Light irradiation device and light irradiation system

Abstract

This light irradiation device has an oblong shape and is for medical use, the light irradiation device including a device body, a laser light source, and a cooling liquid flow path. The device body has an oblong shape. The laser light source is provided at the distal end of the oblong device body and emits laser light. The cooling liquid flow path runs to the laser light source side of the device body, and allows a cooling liquid for cooling the laser light source to pass to the laser light source side.

Description

Light irradiation device and light irradiation system

[0001] The present disclosure relates to a light irradiation device and a light irradiation system that are inserted into a biological lumen to irradiate light.

[0002] Photodynamic therapy (PDT) is known as one of the techniques for treating diseases. In PDT, a photosensitive substance is administered to a living body, and then the body is irradiated with light. As a result, active oxygen generated in cancer cells may kill the cancer cells. However, in PDT, it is difficult to selectively accumulate the photosensitive substance in cancer cells. The occurrence of side effects due to the uptake of the photosensitive substance into normal cells is a problem with PDT.

[0003] In response to this, near-infrared photoimmunotherapy (NIR-PIT) has been proposed in recent years. NIR-PIT uses a complex formed by combining two compounds: an antibody against a cancer cell-specific antigen and a photosensitizer. When administered to a living body, the complex tends to selectively accumulate in cancer cells within the body. The complex is then activated by irradiation with light of an excitation wavelength (e.g., a wavelength including 690 nm) of the photosensitizer in the complex (see, for example, Patent Document 1). In NIR-PIT, the complex is selectively accumulated in cancer cells by the antibody, and when light is locally irradiated onto the cancer cells, side effects are less likely to occur compared to PDT.

[0004] Light in the wavelength range including 690 nm has difficulty penetrating deep into the body even when irradiated from the body surface, making it difficult to treat cancer deep inside the body by irradiating it from the body surface. Therefore, technologies have been proposed for irradiating light from a position closer to cancer cells rather than irradiating it from the body surface. For example, a device described in Patent Document 2 is inserted into a blood vessel and irradiates light from deep inside the body.

[0005] JP 2014-523907 A JP 2018-867 A

[0006] Conventional devices require light emitted from an external light source to be transmitted to the tip of the device via an optical transmission member (e.g., optical fiber, etc.). When an optical transmission member is used, bending or other problems in the optical transmission member within the body lumen can cause the light to leak or attenuate before reaching the tip of the device. Light leakage or attenuation can result in problems such as reduced light transmission efficiency or reduced safety. Furthermore, the characteristics of the light (e.g., wavelength, etc.) can change during the process of light transmission through the optical transmission member, making it difficult to achieve the intended therapeutic effect. Therefore, it is desirable to use a laser light source that can be inserted into the body without using an optical transmission member. However, when using a laser light source inserted into the body, unless the laser light source is miniaturized and its heat dissipation performance is improved, problems caused by temperature increases (e.g., laser light source failure, etc.) can occur.

[0007] A typical object of the present disclosure is to provide a light irradiation device and a light irradiation system that can more efficiently and appropriately irradiate a specific position inside a lumen of a living body with light.

[0008] A light irradiation device provided by a typical embodiment of the present disclosure is a long-shaped medical light irradiation device, and includes a laser light source provided at the tip of a long-shaped device body and emitting laser light, and a coolant flow path that leads to the laser light source side of the device body and allows a coolant that cools the laser light source to pass to the laser light source side.

[0009] A light irradiation system provided by a typical embodiment of the present disclosure is a medical light irradiation system comprising: a catheter formed in a long tubular shape; and a long light irradiation device to be inserted into the lumen of the catheter; the light irradiation device is provided at the tip of the long device main body and comprises: a laser light source that emits laser light; and a coolant flow path that leads to the laser light source side of the device main body and allows a coolant that cools the laser light source to pass to the laser light source side; and a light-transmitting portion that transmits laser light emitted by the laser light source provided in the light irradiation device to the outside is formed in at least a part of the tip of the catheter.

[0010] According to the light irradiation device and light irradiation system of the present disclosure, light is irradiated more efficiently and appropriately to a specific position within a lumen of a living body.

[0011] (First Aspect) The light irradiation device of the present disclosure is a long medical light irradiation device comprising a device main body, a laser light source, and a coolant flow path. The device main body is long. The laser light source is provided at the tip of the long device main body and emits laser light. The coolant flow path leads to the laser light source side of the device main body and allows coolant that cools the laser light source to pass to the laser light source side.

[0012] According to the light irradiation device of the present disclosure, the coolant supplied to the laser light source side through the coolant flow path appropriately suppresses temperature rise at the laser light source and its vicinity. Therefore, problems caused by temperature rise at the tip of the laser light source due to the laser light source (e.g., laser light source failure, blood coagulation, etc.) are appropriately suppressed. Note that the coolant flow path only needs to extend to the laser light source side far enough to supply the coolant to the laser light source. Therefore, the tip of the coolant flow path does not necessarily need to reach the position of the laser light source or a position further distal to the laser light source.

[0013] The laser light source may emit laser light in a direction intersecting with the longitudinal axis direction of the light irradiation device. In this case, the light irradiation device can selectively irradiate a specific position of the living body with the laser light emitted from the laser light source.

[0014] The device body may be formed into a long tubular shape, thereby providing a coolant flow path in the lumen of the device body. When the area of ​​the coolant flow path in a cross section perpendicular to the elongation direction of the device body is defined as the flow path area, the flow path area at a portion proximal to the laser light source may be larger than the flow path area at a portion where the laser light source is installed.

[0015] In this case, pressure loss of the coolant in the path leading to the vicinity of the laser light source within the device is less likely to occur, and the coolant is more likely to flow appropriately near the laser light source. Therefore, the laser light source is more efficiently cooled. The range in which the flow path area is wider than the location where the laser light source is installed (i.e., the range of the "region closer to the base end than the laser light source") can be set appropriately. For example, the flow path area of ​​the entire range extending from the base end of the laser light source itself toward the base end may be wider than the flow path area of ​​the location where the laser light source is installed. Furthermore, a certain distance (e.g., a distance equal to or less than the length L, where L is the length of the laser light source in the axial direction of the device body) may be provided between the range in which the flow path area is wider than the location where the laser light source is installed and the base end of the laser light source itself.

[0016] Note that a specific method for narrowing the flow path area at the location where the laser light source is installed compared to the flow path area at the adjacent location on the proximal side of the laser light source can be selected as appropriate. For example, the inner diameter of the coolant flow path may be constant, while the cross-sectional area of ​​the member adjacent to the proximal side of the laser light source may be smaller than the cross-sectional area of ​​the member at the location where the laser light source is located. In this case, the flow path area at the location where the laser light source is installed can be narrowed compared to the flow path area at the adjacent location on the proximal side of the laser light source while the shape of the coolant flow path is simplified. Also, the inner diameter of the coolant flow path at the location where the laser light source is installed may be narrowed compared to the inner diameter of the coolant flow path at the adjacent location on the proximal side of the laser light source. In this case, the diameter of the light irradiation device near the laser light source can be reduced, while the flow path area at the location where the laser light source is installed can be narrowed compared to the flow path area at the adjacent location on the proximal side of the laser light source.

[0017] The light irradiation device may further include a power supply line. The power supply line extends from the base end side to the tip end side of the device body and connects to the laser light source to supply power to the laser light source. The power supply line may be exposed in the coolant flow path. In this case, heat generated from the laser light source is more easily released into the coolant through the power supply line. Therefore, the laser light source is more easily cooled efficiently.

[0018] The cross-sectional area of ​​the connection portion of the power feeder that connects to the laser light source may be larger than the cross-sectional area of ​​the portion closer to the base end than the connection portion. In this case, heat generated from the laser light source is more easily transmitted to the power feeder than when the cross-sectional area of ​​the power feeder is constant. Therefore, the laser light source can be more efficiently cooled.

[0019] At least a portion of the surface of the power feeder may be covered with an insulating material. The thickness of the insulating material covering the power feeder may be smaller than the thickness of the power feeder when not covered with the insulating material. In this case, heat propagated from the laser light source to the power feeder is more easily released to the outside through the insulating material than when the insulating material is thicker than or equal to the thickness of the power feeder. This makes it easier to cool the laser light source more efficiently.

[0020] The thickness of the insulating material covering the power feeder line may be more preferably 25% or less, and even more preferably 10% or less, of the thickness of the power feeder line, in which case heat transmitted from the laser light source to the power feeder line is more easily dissipated to the outside.

[0021] The light irradiation device may further include a supply detection unit that detects whether or not coolant is being supplied to the coolant flow path, and a supply notification unit that notifies the user of the detection result by the supply detection unit. In this case, the user can properly grasp whether or not coolant is being supplied to the coolant flow path. Therefore, various problems caused by emitting laser light without supplying coolant are less likely to occur.

[0022] The specific configuration of the supply detection unit can be selected as appropriate. For example, the light irradiation device may include a flow path valve that prevents backflow of the coolant toward the base end in the coolant flow path (details will be described later). The supply detection unit may detect whether the coolant is being supplied to the coolant flow path by detecting whether the flow path valve is open. In this case, the presence or absence of the coolant being supplied is appropriately detected depending on whether the flow path valve is open. The supply detection unit may also be a flow sensor or the like that is provided in at least a portion of the coolant flow path to detect the flow of the coolant. A temperature sensor may also be used as the supply detection unit. In this case, the temperature sensor may be used to detect both the ambient temperature and the presence or absence of the coolant being supplied.

[0023] The light irradiation device may further include a temperature detection unit that detects the temperature of the laser light source (or a temperature in the vicinity of the laser light source), and a temperature notification unit that notifies the user of the detection result. In this case, the user can easily know whether the temperature of the laser light source is being maintained appropriately.

[0024] The specific configuration of the temperature detection unit can be selected as appropriate. For example, the temperature detection unit may be installed in the laser light source. The temperature detection unit may also detect the temperature near the laser light source (for example, cooling water near the laser light source). The state of the laser light source may be monitored to detect whether the temperature of the laser light source is below a threshold value.

[0025] The light irradiation device may further include a flow path valve. The flow path valve is provided in the coolant flow path closer to the base end than the laser light source, and prevents the coolant from flowing back toward the base end. By providing the flow path valve, the coolant is prevented from flowing back in the coolant flow path. As a result, it becomes easier to more appropriately suppress the temperature rise of the laser light source and its vicinity.

[0026] The light irradiation device may further include a Peltier element provided at the tip of the device body. The Peltier element may be disposed in contact with or in close proximity to the laser light source with the cooling surface facing the laser light source. By providing the Peltier element, problems caused by a temperature rise at the tip due to the laser light source can be appropriately suppressed by the cooling effect of the element.

[0027] When the Peltier element is placed close to the laser light source, the cooling surface of the Peltier element and the laser light source may be spaced apart enough to ensure that the cooling effect of the Peltier element on the laser light source is properly achieved. Furthermore, the cooling surface of the Peltier element and the laser light source may be placed close to each other with at least one of an adhesive and a member with high thermal conductivity disposed between them. Even in this case, as long as the cooling surface of the Peltier element and the laser light source are thermally connected, the cooling effect of the Peltier element on the laser light source can be properly achieved.

[0028] The outer periphery of the Peltier element may be covered with a covering member (e.g., resin) that prevents liquid from entering the interior. In this case, problems such as breakdown of the Peltier element due to liquid intrusion are appropriately suppressed.

[0029] At least one of the heat-generating surface of the Peltier element located opposite the cooling surface and the indirect heat dissipation member having a thermal conductivity equal to or higher than that of the heat-generating surface and in contact with the heat-generating surface may be exposed to the outside where it is exposed to a liquid (e.g., a cooling liquid, etc.). In this case, the heat generated from the heat-generating surface of the Peltier element is more easily dissipated appropriately than when the heat-generating surface is not directly or indirectly exposed.

[0030] A member with high thermal conductivity (for example, at least one of a heat pipe, carbon nanotube, ceramics (AlN, SiC, etc.), metal plate (platinum, titanium, copper), torque wire, etc.) may be placed on the heat-generating surface of the Peltier element. In this case, the heat generated from the heat-generating surface of the Peltier element can be dissipated more efficiently. When a metal plate is used, the metal plate may be an alloy, or the surface of the metal plate may be plated.

[0031] Furthermore, instead of a Peltier element, a member having high thermal conductivity (for example, at least one of a heat pipe, carbon nanotube, ceramics (AlN, SiC, etc.), a metal plate (platinum, titanium, copper), a torque wire, etc.) may be placed in contact with or close to the laser light source. In this case, too, the heat generated from the laser light source is more easily dissipated appropriately. As described above, when a metal plate is used, the metal plate may be an alloy, or the surface of the metal plate may be plated.

[0032] The light irradiation system of the present disclosure is a medical light irradiation system comprising a catheter formed in a long tubular shape and a long light irradiation device inserted into the lumen of the catheter. The light irradiation device comprises a laser light source and a coolant flow path. The laser light source is provided at the tip of the long device main body and emits laser light. The coolant flow path leads to the laser light source side of the device main body and allows coolant that cools the laser light source to pass to the laser light source side. At least a part of the tip of the catheter is formed with a light-transmitting portion that transmits laser light emitted by the laser light source provided in the light irradiation device to the outside.

[0033] According to the light irradiation system of the present disclosure, the coolant supplied to the laser light source through the coolant flow path appropriately suppresses temperature rise at the laser light source and its vicinity. Therefore, problems caused by temperature rise at the distal end due to the laser light source (e.g., laser light source failure, blood coagulation, etc.) are appropriately suppressed. Furthermore, light emitted from the laser light source passes through the light-transmitting portion of the catheter and is irradiated onto biological tissue. Therefore, light is more efficiently and appropriately irradiated onto a specific location within a lumen of the living body.

[0034] At least a portion of the tip of the catheter may be formed with an outlet for discharging the coolant discharged from the coolant flow path of the light irradiation device to the outside of the catheter. In this case, the coolant supplied through the coolant flow path of the light irradiation device passes near the laser light source and is discharged to the outside from the outlet of the catheter. As a result, the coolant is continuously supplied to the vicinity of the laser light source, which makes it easier to more appropriately suppress temperature increases at and near the laser light source. In addition, the possibility of blood outside the catheter coming into contact with the laser light source is appropriately reduced.

[0035] The specific form of the outlet can be selected as appropriate. For example, a passage hole for passing a guidewire may be provided at the tip of the catheter. The passage hole for the guidewire may also serve as an outlet for the cooling liquid. Alternatively, an outlet for the cooling liquid may be formed at the tip of the catheter, separate from the passage hole for the guidewire.

[0036] The catheter outlet may be provided with a drain valve that allows liquid to be discharged to the outside of the catheter through the drain port while preventing liquid from flowing from the outside into the inside of the catheter. In this case, the drain valve prevents blood or the like from the outside of the catheter from flowing into the inside of the catheter through the drain port. As a result, the possibility of blood coming into contact with the laser light source is further reduced.

[0037] (Second Aspect) The light irradiation device of the present disclosure is a long medical light irradiation device, and includes a device main body, a laser light source, and a Peltier element. The device main body is long. The laser light source is provided at the tip of the long device main body and emits laser light. The Peltier element is provided at the tip of the device main body. The Peltier element is placed in contact with or close to the laser light source, with the cooling surface facing the laser light source.

[0038] According to the light irradiation device of the present disclosure, problems caused by a temperature rise at the tip due to the laser light source are appropriately suppressed by the cooling effect of the Peltier element.

[0039] When the Peltier element is placed close to the laser light source, the cooling surface of the Peltier element and the laser light source may be spaced apart enough to ensure that the cooling effect of the Peltier element on the laser light source is properly achieved. Furthermore, the cooling surface of the Peltier element and the laser light source may be placed close to each other with at least one of an adhesive and a member with high thermal conductivity disposed between them. Even in this case, as long as the cooling surface of the Peltier element and the laser light source are thermally connected, the cooling effect of the Peltier element on the laser light source can be properly achieved.

[0040] The outer periphery of the Peltier element may be covered with a covering member (e.g., resin) that prevents liquid from entering the interior. In this case, problems such as breakdown of the Peltier element due to liquid intrusion are appropriately suppressed.

[0041] The laser light source may emit laser light in a direction intersecting with the longitudinal axis direction of the light irradiation device. In this case, the light irradiation device can selectively irradiate a specific position of the living body with the laser light emitted from the laser light source.

[0042] At least one of the heat-generating surface of the Peltier element located opposite the cooling surface and the indirect heat dissipation member having a thermal conductivity equal to or higher than that of the heat-generating surface and in contact with the heat-generating surface may be exposed to the outside where it is exposed to a liquid (e.g., a cooling liquid, etc.). In this case, the heat generated from the heat-generating surface of the Peltier element is more easily dissipated appropriately than when the heat-generating surface is not directly or indirectly exposed.

[0043] A member with high thermal conductivity (for example, at least one of a heat pipe, carbon nanotube, ceramics (AlN, SiC, etc.), metal plate (platinum, titanium, copper), torque wire, etc.) may be placed on the heat-generating surface of the Peltier element. In this case, the heat generated from the heat-generating surface of the Peltier element can be dissipated more efficiently. When a metal plate is used, the metal plate may be an alloy, or the surface of the metal plate may be plated.

[0044] Furthermore, instead of a Peltier element, a member having high thermal conductivity (for example, at least one of a heat pipe, carbon nanotube, ceramics (AlN, SiC, etc.), a metal plate (platinum, titanium, copper), a torque wire, etc.) may be placed in contact with or close to the laser light source. In this case, too, the heat generated from the laser light source is more easily dissipated appropriately. As described above, when a metal plate is used, the metal plate may be an alloy, or the surface of the metal plate may be plated.

[0045] The light irradiation device may further include a coolant flow path. The coolant flow path extends to the laser light source side of the device body, and allows a coolant for cooling at least one of the laser light source and the Peltier element to pass through to the laser light source side. In this case, the coolant supplied to the laser light source side through the coolant flow path appropriately suppresses temperature rise in the laser light source and its vicinity. Therefore, problems caused by temperature rise at the tip of the laser light source due to the laser light source (e.g., at least one of laser light source failure and blood coagulation) are appropriately suppressed. Note that the coolant flow path only needs to extend to the laser light source side to the extent that coolant can be supplied to the laser light source. Therefore, the tip of the coolant flow path does not necessarily have to reach the laser light source.

[0046] The device body may be formed into a long tubular shape, thereby providing a coolant flow path in the lumen of the device body. When the area of ​​the coolant flow path in a cross section perpendicular to the elongation direction of the device body is defined as the flow path area, the flow path area at a portion adjacent to the proximal end side of the laser light source may be larger than the flow path area at the portion where the laser light source is installed.

[0047] In this case, pressure loss of the coolant in the path leading to the vicinity of the laser light source within the device is less likely to occur, and the coolant is more likely to flow appropriately near the laser light source. Therefore, the laser light source is more efficiently cooled. The range in which the flow path area is wider than the location where the laser light source is installed (i.e., the range of the "region closer to the base end than the laser light source") can be set appropriately. For example, the flow path area of ​​the entire range extending from the base end of the laser light source itself toward the base end may be wider than the flow path area of ​​the location where the laser light source is installed. Furthermore, a certain distance (e.g., a distance equal to or less than the length L, where L is the length of the laser light source in the axial direction of the device body) may be provided between the range in which the flow path area is wider than the location where the laser light source is installed and the base end of the laser light source itself.

[0048] Note that a specific method for narrowing the flow path area at the location where the laser light source is installed compared to the flow path area at the adjacent location on the proximal side of the laser light source can be selected as appropriate. For example, the inner diameter of the coolant flow path may be constant, while the cross-sectional area of ​​the member adjacent to the proximal side of the laser light source may be smaller than the cross-sectional area of ​​the member at the location where the laser light source is located. In this case, the flow path area at the location where the laser light source is installed can be narrowed compared to the flow path area at the adjacent location on the proximal side of the laser light source while the shape of the coolant flow path is simplified. Also, the inner diameter of the coolant flow path at the location where the laser light source is installed may be narrowed compared to the inner diameter of the coolant flow path at the adjacent location on the proximal side of the laser light source. In this case, the diameter of the light irradiation device near the laser light source can be reduced, while the flow path area at the location where the laser light source is installed can be narrowed compared to the flow path area at the adjacent location on the proximal side of the laser light source.

[0049] The light irradiation device may further include a power supply line. The power supply line extends from the base end side to the tip end side of the device body and connects to the laser light source to supply power to the laser light source. The power supply line may be exposed in the coolant flow path. In this case, heat generated from the laser light source is more easily released into the coolant through the power supply line. Therefore, the laser light source is more easily cooled efficiently.

[0050] The cross-sectional area of ​​the connection portion of the power feeder that connects to the laser light source may be larger than the cross-sectional area of ​​the portion closer to the base end than the connection portion. In this case, heat generated from the laser light source is more easily transmitted to the power feeder than when the cross-sectional area of ​​the power feeder is constant. Therefore, the laser light source can be more efficiently cooled.

[0051] At least a portion of the surface of the power feeder may be covered with an insulating material. The thickness of the insulating material covering the power feeder may be smaller than the thickness of the power feeder when not covered with the insulating material. In this case, heat propagated from the laser light source to the power feeder is more easily released to the outside through the insulating material than when the insulating material is thicker than or equal to the thickness of the power feeder. This makes it easier to cool the laser light source more efficiently.

[0052] The thickness of the insulating material covering the power feeder line may be more preferably 25% or less, and even more preferably 10% or less, of the thickness of the power feeder line, in which case heat transmitted from the laser light source to the power feeder line is more easily dissipated to the outside.

[0053] The light irradiation device may further include a supply detection unit that detects whether or not coolant is being supplied to the coolant flow path, and a supply notification unit that notifies the user of the detection result by the supply detection unit. In this case, the user can properly grasp whether or not coolant is being supplied to the coolant flow path. Therefore, various problems caused by emitting laser light without supplying coolant are less likely to occur.

[0054] The specific configuration of the supply detection unit can be selected as appropriate. For example, the light irradiation device may include a flow path valve that prevents backflow of the coolant toward the base end in the coolant flow path (details will be described later). The supply detection unit may detect whether the coolant is being supplied to the coolant flow path by detecting whether the flow path valve is open. In this case, the presence or absence of the coolant being supplied is appropriately detected depending on whether the flow path valve is open. The supply detection unit may also be a flow sensor or the like that is provided in at least a portion of the coolant flow path to detect the flow of the coolant. A temperature sensor may also be used as the supply detection unit. In this case, the temperature sensor may be used to detect both the ambient temperature and the presence or absence of the coolant being supplied.

[0055] The light irradiation device may further include a temperature detection unit that detects the temperature of the laser light source (or a temperature in the vicinity of the laser light source), and a temperature notification unit that notifies the user of the detection result. In this case, the user can easily know whether the temperature of the laser light source is being maintained appropriately.

[0056] The specific configuration of the temperature detection unit can be selected as appropriate. For example, the temperature detection unit may be installed in the laser light source. The temperature detection unit may also detect the temperature near the laser light source (for example, cooling water near the laser light source). The control unit may also detect whether the temperature of the laser light source is below a threshold by monitoring the state of the laser light source.

[0057] The light irradiation device may further include a flow path valve. The flow path valve is provided in the coolant flow path closer to the base end than the laser light source, and prevents the coolant from flowing back toward the base end. By providing the flow path valve, the coolant is prevented from flowing back in the coolant flow path. As a result, it becomes easier to more appropriately suppress the temperature rise of the laser light source and its vicinity.

[0058] The light irradiation system of the present disclosure is a medical light irradiation system comprising a catheter formed in a long tubular shape and a long light irradiation device inserted into the lumen of the catheter. The light irradiation device comprises a laser light source and a Peltier element. The laser light source is provided at the tip of the long device body and emits laser light. The Peltier element is placed in contact with or in close proximity to the laser light source with its cooling surface facing the laser light source. At least a part of the tip of the catheter is formed with a light-transmitting portion that transmits laser light emitted by the laser light source provided in the light irradiation device to the outside.

[0059] According to the light irradiation system of the present disclosure, problems caused by temperature rise at the tip due to the laser light source are appropriately suppressed by the cooling effect of the Peltier element. Furthermore, light emitted from the laser light source passes through the light-transmitting portion of the catheter and is irradiated onto biological tissue. Therefore, light is more efficiently and appropriately irradiated to a specific position within the lumen of the living body. As described above, the cooling surface of the Peltier element and the laser light source may be separated to an extent that the cooling effect of the laser light source by the Peltier element is appropriately obtained. Furthermore, the cooling surface of the Peltier element and the laser light source may be close to each other with at least one of an adhesive and a member with high thermal conductivity disposed between the cooling surface of the Peltier element and the laser light source.

[0060] At least one of the heat-generating surface of the Peltier element located opposite the cooling surface and the indirect heat dissipation member having a thermal conductivity equal to or higher than that of the heat-generating surface and in contact with the heat-generating surface may be exposed to the outside where it is exposed to a liquid (e.g., a cooling liquid, etc.). In this case, the heat generated from the heat-generating surface of the Peltier element is more easily dissipated appropriately than when the heat-generating surface is not directly or indirectly exposed.

[0061] While the light irradiation device is inserted into the catheter, a coolant may be introduced into the lumen of the catheter. In this case, the heat generating surface of the Peltier element or the vicinity of the heat generating surface is more likely to come into contact with the coolant introduced into the lumen of the catheter. As a result, the heat generated from the heat generating surface of the Peltier element is more likely to be dissipated more efficiently.

[0062] FIG. 3 is a longitudinal sectional view of the light irradiation system 1 in a state where the light irradiation device 2 and the catheter 3 are separated. FIG. 4 is a longitudinal sectional view of the light irradiation system 1 in a state where the light irradiation device 2 is attached to the catheter 3 (in use state). FIG. 5 is an enlarged longitudinal sectional view of the vicinity of the tip of the light irradiation system 1 in FIG. 2. FIG. 6 is a sectional view of the power supply line 231 in a direction perpendicular to the axis O2 of the light irradiation device 2. FIG. 7 is an enlarged longitudinal sectional view of the vicinity of the tip of the light irradiation system 1 of a first modified example. FIG. 8 is an enlarged longitudinal sectional view of the vicinity of the tip of the light irradiation system 1 of a second modified example. FIG. 9 is an enlarged longitudinal sectional view of the vicinity of the tip of the light irradiation system 1 of a third modified example.

[0063] Exemplary embodiments of the present disclosure will be described below with reference to the drawings. A light irradiation system 1 of this embodiment is used by being inserted into a lumen of a living body (for example, at least one of a blood vessel, lymph node, urethra, respiratory tract, digestive organ, secretory gland, and reproductive organ). The light irradiation system 1 irradiates biological tissue with light (laser light in this embodiment) while inserted into the lumen of the living body. The light irradiation system can be used for at least one of therapies such as PDT (Photodynamic Therapy) and NIR-PIT (Near-infrared Photoimmunotherapy).

[0064] The light irradiation system 1 of this embodiment includes a light irradiation device 2 and a catheter 3. When using the light irradiation system 1, first, the catheter 3 is inserted into a biological lumen. Next, the light irradiation device 2 is inserted into the lumen 311 of the catheter 3, which has a long tubular shape. Once the insertion is complete, light is irradiated onto biological tissue from the light irradiation device 2. However, it is also possible to use only the light irradiation device 2 alone, without using the catheter 3.

[0065] 1 to 3 and 5 to 7 show mutually orthogonal X and Y axes. In these figures, the lower side (+X direction) of the figures is the "distal side," the upper side (-X direction) of the figures is the "proximal side," the left side (+Y direction) of the figures is the "left side," and the right side (-Y direction) of the figures is the "right side." The light irradiation system 1, light irradiation device 2, and catheter 3 are inserted into a biological lumen from the distal side. The proximal side is operated by a medical professional (e.g., a doctor).

[0066] (Light Irradiation Device) The light irradiation device 2 of this embodiment will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, the light irradiation device 2 has an elongated shape. The light irradiation device 2 includes a connector 201, a device main body 210, a laser light source 211, and a distal tip 220. The connector 201 is located on the proximal end side of the light irradiation device 2 and is held by an operator. The connector 201 includes a pair of blades 202 and a connecting portion 203. The connecting portion 203 is a substantially cylindrical member. The blades 202 are connected to the proximal end of the connecting portion 203. The device main body 210 is connected to the distal end of the connecting portion 203. The blades 202 and the connecting portion 203 may be integrally formed. The device main body 210 is a elongated member extending along the axis O2. The laser light source 211 is a compact laser light source that emits laser light in a predetermined wavelength range. The laser light source 211 is provided at the tip of the elongated device body 210. As an example, in this embodiment, the laser light source 211 is installed at the tip of an elongated torque coil 215 provided inside the device body 210. However, the specific method for installing the laser light source 211 can be changed. For example, another member may be used instead of the torque coil 215. The laser light source 211 may be directly fixed to the tip of the device body 210. The tip tip 220 is connected to the tip of the device body 210, further distal than the laser light source 211. The outer diameter of the tip tip 220 is approximately the same as the outer diameter Φ1 of the device body 210.

[0067] The device body 210 preferably has antithrombogenicity, flexibility, and biocompatibility. The device body 210 can be made of at least one of a resin material and a metal material. Examples of resin materials include polyamide resin, polyolefin resin, polyester resin, polyurethane resin, silicone resin, and fluororesin. The device body 210 of this embodiment is formed from a resin material that transmits the laser light emitted from the laser light source 211 (described later). Therefore, there is no need to form a separate laser light transmission section in the device body 210. However, if a transmission section that transmits the laser light emitted from the laser light source 211 is formed in the device body 210, or if the laser light source 211 is exposed to the outside of the device body 210, the device body 210 may be made from a material that does not transmit the laser light (e.g., a metal material). Examples of metal materials that can be used include stainless steel such as SUS304, nickel-titanium alloy, cobalt-chromium alloy, platinum, and tungsten steel. It is also possible to configure the device body 210 using a combination of multiple materials.

[0068] The device body 210 includes a coolant flow path 213. The coolant flow path 213 runs from the base end side (-X side in the figure) of the device body 210 to the laser light source side (+X side in the figure), and allows the coolant that cools the laser light source 211 to pass to the laser light source 211 side (i.e., the distal end side of the device body 210). Therefore, in the light irradiation device 2 of this embodiment, the coolant that passes through the coolant flow path 213 and is supplied to the laser light source 211 side appropriately suppresses temperature rise in the laser light source 211 and its vicinity. This appropriately suppresses problems caused by temperature rise in the distal end due to the laser light source 211 (e.g., at least one of failure of the laser light source 211 and blood coagulation). Note that in this embodiment, the device body 210 is formed in a long tubular shape, and thus the coolant flow path 213 is provided in the lumen of the device body 210. The coolant flow path 213 of this embodiment extends to a position further distal than the laser light source 211. However, it is sufficient that the coolant flow path 213 extends to the laser light source 211 side to an extent that the coolant can be supplied to the laser light source 211. Therefore, the tip end of the coolant flow path 213 may be located closer to the base end than the laser light source 211.

[0069] As shown in FIG. 1 , the coolant is supplied from the base end side of the coolant flow path 213 to the inside. The light irradiation device 2 includes a flow path valve 214. The flow path valve 214 is provided in the coolant flow path 213 closer to the base end than the laser light source 211. The flow path valve 214 prevents the coolant from flowing back toward the base end within the coolant flow path 213 and allows the coolant to flow toward the tip end. As a result, the problem of the coolant not being supplied to the laser light source 211 and its vicinity is suppressed, which makes it easier to more appropriately suppress temperature rise at the laser light source 211 and its vicinity. Note that various liquids that do not affect biological tissue (e.g., physiological saline solution) can be used as the coolant.

[0070] An outlet 221 is formed at the tip of the device body 210 to discharge the coolant supplied from the base end side of the coolant flow path 213 to the outside. Therefore, the coolant supplied to the inside of the coolant flow path 213 flows smoothly near the laser light source 211 without stagnating inside. As a result, it becomes easier to more appropriately suppress the temperature rise of the laser light source 211 and its vicinity.

[0071] In this embodiment, the discharge port 221 is formed in the distal tip 220 provided at the distal end of the device body 210. However, the specific configuration of the discharge port can be changed. For example, a discharge port may be formed in the side surface of the long tubular device body 210, separate from or together with the discharge port 221 of the distal tip 220. It is desirable that the discharge port be formed further distally in the extension direction of the device body 210 (direction of the axis O2) than the position where the laser light source 211 is installed.

[0072] Furthermore, in this embodiment, at least a part of the distal tip 220 (in this embodiment, the entire distal tip 220) provided at the distal end of the light irradiation device 2 is formed of a radiopaque material. Therefore, when a medical professional (e.g., a surgeon) irradiates biological tissue with laser light using the light irradiation device 2 while taking an image of the inside of a living body using radiation (e.g., X-rays), the medical professional can appropriately adjust the irradiation position of the laser light by checking the position of the distal tip 220 that appears in the captured image. This makes it easier to improve the accuracy of treatment.

[0073] The light irradiation device 2 includes a supply detection unit 216 and a supply notification unit 51. The supply detection unit 216 detects whether or not coolant is being supplied into the coolant flow path 213. The supply notification unit 51 notifies the user of the detection result by the supply detection unit 216. Therefore, the user can properly grasp whether or not coolant is being supplied into the coolant flow path 213. This makes it less likely that various problems will occur due to laser light being emitted without coolant being supplied.

[0074] The specific configurations of the supply detection unit 216 and the supply notification unit 51 can be selected as appropriate. For example, the supply detection unit 216 in this embodiment detects whether the flow path valve 214 is open to detect whether coolant is being supplied into the coolant flow path 213. Therefore, the presence or absence of coolant supply is appropriately detected depending on whether the flow path valve 214 is open. Furthermore, the control unit 5 controls the drive of the supply notification unit 51 (e.g., driving at least one of turning on / off / flashing the light source, outputting audio, and displaying an image) based on the detection result by the supply detection unit 216 to notify the user of the detection result. However, the configurations of the supply detection unit 216 and the supply notification unit 51 can also be changed. For example, the supply detection unit may be a flow sensor or the like that is provided in at least a portion of the coolant flow path to detect the flow of coolant. Alternatively, a temperature sensor can be used as the supply detection unit. In this case, the temperature sensor may be used to detect both the ambient temperature and the presence or absence of coolant supply.

[0075] The light irradiation device 2 includes a temperature detection unit 218 and a temperature notification unit 52. The temperature detection unit 218 detects the temperature of at least one of the laser light source 211 and the vicinity of the laser light source 211. The temperature notification unit 52 notifies the user of the detection result by the temperature detection unit 218. Therefore, the user can easily know whether the temperature of the laser light source 211 (or the vicinity thereof) is being maintained appropriately.

[0076] The specific configurations of the temperature detection unit 218 and the temperature notification unit 52 can be selected as appropriate. As an example, the temperature detection unit 218 of this embodiment is installed in the laser light source 211 to detect the temperature of the laser light source 211. However, the temperature detection unit 218 may also detect the temperature near the laser light source 211 (e.g., a coolant near the laser light source 211). Furthermore, the control unit 5 may monitor the state of the laser light source 211 to detect whether the temperature of the laser light source 211 is below a threshold. Furthermore, in this embodiment, the control unit 5 controls the driving of the temperature notification unit 52 (e.g., driving at least one of turning the light source on / off / blinking, outputting audio, and displaying an image) in accordance with the detection result by the temperature detection unit 218, thereby notifying the user of the detection result. The control unit 5 may notify whether the temperature detected by the temperature detection unit 218 is below a threshold, or may notify the detected temperature itself.

[0077] The configuration of the distal end of the light irradiation device 2 of this embodiment will be described with reference to FIG. 3 . FIG. 3 is an enlarged longitudinal cross-sectional view of the distal end and its vicinity of the light irradiation system 1 in FIG. 2 . As described above, the light irradiation device 2 includes a small laser light source 211 at its distal end, which emits laser light in a predetermined wavelength range. Specifically, the laser light source 211 is formed in a rectangular shape and is installed in a coolant flow path 213, which is the inner cavity (lumen) of the long tubular light irradiation device 2. However, the method of fixing the laser light source 211 can be changed. For example, at least a portion of the laser light source 211 (e.g., a light-emitting portion that emits laser light, etc.) may be exposed to the outside of the device main body 210.

[0078] The laser light source 211 emits laser light in a direction intersecting the longitudinal axis direction (the direction of the axis O2) of the light irradiation device 2 (in the example shown in FIG. 3 , the direction of the arrow perpendicular to the axis O2). Therefore, the light irradiation device 2 can directly irradiate a specific position on a living body with light from the laser light source 211 provided at the tip without using an optical transmission member such as an optical fiber. This appropriately prevents various problems that arise when using an optical transmission member (e.g., at least one of the problems of light leakage and attenuation along the optical transmission member and the problem of light characteristics changing during transmission). Furthermore, the laser light source 211 emits laser light from the tip of the light irradiation device 2 in a direction intersecting the direction of the axis O2. Compared to light-emitting diodes, the laser light source 211 is less likely to diverge and is more easily capable of emitting light with high directivity. Therefore, the light irradiation device 2 of this embodiment can selectively irradiate a specific position on a living body with laser light emitted from the laser light source 211. As a result, various problems (e.g., side effects) caused by light being irradiated to unintended locations are less likely to occur. Furthermore, the laser light source 211 has the property of being able to irradiate light with wavelengths having a narrower spectral width than light-emitting diodes. Therefore, by providing the laser light source 211 at the tip of the light irradiation device 2, various problems (e.g., reduced irradiation efficiency and / or unintended tissue changes) caused by irradiating tissue with a wavelength different from the wavelength required for treatment (e.g., the excitation wavelength of a photosensitizer) are also suppressed. This makes it easier to irradiate specific locations within a lumen of a living body with light more efficiently and appropriately.

[0079] A surface-emitting laser that irradiates laser light in a direction perpendicular to the substrate can be used as the laser light source 211. By using a surface-emitting laser, laser light can be appropriately emitted with low power, and the light irradiation device 2 has high resistance to temperature changes. Furthermore, since a surface-emitting laser can emit laser light in a direction perpendicular to the substrate surface, it becomes easier to adjust the irradiation position of the laser light more accurately.

[0080] It is also possible to use a semiconductor laser, which is a circuit element manufactured using semiconductor materials, for the laser light source 211. Semiconductor lasers are easy to miniaturize, so they can be easily incorporated into light irradiation devices 2 with small diameters. Furthermore, semiconductor lasers can emit highly directional laser light with a uniform phase using low power. This makes it easier to stabilize the therapeutic effect.

[0081] The laser light source 211 may emit laser light having a wavelength of 300 nm or more and 2000 nm or less. More preferably, the laser light source 211 may emit laser light having a wavelength of 600 nm or more and 1000 nm or less. In this case, by using the light irradiation device 2 in the treatment of a disease using a photosensitive substance, it becomes easier to obtain an appropriate therapeutic effect. In this embodiment, the center wavelength of the laser light emitted by the laser light source 211 is approximately 690 nm.

[0082] The light irradiation device 2 includes a power supply line 231 (a pair of power supply lines 231 in this embodiment). The power supply line 231 extends from the base end side to the tip end side of the device main body 210 and supplies at least power to the laser light source 211 by connecting to the laser light source 211. The base end side of the power supply line 231 in this embodiment is connected to the control unit 5 (see FIGS. 1 and 2 ). The power supply line 231 (both of the pair of power supply lines 231 in this embodiment) is exposed in the coolant flow path 213 in the device main body 210. Therefore, heat generated from the laser light source 211 is easily released into the coolant through the power supply line 231. As a result, the laser light source 211 is easily cooled more efficiently. Note that in this embodiment, a metal material with high thermal conductivity (e.g., at least one of copper and nickel) is used as the material for the power supply line 231. Therefore, heat generated from the laser light source 211 is easily transmitted to the power supply line 231. The heat transmitted to the power supply line 231 is smoothly released into the cooling liquid.

[0083] As shown in FIG. 3 , the outer diameter of the connection portion 231B of the power feeder 231 (each of the pair of power feeders 231 in this embodiment), which connects to the laser light source 211, is larger than the outer diameter of the base portion 231A extending from the connection portion 231B toward the base end (the +X side in FIG. 3 ) from the connection portion 231B. In other words, when the cross-sectional area of ​​the power feeder 231 is viewed in a cross section perpendicular to the axis O2 of the light irradiation device 2, the cross-sectional area of ​​the connection portion 231B connected to the laser light source 211 is larger than the cross-sectional area of ​​the base portion 231A extending from the connection portion 231B toward the base end. Therefore, compared to when the cross-sectional area of ​​the power feeder 231 is constant, heat generated from the laser light source 211 is more easily transmitted to the power feeder 231. The heat transmitted to the power feeder 231 is smoothly released into the coolant. This makes it easier to cool the laser light source 211 more efficiently.

[0084] 4 is a cross-sectional view of the power supply line 231 taken along a direction perpendicular to the axis O of the light irradiation device 2. As shown in Fig. 4, at least a portion of the power supply line 231 of this embodiment (in this embodiment, both the base end portion 231A and the connection portion 231B of the power supply line 231) is covered with an insulating material 232. As a result, leakage of electricity from the power supply line 231 to the outside is appropriately suppressed. The insulating material 232 may be made of at least one insulating material, such as polyurethane, polyester, polyesterimide, polyamideimide, or polyimide.

[0085] In this embodiment, the cross section of the long power supply line 231 perpendicular to the axis O2 has a circular shape. However, the cross section of the power supply line 231 may have a shape other than a circular shape (for example, a rectangular shape or an elliptical shape).

[0086] As shown in FIG. 4 , in this embodiment, the thickness TI of the insulating material 232 covering the power feeder 231 is designed to be smaller than the thickness TF of the power feeder 231 (more specifically, the thickness of the base end portion 231A of the power feeder 231) when the power feeder 231 is not covered with the insulating material 232. The "thickness" refers to the thickness of the power feeder 231 in a cross section perpendicular to the extension direction of the power feeder 231. In other words, in this embodiment, the thickness TI of the insulating material 232 is designed to be smaller than the diameter TF of the power feeder 231. As a result, the thickness TI of the insulating material 232 is reduced, and heat transmitted from the laser light source 211 to the power feeder 231 is more easily released to the outside (to the coolant in this embodiment) through the thin insulating material 232. This makes it easier to cool the laser light source 211 more efficiently. As an example, the thickness of the power feed line 231 may be designed to be 0.05 mm to 0.20 mm, and the thickness of the insulating material 232 may be designed to be 0.003 mm to 0.02 mm. The thickness of the insulating material 232 covering the power feed line 231 may more desirably be 25% or less, and even more desirably be 10% or less, of the thickness of the power feed line 231. In this case, heat propagated from the laser light source to the power feed line is more easily released to the outside.

[0087] As shown in FIG. 3 , in this embodiment, the device body 210 is formed in a long tubular shape, thereby providing a coolant flow path 213 in the lumen of the device body 210. Here, the area of ​​the coolant flow path 213 in a cross section perpendicular to the elongation direction (direction of the axis O2) of the device body 210 is referred to as the flow path area. In this embodiment, in the elongation direction (direction of the axis O2) of the device body 210, the flow path area FA1 of the coolant flow path 213 at the portion where the laser light source 211 is installed is larger than the flow path area FA2 of the coolant flow path 213 at the proximal end side of the laser light source 211. As a result, pressure loss of the coolant in the path up to the vicinity of the laser light source 211 within the device body 210 is less likely to occur, and the coolant is more likely to flow appropriately near the laser light source 211. This makes it easier to cool the laser light source more efficiently.

[0088] The range in which the flow path area is wider than the portion where the laser light source 211 is installed (i.e., the range of the "portion on the proximal side of the laser light source") can be set appropriately. As an example, in the present embodiment, the flow path area of ​​the entire range extending from the proximal end of the laser light source 211 itself toward the proximal end is wider than the flow path area of ​​the portion where the laser light source 211 is installed. However, a certain distance (for example, a distance equal to or shorter than the length L, where L is the length of the laser light source 211 in the direction of the axis O2) may be provided between the range in which the flow path area is wider than the portion where the laser light source 211 is installed and the proximal end of the laser light source 211 itself.

[0089] In this embodiment, as shown in FIG. 3 , while the inner diameter of the coolant flow path 213 is constant, the cross-sectional area of ​​the member adjacent to the laser light source 211 on the proximal side is made smaller than the cross-sectional area of ​​the member at the location where the laser light source 211 is located (in this embodiment, the sum of the cross-sectional areas of the laser light source 211 and the Peltier element 230, described later). In this case, while the shape of the device main body 210 forming the coolant flow path 213 is simplified, the flow path area FA1 at the location where the laser light source 211 is installed can be made smaller than the flow path area FA2 at the location adjacent to the proximal side of the laser light source 211. However, it is also possible to change the method for making the flow path area FA2 larger than the flow path area FA1. For example, the inner diameter of the coolant flow path 213 at the location where the laser light source 211 is installed may be made smaller than the inner diameter of the coolant flow path 213 at the location adjacent to the proximal side of the laser light source 211. In this case, the diameter of the light irradiation device 2 in the vicinity of the laser light source 211 can be reduced, while the flow path area FA1 of the portion where the laser light source 211 is installed can be made narrower than the flow path area FA2 of the adjacent portion on the base end side of the laser light source 211.

[0090] As shown in FIG. 3 , the light irradiation device 2 of this embodiment includes a Peltier element 230 at the distal end of the device body 210. A wiring 233 extending from the base end along the elongation direction (the direction of the axis O2) of the light irradiation device 2 is connected to the Peltier element 230 (the wiring 233 is not shown in FIGS. 1 and 2 ). The Peltier element 230 is a semiconductor element utilizing the Peltier effect and has a heat-generating surface 230A and a cooling surface 230B. When a direct current is applied to the Peltier element 230, the cooling surface 230B absorbs heat while the heat-generating surface 230A generates heat. The Peltier element 230 is disposed in contact with the laser light source 211 with the cooling surface 230B facing the laser light source 211. However, the cooling surface 230B of the Peltier element 230 may be disposed in close proximity to the laser light source 211 (i.e., at a position where a gap is formed between the Peltier element 230B and the laser light source 211) while facing the laser light source 211. That is, the cooling surface 230B of the Peltier element 230 and the laser light source 211 may be spaced apart to an extent that the cooling effect of the Peltier element 230 on the laser light source 211 can be appropriately obtained. Alternatively, the cooling surface 230B of the Peltier element 230 and the laser light source 211 may be close to each other with at least one of an adhesive and a member having high thermal conductivity disposed between the cooling surface 230B of the Peltier element 230 and the laser light source 211. By facing the cooling surface 230B side of the Peltier element 230 to the laser light source 211, various problems caused by a rise in temperature of the tip portion due to the laser light source 211 are appropriately suppressed by the cooling effect of the Peltier element 230.

[0091] In this embodiment, the outer periphery of the Peltier element 230 is covered with a covering member (e.g., resin) that prevents liquid from entering the interior, thereby appropriately suppressing malfunctions of the Peltier element 230 due to the intrusion of liquid.

[0092] The heat-generating surface 230A of the Peltier element 230 is exposed to the outside and is exposed to the liquid. More specifically, in this embodiment, the heat-generating surface 230A is exposed to the space within the coolant flow path 213, through which the coolant flows. Therefore, when the coolant is supplied into the coolant flow path 213, the heat-generating surface 230A of the Peltier element 230 is exposed to (comes into contact with) the coolant. Therefore, compared to when the heat-generating surface 230A is not exposed to the outside, the heat generated from the heat-generating surface 230A of the Peltier element 230 is more easily released to the outside in an appropriate manner.

[0093] In this embodiment, at least some components of the Peltier element 230 (e.g., at least one of the heating surface 230A and the cooling surface 230B) are formed of a radiopaque material. Therefore, when a medical professional irradiates biological tissue with laser light using the light irradiation device 2 while capturing an image of the inside of a living body using radiation, the medical professional can appropriately adjust the irradiation position of the laser light by checking the position of the Peltier element 230 that appears in the captured image. Specifically, in this embodiment, the installation position of the Peltier element 230 in the light irradiation device 2 is offset from the axis O2 of the light irradiation device 2. Therefore, the medical professional can appropriately grasp the emission direction of the laser light from the laser light source 211 by checking the position of the Peltier element 230 relative to the axis O2 of the light irradiation device 2 on the captured image.

[0094] (Catheter) The catheter 3 of this embodiment will be described with reference to Figures 1 to 3. As shown in Figure 1, the catheter 3 has a long tubular shape. The catheter 3 includes a connector 301, a shaft 310, and a distal tip 320. The connector 301 is located on the proximal end side of the catheter 3 and is held by the surgeon. The connector 301 includes a pair of wings 302 and a connecting portion 303. The connecting portion 303 is a substantially cylindrical member. The wings 302 are connected to the proximal end of the connecting portion 303. The shaft 310 is connected to the distal end of the connecting portion 303. The wings 302 and the connecting portion 303 may be formed integrally.

[0095] Like the device body 210 of the light irradiation device 2, the shaft 310 desirably has antithrombogenicity, flexibility, and biocompatibility. The same material as that of the device body 210 of the light irradiation device 2 can be used as the material of the shaft 310. The shaft 310 is a long tubular member extending along the axis O3. The shaft 310 of this embodiment is formed into a hollow cylindrical shape with both the distal end and the proximal end open. A lumen 311 inside the shaft 310 functions as a guidewire lumen for inserting a guidewire into the catheter 3 during delivery of the catheter 3. After delivery of the catheter 3, the lumen 311 functions as a device lumen for inserting the light irradiation device 2 into the catheter 3.

[0096] The distal tip 320 is connected to the distal end of the shaft 310. The distal tip 320 has an outer shape that tapers from the proximal end to the distal end to allow the catheter 3 to move smoothly within a biological lumen. A through-hole 321 that penetrates the distal tip 320 in the direction of the axis O2 is formed approximately at the center of the distal tip 320. The inner diameter of the through-hole 321 is smaller than the inner diameter of the lumen 311 of the shaft 310 and smaller than the outer diameter Φ1 of the distal tip 220 of the light irradiation device 2. Furthermore, the outer diameter Φ1 of the device body 210 and the distal tip 220 of the light irradiation device 2 is equal to or smaller than the inner diameter of the lumen 311 of the catheter 3. Therefore, the light irradiation device 2 moves within the lumen 311 of the catheter 3 along the axis O2. When the light irradiation device 2 is sufficiently advanced inside the lumen 311 of the catheter 3, the distal tip 220 of the light irradiation device 2 comes into contact with the distal tip 320 of the catheter 3, thereby positioning the light irradiation device 2 in the directions of the axes O2 and O3 relative to the catheter 3. At least a part of the distal tip 320 (in this embodiment, the entire distal tip 320) is made of a radiopaque material. Therefore, the position of the distal end of the catheter 3 can be properly grasped by a radiographic image.

[0097] In this embodiment, a coolant is supplied into the lumen 311 of the catheter 3 (the space between the outer peripheral surface of the light irradiation device 2 and the inner peripheral surface of the lumen 311 of the catheter 3). That is, in this embodiment, a coolant is supplied to both the coolant flow path 213 of the light irradiation device 2 and the lumen 311 of the catheter 3. As a result, problems caused by a rise in temperature at the tip portion due to the laser light source 211 are more easily suppressed.

[0098] 3 , a light-transmitting portion 330 that transmits to the outside the laser light emitted by the laser light source 211 included in the light irradiation device 2 is provided on the distal end side surface (in this embodiment, a part of the distal end side surface) of the shaft 310 of the catheter 3. Therefore, the light irradiation system 1 of this embodiment can selectively irradiate a specific position of a living body with the laser light emitted by the laser light source 211 of the light irradiation device 2 in a direction intersecting the axes O2 and O3.

[0099] In this embodiment, the light-transmitting portion 330 is provided by partially forming a portion of the shaft 310 of the catheter 3 that transmits the laser light emitted by the laser light source 211 using a material that transmits the laser light. However, the configuration of the light-transmitting portion can be changed. For example, the light-transmitting portion may be provided in the catheter by using a material that transmits the laser light for the shaft 310 itself or the entire tip end of the shaft 310.

[0100] A radiopaque catheter marker 332 is provided on the shaft 310 of the catheter 3 in a position close to the light-transmitting portion 330. Therefore, when a medical professional irradiates biological tissue with laser light using the light irradiation device 2 while taking an image of the inside of a living body using radiation, the medical professional can appropriately irradiate the laser light from the light-transmitting portion 330 to the outside by aligning the position of the laser light source 211 of the light irradiation device 2 with the position of the catheter marker 332 that appears in the captured image. This makes it easier to further improve the accuracy of treatment.

[0101] As shown in FIG. 3 , the distal end of the catheter 3 is formed with an outlet 341 for discharging the coolant from inside the lumen 311 to the outside of the catheter 3. Therefore, the coolant supplied to the inside of the catheter 3 (in this embodiment, both the coolant supplied to the coolant flow path 213 of the light irradiation device 2 and the coolant supplied into the lumen 311 of the catheter 3) passes near the distal end of the light irradiation device 2 where the laser light source 211 is installed and is discharged to the outside of the catheter 3 through the outlet 341. As a result, the coolant is continuously supplied to the vicinity of the laser light source 211, which more appropriately suppresses temperature rise in the laser light source 211 and its vicinity. Furthermore, the possibility of blood outside the catheter 3 coming into contact with components inside the catheter 3 (e.g., the laser light source 211, etc.) is appropriately reduced. Therefore, blood coagulation due to the heat of the laser light source 211 is less likely to occur.

[0102] In the catheter 3 of this embodiment, the through-hole 321 of the distal tip 320, through which a guidewire is inserted during delivery of the catheter 3, also serves as the coolant outlet 341. Therefore, both delivery of the catheter 3 and cooling of the vicinity of the laser light source 211 can be appropriately performed without increasing the complexity of the configuration of the catheter 3. However, the specific configuration of the outlet of the catheter 3 can be changed. For example, an outlet may be formed on the side surface of the elongated tubular shaft 310, separate from or together with the through-hole 321 of the distal tip 320. It is desirable that the outlet be formed further distally in the extension direction (direction of the axis O3) of the catheter 3 than the position where the laser light source 211 is disposed during use.

[0103] 3, the outlet 341 of the catheter 3 is provided with an outlet valve 322 that allows liquid to be discharged to the outside of the catheter 3 through the outlet 341 while preventing liquid from flowing from the outside into the inside of the catheter 3. As a result, the outlet valve 322 prevents blood and other substances outside the catheter 3 from flowing into the inside of the catheter 3 through the outlet 341. This makes it even more difficult for blood to coagulate due to the heat of the laser light source 211.

[0104] (Method of Use) An example of a method of using the light irradiation system 1 of this embodiment will be described. First, the surgeon inserts a guidewire (not shown) into a biological lumen. Next, the surgeon inserts the proximal end of the guidewire into the lumen 311 through the through-hole 321 of the distal tip 320 of the catheter 3, causing it to protrude from the proximal end of the connector 301. The surgeon advances the catheter 3 along the guidewire, moving the light-transmitting portion 330 of the catheter 3 to the target site for light irradiation. Note that, when moving the catheter 3 within the biological lumen, the surgeon can appropriately move the catheter 3 to the target site by checking the position of the catheter marker portion 332 using a radiographic image. Thereafter, the surgeon removes the guidewire from the catheter 3.

[0105] The surgeon supplies coolant to the coolant flow path 213 of the light irradiation device 2 and the lumen 311 of the catheter 3. The surgeon inserts the light irradiation device 2 from the proximal opening of the connector 301 of the catheter 3 and advances the light irradiation device 2 along the lumen 311 of the catheter 3 within the biological lumen. When the light irradiation device 2 is sufficiently advanced within the lumen 311 of the catheter 3, the distal tip 220 of the light irradiation device 2 comes into contact with the distal tip 320 of the catheter 3. As shown in FIG. 3 , the light transmitting portion 330 of the catheter 3 is formed at a position along the axes O2 and O3 where the laser light source 211 is to be positioned with the distal tip 220 of the light irradiation device 2 in contact with the distal end of the lumen of the catheter 3 (the distal tip 320 of the catheter 3). Therefore, simply by advancing the light irradiation device 2 until it comes into contact with the distal tip 320 of the catheter 3, the positions of the laser light source 211 and the light transmitting portion 330 automatically coincide with each other along the axes O2 and O3. Furthermore, while checking the position of the Peltier element 230 relative to the axes O2 and O3 on the radiographic image, the surgeon rotates the light irradiation device 2 around the axis O2 to adjust the emission direction of the laser light from the laser light source 211. In this state, the laser light is emitted from the laser light source 211, so that the laser light is selectively irradiated onto the target area.

[0106] (Modifications) The techniques disclosed in the above embodiments are merely examples. Therefore, it is possible to modify the techniques exemplified in the above embodiments. Some of the modifications of the above embodiments will be described with reference to FIGS. 5 to 7. Note that the same configuration as in the above-described embodiments can be adopted for part of the configuration of the first modification shown in FIG. 5, the second modification shown in FIG. 6, and the third modification shown in FIG. 7. Therefore, among the configurations of the first to third modifications, parts that can adopt the same configuration as in the above-described embodiments are assigned the same numbers as in the above-described embodiments, and their description will be omitted or simplified.

[0107] In the light irradiation system 1 of the first modified example shown in FIG. 5 , an indirect heat dissipation member 235 is arranged in contact with the heat-generating surface 230A of the Peltier element 230. The indirect heat dissipation member 235 is made of a material having a thermal conductivity equal to or higher than that of the heat-generating surface 230A (e.g., at least one of a heat pipe, carbon nanotube, ceramics (e.g., AlN, SiC), metal plate (e.g., platinum, titanium, copper), torque wire, etc.). When a metal plate is used, the metal plate may be an alloy, or the surface of the metal plate may be plated. The indirect heat dissipation member 235 is exposed to the outside and exposed to liquid. As an example, the indirect heat dissipation member 235 of the light irradiation system 1 shown in FIG. 5 is exposed to the outside from the side of the device body 210 of the light irradiation device 2. Therefore, the indirect heat dissipation member 235 is exposed to the coolant supplied into the lumen 311 of the catheter 3 (the space between the outer circumferential surface of the light irradiation device 2 and the inner circumferential surface of the lumen 311 of the catheter 3). Therefore, the heat generated from the heat generating surface 230A of the Peltier element 230 is easily and appropriately released to the outside through the indirect heat dissipation member 235.

[0108] Unlike the other embodiments, the light irradiation system 1 of the second modified example shown in FIG. 6 does not use a Peltier element to cool the laser light source 211. However, in the light irradiation system 1 shown in FIG. 6, a heat dissipation member 236 is arranged in contact with the laser light source 211. As an example, in the light irradiation system 1 shown in FIG. 6, the heat dissipation member 236 is arranged over a wide area of ​​the surface of the laser light source 211 opposite the side from which the laser light is emitted. The heat dissipation member 236 is made of a material with high thermal conductivity (e.g., at least one of a heat pipe, carbon nanotube, ceramics (AlN, SiC, etc.), a metal plate (platinum, titanium, copper, etc.), torque wire, etc.). As a result, heat generated from the laser light source 211 is conducted to the heat dissipation member 236 and then dissipated to the surroundings. As described above, when a metal plate is used, the metal plate may be an alloy, or the surface of the metal plate may be plated.

[0109] 6 is exposed to the outside from the side surface of the device body 210 of the light irradiation device 2. Therefore, the heat dissipation member 236 is exposed to the coolant supplied to the lumen 311 of the catheter 3 (the space between the outer peripheral surface of the light irradiation device 2 and the inner peripheral surface of the lumen 311 of the catheter 3). This makes it easier for the heat generated from the laser light source 211 to be appropriately dissipated to the outside through the heat dissipation member 236. It is more desirable that the heat dissipation member 236 be in contact with the laser light source 211. However, even if the heat dissipation member 236 is not in contact with the laser light source 211, the effect of suppressing the temperature rise of the laser light source 211 can be obtained as long as it is close to the laser light source 211.

[0110] Unlike the other embodiments, the light irradiation system 1 of the third modified example shown in Fig. 7 does not use a discharge valve 322 at the discharge port 341 of the catheter 3. However, in the light irradiation system 1 shown in Fig. 7, a discharge valve 238 is provided at the discharge port 221 formed at the tip of the light irradiation device 2. The discharge valve 238 allows liquid to be discharged from the inside of the coolant flow path 213 to the outside through the discharge port 341, while preventing liquid from flowing from the outside of the coolant flow path 213 into the inside. As a result, the discharge valve 238 appropriately prevents blood and the like outside the coolant flow path 213 from flowing into the inside through the discharge port 221.

[0111] It is also possible to employ only a part of the configurations exemplified in the above-described embodiment and modified examples in the light irradiation system, light irradiation device, or catheter. For example, only one of the coolant flow path 213 and the Peltier element 230 may be employed in the light irradiation device. It is also possible to combine multiple configurations shown in different embodiments. As described above, it is also possible to use only the light irradiation device 2 alone, without using the catheter 3.

[0112] The technology of the first aspect according to the present disclosure can also be expressed as follows: (1) A long medical light irradiation device comprising: a laser light source provided at a distal end of a long device main body and emitting laser light; and a coolant flow path leading to the laser light source side of the device main body and allowing a coolant for cooling the laser light source to pass to the laser light source side. (2) The light irradiation device according to (1), wherein the device main body is formed in a long tubular shape, thereby providing the coolant flow path in the lumen of the device main body, and when the area of ​​the coolant flow path in a cross section in a direction perpendicular to the elongation direction of the device main body is defined as the flow path area, the flow path area at a portion proximal to the laser light source is larger than the flow path area at a portion where the laser light source is installed. (3) The light irradiation device according to (1) or (2), further comprising a power supply line extending from a base end side to a tip end side of the device body and connecting to the laser light source to supply power to the laser light source, the power supply line being exposed in the coolant flow path. (4) The light irradiation device according to (3), characterized in that a cross-sectional area of ​​a connection portion of the power supply line that connects to the laser light source is larger than a cross-sectional area of ​​a portion of the power supply line that is closer to the base end than the connection portion. (5) The light irradiation device according to (3) or (4), characterized in that at least a portion of a surface of the power supply line is covered with an insulating material, and the thickness of the insulating material covering the power supply line is smaller than the thickness of the power supply line in a state where it is not covered with the insulating material. (6) The light irradiation device according to any of (1) to (5), further comprising: a supply detection unit that detects whether coolant is being supplied into the coolant flow path, and a supply notification unit that notifies a result of the detection by the supply detection unit. (7) The light irradiation device according to any one of (1) to (6), further comprising: a temperature detection unit that detects the temperature of the laser light source; and a temperature notification unit that notifies the detection result by the temperature detection unit.(8) The light irradiation device according to any one of (1) to (7), further comprising a flow path valve provided in the coolant flow path closer to the base end than the laser light source, for preventing backflow of the coolant toward the base end side. (9) The light irradiation device according to any one of (1) to (8), further comprising a Peltier element provided at the tip of the device body, the Peltier element being disposed in contact with or in proximity to the laser light source with its cooling surface facing the laser light source. (10) The light irradiation device according to (9), wherein at least one of the heat-generating surface of the Peltier element located opposite the cooling surface and an indirect heat dissipation member having a thermal conductivity equal to or higher than that of the heat-generating surface and in contact with the heat-generating surface is exposed to the outside where it is exposed to the liquid. (11) A medical light irradiation system comprising: a catheter formed in a long tubular shape; and a long light irradiation device inserted into an inner cavity of the catheter, wherein the light irradiation device comprises: a laser light source provided at a tip portion of a long device main body and emitting laser light, and a coolant flow path leading to the laser light source side of the device main body and through which a coolant for cooling the laser light source passes to the laser light source side, wherein at least a part of the tip portion of the catheter is formed with a light-transmitting part that transmits the laser light emitted by the laser light source provided in the light irradiation device to the outside. (12) The light irradiation system according to (11), wherein at least a part of the tip portion of the catheter is formed with an outlet for discharging the coolant discharged from the coolant flow path of the light irradiation device to the outside of the catheter. (13) The light irradiation system according to (12), wherein the outlet of the catheter is provided with a discharge valve that allows the liquid to be discharged to the outside of the catheter through the outlet while preventing the liquid from flowing from the outside to the inside of the catheter.

[0113] The technology of a second aspect according to the present disclosure can also be expressed as follows: (1) A long medical light irradiation device comprising: a laser light source provided at the tip of a long device main body and emitting laser light; and a Peltier element provided at the tip of the device main body, wherein the Peltier element is disposed in contact with or in proximity to the laser light source with its cooling surface facing the laser light source. (2) The light irradiation device according to (1), wherein at least one of a heat-generating surface of the Peltier element located opposite the cooling surface and an indirect heat dissipation member having a thermal conductivity equal to or higher than that of the heat-generating surface and in contact with the heat-generating surface is exposed to the outside and exposed to a liquid. (3) The light irradiation device according to (1) or (2), further comprising a coolant flow path leading to the laser light source side of the device main body and allowing a coolant for cooling at least one of the laser light source and the Peltier element to pass to the laser light source side. (4) The light irradiation device according to (3), wherein the device main body is formed into a long tubular shape, thereby providing the coolant flow path in an inner cavity of the device main body, and when the cross-sectional area of ​​the coolant flow path in a cross section perpendicular to the elongation direction of the device main body is taken as the flow path area, the flow path area at a portion proximal to the laser light source is larger than the flow path area at a portion where the laser light source is installed. (5) The light irradiation device according to (3) or (4), further comprising a power supply line extending from the proximal side to the distal side of the device main body and connecting to the laser light source to supply power to the laser light source, the power supply line being exposed in the coolant flow path. (6) The light irradiation device according to (5), wherein the cross-sectional area of ​​a connection portion of the power supply line connected to the laser light source is larger than the cross-sectional area of ​​a portion proximal to the connection portion.(7) The light irradiation device according to (5) or (6), wherein at least a part of the surface of the power feeder line is covered with an insulating material, and the thickness of the insulating material covering the power feeder line is smaller than the thickness of the power feeder line when not covered with the insulating material. (8) The light irradiation device according to any of (3) to (7), further comprising: a supply detection unit that detects whether coolant is being supplied into the coolant flow path, and a supply notification unit that notifies the detection result by the supply detection unit. (9) The light irradiation device according to any of (1) to (8), further comprising: a temperature detection unit that detects the temperature of the laser light source, and a temperature notification unit that notifies the detection result by the temperature detection unit. (10) The light irradiation device according to any of (3) to (9), further comprising: a flow path valve that is provided in the coolant flow path closer to the base end than the laser light source, and that prevents the coolant from flowing back toward the base end. (11) A medical light irradiation system comprising: a catheter formed in a long tubular shape; and a long light irradiation device inserted into an inner cavity of the catheter, wherein the light irradiation device comprises: a laser light source provided at a tip portion of a long device main body and emitting laser light; and a Peltier element provided at the tip portion of the device main body, wherein the Peltier element is disposed in contact with or in proximity to the laser light source with its cooling surface facing the laser light source, and wherein at least a light transmitting portion is formed in at least a part of the tip portion of the catheter to transmit the laser light emitted by the laser light source provided in the light irradiation device to the outside. (12) The light irradiation system according to (11), wherein at least one of a heat generating surface of the Peltier element located opposite the cooling surface and an indirect heat dissipation member having a thermal conductivity equal to or higher than that of the heat generating surface and in contact with the heat generating surface is exposed to the outside and is exposed to a liquid.(13) The light irradiation system according to (11) or (12), wherein a cooling liquid is flowed into the inner cavity of the catheter while the light irradiation device is inserted into the catheter.

Claims

1. A long medical light irradiation device comprising: a laser light source that is provided at the tip of a long device body and emits laser light; and a cooling liquid flow path that leads to the laser light source side of the device body and allows a cooling liquid that cools the laser light source to pass to the laser light source side.

2. A light irradiation device as claimed in claim 1, wherein the device body is formed in a long tubular shape, so that the coolant flow path is provided in the inner cavity of the device body, and when the area of ​​the coolant flow path in a cross section in a direction perpendicular to the elongation direction of the device body is taken as the flow path area, the flow path area at a portion on the base end side of the laser light source is larger than the flow path area at the portion where the laser light source is installed.

3. A light irradiation device according to claim 1, further comprising a power supply line extending from the base end side to the tip end side of the device body and connecting to the laser light source to supply power to the laser light source, the power supply line being exposed in the cooling liquid flow path.

4. A light irradiation device according to claim 3, characterized in that the cross-sectional area of ​​the connection portion of the power supply line which connects to the laser light source is larger than the cross-sectional area of ​​the portion of the power supply line which is located on the base end side of the connection portion.

5. A light irradiation device according to claim 3, characterized in that at least a portion of the surface of the power supply line is covered with an insulating material, and the thickness of the insulating material covering the power supply line is smaller than the thickness of the power supply line when not covered with the insulating material.

6. A light irradiation device according to claim 1, further comprising: a supply detection unit which detects whether or not cooling liquid is being supplied into said cooling liquid flow path; and a supply notification unit which notifies the result of detection by said supply detection unit.

7. A light irradiation device according to claim 1, further comprising: a temperature detection unit for detecting the temperature of said laser light source; and a temperature notification unit for notifying the result of detection by said temperature detection unit.

8. A light irradiation device according to claim 1, further comprising a flow passage valve provided on the base end side of the cooling liquid flow passage relative to the laser light source, for preventing backflow of the cooling liquid towards the base end side.

9. A light irradiation device as claimed in claim 1, further comprising a Peltier element provided at the tip of the device body, the Peltier element being arranged in contact with or in close proximity to the laser light source with its cooling surface facing the laser light source.

10. A light irradiation device as claimed in claim 9, characterized in that at least one of the heat generating surface of the Peltier element located opposite the cooling surface and an indirect heat dissipation member having a thermal conductivity equal to or higher than that of the heat generating surface and in contact with the heat generating surface is exposed to the outside and exposed to liquid.

11. A long-shaped medical light irradiation device comprising: a laser light source provided at the tip of a long-shaped device body and emitting laser light; and a Peltier element provided at the tip of the device body, wherein the Peltier element is disposed in contact with or in close proximity to the laser light source with its cooling surface facing the laser light source.

12. A medical light irradiation system comprising: a catheter formed in a long tubular shape; and a long light irradiation device inserted into an inner cavity of the catheter, wherein the light irradiation device comprises: a laser light source provided at a tip portion of a long device body and emitting laser light; and a cooling liquid flow path leading to the laser light source side of the device body and allowing a cooling liquid for cooling the laser light source to pass to the laser light source side, wherein at least a part of the tip portion of the catheter is formed with a light transmitting portion that transmits laser light emitted by the laser light source provided in the light irradiation device to the outside.

13. A light irradiation system as described in claim 12, characterized in that an outlet is formed in at least a portion of the tip of the catheter, for discharging the cooling liquid discharged from the cooling liquid flow path of the light irradiation device to the outside of the catheter.

14. A light irradiation system as described in claim 13, characterized in that the outlet of the catheter is provided with an outlet valve that allows liquid to be discharged to the outside of the catheter through the outlet while preventing liquid from flowing from the outside to the inside of the catheter.

15. A medical light irradiation system comprising: a catheter formed in a long tubular shape; and a long light irradiation device inserted into an inner cavity of the catheter, wherein the light irradiation device comprises: a laser light source provided at a tip portion of a long device body and emitting laser light; and a Peltier element provided at the tip portion of the device body, wherein the Peltier element is disposed in contact with or in close proximity to the laser light source with its cooling surface facing the laser light source, and wherein at least a part of the tip portion of the catheter is formed with a light transmitting portion that transmits laser light emitted by the laser light source provided in the light irradiation device to the outside.

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