Light irradiation device

Abstract

This light irradiation device comprises: a tubular member that has a longitudinal axis and an internal insertion path onto which a light irradiation body that includes a light irradiation part can be inserted; and a balloon that covers the outside in the radial direction of the tubular member and can expand and contract in the radial direction. The balloon comprises: a light transmission window part that, in an expanded state, can transmit light irradiated from the light irradiation part as inserted onto the insertion path and transmitted by the tubular member in the radial direction; and a light-blocking part that is provided in a region outside the light transmission window part and has a lower transmittance with respect to light from the light irradiation part than the light transmission window part. The tubular member comprises a diffuse transmission part that can diffusely transmit light from the light irradiation part closer to the distal side than a distal end of the light transmission window part in a longitudinal axis direction that runs along the longitudinal axis and closer to the proximal side than a distal end of the balloon in the longitudinal axis direction.

Description

Light irradiation device

[0001] The present disclosure relates to a light illumination device.

[0002] Conventionally, light irradiation devices used to irradiate abnormal tissue with therapeutic light have been known. Patent Document 1 discloses such a light irradiation device. The light irradiation device of Patent Document 1 is an apparatus including a balloon catheter having a defined treatment window, and includes a central channel, an outer sleeve, and an optical fiber cable.

[0003] Japanese Patent Application Laid-Open No. 2005-46640

[0004] In a treatment using the light irradiation device of Patent Document 1, it is conceivable to insert an optical fiber cable including a light irradiation unit into a central channel, and then insert the light irradiation device into a living body with the light irradiation unit positioned appropriately relative to a treatment window serving as a light-transmitting window. However, with the light irradiation device of Patent Document 1, the position of the light irradiation unit may shift during treatment. Furthermore, with the light irradiation device of Patent Document 1, it is difficult to confirm whether the position of the light irradiation unit has shifted while the light irradiation device is inserted into a living body. Performing treatment with the light irradiation unit shifted from the appropriate position is undesirable, as it may affect the therapeutic effect.

[0005] An object of the present disclosure is to provide a light irradiation device that can check whether a light irradiation unit is in an appropriate position relative to a light-transmitting window unit even when the light irradiation device is inserted into a living body.

[0006] A light irradiation device according to a first aspect of the present disclosure is a light irradiation device comprising: (1) a tubular member having a longitudinal axis, defining an insertion path therein into which a light irradiator including a light irradiation unit can be inserted; and a balloon covering the radial outside of the tubular member and capable of expanding and contracting in the radial direction, wherein the balloon comprises: a light-transmitting window portion in an expanded state, which is irradiated from the light irradiation unit inserted into the insertion path and is capable of transmitting light that has passed through the tubular member in the radial direction; and a light-shielding portion provided in an area other than the light-transmitting window portion and has a transmittance of light from the light irradiation unit lower than that of the light-transmitting window portion; and wherein the tubular member comprises a diffusively transmitting portion, which is located distal to a distal end of the light-transmitting window portion in the longitudinal axis direction along the longitudinal axis and proximal to the distal end of the balloon in the longitudinal axis direction, and which is capable of diffusively transmitting light from the light irradiation unit.

[0007] A light irradiation device according to one embodiment of the present disclosure is (2) the light irradiation device according to (1) above, in which the diffuse transmission portion is a rough surface portion provided on the outer surface of the tubular member.

[0008] A light irradiation device according to one embodiment of the present disclosure is (3) the light irradiation device according to (1) or (2) above, in which, when the diffusive transmission portion is a first diffusive transmission portion, the tubular member is provided with a second diffusive transmission portion that is arranged proximal to the proximal end of the light transmission window portion in the longitudinal axis direction and that diffuses and transmits light from the light irradiation portion.

[0009] A light irradiation device according to one embodiment of the present disclosure is (4) the light irradiation device according to (3) above, wherein the tubular member is provided with a third diffuse transmission portion that is disposed proximal to a proximal end of the second diffuse transmission portion in the longitudinal axis direction and that diffuses and transmits light from the light irradiation portion.

[0010] A light irradiation device according to one embodiment of the present disclosure is (5) the light irradiation device according to any one of (1) to (4) above, wherein the tubular member is provided with a positioning portion that restricts the light irradiation portion from moving distally in the longitudinal axis direction beyond a predetermined position.

[0011] A light irradiation device according to one embodiment of the present disclosure is (6) the light irradiation device described in (5) above, in which the predetermined position is located distal to the distal end of the diffusively transmitting portion in the longitudinal axis direction and proximal to the distal end of the balloon in the longitudinal axis direction.

[0012] A light irradiation device according to one embodiment of the present disclosure is (7) the light irradiation device according to any one of (1) to (6) above, wherein the balloon, in an expanded state, has a viewing window portion that is disposed proximal to and spaced apart from the light-transmitting window portion in the longitudinal axis direction and that is capable of transmitting light diffused by the diffusing and transmitting portion.

[0013] An embodiment of the light irradiation device of the present disclosure is (8) the light irradiation device described above in (7), wherein the balloon, in an expanded state, comprises a substantially cylindrical central portion and a proximal tapered portion that is connected to the central portion on the proximal side in the longitudinal axis direction and that taperes toward the tubular member as it moves toward the proximal side in the longitudinal axis direction, the light-transmitting window portion is disposed in the central portion, and the viewing window portion is disposed in the proximal tapered portion.

[0014] According to the present disclosure, it is possible to provide a light irradiation device that can check whether the light irradiation section is in an appropriate position relative to the light-transmitting window section even when the light irradiation device is inserted into a living body.

[0015] FIG. 5 is a diagram showing an example of an endoscopic system including a light irradiation device according to an embodiment of the present disclosure. FIG. 6 is a diagram showing the vicinity of a balloon of the endoscopic system shown in FIG. 1. FIG. 7 is a diagram showing a state in which the light irradiation unit has been moved to the distal side in the longitudinal axis direction from the state of FIG. 2A. FIG. 8 is a diagram showing an example of observation of a tubular member in the state shown in FIG. 2A. FIG. 9 is a diagram showing an example of observation of a tubular member in the state shown in FIG. 2B. FIG. 10 is a diagram showing the vicinity of a balloon of an endoscopic system including a light irradiation device according to an embodiment of the present disclosure. FIG. 11 is a diagram showing a state in which the light irradiation unit has been moved to the distal side in the longitudinal axis direction from the state shown in FIG. 5A. FIG. 12 is a diagram showing the vicinity of a balloon of an endoscopic system including a light irradiation device according to an embodiment of the present disclosure.

[0016] Hereinafter, embodiments of the light irradiation device according to the present disclosure will be described with reference to the drawings, in which the same components are designated by the same reference numerals.

[0017] First Embodiment FIG. 1 is a diagram illustrating an example of an endoscopic system 100 including a light irradiation device 1 as an embodiment of a light irradiation device according to the present disclosure. The endoscopic system 100 illustrated in FIG. 1 includes an endoscopic apparatus 101, a control device 102 connected to the endoscopic apparatus 101, a display unit 103 such as a monitor connected to the control device 102, a light source apparatus 104, a fluid supply tool 105, and a light irradiation device 1. The endoscopic apparatus 101 is defined with a treatment tool channel 101a through which the light irradiation device 1 serving as a treatment tool can be inserted (see FIG. 2A , etc.). As illustrated in FIG. 1, the light irradiation device 1 is inserted into the treatment tool channel 101a of the endoscopic apparatus 101 and delivered to a lesion in a cavity such as a biological lumen. The control device 102 includes a light source unit 102a that supplies illumination light to the endoscopic apparatus 101 and a processor unit 102b that performs various image processing on an image signal from the endoscopic apparatus 101 to convert it into a video signal. The control device 102 may also include an input unit such as a keyboard. The display unit 103 can display an image captured by the endoscope device 101 based on a video signal generated by the processor unit 102b of the control device 102. The fluid supply tool 105 can supply a fluid to a fluid storage space 30a of the balloon 30, which will be described later.

[0018] The light irradiation device 1 can be used for, for example, photodynamic therapy (PDT) treatment or photoimmunotherapy (PIT) treatment. The light irradiation device 1 can be inserted into a cavity such as a biological lumen. As shown in FIG. 1 , the light irradiation device 1 may be used together with an endoscope apparatus 101. The cavity into which the light irradiation device 1 can be inserted is not particularly limited. As shown in FIG. 2A and other figures, the light irradiation device 1 may be used to treat a lesion treatable with light of a specific wavelength, such as cancer of a hollow organ, through a treatment instrument channel 101a of an endoscope apparatus 101 inserted into a hollow organ such as the digestive tract (e.g., esophagus, stomach, small intestine, large intestine), urinary tract, or blood vessel.

[0019] 1, the light irradiation device 1 includes an insertion section 1a to be inserted into a living body and a handheld operation section 1b to be operated outside the living body. The insertion section 1a includes a tubular member 10 and a balloon 30.

[0020] The tubular member 10 has a longitudinal axis O. The light irradiation device 1 can be inserted into and removed from a living body along the longitudinal axis O of the tubular member 10. Hereinafter, for convenience of explanation, the direction along the longitudinal axis O will be referred to as the "longitudinal axis direction A." Furthermore, the side of the light irradiation device 1 in the longitudinal axis direction A where the insertion section 1a is located will be referred to as the "distal side" or the "distal side of the longitudinal axis direction A," and the side of the light irradiation device 1 in the longitudinal axis direction A where the handheld operation section 1b is located will be referred to as the "proximal side" or the "proximal side of the longitudinal axis direction A." Furthermore, the direction around the longitudinal axis O will be referred to as the "circumferential direction B." Furthermore, the radial direction of an imaginary circle centered on the longitudinal axis O will be referred to as the "radial direction C."

[0021] 2A and 2B are diagrams showing the vicinity of the balloon 30 of the endoscope system 100. More specifically, Fig. 2A and 2B are cross-sectional views showing the vicinity of the balloon 30 in a cross section parallel to the longitudinal axis direction A and passing through the longitudinal axis O of the tubular member 10.

[0022] As shown in FIGS. 2A and 2B , the tubular member 10 defines an insertion path 10a therein, into which a light irradiator 201 including a light irradiation unit 200 can be inserted. The light irradiation device 1 may have an outer tube 20 arranged to surround the outside of the tubular member 10 in the radial direction C. The tubular member 10 and the outer tube 20 are arranged concentrically. The tubular member 10 extends distally from the outer tube 20. The tubular member 10 extends proximally from the outer tube 20. In this configuration, a gap between the outer surface of the tubular member 10 and the inner surface of the outer tube 20 is defined as an expansion lumen 20a, which serves as a flow path for supplying or discharging a fluid to or from the fluid storage space 30a. The light irradiator 201 is separate from the light irradiation device 1. The light irradiator 201 may include a light irradiating unit 200 that irradiates light circumferentially outward in the radial direction C, and a light transmission member 202 that includes an optical fiber that transmits light from the light source device 104 (see FIG. 1 ) to the light irradiating unit 200, or a light emitting element such as an LED that emits light when energized, and an electric wire, etc. In the light irradiator 201 of this embodiment, the light irradiating unit 200 is attached to the distal end of the light transmission member 202. The light irradiating unit 200 of this embodiment can irradiate light over the entire area in the circumferential direction B. Furthermore, the light irradiating unit 200 of this embodiment is longer in the longitudinal axis direction A than a light-transmitting window portion 31, which will be described later.

[0023] The intensity and wavelength of the light irradiated from the light irradiating unit 200 may be appropriately selected depending on, for example, the type of drug used in combination, the condition and position of the lesion, etc. The light irradiated from the light irradiating unit 200 may be visible light such as near-infrared light with a wavelength of around 690 nm.

[0024] The insertion path 10a extends along the longitudinal axis direction A. The insertion path 10a of this embodiment is open on the proximal side and closed on the distal side. As long as the insertion path 10a is open on the proximal side, the distal side of the insertion path 10a does not have to be closed. Therefore, in the insertion path 10a of this embodiment, the light irradiator 201 can be inserted from the opening on the proximal side until it hits the closing wall 11 of the tubular member 10 that defines the distal end of the insertion path 10a.

[0025] The outer shape of the cross section perpendicular to the longitudinal axis direction A of the tubular member 10 is not particularly limited. The outer shape of the cross section perpendicular to the longitudinal axis direction A of the tubular member 10 may be, for example, a circular shape or an oval shape such as an ellipse. Furthermore, the outer shape of the cross section perpendicular to the longitudinal axis direction A of the insertion path 10a is not particularly limited. The outer shape of the cross section perpendicular to the longitudinal axis direction A of the insertion path 10a may be, for example, a circular shape or an oval shape such as an ellipse.

[0026] The tubular member 10 is configured to allow light from the light irradiation unit 200 inserted into the insertion path 10a to pass through in the radial direction C. The tubular member 10 may be formed, for example, from a transparent resin material that is a light-transmitting material that allows light from the light irradiation unit 200 to pass through. In other words, the tubular member 10 may be configured to allow light from the light irradiation unit 200 to pass outward in the radial direction C over the entire area in the circumferential direction B.

[0027] The tubular member 10 includes a diffuse transmission section 15 that can diffuse and transmit light from a light irradiation section 200 inserted into the insertion path 10a. This will be described in detail later.

[0028] The resin material used to form the tubular member 10 is not particularly limited, but examples thereof include polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymers; ethylene-vinyl acetate copolymers (EVA); polyvinyl chloride; polyvinylidene chloride; polystyrene; polyamide; polyamide elastomers; polyimides; polyamideimides; polycarbonates; poly-(4-methylpentene-1); ionomers; acrylic resins; polymethyl methacrylate; acrylonitrile-butadiene-styrene copolymers (ABS resins); acrylonitrile-styrene copolymers (AS resins); and butadiene-styrene copolymers. Examples of the resin material include various resin materials such as polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polycyclohexane terephthalate (PCT); polyethers; polyether ketones (PEK); polyether ether ketones (PEEK); polyetherimides; polyacetals (POM); polyphenylene oxides; modified polyphenylene oxides; polysulfones; polyether sulfones; polyphenylene sulfide; polyarylates; aromatic polyesters (liquid crystal polymers); polytetrafluoroethylene, polyvinylidene fluoride, and other fluorine-based resins. Blends containing two or more of these may also be used.

[0029] The balloon 30 covers the outside of the tubular member 10 in the radial direction C and is configured to be expandable and contractible in the radial direction C. The balloon 30 of this embodiment defines an annular fluid storage space 30a between itself and the outer surface of the tubular member 10. The balloon 30 of this embodiment can expand outward in the radial direction C by supplying fluid to the fluid storage space 30a. Furthermore, the balloon 30 of this embodiment can contract inward in the radial direction C by discharging fluid from the fluid storage space 30a. FIGS. 2A and 2B show the balloon 30 in an expanded state. The fluid supplied to the fluid storage space 30a may be a liquid such as saline, or a gas such as air. The balloon 30 of this embodiment has a central axis that substantially coincides with the longitudinal axis O of the tubular member 10 in an expanded state.

[0030] The balloon 30 of this embodiment spans the outer surface of the tubular member 10 and the outer surface of the outer tube 20 and is fixed to both the outer surface of the tubular member 10 and the outer surface of the outer tube 20. More specifically, the distal end of the balloon 30 of this embodiment is fixed by adhesive or the like to the outer surface of the portion of the tubular member 10 that protrudes distally beyond the outer tube 20. Furthermore, the proximal end of the balloon 30 of this embodiment is fixed by adhesive or the like to the outer surface of the distal end of the outer tube 20.

[0031] As shown in Figures 2A and 2B, the balloon 30 of this embodiment, in its expanded state, comprises a central portion 41, a proximal tapered portion 42, and a distal tapered portion 43. The central portion 41 is generally cylindrical and has a side surface formed generally parallel to the longitudinal axis direction A in a cross section parallel to the longitudinal axis direction A. The proximal tapered portion 42 is continuous with the central portion 41 on the proximal side in the longitudinal axis direction A and tapers in diameter toward the tubular member 10 as it moves proximal to the longitudinal axis direction A. The distal tapered portion 43 is continuous with the central portion 41 on the distal side in the longitudinal axis direction A and tapers in diameter toward the tubular member 10 as it moves distal to the longitudinal axis direction A. In this embodiment, the proximal tapered portion 42 and the distal tapered portion 43 may be hemispherical. However, the shapes of the proximal tapered portion 42 and the distal tapered portion 43 are not limited to hemispherical and may be, for example, conical.

[0032] 2A and 2B , the balloon 30 in an expanded state includes a light-transmitting window 31 and a light-shielding portion 32. The light-transmitting window 31 is located proximal to the distal end 36 of the balloon 30. Specifically, in this embodiment, the light-transmitting window 31 is located only in the central portion 41. However, the location of the light-transmitting window 31 is not limited thereto. For example, the light-transmitting window 31 may be located so as to straddle the central portion 41 and either the proximal tapered portion 42 or the distal tapered portion 43, or may be located so as to straddle the central portion 41 and both the proximal tapered portion 42 and the distal tapered portion 43.

[0033] The light-transmitting window 31 of this embodiment is disposed in only a part of the circumferential direction B. However, the light-transmitting window 31 may be disposed over the entire area of ​​the circumferential direction B. Furthermore, the light-transmitting window 31 of this embodiment extends substantially parallel to or parallel to the longitudinal axis direction A.

[0034] The light-transmitting window 31 is configured to allow light that is irradiated from the light irradiation unit 200 inserted into the insertion path 10a and that passes through the tubular member 10 to transmit outward in the radial direction C. The light-shielding unit 32 is provided in an area of ​​the balloon 30 other than the light-transmitting window 31 and a viewing window 33, which will be described later. More specifically, the light-shielding unit 32 is disposed adjacent to the light-transmitting window 31 in the longitudinal axis direction A and the circumferential direction B. The transmittance of the light-shielding unit 32 outward in the radial direction C of light from the light irradiation unit 200 inserted into the insertion path 10a is smaller than the transmittance of the light-transmitting window 31 outward in the radial direction C of light from the light irradiation unit 200 inserted into the insertion path 10a.

[0035] In this embodiment, the light-transmitting window portion 31 and the light-shielding portion 32 of the balloon 30 are realized by a layered relationship between a base body 45 and a coating layer 46. Specifically, the balloon 30 of this embodiment includes a base body 45 and a coating layer 46 coated on the outer surface of the base body 45. The base body 45 is made of a light-transmitting material that allows light from the light-irradiating unit 200 inserted into the insertion path 10a to transmit outward in the radial direction C. The coating layer 46 is made of a light-transmitting limited material whose transmittance in the radial direction C of light from the light-irradiating unit 200 inserted into the insertion path 10a is lower than that of the base body 45. In the light-transmitting window portion 31 of the balloon 30 of this embodiment, the base body 45 is not covered with the coating layer 46, and the light-shielding portion 32 of the balloon 30 of this embodiment is made of only the base body 45. In contrast, the base body 45 is covered with the coating layer 46, and the light-shielding portion 32 of the balloon 30 of this embodiment is made of the base body 45 and the coating layer 46.

[0036] In this embodiment, the balloon 30, in its inflated state, includes a viewing window 33 that is disposed proximal to the light-transmitting window 31 in the longitudinal axis direction A and spaced apart from the light-transmitting window 31. More specifically, the viewing window 33 in this embodiment is disposed proximal to the light-transmitting window 31 and spaced apart from the light-transmitting window 31, with a light-shielding portion 32 sandwiched therebetween. The viewing window 33 is capable of transmitting light diffused by the diffuse-transmitting portion 15 of the tubular member 10. Similar to the light-transmitting window 31, the viewing window 33 in this embodiment is configured solely from the base body 45, without the base body 45 being covered with the coating layer 46. The provision of such a viewing window 33 allows the endoscope device 101 to observe the light-transmitting window 31 and the tubular member 10 through the viewing window 33.

[0037] The viewing window 33 in this embodiment is disposed only in the proximal reduced diameter portion 42. Therefore, the viewing window 33 in this embodiment extends at an angle relative to the light-transmitting window 31 with respect to the longitudinal axis direction A. However, the arrangement of the viewing window 33 is not limited, and it may be disposed, for example, so as to straddle the central portion 41 and the proximal reduced diameter portion 42. Furthermore, the viewing window 33 in this embodiment is disposed over the entire area in the circumferential direction B. However, the viewing window 33 may be disposed over only a portion of the circumferential direction B.

[0038] The viewing window portion 33 of this embodiment extends at an angle relative to the light-transmitting window portion 31 with respect to the longitudinal axis direction A. Furthermore, the proximal end 33 a of the viewing window portion 33 of this embodiment coincides with the proximal end 35 of the balloon 30.

[0039] In the balloon 30 of this embodiment, the entire area other than the light-transmitting window 31 and the viewing window 33 is the light-shielding section 32. However, the balloon 30 is not limited to this configuration, and may have, for example, an area other than the light-transmitting window 31 and the viewing window 33 where the base body 45 is not covered with the coating layer 46 and is composed only of the base body 45.

[0040] The coating layer 46 of the present embodiment may be, for example, a coating material applied to the outer surface of the base body 45, and there are no particular limitations on the method of applying the coating material to the outer surface of the base body 45. The coating material constituting the coating layer 46 may be applied to the outer surface of the base body 45 by, for example, a dipping method, a spray coating method, a roll coating method, a screen printing method, a vacuum deposition method, a low-vacuum sputtering method, or the like.

[0041] The base body 45 may be made of, for example, a transparent resin material that is a light-transmitting material. Examples of resin materials that make up the base body 45 include polyethylene terephthalate (PET), polyurethane, polyamide, and polyamide elastomer. The base body 45 may be made of a single layer of transparent resin material, or may be a laminate in which multiple layers of transparent resin material are stacked.

[0042] The material of the coating layer 46 is not particularly limited, and various metal materials such as titanium oxide, barium sulfate, zinc oxide, silver, aluminum, etc. Alternatively, the coating layer 46 may be a resin containing particles of the above-mentioned metal materials, carbon black, or the like.

[0043] Next, an example of a method of using the light irradiation device 1 will be described. First, the light irradiator 201 is inserted into the insertion path 10a of the tubular member 10 of the light irradiation device 1 toward the distal side in the longitudinal axis direction A, and the light irradiation unit 200 is placed at a predetermined position within the tubular member 10. The predetermined position is, for example, a position where the light irradiation unit 200 is placed so as to overlap the entire area of ​​the light-transmitting window portion 31 in the longitudinal axis direction A. In this state, the balloon 30 of the light irradiation device 1 is in a deflated state.

[0044] Thereafter, the light irradiation device 1 and the light irradiator 201 inserted into the light irradiation device 1 are inserted into a living body through the treatment instrument channel 101a of the endoscopic apparatus 101. At this time, the position of the light-transmitting window portion 31 of the balloon 30 is aligned in the longitudinal axis direction A and the circumferential direction B with a position to be irradiated, such as a lesion formed in biological tissue that defines the lumen. One or both of the alignments with the position to be irradiated in the longitudinal axis direction A and the circumferential direction B are performed as needed. Alignment in the longitudinal axis direction A is performed by moving the light irradiation device 1 distally or proximally in the longitudinal axis direction A. Alignment in the circumferential direction B is performed by rotating the light irradiation device 1 in the circumferential direction B. Alignment in the circumferential direction B may be performed when the balloon 30 of the light irradiation device 1 is changed from a contracted state to a first expanded state, in which the balloon 30 is expanded by adjusting the first expansion amount to an extent that the balloon 30 does not come into contact with or lightly comes into contact with the inner wall of the irradiation target, such as a lesion, and the irradiation target, such as a lesion. More specifically, the light-transmitting window portion 31 of the balloon 30 in the first expanded state may be observed through the viewing window portion 33, while being aligned with the irradiation target such as a lesion.

[0045] The balloon 30 is then expanded from its contracted state to its expanded state, bringing the light-transmitting window 31 into close contact with or in close contact with the target of irradiation, such as a lesion. When the balloon 30 is in the first expanded state, the balloon 30 is expanded by a second amount greater than the first amount of expansion, bringing the light-transmitting window 31 into close contact with or in close contact with the target of irradiation, such as a lesion. The expanded state and the second expanded state are the same. In the expanded state (second expanded state), the light irradiation unit 200 may be repositioned (aligned) to a predetermined position in the longitudinal axis direction A. This alignment is performed by observing whether light from the light irradiation unit 200 is diffusely transmitted through the diffusely transmitting unit 15. By expanding the balloon 30 to its expanded state (second expanded state), the light-transmitting window 31 of the balloon 30 is brought into close contact with the target of irradiation. In this state, the target of irradiation can be irradiated with light emitted from the light irradiation unit 200 and transmitted through the light-transmitting window 31 outward in the radial direction C. By bringing the light-transmitting window 31 close to or in close contact with the target to be irradiated, such as a lesion, light can be more reliably irradiated onto the target to be irradiated, such as a lesion. Furthermore, the state of the target to be irradiated, such as a lesion, can be more clearly visualized through the viewing window 33 and the light-transmitting window 31, and displacement of the balloon 30 during treatment can be prevented. The step of irradiating the target to be irradiated with light that is emitted from the light irradiating unit 200 and passes through the light-transmitting window 31 outward in the radial direction C may be repeated. In this case, the balloon 30 is put into the deflated state or the first expanded state, realigned with the target to be irradiated, such as a lesion, and then put into the expanded state or the second expanded state to irradiate the target to be irradiated.

[0046] In order to perform an operation of aspirating fluid such as a body fluid from inside a living body (a suction operation), the light irradiation device 1 and the light irradiator 201 inserted into the light irradiation device 1 may be temporarily removed from the living body through the treatment instrument channel 101a of the endoscope apparatus 101. In such a case, the balloon 30 is changed from an expanded state to a contracted state, and the light irradiation device 1 and the light irradiator 201 are removed. After the suction operation, the light irradiation device 1 and the light irradiator 201 are reinserted into the living body again through the treatment instrument channel 101a of the endoscope apparatus 101. In such a case, the position of the light irradiation portion 200 of the light irradiator 201 inserted into the light irradiation device 1 within the tubular member 10 may be displaced from the predetermined position. Even if the position of the light irradiation unit 200 within the tubular member 10 is displaced from the predetermined position, by observing whether the light from the light irradiation unit 200 is diffusing and transmitting through the diffuse transmission portion 15, it is possible to confirm whether the light irradiation unit 200 is in an appropriate position (predetermined position) with respect to the light transmission window portion 31. In other words, when the light irradiation device 1 and the light irradiator 201 inserted into this light irradiation device 1 are both reinserted into a living body, it is possible to confirm whether the light irradiation unit 200 has been inserted up to the position of the diffuse transmission portion 15 in the longitudinal axis direction A.

[0047] Furthermore, the placement of the light irradiator 201 in the insertion path 10a may be performed after the balloon 30 is expanded from a contracted state to a first expanded state or a second expanded state. By placing the light irradiator 201 in the insertion path 10a with the balloon 30 in an expanded state, it is possible to prevent the light irradiator 201 from bending or breaking when the light irradiation device 1 is inserted into a living body through the treatment tool channel 101a of the endoscope apparatus 101.

[0048] After the treatment is completed, the balloon 30 is deflated, and the light irradiation device 1, together with the light irradiator 201, is removed from the living body through the treatment instrument channel 101a of the endoscope apparatus 101.

[0049] Next, the diffuse transmission section 15 of this embodiment will be described in detail with reference to FIGS. 2A to 3B. FIG. 2A illustrates a state in which the distal end 200b of the light irradiation section 200 is disposed proximal to the proximal end of the diffuse transmission section 15. FIG. 2B illustrates a state in which the light irradiation section 200 is moved distally in the longitudinal axis direction A from the state of FIG. 2A, and the distal end 200b of the light irradiation section 200 is disposed distal to the distal end of the diffuse transmission section 15. In the states illustrated in FIGS. 2A and 2B, light is emitted from the light irradiation section 200. FIG. 3A illustrates an example of observation of the tubular member 10 in the state illustrated in FIG. 2A. FIG. 3B illustrates an example of observation of the tubular member 10 in the state illustrated in FIG. 2B.

[0050] The diffuse transmission portion 15 is formed in a portion of the longitudinal axis direction A of the tubular member 10. As described above, the diffuse transmission portion 15 is capable of diffusively transmitting light from the light irradiation portion 200 inserted into the insertion path 10a. Being capable of diffusively transmitting light from the light irradiation portion 200 means that the light from the light irradiation portion 200 can be transmitted while being diffused. In other words, the light from the light irradiation portion 200 is diffused by passing through the diffuse transmission portion 15. In this embodiment, by observing through the viewing window 33 with the endoscope device 101 whether the light from the light irradiation portion 200 is diffusively transmitting through the diffuse transmission portion 15 (whether the diffuse transmission portion 15 is emitting light at a desired light emission amount), it can be confirmed whether the light irradiation portion 200 is in an appropriate position with respect to the light transmission window 31.

[0051] Specifically, in the state shown in FIG. 2A , the diffuse transmission portion 15 and the light irradiation portion 200 do not overlap in the longitudinal axis direction A. Therefore, light from the light irradiation portion 200 is unlikely to diffusely transmit through the diffuse transmission portion 15. Therefore, in the state shown in FIG. 2A , the light that has diffused and transmitted through the diffuse transmission portion 15 is unlikely to be observed by the endoscope device 101 (see FIG. 3A ). On the other hand, in the state shown in FIG. 2B , the diffuse transmission portion 15 and the light irradiation portion 200 overlap in the longitudinal axis direction A. Therefore, light from the light irradiation portion 200 is diffusely transmitted through the diffuse transmission portion 15. Therefore, in the state shown in FIG. 2B , the light that has diffused and transmitted through the diffuse transmission portion 15 can be observed by the endoscope device 101 (see FIG. 3B ). In other words, by observing whether the light from the light irradiation portion 200 is diffusely transmitted through the diffuse transmission portion 15, it is possible to confirm whether the light irradiation portion 200 has been inserted up to the position of the diffuse transmission portion 15 in the longitudinal axis direction A.

[0052] In the region of the tubular member 10 of this embodiment other than the diffuse transmission portion 15, light from the light irradiation unit 200 is transmitted without being diffused. Light that is transmitted without being diffused is more difficult to observe with the endoscopic device 101 than diffusely transmitted light. The reason why light that is transmitted without being diffused is difficult to observe with the endoscopic device 101 is that the light emitted from the light irradiation unit 200 and directed toward the lens disposed at the distal end of the endoscopic device 101 has a large angle of incidence at the boundary between the tubular member 10 and the fluid storage space 30a, and total reflection occurs due to the difference in refractive index at the boundary between the tubular member 10 and the fluid storage space 30a. Due to total reflection, most of the light directed toward the lens disposed at the distal end of the endoscopic device 101 is guided into the insertion path 10a of the tubular member 10, making it difficult to visualize. Therefore, light that is transmitted without being diffused is more difficult to observe with the endoscopic device 101. In contrast, in the state shown in FIG. 2B, the state in which the light from the light emitting unit 200 is diffused and transmitted through the diffuse transmission unit 15 can be clearly observed by the endoscope device 101 (see FIG. 3B).

[0053] The light irradiation unit 200 is preferably arranged to overlap the entire area of ​​the light transmission window 31 in the longitudinal axis direction A. In other words, the light irradiation unit 200 is preferably arranged such that, in the longitudinal axis direction A, the distal end 200b is located distal to the distal end 31b of the light transmission window 31, and the proximal end 200a (the boundary between the light irradiation unit 200 and the optical transmission member 202) is located proximal to the proximal end 31a of the light transmission window 31, and distal to the distal end 33b of the viewing window 33 (described later). In contrast, the diffuse transmission unit 15 of the present embodiment is arranged distal to the distal end 31b of the light transmission window 31 in the longitudinal axis direction A and proximal to the distal end 36 of the balloon 30 in the longitudinal axis direction A when the balloon 30 is in an inflated state. Therefore, by observing with the endoscope apparatus 101 whether the light from the light irradiation unit 200 is diffusing and transmitting through the diffuse transmission unit 15, it is possible to confirm whether the distal end 200b of the light irradiation unit 200 is located distal to the distal end 31b of the light transmission window unit 31. This makes it possible to confirm whether the light irradiation unit 200 is in an appropriate position with respect to the light transmission window unit 31, even when the light irradiation device 1 is inserted into a living body.

[0054] Furthermore, by providing such a diffuse transmission section 15, even if the light irradiation section 200 stops irradiating light due to a malfunction of the light irradiation section 200 during treatment, it is easy to notice that light has stopped being irradiated from the light irradiation section 200 by observing with the endoscope device 101 whether the light from the light irradiation section 200 is diffusing and transmitting through the diffuse transmission section 15. In other words, by providing such a diffuse transmission section 15, it is possible to quickly respond to problems such as a malfunction of the light irradiation section 200 that occur during treatment.

[0055] Furthermore, by providing such a diffusing and transmitting portion 15, it is easy to perform the procedure of inserting the light irradiation device 1 into a living body and then inserting the light irradiator 201 into the tubular member 10. More specifically, if the light irradiation device 1 does not include the diffusing and transmitting portion 15, it is difficult to confirm the position of the light irradiation unit 200 after inserting the light irradiation device 1 into a living body. Therefore, as in the example of the usage method described above, it is preferable to insert the light irradiator 201 into the tubular member 10, position the light irradiation unit 200 at a predetermined position within the tubular member 10, and then insert the light irradiation device 1 into the living body. In contrast, when the light irradiation device 1 includes the diffusing and transmitting portion 15 as in the present embodiment, it is possible to confirm whether the light irradiation unit 200 is in an appropriate position relative to the light transmitting window 31 even when the light irradiation device 1 is inserted into a living body. Therefore, it is easy to perform the procedure of inserting the light irradiation device 1 into a living body and then inserting the light irradiator 201 into the tubular member 10. By inserting the light irradiation device 1 into a living body and then inserting the light irradiator 201 into the tubular member 10, it is possible to prevent the light irradiator 201 inserted into the tubular member 10 from interfering with the operation of inserting the light irradiation device 1 into a living body. Furthermore, since the light irradiation unit 200 can be disposed at an appropriate position with respect to the light-transmitting window portion 31 without performing the operation of inserting the light irradiation device 1 into a living body while the light irradiator 201 is inserted into the tubular member 10, it is possible to prevent the light irradiator 201 from being broken due to a load being applied thereto.

[0056] The diffuse transmission portion 15 of this embodiment is a rough surface portion provided on the outer surface of the tubular member 10. The method for forming the rough surface portion is not particularly limited, and may be, for example, a method for physically roughening the outer surface of the tubular member 10 with a file or the like. Alternatively, it may be a method for chemically roughening the outer surface of the tubular member 10 with a chemical solution or the like.

[0057] The diffuse transmission portion 15 of the present embodiment is formed over the entire area in the circumferential direction B in a part of the longitudinal axis direction A of the tubular member 10. However, the diffuse transmission portion 15 may be configured to be formed over only a part of the circumferential direction B of the tubular member 10.

[0058] Second Embodiment Next, a light irradiation device 2 as a second embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram showing the vicinity of the balloon 30 of the insertion section 2a of an endoscope system 120 including the light irradiation device 2. Fig. 4 is also a cross-sectional view taken at the same position as Figs. 2A and 2B. The light irradiation device 2 of this embodiment differs from the light irradiation device 1 of the first embodiment described above (see Figs. 2A and 2B) in the presence or absence of a second diffuse transmission section 15b, but the other configurations are the same. Here, the above-mentioned differences will be mainly described, and a description of the configurations common to the light irradiation device 1 will be omitted.

[0059] As shown in Fig. 4, the tubular member 12 of this embodiment includes two diffuse transmission portions 15 spaced apart in the longitudinal axis direction A. Of the two diffuse transmission portions 15, the distal diffuse transmission portion 15 is disposed at a position similar to that of the diffuse transmission portion 15 of the light irradiation device 1 of the first embodiment described above. Hereinafter, this diffuse transmission portion 15 disposed at a position similar to that of the diffuse transmission portion 15 of the light irradiation device 1 of the first embodiment will be referred to as a "first diffuse transmission portion 15a." Since the first diffuse transmission portion 15a has a configuration similar to that of the diffuse transmission portion 15 of the first embodiment described above, a description thereof will be omitted here.

[0060] 4 , the tubular member 12 of this embodiment includes a second diffuse transmission portion 15b that is disposed proximal to the proximal end 31a of the light transmission window portion 31 in the longitudinal axis direction A when the balloon 30 is in an inflated state, and that diffusely transmits light from the light irradiator 201. Therefore, by observing with the endoscopic device 101 whether light from the light irradiation portion 200 is diffusely transmitted through the second diffuse transmission portion 15b, it is possible to confirm whether the proximal end 200a of the light irradiation portion 200 is located proximal to the proximal end 31a of the light transmission window portion 31 and distal to the distal end 33b of the viewing window portion 33 (described later). In other words, by observing with the endoscopic device 101 whether light from the light irradiation portion 200 is diffusely transmitted through both the first diffuse transmission portion 15a and the second diffuse transmission portion 15b, it is possible to confirm whether the light irradiation portion 200 is disposed so as to overlap the entire area of ​​the light transmission window portion 31 in the longitudinal axis direction A. This makes it possible to reliably check whether the light irradiation unit 200 is in an appropriate position relative to the light transmission window unit 31 .

[0061] Third Embodiment Next, a light irradiation device 3 as a third embodiment will be described with reference to FIGS. 5A and 5B. FIGS. 5A and 5B are views showing the vicinity of the balloon 30 of the insertion section 3a of an endoscope system 130 including the light irradiation device 3. FIGS. 5A and 5B are cross-sectional views taken at the same positions as FIGS. 2A and 2B. The light irradiation device 3 of this embodiment differs from the light irradiation device 2 of the second embodiment (see FIG. 4) in the presence or absence of a third diffusing and transmitting section 15c, but the other configurations are the same. Here, the above-mentioned differences will be mainly described, and a description of the configurations common to the light irradiation device 2 will be omitted.

[0062] As shown in FIGS. 5A and 5B , the tubular member 13 of this embodiment includes three diffuse transmission portions 15 spaced apart in the longitudinal axis direction A. Of the three diffuse transmission portions 15, the most distal diffuse transmission portion 15 is located in a position similar to the first diffuse transmission portion 15a of the light irradiation device 2 of the second embodiment described above. Furthermore, of the three diffuse transmission portions 15, the diffuse transmission portion 15 located between two of the three diffuse transmission portions 15 is located in a position similar to the second diffuse transmission portion 15b of the light irradiation device 2 of the second embodiment described above. Hereinafter, the two diffuse transmission portions 15 located in the same positions as the first diffuse transmission portion 15a and the second diffuse transmission portion 15b of the second embodiment will be referred to as the “first diffuse transmission portion 15a” and the “second diffuse transmission portion 15b.” The first diffuse transmission portion 15a and the second diffuse transmission portion 15b have the same configuration as the first diffuse transmission portion 15a and the second diffuse transmission portion 15b of the second embodiment described above, and therefore will not be described here.

[0063] 5A and 5B , the tubular member of this embodiment includes a third diffuse transmission portion 15c that is disposed proximal to the proximal end of the second diffuse transmission portion 15b in the longitudinal axis direction A when the balloon 30 is in an inflated state, and that diffusely transmits light from the light irradiator 201. Therefore, by observing with the endoscope device 101 whether or not the light from the light irradiator 200 is diffusely transmitted through the third diffuse transmission portion 15c while the light from the light irradiator 200 is diffusely transmitted through the second diffuse transmission portion 15b, it is possible to confirm whether or not the proximal end of the light irradiator 200 is located between the second diffuse transmission portion 15b and the third diffuse transmission portion 15c in the longitudinal axis direction A.

[0064] More specifically, Fig. 5A shows a state in which the distal end 200b of the light irradiation unit 200 is located distal to the first diffuse transmission unit 15a, and the proximal end 200a of the light irradiation unit 200 is located proximal to the third diffuse transmission unit 15c and proximal to the distal end 33b of the viewing window unit 33 (described later). In this state, the first diffuse transmission unit 15a, the second diffuse transmission unit 15b, and the third diffuse transmission unit 15c all diffusely transmit light from the light irradiation unit 200. On the other hand, Fig. 5B shows a state in which the light irradiation unit 200 has been moved distally in the longitudinal axis direction A from the state shown in Fig. 5A. 5A , the distal end 200b of the light irradiation unit 200 is located distal to the first diffuse transmission portion 15a, while the proximal end 200a of the light irradiation unit 200 is located proximal to the second diffuse transmission portion 15b and distal to the third diffuse transmission portion 15c. That is, in the state shown in FIG. 5B , the proximal end 200a of the light irradiation unit 200 is located between the second diffuse transmission portion 15b and the third diffuse transmission portion 15c in the longitudinal axis direction A. In this state, the first diffuse transmission portion 15a and the second diffuse transmission portion 15b diffusely transmit the light from the light irradiation unit 200 and emit light at a desired intensity, but the third diffuse transmission portion 15c has difficulty diffusing and transmitting the light from the light irradiation unit 200 and therefore has difficulty emitting light at a desired intensity. In other words, the amount of light diffusely transmitted through the third diffuse transmission portion 15 c is smaller than the amount of light diffusely transmitted through the first diffuse transmission portion 15 a and the second diffuse transmission portion 15 b. In other words, by observing with the endoscope device 101 whether the light from the light irradiation portion 200 is diffusely transmitted through the third diffuse transmission portion 15 c in a state in which the light from the light irradiation portion 200 is diffusely transmitted through the second diffuse transmission portion 15 b, it is possible to confirm whether the proximal end of the light irradiation portion 200 is located between the second diffuse transmission portion 15 b and the third diffuse transmission portion 15 c in the longitudinal axis direction A.

[0065] In this embodiment, the third diffuse transmission portion 15c is disposed in a position that overlaps with the distal end 33b of the viewing window portion 33 in the longitudinal axis direction A when the balloon 30 is in an inflated state. Therefore, by observing with the endoscopic device 101 whether the light from the light irradiation portion 200 is diffusely transmitting through the third diffuse transmission portion 15c while the light from the light irradiation portion 200 is diffusely transmitting through the second diffuse transmission portion 15b, it is possible to confirm whether the proximal end 200a of the light irradiation portion 200 is located proximal to the distal end 33b of the viewing window portion 33. If the proximal end 200a of the light irradiation portion 200 is located proximal to the distal end 33b of the viewing window portion 33, the light from the light irradiation portion 200 is likely to transmit through the viewing window portion 33. If the light from the light irradiation portion 200 transmits through the viewing window portion 33, the transmitted light may irradiate normal tissue, potentially causing damage to the normal tissue. In contrast, in the present embodiment, when it is confirmed that the proximal end 200a of the light irradiation unit 200 is located proximal to the distal end 33b of the viewing window 33, the light irradiation unit 200 can be moved distally so that the proximal end 200a of the light irradiation unit 200 is located distal to the distal end 33b of the viewing window 33. This prevents light from the light irradiation unit 200 from passing through the viewing window 33 and irradiating normal tissue, thereby preventing damage to the normal tissue. However, to prevent damage to the normal tissue, it is preferable that the proximal end 200a of the light irradiation unit 200 be as far distal as possible in the longitudinal axis direction A as possible from the distal end 33b of the viewing window 33. Therefore, the position of the diffuse transmission portion 15c is not particularly limited as long as the diffuse transmission portion 15c is at least not proximal to the distal end 33b of the viewing window 33.

[0066] <Fourth Embodiment> Next, a light irradiation device 4 as a fourth embodiment will be described with reference to Fig. 6. Fig. 6 is a diagram showing the vicinity of the balloon 30 of the insertion section 4a of an endoscope system 140 including the light irradiation device 4. Fig. 6 is also a cross-sectional view taken at the same position as Figs. 2A and 2B. The light irradiation device 4 of this embodiment differs from the light irradiation device 1 of the first embodiment described above (see Figs. 2A and 2B) in the presence or absence of a positioning section 17, but the other configurations are the same. Here, the above-mentioned differences will be mainly described, and a description of the configurations common to the light irradiation device 1 will be omitted.

[0067] 6 , the tubular member 14 of this embodiment includes a positioning portion 17 that restricts the light irradiation portion 200 from moving distally from a predetermined position in the longitudinal axis direction A. The positioning portion 17 of this embodiment is configured so that the predetermined position is located distally from the distal end of the diffuse transmission portion 15 in the longitudinal axis direction A and proximal to the distal end 36 of the balloon 30 in the longitudinal axis direction A.

[0068] Specifically, the positioning portion 17 of this embodiment is a reduced diameter portion 18 formed by partially reducing the diameter of the inner surface of the tubular member 14. In addition, in this embodiment, the predetermined position is the position of the proximal end 18a of the reduced diameter portion 18. In other words, the reduced diameter portion 18 serving as the positioning portion 17 of this embodiment is configured such that the proximal end 18a is located distal to the distal end of the diffuse transmission portion 15 in the longitudinal axis direction A and proximal to the distal end 36 of the balloon 30 in the longitudinal axis direction A.

[0069] In this embodiment, by abutting the light irradiation unit 200 inserted into the insertion path 10a of the tubular member against the reduced diameter portion 18 serving as the positioning unit 17, the light irradiation unit 200 can be positioned so as to overlap the entire area of ​​the light transmission window 31 in the longitudinal axis direction A when the balloon 30 is in an expanded state. Providing such a positioning unit 17 makes it easy to position the light irradiation unit 200 at an appropriate position relative to the light transmission window 31. Furthermore, even if the light irradiation unit 200 deviates from the appropriate position when the light irradiation device 4 is inserted into a living body, it is possible to confirm whether the light irradiation unit 200 has deviated from the appropriate position by checking whether the distal movement of the light irradiation unit 200 in the longitudinal axis direction A is restricted by the positioning unit 17. In other words, in this embodiment, by checking the position of the light irradiation unit 200 using both the diffuse transmission unit 15 and the positioning unit 17, it is possible to reliably confirm whether the light irradiation unit 200 is at an appropriate position relative to the light transmission window 31, even when the light irradiation device 4 is inserted into a living body.

[0070] Furthermore, by providing such a positioning portion 17, it is possible to check whether the light irradiation unit 200 is arranged to overlap the entire area of ​​the longitudinal axis direction A of the light transmission window 31 by checking whether the movement of the light irradiation unit 200 toward the distal side in the longitudinal axis direction A is restricted by the positioning portion 17, even without providing the diffuse transmission portion 15 arranged proximal to the proximal end 31 a of the light transmission window 31 as in the second and third embodiments described above. In other words, providing such a positioning portion 17 reduces the need for the diffuse transmission portion 15 arranged proximal to the proximal end 31 a of the light transmission window 31. This makes it possible to realize a configuration that does not include the diffuse transmission portion 15 arranged proximal to the proximal end 31 a of the light transmission window 31, and prevents light from the light irradiation unit 200 from diffusing and transmitting through the diffuse transmission portion 15 arranged proximal to the proximal end 31 a of the light transmission window 31 and transmitting through the viewing window 33 to irradiate normal tissue, thereby preventing damage to the normal tissue.

[0071] The light irradiation device according to the present disclosure is not limited to the specific configurations shown in the above-described embodiments, and various modifications, changes, and combinations are possible without departing from the scope of the claims.

[0072] The present disclosure relates to light illumination devices.

[0073] 1, 2, 3, 4: Light irradiation device 1a, 2a, 3a, 4a: Insertion section 1b: Hand operation section 10, 12, 13, 14: Tubular member 10a: Insertion path 11: Closure wall 15: Diffusive transmission section 15a: First diffuse transmission section 15b: Second diffuse transmission section 15c: Third diffuse transmission section 17: Positioning section 18: Diameter-reducing section 20: Outer tube 20a: Expansion lumen 30: Balloon 30a: Fluid storage space 31: Light-transmitting window section 31a: Proximal end of light-transmitting window section 31b: Distal end of light-transmitting window section 32: Light-shielding section 33: Viewing window section 33a: Proximal end of viewing window section 33b: Distal end of viewing window section 35: Proximal end of balloon 36: Distal end of balloon 41: Central section 42: Proximal reduced diameter portion 43: Distal reduced diameter portion 45: Base body 46: Covering layer 100, 120, 130, 140: Endoscope system 101: Endoscope device 101a: Treatment instrument channel 102: Control device 102a: Light source unit 102b: Processor unit 103: Display unit 104: Light source device 105: Fluid supply tool 200: Light irradiation unit 201: Light irradiator 201a: Proximal end of light irradiator 201b: Distal end of light irradiator 202: Light transmission member A: Longitudinal axis direction B: Circumferential direction C: Radial direction O: Longitudinal axis of tubular member

Claims

1. A light irradiation device comprising: a tubular member having a longitudinal axis, defining an insertion path therein through which a light irradiator including a light irradiation unit can be inserted; and a balloon covering the radial outside of the tubular member and capable of expanding and contracting in the radial direction, wherein the balloon, in an expanded state, comprises a light-transmitting window portion which is irradiated from the light irradiation unit inserted into the insertion path and which can transmit light that has passed through the tubular member in the radial direction, and a light-shielding portion which is provided in an area other than the light-transmitting window portion and has a transmittance of light from the light irradiation unit lower than that of the light-transmitting window portion, and wherein the tubular member comprises a diffusively transmitting portion which is located distal to the distal end of the light-transmitting window portion in the longitudinal axis direction along the longitudinal axis and proximal to the distal end of the balloon in the longitudinal axis direction and which can diffusely transmit light from the light irradiation unit.

2. The light irradiation device according to claim 1, wherein the diffuse transmission portion is a rough surface portion provided on the outer surface of the tubular member.

3. A light irradiation device according to claim 1 or 2, wherein when the diffusively transmitting portion is a first diffusively transmitting portion, the tubular member is provided with a second diffusively transmitting portion that is arranged proximal to the proximal end of the light-transmitting window portion in the longitudinal axis direction and that diffuses and transmits light from the light irradiation portion.

4. The light irradiation device according to claim 3, wherein the tubular member is provided with a third diffuse transmission section that is positioned proximal to the proximal end of the second diffuse transmission section in the longitudinal axis direction and that diffuses and transmits light from the light irradiation section.

5. A light irradiation device according to claim 1 or 2, wherein the tubular member is provided with a positioning portion that restricts the light irradiation portion from moving distally in the longitudinal axis direction beyond a predetermined position.

6. A light irradiation device as described in claim 5, wherein the predetermined position is located distal to the distal end of the diffusively transmitting portion in the longitudinal axis direction and proximal to the distal end of the balloon in the longitudinal axis direction.

7. A light irradiation device as described in any one of claims 1 or 2, wherein the balloon, in an expanded state, has a viewing window portion that is positioned proximal to and spaced apart from the light-transmitting window portion in the longitudinal axis direction and that is capable of transmitting light diffused by the diffusing and transmitting portion.

8. The light irradiation device described in claim 7, wherein the balloon, in an expanded state, comprises a substantially cylindrical central portion and a proximal tapered portion that is connected to the central portion on the proximal side in the longitudinal axis direction and that taperes toward the tubular member as it moves proximally in the longitudinal axis direction, the light-transmitting window portion being disposed in the central portion, and the viewing window portion being disposed in the proximal tapered portion.

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