripheral surface of the core 25 of the third section 33.

[0158] As shown in FIG. 2, it is preferable that the outer peripheral surface 54 of the coil member 50 is arranged away from the inner peripheral surface 12 of the shaft 10. With this configuration, the movement operation of the coil member 50 with respect to the optical fiber 20 becomes easier. Note that when the coil member 50 is moved distally or proximally with respect to the optical fiber 20 in a state where the device 1 is inserted into the curved shape in the body cavity, it is allowed that a part of the outer peripheral surface 54 of the coil member 50 temporarily contacts the inner peripheral surface 12 of the shaft 10.

[0159] As shown in FIG. 2, it is preferable that the outer peripheral surface 23 of the light diffusing portion 21 is arranged away from the inner peripheral surface 12 of the shaft 10. In the exposed portion 22, it is more preferable that the outer peripheral surface 23 of the light diffusing portion 21 is arranged away from the inner peripheral surface 12 of the shaft 10. Further, it is even more preferable that the outer peripheral surface 23 of the light diffusing portion 21 is arranged away from the inner peripheral surface 12 of the shaft 10 over the entire longitudinal axis direction x. By arranging the light diffusing portion 21 in the inner cavity 11 of the shaft 10 in this way, the flexibility of the shaft 10 at the light diffusing portion 21 can be maintained.

[0160] Preferably, the outer peripheral surface 23 of the light diffusing portion 21 is arranged apart from the inner peripheral surface 12 of the shaft 10 over the entire circumferential direction p of the shaft 10. Further, it is preferable that the distance between the outer peripheral surface 23 of the light diffusing portion 21 and the inner peripheral surface 12 of the shaft 10 in the radial direction of the shaft 10 is uniform at any position in the circumferential direction p of the shaft 10. Thereby, the light emission intensity distribution of the exposed portion 22 is likely to be made uniform in the circumferential direction p.

Explanation of Signs

[0161] 1: Light irradiation medical device 10: Shaft 20: Optical fiber 21: Light diffusing portion 22: Exposed portion 25: Core 26: First cladding 27: Second cladding 31: First section 32: Second section 33: Third section 40: Cylindrical member 50: Coil member x: Longitudinal axis direction p: Circumferential direction

Claims

1. A shaft having a distal end and a proximal end in the longitudinal axis direction and having a lumen extending in the longitudinal axis direction, An optical fiber disposed in the lumen of the shaft, A cylindrical member disposed in the lumen of the shaft and covering a part of the distal portion of the optical fiber, A coil member disposed proximal to the cylindrical member in the lumen of the shaft and having a wire wound in a helical shape so as to surround the optical fiber, The optical fiber has a light diffusing portion that extends in the longitudinal axis direction in a predetermined section of its distal portion and emits light outward in the radial direction of the shaft, The cylindrical member covers a part of the light diffusing portion, The light diffusing portion has an exposed portion not covered by the cylindrical member, The coil member is movable in the longitudinal axis direction with respect to the optical fiber, The maximum outer diameter of the cylindrical member is larger than the maximum outer diameter of the coil member, The light emitted from the light diffusing portion is reflected by the inner peripheral surface of the cylindrical member, and the reflected light is diffused from the exposed portion, a light irradiation medical device.

2. The light irradiation medical device according to claim 1, wherein the coil member is movable to a position distal to the proximal end of the light diffusing portion.

3. The light irradiation medical device according to claim 1 or 2, wherein when the coil member is moved to the most distal side, the distal end of the coil member is located proximal to the proximal end of the cylindrical member.

4. The light irradiation medical device according to any one of claims 1 to 3, wherein when the coil member is moved to the most proximal side, the distal end of the coil member is located proximal to the proximal end of the light diffusing portion.

5. The light irradiation medical device according to any one of claims 1 to 4, wherein the minimum inner diameter of the coil member is larger than the minimum inner diameter of the cylindrical member.

6. The light irradiation medical device according to any one of claims 1 to 5, wherein in the longitudinal axis direction, the coil member is longer than the cylindrical member.

7. The light irradiation medical device according to any one of claims 1 to 6, wherein the coil member has a second pitch portion having a pitch of 2 times or less the wire diameter of the wire.

8. The light irradiation medical device according to any one of claims 1 to 7, wherein the cylindrical member has a first coil portion in which a wire is wound in a helical shape so as to surround the light diffusing portion.

9. The light irradiation medical device according to claim 8, wherein the cylindrical member has a second coil portion in which a wire is wound in a spiral shape so as to surround the light diffusion portion in the inner cavity of the first coil portion.

10. The light irradiation medical device according to claim 9, wherein the wire diameter of the wire of the first coil portion is larger than the wire diameter of the wire of the second coil portion.

11. The optical fiber has a core extending in the longitudinal axis direction, The optical fiber has a first section having a first cladding disposed on the outer periphery of the core, The optical fiber has a second section having a second cladding disposed on the outer periphery of the core and having a larger surface roughness of the outer peripheral surface than the first cladding in the light diffusion portion and located on the distal side of the first section. The light irradiation medical device according to any one of claims 1 to 10.

12. The optical fiber has a core extending in the longitudinal axis direction, The optical fiber has a first section having a first cladding disposed on the outer periphery of the core, The optical fiber has a third section in which the cladding does not exist in the light diffusion portion and is located on the distal side of the first section. The light irradiation medical device according to any one of claims 1 to 10.

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