Catheter tip position confirmation device and medical catheter set

Abstract

Provided are: a catheter tip position confirmation device which makes it possible to ascertain the positional relationship between the tip portion of a catheter and a target object such as an inner wall of a visceral organ of a living body and the like; and a medical catheter set provided with the same.　A catheter tip position confirmation device 2 has: an optical fiber 10 which has a base end portion 10b and a tip portion 10t and is disposed such that the tip portion 10t is positioned at or near the tip 3t of a catheter 3; a first light source 20 which allows measurement light to enter the optical fiber 10 from the base end portion 10b; a second light source 20 which allows visible light to enter the optical fiber 10 from the base end portion 10b; and an analyzer 30 which comprises a function of measuring the distance between the tip portion 10t of the optical fiber 10 and a target object 4 on the basis of signal information regarding the measurement light and signal information regarding return light resulting from reflection, on the target object 4, of the measurement light emitted from the tip portion 10t of the optical fiber 10, or a function of examining information regarding the state of the target object 4 and / or the tip 3t of the catheter 3. The visible light is emitted from the tip portion 10t of the optical fiber 10 and the proximity thereof.

Description

Catheter tip position confirmation device and medical catheter set

[0001] The present invention relates to a catheter tip position confirmation device and a medical catheter set equipped with the same.

[0002] In medical settings, for patients who have difficulty taking food and drink orally, a catheter has been inserted through the patient's nasal cavity, and the tip of the catheter has been extended to the stomach to directly supply food and drink, such as liquid food or nutritional supplements. To grasp the position of the catheter tip, a catheter tip position confirmation device has been proposed, which is inserted into the body together with the catheter and projects the catheter tip onto the body surface from inside the body in order to visualize the catheter tip (see, for example, Patent Document 1).

[0003] The catheter tip position confirmation device projects visible light emitted from a light source into the base end of an optical fiber and then outgoing from the tip end onto the body surface from inside the body, allowing the position of the catheter tip to be visually confirmed from outside the body.

[0004] However, even with such a catheter tip position confirmation device, it may be difficult to visually confirm the catheter tip position from outside the body depending on the patient's physique and the location of the catheter tip. Furthermore, even if the catheter tip position confirmation device can roughly determine the position of the catheter tip, it cannot determine its position relative to the inner wall of an internal organ such as the stomach wall.

[0005] Re-table 2019 / 215791 publication

[0006] Therefore, an object of the present invention is to provide a catheter tip position confirmation device that can grasp the positional relationship between an object such as the inner wall of an internal organ of a living body and the tip of a catheter, and a medical catheter set equipped with the same.

[0007] The above object can be achieved by the present invention, which is described below.

[0008] <1> A catheter tip position confirmation device comprising: an optical fiber having a base end and a tip end, the tip end being positioned at or near the tip of a catheter; a first light source that inputs measurement light from the base end into the optical fiber; a second light source that inputs visibility light from the base end into the optical fiber; and an analyzer having a function of measuring a distance between the tip end of the optical fiber and an object, or analyzing information relating to the state of the object and / or the tip of the catheter, based on signal information of return light when the measurement light output from the tip end of the optical fiber is reflected by an object and signal information of the measurement light, wherein the visibility light is output from the tip end of the optical fiber or near the tip end.

[0009] <2> The catheter tip position confirmation device according to <1>, wherein the analyzer has a function of analyzing information relating to the state of the tip of the catheter, and the information relating to the state of the tip of the catheter is information relating to at least one state selected from the group consisting of three states: bending at the tip of the catheter, breaking at the tip of the catheter, and pressure acting on the tip of the catheter.

[0010] <3> The catheter tip position checking device according to <1>, wherein the visibility light is visible light or near-infrared light.

[0011] <4> The catheter tip position confirmation device according to <1>, wherein the target object is an inner wall of an internal organ of a living body.

[0012] <5> The catheter tip position checking device according to <1>, wherein the measurement light emitted by the first light source is laser light.

[0013] <6> The catheter tip position checking device according to <1>, wherein the measurement light emitted by the first light source is light that changes over time.

[0014] <7> The catheter tip position confirmation device according to <6>, wherein the analyzer has a function of monitoring changes over time in the returned light.

[0015] <8> The catheter tip position checking device according to <1>, further comprising a spectroscope that disperses the returned light, and the analyzer has a function of monitoring wavelength characteristics of the dispersed light dispersed by the spectroscope.

[0016] <9> The catheter tip position checking device according to <1>, wherein the optical fibers are two types of optical fibers: a first optical fiber having a single-mode transmission path and a second optical fiber having a multi-mode transmission path; the measurement light is incident on the first optical fiber; and the visualization light is incident on the second optical fiber.

[0017] <10> The catheter tip position confirmation device according to <1>, wherein the optical fiber has a single-mode transmission path and a multi-mode transmission path, and the measurement light is incident on the single-mode transmission path and the visualization light is incident on the multi-mode transmission path.

[0018] <11> The catheter tip position confirmation device according to <1>, comprising: a core provided with a plurality of diffraction gratings at intervals according to a position in a longitudinal direction, and a cladding located on the outer circumferential side of the core, the sensing optical fiber being arranged along the optical fiber; a detection light source that inputs detection light having a band from a proximal end of the sensing optical fiber; and a measuring instrument having a function of performing FBG sensing by monitoring the wavelength characteristics of light reflected by any of the plurality of diffraction gratings from the detection light input to the sensing optical fiber.

[0019] <12> A medical catheter set comprising the catheter tip position confirmation device according to any one of <1> to <11> and a catheter.

[0020] <13> The medical catheter set according to <12>, wherein the optical fiber in the catheter tip position confirmation device is inserted into the catheter, and the tip of the optical fiber is located at or near the tip of the catheter.

[0021] According to the present invention, it is possible to provide a catheter tip position confirmation device that can grasp the positional relationship between an object such as the inner wall of an internal organ of a living body and the tip of a catheter, and a medical catheter set equipped with the same.

[0022] 1 is a schematic diagram of a medical catheter set equipped with a catheter tip position confirmation device according to a first embodiment of the present invention. FIG. 2 is a graph showing an example of an analysis result of optical signal information analyzed by an optical analyzer in the catheter tip position confirmation device according to the first embodiment of the present invention. FIG. 3 is an enlarged sectional view of an optical fiber used in a first modified example of the catheter tip position confirmation device according to the first embodiment of the present invention. FIG. 4 is a partially enlarged perspective view of an optical fiber used in a second modified example of the catheter tip position confirmation device according to the first embodiment of the present invention. FIG. 5 is a schematic diagram of a medical catheter set equipped with a catheter tip position confirmation device according to a second embodiment of the present invention. FIG. 6 is a schematic enlarged view of a sensing optical fiber used in the catheter tip position confirmation device according to the second embodiment of the present invention. FIG. 7 is a graph showing the results of monitoring the wavelength characteristics of reflected light from one of the diffraction gratings when detection light is incident on the core of the sensing optical fiber.

[0023] In the present invention, a "catheter tip position confirmation device" is a device that, for example, measures the distance between the inner wall of an internal organ and the catheter tip position, or detects whether the inner wall of an internal organ is near the catheter tip. In some cases, it may also be possible to detect the condition of the catheter tip, such as whether the catheter is bent or folded, or the pressure applied to the catheter.

[0024] Hereinafter, a catheter tip position confirmation device according to three embodiments, which are exemplary aspects of the present invention, and a medical catheter set including the same will be specifically described with reference to the drawings.

[0025] <First embodiment> Figure 1 is a schematic diagram of a medical catheter set 1 equipped with a catheter tip position confirmation device 2 according to a first embodiment. As shown in Figure 1, the medical catheter set 1 includes the catheter tip position confirmation device 2 and a catheter 3. In Figure 1, the base end side (proximal end side) of the optical fiber is indicated by arrow b, and the tip end side (tip end side) is indicated by arrow t (the same applies to the subsequent figures). The axial direction of the optical fiber is also indicated.

[0026] The term "medical catheter set" is a general term referring to a set of a catheter tip position confirmation device and a catheter. Therefore, in addition to the state in which the catheter tip position confirmation device and the catheter are integrated when in use, even if the two are packaged or displayed separately when traded in the market, the term "medical catheter set" includes the case in which the two are associated and combined.

[0027] The catheter tip position confirmation device 2 according to this embodiment includes an optical fiber 10 having a base end 10b and a tip end 10t, a light source 20, and an analyzer 30. The optical fiber 10 is composed of a core located radially toward the center and a cladding located on the outer periphery of the core. One end of the optical fiber 10 is inserted into the catheter 3, and the tip end 10t is positioned at or near the tip end 3t of the catheter 3.

[0028] Although not shown in the drawing, the light source 20 includes a first light source that emits measurement light and a second light source that emits visibility light. The measurement light emitted by the first light source in the light source 20 and the visibility light emitted by the second light source are incident on the base end 10b of the optical fiber 10. The optical fiber 10 is made up of two types of optical fiber: a first optical fiber having a single-mode transmission path and a second optical fiber having a multimode transmission path. The measurement light is incident on the first optical fiber, and the visibility light is incident on the second optical fiber.

[0029] The measurement light incident on the optical fiber 10 travels in a direction toward the tip end t (direction of arrow Oe) and is emitted from the tip end 10t. The measurement light emitted from the tip end 10t of the optical fiber 10 in the direction of arrow Os is reflected by the object 4, such as the stomach wall, returns in the direction of arrow Orf, and enters the optical fiber 10 again from the tip end 10t as returned light. The returned light incident on the optical fiber 10 travels in a direction toward the base end b (direction of arrow Ort), is branched at a branching portion 13 located near the base end 10b of the optical fiber 10 (direction of arrow Od) and travels to the photodetector 31.

[0030] The measurement light emitted by the first light source in the light source 20 may be an LED (light-emitting diode) or a laser, but laser light is preferred because it allows precise control of the time change of the light. Furthermore, the measurement light emitted by the first light source is preferably time-varying light such as pulsed light (rectangular wave), triangular wave, or sine wave.

[0031] The analyzer 30 has a function of measuring the distance between the tip 10t of the optical fiber 10 and the object 4 from signal information of returned light when measurement light emitted from the tip 10t of the optical fiber 10 is reflected by the object 4 and signal information of the measurement light, or analyzing information about the state of the object 4 and / or the tip of the catheter 3. Information about the state of the tip of the catheter 3 can be information about three states: bending at the tip of the catheter 3, breaking at the tip of the catheter 3, and pressure applied to the tip of the catheter 3. The analyzer 30 may have a function of analyzing information about one of these three states, or information about two or more states. In this embodiment, the analyzer 30 has a photodetector (PD) 31 that detects an optical signal and outputs it as signal information, and an optical analyzer 32 that analyzes the output signal information.

[0032] The photodetector 31 is a device that detects the received return light, converts it into an electrical signal, and generates signal information. Specifically, it measures the intensity of the return light and detects whether an object 4, such as the inner wall of an internal organ, is present near the tip 3t ​​of the catheter 3. If an object 4 is present near the tip 3t ​​of the catheter 3, the intensity of the return light will be greater. The signal information of the obtained return light is output to the optical analyzer 32.

[0033] The optical analyzer 32 receives signal information of the returned light from the photodetector 31, and also receives signal information of the measurement light emitted from the first light source in the light source 20. The optical analyzer 32 preferably has a function of monitoring the time change of the returned light. By having the function of monitoring the time change of the returned light, the optical analyzer 32 analyzes the delay state of the returned light from the signal information of the measurement light and the returned light, and measures the distance between the tip 10t of the optical fiber 10 and the object 4. In other words, the analyzer (optical analyzer 32) has a function of measuring the distance between the tip 10t of the optical fiber 10 and the object 4 from the signal information of the returned light when the measurement light emitted from the tip 10t of the optical fiber 10 is reflected by the object 4 and the signal information of the measurement light.

[0034] An oscilloscope, for example, can be used as the optical analyzer 32. Note that the optical analyzer 32 may simply monitor the intensity of the returned light rather than monitoring the change over time of the returned light, and may only have the function of determining whether or not an object 4, such as the inner wall of an internal organ, is present near the tip 3t ​​of the catheter 3.

[0035] The practitioner inserts the catheter 3 in the medical catheter set 1 equipped with the catheter tip position confirmation device 2 according to this embodiment into the patient's oral cavity from the tip end 3t side, and then inserts it through the esophagus to an internal organ such as the stomach, to perform treatment. At this time, it is desirable that the position of the tip end 3t of the catheter 3 is appropriate. In particular, since there is a concern that contact with the inner wall of an internal organ may damage the inner wall, it is desirable to keep a certain distance from the inner wall for safety.

[0036] 2 is a graph showing an example of the analysis results of the optical signal information analyzed by the optical analyzer 32, in which the relationship between the measurement light emitted from the light source 20 and the return light reflected by the object 4 is plotted with time on the horizontal axis and light intensity on the vertical axis. At this time, the measurement light emitted from the light source 20 is a triangular wave.

[0037] As shown in the graph in Figure 2, the returned light travels a long path, as indicated by the arrows Oe, Os, Orf, Ort, and Od, as described above, and is therefore delayed relative to the measurement light. The distance from the time when the returned light is emitted from the tip 10t of the optical fiber 10, reflected by the object 4, returned in the direction of the arrow Orf, and re-enters the optical fiber 10 from the tip 10t is a variable, while the distances for the other paths are constant. Therefore, by measuring the time difference Δt between the measurement light and the returned light shown in the graph in Figure 2, the distance between the tip 10t of the optical fiber 10 and the object 4 can be measured. When the returned light contacts the object 4, such as the stomach wall, Δt reaches its minimum value, and the intensity of the returned light reaches its maximum value.

[0038] The actual distance between the tip 10t of the optical fiber 10 and the object 4 may be measured using an OTDR (Optical Time Domain Reflectometer) or OCT (Optical Coherence Tomography).

[0039] As described above, according to this embodiment, the distance between the tip 10t of the optical fiber 10 and the object 4, such as the inner wall of an internal organ of a living body, can be determined, and the positional relationship between the object 4 and the tip 3t ​​of the catheter 3 can be grasped.

[0040] The result of measuring the distance between the tip 10t of the optical fiber 10 and the object 4 may simply be recorded as data, but it is preferable that the result be notified to the practitioner, other persons, or to an external device such as an external device by the analyzer 32 or by a device attached to or connected to the analyzer 32.

[0041] The distance between the tip 10t of the optical fiber 10 and the object 4 can be displayed, for example, as the actual distance using numbers or a gauge on a monitor or notified by voice, but it is also possible to display a warning image or sound a warning when the distance to the object 4 falls below a predetermined threshold.

[0042] Furthermore, the interval between intermittent signal sounds or the pitch of the signal sound may be changed depending on the distance between the tip 10t of the optical fiber 10 and the object 4. In these cases, it is also preferable to change the signal sound to a warning sound when the distance to the object 4 falls below a predetermined threshold. Notification by sound such as voice, warning sound, or signal sound is preferable because it does not require the practitioner to take their eyes off the treatment area or the patient during treatment.

[0043] In this embodiment, it is preferable that the optical fiber 10 that transmits the measurement light is a single mode. In a single mode optical fiber, the core, which is the transmission path, is a single mode. A single mode optical fiber has low transmission loss, and because the measurement light travels linearly within the core, the shape (pulse-like, triangular, etc.) of the measurement light is less likely to deform. Therefore, if the optical fiber 10 is a single mode, the distance between the tip 10t of the optical fiber 10 and the object 4 can be measured more accurately from the signal information of the returned light and the signal information of the measurement light.

[0044] In this embodiment, the optical fiber 10 may further include a spectrometer that disperses the return light, and the analyzer 30 may have a function of monitoring the wavelength characteristics of the spectral light dispersed by the spectrometer. The spectrometer that disperses the return light may be located between the branching section 13 and the photodetector 31. When pressure acts on the tip of the catheter 3 located inside the body, or when the tip changes in posture, such as by being bent or folded, this also affects the wavelength characteristics of the return light traveling through the optical fiber 10. Therefore, by monitoring the wavelength characteristics of the spectral light dispersed by the spectrometer, i.e., the wavelength characteristics of the return light, and analyzing information regarding conditions such as bending at the tip of the catheter 3, bending at the tip of the catheter 3, and pressure acting on the tip of the catheter 3, the posture of the catheter 3, such as bending or folding, can be determined, or the pressure state inside the body can be measured.

[0045] The catheter tip position confirmation device 2 according to this embodiment further includes a catheter tip position confirmation mechanism (hereinafter referred to as the "catheter visualization mechanism") that enables the catheter tip to be visualized by projecting it onto the body surface from inside the body. The catheter tip position confirmation device 2 according to this embodiment is equipped with the catheter visualization mechanism, which makes it possible to visualize the position of the tip 3t ​​of the catheter 3 from outside the body and to grasp the positional relationship between the target 4, such as the stomach wall, and the tip 3t ​​of the catheter 3, thereby enabling more accurate treatment.

[0046] When the catheter tip position confirmation device 2 according to this embodiment is equipped with a catheter visualization mechanism, it can also share the optical fiber 10. In this case, however, a multimode optical fiber is used as the optical fiber 10 because a single-mode optical fiber cannot allow both the visualization light for visually confirming the tip position of the catheter 3 (hereinafter abbreviated as "tip visualization") and the measurement light for measuring the distance between the catheter tip and an object (hereinafter abbreviated as "distance measurement") to be incident on a single core.

[0047] However, if a multimode optical fiber 10 is used, transmission loss increases and the shape of the measurement light is easily deformed, which reduces the accuracy of measuring the distance between the tip 10t of the optical fiber 10 and the object 4 from the signal information of the return light and the signal information of the measurement light. Therefore, when providing the catheter visualization mechanism in the catheter tip position confirmation device 2 according to this embodiment, it is preferable to ensure separate transmission paths for the visualization light and the measurement light, rather than sharing the optical fiber 10.

[0048] To ensure the transmission paths of the visible light and the measurement light, two types of optical fibers are prepared: a first optical fiber (i.e., a single-mode optical fiber) having a single-mode transmission path (core) and a second optical fiber (i.e., a multi-mode optical fiber) having a multi-mode transmission path (core), and these two types of optical fibers are arranged in parallel as the optical fiber 10 in Fig. 1. Then, the measurement light emitted from the first light source in the light source 20 is made incident on the first optical fiber, and the visible light emitted from the second light source in the light source 20 is made incident on the second optical fiber.

[0049] The term "visible light" refers to light whose position can be determined from outside the body by visual inspection or by using a device such as a camera, and specifically includes visible light and near-infrared light. The wavelength range that can be used for near-infrared light as visible light is approximately 0.7 μm to 2.5 μm.

[0050] The visual light emitted from the second light source in the light source 20 and incident on the second optical fiber is emitted from or near the tip of the optical fiber 10 and projected onto the body surface from inside the body. When the second light source in the light source 20 emits visible light as the visual light, the practitioner can directly visually confirm the position of the tip 3t ​​of the catheter 3 from outside the body. On the other hand, when the second light source in the light source 20 emits near-infrared light as the visual light, the practitioner cannot distinguish it with the naked eye, but can visually confirm the position of the tip 3t ​​of the catheter 3 from outside the body by using a near-infrared camera.

[0051] Furthermore, when providing the catheter tip position confirmation device 2 according to this embodiment with a catheter visualization mechanism, a double-clad fiber, a dual fiber, or a multi-core fiber can be used instead of the optical fiber 10 in which two types of optical fibers run parallel to each other. When using a dual fiber, the procedure should be similar to the above example in which a single-mode optical fiber and a multi-mode optical fiber are prepared.

[0052] Below, we will explain Modification 1, in which a double-clad fiber is used instead of the optical fiber 10, and Modification 2, in which a multi-core fiber is used, when providing a catheter visualization mechanism in the catheter tip position confirmation device 2 according to this embodiment.

[0053] <Modification 1> Modification 1 has the same configuration as the first embodiment, except that an optical fiber 10A that is a double-clad fiber is used instead of the optical fiber 10 in which two types of optical fibers run parallel to one another. Therefore, the schematic configuration of a catheter tip position confirmation device 2A of modification 1 and a medical catheter set 1A including the same will be described with reference to Fig. 1. However, the medical catheter set 1, catheter tip position confirmation device 2, and optical fiber 10 (including the base end portion 10b and the tip portion 10t) in Fig. 1 should be interpreted with the letter "A" added to the end of their reference numerals.

[0054] Figure 3 is an enlarged cross-sectional view of the optical fiber 10A used in Modification 1 of the catheter tip position confirmation device 2 according to the first embodiment. In Figure 3, (A) is an enlarged cross-sectional view of a cross section perpendicular to the axial direction (directions of arrows b and t; hereinafter referred to as the "axial direction bt") of the optical fiber 10A, and (B) is an enlarged cross-sectional view of a cross section including the axis of the optical fiber 10A. The graph on the right side of Figure 3 is a graph showing the magnitude of the refractive index as a function of the radial position of the optical fiber 10A. These drawings and graphs are arranged so that the radial positions of the optical fiber 10A coincide, and identical radial positions are connected by a dashed line.

[0055] A double-clad fiber is an optical fiber having a structure in which two cladding layers are formed around the outer periphery of a core. As shown in Figure 3, in the optical fiber 10A of this modification, the outer periphery of a core 11A is covered with a first cladding layer 12A-1, and the outer periphery of that is further covered with a second cladding layer 12A-2.

[0056] 3, of the three layers of the core 11A, the first cladding 12A-1, and the second cladding 12A-2, the core 11A has the highest refractive index and the second cladding 12A-2 has the lowest refractive index. That is, there is a large difference in refractive index between the core 11A and the first cladding 12A-1, and between the first cladding 12A-1 and the second cladding 12A-2.

[0057] In the optical fiber 10A, which is a double-clad fiber, not only the core 11A closed by the first cladding 12A-1 serves as an optical transmission path, but also the layer of the first cladding 12A-1 closed by the second cladding 12A-2 serves as an optical transmission path. In the optical fiber 10A, the core 11A serves as a single-mode transmission path, and the layer of the first cladding 12A-1 serves as a multi-mode transmission path.

[0058] In this modified example, the measurement light for distance measurement emitted from the first light source in the light source 20A is incident on the core 11A, which is a single-mode transmission path, and separately from the measurement light, the visual recognition light for tip recognition is incident on the layer of the first clad 12A-1, which is a multi-mode transmission path.

[0059] 3B, the measurement light 21 incident on the core 11A travels straight through the core 11A, while the visual light 22 incident on the first cladding 12A-1 travels through the first cladding 12A-1 while repeatedly reflecting at the boundary between the first cladding 12A-1 and the second cladding 12A-2.

[0060] The measurement light 21 incident on the core 11A is emitted from the core 11A at the tip 10tA of the optical fiber 10A and is used to measure the distance between the tip 10tA of the optical fiber 10A and the object 4. The method and principle of measuring the distance between the tip 10tA of the optical fiber 10A and the object 4 are the same as those described in the first embodiment.

[0061] On the other hand, the visualizing light 22 emitted from the second light source in the light source 20A and incident on the first cladding layer 12A-1 is emitted from the tip 10tA of the optical fiber 10A or its vicinity 10t'A. The visualizing light emitted by the emission is projected onto the body surface from inside the body, making the position of the tip 3t ​​of the catheter 3 visible from outside the body.

[0062] In order to enable visible light to be emitted from the tip 10tA of the optical fiber 10A or its vicinity 10t'A, it is sufficient to remove part or all of the second cladding 12A-2 on the outer surface of the vicinity 10t'A of the tip, or further, to cut the tip 10tA at an angle, or other known methods may be adopted.

[0063] According to this modification, the position of the tip 3t ​​of the catheter 3 can be visually confirmed from outside the body, and the positional relationship between the target 4, such as the stomach wall, and the tip 3t ​​of the catheter 3 can be grasped, enabling more accurate treatment. Furthermore, the visualization light for visualizing the tip and the measurement light for distance measurement can be transmitted through a single optical fiber, making it possible to apply this to thinner catheters.

[0064] <Modification 2> Modification 2 has the same configuration as the first embodiment, except that an optical fiber 10B, which is a multi-core fiber, is used instead of the optical fiber 10 in which two types of optical fibers run parallel to one another. Therefore, the schematic configuration of a catheter tip position confirmation device 2B of modification 2 and a medical catheter set 1B including the same will be described with reference to Fig. 1. However, the medical catheter set 1, catheter tip position confirmation device 2, and optical fiber 10 (including the base end portion 10b and the tip portion 10t) in Fig. 1 should be interpreted with the letter "B" added to the end of their reference numerals.

[0065] Fig. 4 is a partially enlarged perspective view of the optical fiber 10B used in Modification 2 of the catheter tip position confirmation device 2 according to the first embodiment. In Fig. 4, the leftmost diagram is a partially enlarged perspective view of the optical fiber 10B sliced ​​perpendicularly to the axial direction bt, and the central and rightmost diagrams are graphs showing the intensities of the measurement light and the returned light in adjacent cores (11b-1, 11b-2).

[0066] A multicore fiber is an optical fiber in which multiple cores are arranged in one cladding. As shown in Fig. 4, an optical fiber 10B in this modification has seven cores 11B arranged in one cladding 12B. The optical fiber 10B is configured so that each of the seven cores 11B can independently transmit a different light.

[0067] In this modification, for example, only one of the cores 11B is used as a transmission path for measurement light for distance measurement, and the other six are used as transmission paths for visibility light for tip visibility. It is preferable that the core 11 serving as the transmission path for measurement light is a single-mode transmission path, and the other six cores 11 are multi-mode transmission paths.

[0068] In this modified example, the measurement light for distance measurement emitted from the first light source in light source 20B is incident on core 11B, which is a single-mode transmission path, and separately from the measurement light, visualization light for tip visualization is incident on the other six cores 11B, which are multi-mode transmission paths.

[0069] The measurement light incident on the core 11B is emitted from the core 11B at the tip 10tB of the optical fiber 10B, and is used to measure the distance between the tip 10tB of the optical fiber 10B and the object 4. The method and principle of measuring the distance between the tip 10tB of the optical fiber 10B and the object 4 are the same as those described in the first embodiment.

[0070] On the other hand, the visualizing light emitted from the second light source in the light source 20B and incident on the other six cores 11B is emitted from the tip 10tB of the optical fiber 10B or its vicinity 10t'B. The visualizing light emitted by the emission is projected onto the body surface from inside the body, making the position of the tip 3t ​​of the catheter 3 visible from outside the body.

[0071] In order to enable visible light to be emitted from the tip 10tB of the optical fiber 10B or its vicinity 10t'B, a portion of the cladding 12B on the outer surface near the tip 10t'B may be removed, or the tip of the exposed core 11B may be cut obliquely, or other known methods may be employed.

[0072] According to this modification, the position of the tip 3t ​​of the catheter 3 can be visually confirmed from outside the body, and the positional relationship between the target 4, such as the stomach wall, and the tip 3t ​​of the catheter 3 can be grasped, enabling more accurate treatment. Furthermore, the visualization light for visualizing the tip and the measurement light for distance measurement can be transmitted through a single optical fiber, making it possible to apply this to thinner catheters.

[0073] In this modification, two or more of the seven cores 11B can be used as transmission paths for measurement light for distance measurement. The measurement light incident on these multiple transmission paths can be separate and independent measurement light. In this case, for example, one can emit measurement light from the tip 10tB of the optical fiber 10B in the direction toward the tip t (axial direction bt of the optical fiber 10B), and the others can emit measurement light in other directions. The "other directions" mentioned here include directions intersecting with the axis of the optical fiber 10B.

[0074] Then, by receiving the return light of each measurement light and measuring it using an analyzer (optical analyzer 32), it is possible to measure not only the distance from the tip 10tB of fiber 10B to the object 4 in the axial direction bt, but also the distance from the tip 10tB of fiber 10B to the object 4 to the side.

[0075] However, in this case, it is desirable that the distance between the cores 11B that serve as the transmission path of the measurement light is not too small (not too narrow). For example, when the cores 11B-1 and 11B-2 shown in Fig. 4 are used as the transmission path of the measurement light, if the distance L between the cores 11B-1 and 11B-2 is small, as shown in the graph of L = short in Fig. 4, even if pulsed (rectangular wave) measurement light Os-1 and Os-2 are emitted, the returning light Orf-1 and Orf-2 that return broadly will have wide tails, causing crosstalk CT.

[0076] Therefore, as shown in the graph for L=long, it is preferable that the distance L between the core 11B-1 and the core 11B-2 is sufficiently large so that the tails of the waveforms of the return light Orf-1 and Orf-2 do not overlap (so that crosstalk CT does not occur). When the waveforms of the return light Orf-1 and Orf-2 are as shown in the graph for L=short in Figure 4, for example, the core 11B-3 and the core 11B-4 may be used as the transmission path of the measurement light.

[0077] <Second embodiment> Figure 5 is a schematic diagram of a medical catheter set 1A equipped with a catheter tip position confirmation device 2A according to a second embodiment. In Figure 5 showing the medical catheter set 1A equipped with a catheter tip position confirmation device 2A according to this embodiment, the same reference numerals as those in the medical catheter set 1 to the catheter tip position confirmation device 2 according to the first embodiment are used to designate the same components, and a description of the same configurations of the components will be omitted. Below, differences from the first embodiment will be mainly described.

[0078] The catheter tip position confirmation device 2A of this embodiment differs from the catheter tip position confirmation device 2 of the first embodiment in that it incorporates a sensing optical fiber 40 and a light-source-equipped measuring device 50 as components having an FBG sensing function, which will be described later.

[0079] 6 is a schematic enlarged view of the sensing optical fiber 40 used in the catheter tip position confirmation device 2A according to this embodiment. The sensing optical fiber 40 comprises multiple (seven in this embodiment) cores 41 and a cladding 42 located on the outer periphery of the cores 41. The sensing optical fiber 40 is a type of multicore fiber, as it has multiple cores 41 arranged in a single cladding 42. These multiple cores 41 form a single-mode transmission path.

[0080] The sensing optical fiber 40 is provided with a plurality of diffraction gratings 43 at intervals according to the position in the longitudinal direction bt in each core 41. Specifically, the intervals between the diffraction gratings 43 are adjusted so that they gradually increase in width as they move away from the base end 40b. Alternatively, the intervals may be adjusted so that they gradually decrease in width as they move away from the base end 40b.

[0081] The light source portion of the light-source-equipped measuring instrument 50 is a detecting light light source that emits detecting light having a band from the base end 40b of the sensing optical fiber 40 to the core 41. The measuring instrument portion of the light-source-equipped measuring instrument 50 also has an FBG sensing function that monitors the wavelength characteristics of the reflected light that is produced when the detecting light that has been incident on the core 41 of the sensing optical fiber 40 is reflected by one of the diffraction gratings 43. The FBG sensing function is as described in, for example, U.S. Patent No. 7,781,724 (US7,781,724B2).

[0082] The catheter tip position confirmation device 2A according to this embodiment will be described below while explaining the FBG sensing function. "FBG" in FBG sensing stands for Fiber Bragg Gratings, and refers to the portion of the core 41 that is engraved with multiple diffraction gratings (Gratings) 43. The portion corresponding to this FBG becomes the sensor unit.

[0083] When detection light having a band (broad wavelength) is incident from the base end 40b of the core 41 and transmitted through the sensing optical fiber 40, a specific wavelength component λ 1 proportional to the interval L of the diffraction grating 43 is generated when passing through the part corresponding to the FBG. Ｂ is reflected, and other wavelength components are transmitted. Ｂ is called the Bragg wavelength.

[0084] 7 is a graph showing the results of monitoring the wavelength characteristics of the reflected light that is generated when the detection light that is incident on the core 41 of the sensing optical fiber 40 is reflected by one of the diffraction gratings 43. When no external force is applied to the portion of the core 41 of the sensing optical fiber 40 that corresponds to the FBG, the pulses of the reflected light are arranged at equal intervals, as shown by the solid line.

[0085] When an external force is applied to a portion of the core 41 of the sensing optical fiber 40 that corresponds to the FBG, the sensing optical fiber 40 and the core 41 expand and contract at the portion to which the external force is applied. With this expansion and contraction, the spacing of the diffraction grating 43 changes (spacing L' after the change), and further, the Bragg wavelength λ Ｂ (After the change, the Bragg wavelength λＢ In FIG. 7, the dotted line graph indicates the Bragg wavelength λ Ｂ ' pulse.

[0086] Bragg wavelength λ Ｂ From the change in the wavelength λ′ and the change in the spacing of the diffraction grating 43, the following equation 1 can be derived: L′−L=a(λ Ｂ ′-λ Ｂ ) ...Equation 1 (In the above equation 1, a is a constant)

[0087] In the above formula 1, L'-L is the amount of expansion and contraction of the portion of the core 41 of the sensing optical fiber 40 to which an external force is applied, and λ Ｂ ′-λ Ｂ is the shift amount of the Bragg wavelength. Furthermore, if the spacing L of the diffraction grating 43 is specified, the position of the core 41 in the axial direction bt is specified.

[0088] Therefore, the wavelength characteristic of the reflected light (more specifically, the Bragg wavelength shift amount λ ) of the detection light incident on the sensing optical fiber 40 and reflected by one of the diffraction gratings 43 is Ｂ ′-λ Ｂ ) with the measuring instrument 32, the location where the external force is applied in the sensing optical fiber 40 and the strain caused by the external force can be determined. This completes the FBG sensing in the core 41 of the sensing optical fiber 40.

[0089] 6 , the cores 41 are arranged dispersedly in the circumferential direction or radial direction within the sensing optical fiber 40. Therefore, by performing FBG sensing on each core 41, it is possible to determine the state of strain at the circumferential direction or radial position within the sensing optical fiber 40. Therefore, by analyzing the results of FBG sensing on all the cores 41, it is possible to estimate where, in which direction, and to what extent the sensing optical fiber 40 is bent in the axial direction bt, and it is possible to grasp the shape and attitude of the sensing optical fiber 40.

[0090] As described above, according to this embodiment, it is possible to determine the distance between the tip 10t of the optical fiber 10 and the object 4, such as the inner wall of an internal organ of a living body, and therefore it is possible to grasp the positional relationship between the object 4 and the tip 3t ​​of the catheter 3. Furthermore, according to this embodiment, the sensing optical fiber 40 is arranged along the optical fiber 10, and a measuring device with an FBG sensing function is provided, so it is possible to grasp the shape and posture of the catheter 3.

[0091] Furthermore, the catheter tip position confirmation device 2A of this embodiment is equipped with a catheter visualization mechanism, as in the first embodiment, which allows the position of the tip 3t ​​of the catheter 3 to be visually confirmed from outside the body, and also allows the positional relationship between an object 4 such as the stomach wall and the tip 3t ​​of the catheter 3 to be grasped, as well as the shape and posture of the catheter 3, enabling more accurate treatment.

[0092] The above-described embodiment and modifications merely show examples of typical forms of the present invention, and the present invention is not limited to the above-described embodiment and modifications. For example, when providing a catheter visualization mechanism in the catheter tip position confirmation device 2A according to the second embodiment, the configurations of Modifications 1 and 2 of the first embodiment can be applied, in which a double-clad fiber or a multi-core fiber is used instead of the optical fiber 10 in which two types of optical fibers run parallel to each other.

[0093] In addition, those skilled in the art may implement various modifications in accordance with conventionally known knowledge without departing from the gist of the present invention. As long as such modifications still comprise the configuration of the catheter tip position confirmation device and medical catheter set of the present invention, they are of course included in the scope of the present invention.

[0094] 1, 1A: Medical catheter set, 2, 2A: Catheter tip position confirmation device, 3: Catheter, 4: Object, 10: Optical fiber, 11A: Core, 12A-1: First clad, 12A-2: Second clad, 13: Branching section, 20, 20A: Light source, 21: Measurement light, 22: Visual light, 30: Analyzer, 31: Photodetector, 32: Optical analyzer, 40: Sensing optical fiber, 41: Core, 42: Clad, 43: Diffraction grating, 50: Measuring device with light source (detection light source, measuring device)

Claims

1. A catheter tip position confirmation device comprising: an optical fiber having a base end and a tip end, the tip end being positioned at or near the tip of a catheter; a first light source that inputs measurement light from the base end into the optical fiber; a second light source that inputs visibility light from the base end into the optical fiber; and an analyzer having the function of measuring the distance between the tip end of the optical fiber and an object from signal information of return light when the measurement light emitted from the tip end of the optical fiber is reflected by an object and from signal information of the measurement light, or analyzing information relating to the state of the object and / or the tip of the catheter, wherein the visibility light is emitted from or near the tip end of the optical fiber.

2. A catheter tip position confirmation device according to claim 1, wherein the analyzer has a function of analyzing information relating to the state of the tip of the catheter, and the information relating to the state of the tip of the catheter is information relating to at least one state selected from the group consisting of three states: bending at the tip of the catheter, breaking at the tip of the catheter, and pressure acting on the tip of the catheter.

3. A catheter tip position confirmation device according to claim 1, wherein the visualizing light is visible light or near-infrared light.

4. A catheter tip position confirmation device according to claim 1, wherein the target object is the inner wall of an internal organ of a living body.

5. A catheter tip position confirmation device according to claim 1, wherein the measurement light emitted by the first light source is laser light.

6. A catheter tip position confirmation device according to claim 1, wherein the measurement light emitted by the first light source is time-varying light.

7. A catheter tip position confirmation device according to claim 6, wherein the analyzer has a function of monitoring the change over time of the returned light.

8. A catheter tip position confirmation device according to claim 1, further comprising a spectroscope for dispersing the returned light, and the analyzer has a function for monitoring the wavelength characteristics of the dispersed light dispersed by the spectroscope.

9. A catheter tip position confirmation device according to claim 1, wherein the optical fibers are two types of optical fibers: a first optical fiber having a single-mode transmission path and a second optical fiber having a multi-mode transmission path, the measurement light is incident on the first optical fiber, and the visualization light is incident on the second optical fiber.

10. A catheter tip position confirmation device according to claim 1, wherein the optical fiber has a single-mode transmission path and a multi-mode transmission path, and the measurement light is incident on the single-mode transmission path, and the visualization light is incident on the multi-mode transmission path.

11. A catheter tip position confirmation device as claimed in claim 1, comprising: a core provided with a plurality of diffraction gratings at intervals according to longitudinal position, and a cladding located on the outer periphery of the core, a sensing optical fiber arranged along the optical fiber; a detection light source that inputs detection light having a band from the base end of the sensing optical fiber; and a measuring instrument having an FBG sensing function by monitoring the wavelength characteristics of light reflected by any of the plurality of diffraction gratings from the detection light input to the sensing optical fiber.

12. A medical catheter set comprising a catheter tip position confirmation device according to any one of claims 1 to 11 and a catheter.

13. A medical catheter set according to claim 12, wherein the optical fiber in the catheter tip position confirmation device is inserted into the catheter, and the tip of the optical fiber is located at or near the tip of the catheter.

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