Metal wire for medical device, and guide wire

Abstract

To provide a metal wire for a medical device, in which the degree of susceptibility to shape set due to bending can be varied.SOLUTION: The metal wire for a medical device includes: a predetermined region having a coating exhibiting at least one color selected from a predetermined color group; and a specific region having a coating exhibiting at least one color selected from a specific color group.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a metal wire for a medical device, a medical device, and a method for manufacturing a metal wire for a medical device. [Background technology]

[0002] Guidewires used for inserting a catheter or the like into a blood vessel are known. In such guidewires, a wire (metal wire) made of a superelastic alloy such as a nickel-titanium alloy may be used as a core material. Superelastic alloys have a property of being less prone to bending. It is known that nickel-titanium alloys lose their superelastic properties by being subjected to heat treatment, making them more prone to bending. For example, Patent Documents 1 and 2 disclose guidewires that utilize such properties and improve shaping performance by subjecting a metal wire to heat treatment. The "metal wire" is also called a core, wire, core wire, core shaft, or metal wire for medical devices. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 161832 Brochure [Patent Document 2] JP 2017-153615 A Summary of the Invention [Problem to be solved by the invention]

[0004] In this way, metal wires may be processed by utilizing the change in the physical properties of metals due to heat treatment. Methods for heat treating metal wires include annealing in an electric furnace and heat treatment using a laser. The above-mentioned patent documents do not take into consideration changing the degree of susceptibility to bending. Note that such problems are not limited to the vascular system, but are common to medical devices inserted into various organs in the human body, such as the lymphatic system, biliary system, urinary system, respiratory system, digestive system, secretory glands, and reproductive organs, and to metal wires used in these medical devices.

[0005] The present invention has been made to solve at least part of the above-mentioned problems, and has an object to provide a metal wire for medical devices that has a variable degree of susceptibility to bending. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0007] (1) According to one aspect of the present invention, there is provided a metal wire for a medical device, the metal wire for a medical device comprising a predetermined region having a coating exhibiting at least one color selected from a predetermined color group, and a specific region having a coating exhibiting at least one color selected from a specific color group. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a shape test. [Diagram 2] 1 is a table showing the physical properties of each region of a metal wire. [Diagram 3] FIG. 1 is an explanatory diagram illustrating the configuration of a medical device according to a first embodiment. [Figure 4] FIG. 1 is a diagram showing the relationship between coating thickness and color. [Diagram 5] FIG. 2 is a diagram showing an example of a tip portion of a metal wire. [Figure 6]FIG. 2 is a diagram showing an example of the surface structure of the tip of a metal wire. [Figure 7] FIG. 2 is an enlarged view of the tip of the metal wire. [Figure 8] 1 is a flow chart illustrating a method for manufacturing a medical device. [Figure 9] 13 is a diagram showing an example of a tip portion of a metal wire according to a second embodiment. FIG. [Figure 10] 13 is a diagram showing an example of a tip portion of a metal wire according to a third embodiment. FIG. [Figure 11] 13 is a diagram showing an example of a tip portion of a metal wire according to a fourth embodiment. FIG. [Figure 12] 13 is a diagram showing an example of a tip portion of a metal wire according to a fifth embodiment. FIG. [Figure 13] 13 is a diagram showing an example of a tip portion of a metal wire according to a sixth embodiment. FIG. [Figure 14] FIG. 13 is a diagram showing an example of a tip portion of a metal wire according to a seventh embodiment. [Figure 15] 13 is a diagram showing an example of a tip portion of a metal wire according to an eighth embodiment. FIG. [Figure 16] FIG. 13 is an enlarged view of a tip portion of a metal wire according to a ninth embodiment. [Figure 17] 13 is a flowchart showing a method for manufacturing a medical device according to a ninth embodiment. [Figure 18] FIG. 23 is an enlarged view of a tip portion of a metal wire according to a tenth embodiment. [Figure 19] 13 is a flowchart showing a method for manufacturing a medical device according to a tenth embodiment. [Figure 20] FIG. 23 is an enlarged view of a tip portion of a metal wire according to an eleventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Shaping performance can be improved by applying heat treatment to metal wire. In the following, shaping tests were conducted on metal wires with first and second regions, which have different physical properties, and an unheat-treated region. As a result, it was found that the first region is most susceptible to bending, and the second region is less susceptible to bending than the first region.

[0010] FIG. 1 is a diagram for explaining the shape test. FIG. 1(A) shows a test tool used in the shape test. The test tool includes a silicon base 901 and a pin 902 with a diameter of 0.5 mm. The metal wire to be the sample SW is a wire made of nickel-titanium alloy, and has a first region, a second region, and an unheated region formed by changing the heat treatment conditions. First, as shown in FIG. 1(A), the tip of the sample SW is placed on the base 901, the first region of the sample SW is pressed down by the pin 902, and the sample SW is pulled out vertically upward (in the direction of the white arrow) while a load of 0.98 N is applied to the pin 902. The pulling length is set to 2 mm. Then, the angle of the curved shape of the pulled-out portion of the sample SW is measured, and the shape angle is determined. The second region of the sample SW and the unheated region of the sample SW are also tested in the above-mentioned procedure, and the shape angles are measured.

[0011] FIG. 1(B) shows the results of the shape test (shape angle at each pulled portion of the sample SW). FIG. 2 is a table showing the physical properties of each region of the metal wire that becomes the sample SW. The shape angle of the first region is 60°. The first region is heat-treated at a first temperature. The thickness of the oxide film of the first region is 100 nm or more. The oxide film of the first region exhibits at least one color selected from a first color group. The first color group includes green, blue-green, red-purple, and yellow. The shape angle of the second region is 18°. The second region is heat-treated at a second temperature. The thickness of the oxide film of the second region is 10 nm or more and 30 nm or less. The oxide film of the second region exhibits at least one color selected from a third color group. The third color group includes purple and gold. The shape angle of the transition region is estimated to be greater than 18° and less than 60°. The transition region is formed by the heat applied to the first region being conducted on the sample SW. The heat treatment temperature of the transition region is estimated to be lower than the first temperature and higher than the second temperature. The thickness of the oxide film in the transition region is greater than 30 nm and less than 100 nm. The oxide film in the transition region exhibits at least one color selected from a second color group. The second color group includes blue and white. The shape angle of the unheated treatment region is 9°. The thickness of the oxide film in the unheated treatment region is approximately 0 nm. The color of the oxide film in the unheated treatment region exhibits at least one color selected from a fourth color group. The fourth color group includes gray and silver. The magnitude relationship between the first temperature and the second temperature is first temperature>second temperature.

[0012] As is clear from FIG. 1(B) and FIG. 2, a correlation was obtained in which the thicker the oxide film of the metal wire, the larger the shape angle (curved angle). There is a correlation between the thickness and color of the oxide film, as described below. In other words, it was found that there is a correlation between the color of the oxide film and the ease of bending. As shown in FIG. 2, it is presumed that the shape angle of the transition region between the first region and the second region has the following relationship: first region>transition region>second region. The first region corresponds to the "predetermined region" in the claims. The transition region corresponds to the "specific region" in the claims. The second region corresponds to the "predetermined region" in the claims. The first color group corresponds to the "predetermined color group" in the claims. The second color group corresponds to the "specific color group" in the claims. The third color group corresponds to the "predetermined color group" in the claims. The first temperature corresponds to the "predetermined temperature" in the claims. The second temperature corresponds to the "specific temperature" in the claims.

[0013] Taking advantage of this, in each of the embodiments described below, medical devices with varying degrees of ease of bending were successfully produced.

[0014] First Embodiment FIG. 3 is an explanatory diagram illustrating the configuration of the medical device 1 of the first embodiment. The medical device 1 is a guidewire. The medical device 1 is used when inserting other medical devices (catheters, etc.) into blood vessels or digestive organs. The medical device 1 includes a first metal wire 10. The medical device 1 includes a second metal wire 20. The medical device 1 includes a coil 40. The medical device 1 includes a distal tip 51. The medical device 1 includes a base-end joint 52. The distal end portion 100 of the first metal wire 10 has a coating formed by heat treatment. The medical device 1 has improved tendency to bend at the distal end portion 100 (shaping performance).

[0015] For the sake of convenience, FIG. 3 includes parts in which the relative ratio of the sizes of the components is different from the actual ratio. FIG. 3 includes parts in which some of the components are exaggerated. FIG. 3 shows an axis O (dotted line) that passes through the center of the medical device 1. The axis O coincides with the axis that passes through the centers of the first metal wire 10, the second metal wire 20, and the coil 40. The axis O may be different from the central axis of each of the components described above. FIG. 3 illustrates XYZ axes that are mutually perpendicular. The X axis corresponds to the length direction of the medical device 1. The Y axis corresponds to the thickness direction of the medical device 1. The Z axis corresponds to the width direction of the medical device 1. The left side (-X axis direction) of FIG. 3 is called the "distal side" of the medical device 1 and each component, and the right side (+X axis direction) of FIG. 3 is called the "base side" of the medical device 1 and each component. In addition, for the medical device 1 and each component, the end portion located on the distal side is called the "distal end", and the distal end and its vicinity are called the "distal portion". The end located on the proximal side is called the "proximal end," and the proximal end and its vicinity are called the "proximal end portion." The distal end side is inserted into the living body, and the proximal end side is operated by the doctor. These points are the same in Fig. 3 and subsequent figures.

[0016] The first metal wire 10 is a metal wire for a medical device. The first metal wire 10 is disposed on the distal end side of the medical device 1. The first metal wire 10 is disposed closer to the distal end side than the second metal wire 20. The first metal wire 10 is formed of, for example, a nickel-titanium alloy or an alloy of nickel-titanium and another metal. The first metal wire 10 has, in order from the distal end side to the proximal end side, a first section 11, a second section 12, a third section 13, a fourth section 14, and a fifth section 15. The thickness, width, and length of each section can be determined arbitrarily.

[0017] The first portion 11 is the portion of the first metal wire 10 that is located closest to the tip. The first portion 11 is the portion of the first metal wire 10 that is the thinnest. A coating containing titanium oxide is formed on the surface of the first portion 11. The first portion 11 is press-processed to improve the ease with which it can bend (shaping performance). Details will be described later. Hereinafter, the entire first portion 11, except for a portion on the base end side, will be referred to as the "tip portion 100 of the first metal wire 10" or simply the "tip portion 100".

[0018] The second portion 12 is a portion of the first metal wire 10 located between the first portion 11 and the third portion 13. The third portion 13 is a portion of the first metal wire 10 located between the second portion 12 and the fourth portion 14. The fourth portion 14 is a portion of the first metal wire 10 located between the third portion 13 and the fifth portion 15. The thickness of the second portion 12 becomes thinner toward the tip. The thickness of the third portion 13 becomes thinner toward the tip. The thickness of the fourth portion 14 becomes thinner toward the tip. The rate of change in thickness of the second portion 12, the rate of change in thickness of the third portion 13, and the rate of change in thickness of the fourth portion 14 are different from each other. The fifth portion 15 is a portion of the first metal wire 10 located closest to the base end. The fifth portion 15 has a substantially cylindrical shape and is the portion of the first metal wire 10 where the thickness is maximum.

[0019] In this embodiment, "substantially constant" is synonymous with "generally constant" and means that the shape is generally constant while allowing for deviations due to manufacturing errors, etc. Similarly, "substantially cylindrical / substantially truncated conical" is synonymous with "generally cylindrical / generally truncated conical" and means that the shape is generally the same while allowing for deviations due to manufacturing errors, etc. In this embodiment, "same" and "equal" do not necessarily mean that the shape is strictly the same, but also mean that differences due to manufacturing errors, etc. are allowed.

[0020] The second metal wire 20 is disposed on the proximal side of the medical device 1. The second metal wire 20 is disposed closer to the proximal side than the first metal wire 10. The second metal wire 20 is a substantially cylindrical member having a constant outer diameter. The outer diameter of the second metal wire 20 is the same as the outer diameter of the fifth portion 15 of the first metal wire 10. The second metal wire 20 is made of a material having a larger Young's modulus in a linear deformation region than the first metal wire 10, for example, a stainless steel alloy such as SUS304 or SUS316.

[0021] The joint 30 is a portion where the first metal wire 10 and the second metal wire 20 are joined by welding. The joint 30 may be formed by fixing the first metal wire 10 and the second metal wire 20 by a means other than welding, for example, a fixture. The member where the first metal wire 10 and the second metal wire 20 are joined is a core shaft. The joint 30 is formed between the base end surface of the fifth portion 15 of the first metal wire 10 and the tip surface of the second metal wire 20. In the illustrated example, the joint 30 is a plane shape that is approximately perpendicular to the axis O. The joint 30 may be inclined with respect to the axis O. The first metal wire 10 and the second metal wire 20 are fixed by this joint 30.

[0022] Of the first metal wire 10, the tip sides of the first portion 11, the second portion 12, and the third portion 13 are covered by the coil 40. Of the first metal wire 10, the base end side of the third portion 13, the fourth portion 14, and the fifth portion 15 are not covered by the coil 40 and are exposed from the coil 40. The base end of the second metal wire 20 is used when a doctor grasps the medical device 1.

[0023] The coil 40 is formed of wire 41 wound in a spiral shape, and has a substantially cylindrical shape. The coil 40 may be a single-strand coil formed by winding one wire into a single strand. The coil 40 may be a multi-strand coil formed by winding a plurality of wires into multiple strands. The coil 40 may be a single-strand stranded coil formed by winding a strand obtained by twisting a plurality of wires into a single strand. The coil 40 may be a multi-strand stranded coil formed by using a plurality of strands obtained by twisting a plurality of wires together, and winding each strand into multiple strands. The wire diameter of the wire 41 of the coil 40, the outer diameter and inner diameter of the coil 40, and the length of the coil 40 can be determined arbitrarily.

[0024] The wire 41 can be formed from, for example, stainless steel alloys such as SUS304 and SUS316, nickel-titanium alloys, radiopaque alloys such as piano wire, nickel-chromium alloys, cobalt alloys, radiopaque alloys such as gold, platinum, tungsten, and alloys containing these elements (e.g., platinum-nickel alloys), as well as other known materials.

[0025] The distal tip 51 is provided at the distal end of the medical device 1. The distal tip 51 integrally holds the distal end of the first portion 11 of the first metal wire 10 and the distal end of the coil 40. The proximal joint 52 faces the middle portion of the medical device 1. The proximal joint 52 integrally holds a part of the third portion 13 of the first metal wire 10 and the proximal end of the coil 40. The distal tip 51 is formed of any bonding agent, for example, a metal solder such as silver solder, gold solder, zinc, a Sn-Ag alloy, or a Au-Sn alloy. The proximal joint 52 is formed of any bonding agent, for example, a metal solder such as silver solder, gold solder, zinc, a Sn-Ag alloy, or a Au-Sn alloy. The distal tip 51 and the proximal joint 52 may use the same bonding agent or different bonding agents.

[0026] Hereinafter, the coating formed on the tip portion 100 of the first metal wire 10 and the detailed configuration of the tip portion 100 will be described with reference to Figs. 4 to 7. When a metal wire containing titanium (Ti), such as a nickel-titanium alloy or an alloy of nickel-titanium and another metal, like the first metal wire 10 described in Fig. 3, is subjected to heat treatment, the titanium is oxidized to form a titanium oxide coating on the surface of the metal wire. Hereinafter, the titanium oxide coating will also be simply referred to as "coating".

[0027] FIG. 4 is a diagram showing the relationship between the thickness and color of the coating. The higher the heat treatment temperature, the thicker the coating formed on the metal wire. The lower the heat treatment temperature, the thinner the coating formed on the metal wire. The thickness of the coating is related to the heat treatment temperature. The thickness of this coating is related to the color of the appearance of the metal wire. As shown in FIG. 4, when the coating is "green", the coating is the thickest, when the coating is "blue-green", the coating is the second thickest, when the coating is "red-purple", the coating is the third thickest, when the coating is "yellow", the coating is the fourth thickest, when the coating is "white", the coating is the fifth thickest, when the coating is "blue", the coating is the sixth thickest, when the coating is "purple", the coating is the seventh thickest, and when the coating is "gold", the coating is the eighth thickest. Note that when heat treatment is not performed and no coating is formed, the appearance color of the metal wire is gray or silver.

[0028] In this embodiment, "green" includes green, lime green, sky green, and other green-based colors. "Blue-green" includes peacock green, aquamarine, turquoise, and other colors that are intermediate between green and blue. "Red-purple" includes claret, plum, magenta, and other colors that are intermediate between red and purple. "Yellow" includes yellow, lemon yellow, topaz, and other yellow-based colors. "White" includes white, silver white, oyster white, and other white-based colors. "Blue" includes blue, cyan, navy blue, and other blue-based colors. "Purple" includes purple, violet, grape, and other purple-based colors. "Gold" includes antique gold, buff, beige, and other gold-based colors.

[0029] The color of the coating can be visually identified by the appearance of the heat-treated metal wire. Specifically, the worker takes a photograph of the appearance of the heat-treated metal wire using a digital microscope "VHX-7000" (manufactured by Keyence Corporation). The worker then visually checks the photographed appearance to identify the color of the coating. That is, the above-mentioned color of the coating is the color under the light environment of the digital microscope VHX-7000. The location where the oxide coating is confirmed (the location where the appearance photograph is taken) is the side surface viewed from the Y-axis direction (the side surface shown in FIG. 7(B) described later). The first color group C1 includes green, blue-green, red-purple, and yellow. The third color group C3 includes purple and gold. The second color group C2 includes white and blue. The first color group C1 has a relatively thick coating. The third color group C3 has a relatively thin coating. The second color group C2 has a coating thickness that is thinner than the coatings of the first color group C1 and thicker than the coatings of the third color group C3.

[0030] FIG. 5 is a diagram showing an example of the tip portion 100 of the first metal wire 10. FIG. 5(A) is a line diagram in which the color of the coating of the tip portion 100 is represented by the type of hatched line. FIG. 5(B) is a photograph of the tip portion 100. The line diagram corresponds to the photograph. Both the line diagram and the photograph in FIG. 5 show the width direction of the flat shape of the first metal wire 10. As shown in the figure, the tip portion 100 of the first metal wire 10 has portions 91a to 91l from the tip to the base end. As the alphabet attached to the end progresses from a to c, the position in the longitudinal direction of the first metal wire 10 moves toward the base end side. At least a part of the unheated processed portion at the tip of the first metal wire 10 may be cut and removed during the manufacture of the medical device 1 using the first metal wire 10. The unheated processed portion at the tip of the first metal wire 10 may be used as it is without being cut during the manufacture of the medical device 1 using the first metal wire 10.

[0031] As shown in the figure, the portion 91a is silver, indicating that it is not heat-treated. The portion 91b has a blue coating. The portion 91c has a white coating. The portion 91d has a yellow coating. The portion 91e has a reddish purple coating. The portion 91f has a green coating. The portion 91g has a cyan coating. The portion 91h has a reddish purple coating. The portion 91i has a white coating. The portion 91j has a blue coating. The portion 91k has a purple coating. The portion 91l has a gold coating. In FIG. 5(A), for convenience of illustration, the boundary between a certain portion and another portion adjacent to the certain portion is clearly shown. However, as shown in FIG. 5(B), the boundary between a certain portion and another portion may be a gradation in which the color of the coating changes stepwise. As shown in FIG. 5(B), the color of the coating of each of the portions 91b to 91l (including not only the color itself but also the hue and texture) and the color gradation at the boundaries between each of the portions 91b to 91l are developed by heat treatment of the metal wire.

[0032] The "first region A1" is a region located at the center of the tip portion 100 of the first metal wire 10. The first region A1 has a coating of a color included in the first color group C1 (specifically, at least one of green, cyan, magenta, and yellow).

[0033] The "distal transition region AT1" is a region at a different position in the longitudinal direction from the first region A1. The distal transition region AT1 is located on the distal side of the first region A1 of the first metal wire 10. The distal transition region AT1 has a coating of a color included in the second color group C2 (specifically, at least one of white and blue). The distal transition region AT1 is adjacent to the distal end of the first region A1. The "base transition region AT2" is a region at a different position in the longitudinal direction from the first region A1. The base transition region AT2 is located on the proximal side of the first region A1 of the first metal wire 10. The base transition region AT2 has a coating of a color included in the second color group C2 (specifically, at least one of white and blue). The base transition region AT2 is adjacent to the proximal end of the first region A1. The region having a coating of a color included in the second color group C2 is the transition region AT. The distal transition region AT1 is the transition region AT. The proximal transition region AT2 is the transition region AT. The coating of the transition region AT (the distal transition region AT1 and the proximal transition region AT2) exhibits a gradation that includes colors (white, blue) included in the second color group C2. In the transition region AT, the white coating is located closer to the first region A1 than the blue coating. The distal transition region corresponds to the "tip specific region" in the claims. The proximal transition region corresponds to the "proximal specific region" in the claims.

[0034] The "second region A2" is a region at a different position in the longitudinal direction from the first region A1. The second region A2 is located on the opposite side of the first region A1 from the transition region AT (specifically, the base end side transition region AT2) of the first metal wire 10. The second region A2 has a coating of a color included in the third color group C3 (specifically, at least one of purple and gold). The second region A2 is adjacent to the base end of the transition region AT. The second region A2 is adjacent to the base end of the base end side transition region AT2. In other words, the second region A2 is provided at a position away from the first region A1 in the longitudinal direction of the first metal wire 10.

[0035] As shown in FIG. 2, the first region A1 has a shape angle of 60° when the shape test is performed. The transition region AT has a shape angle greater than 18° and less than 60° when the shape test is performed. The second region A2 has a shape angle of 18° when the shape test is performed. The unheated treated region has a shape angle of 9° when the shape test is performed. The first region A1 has a shape angle greater than the transition region AT when the shape test is performed. The first region A1 has a shape angle greater than the second region A2 when the shape test is performed.

[0036] FIG. 6 is a diagram showing an example of the surface structure of the tip portion 100 of the first metal wire 10. FIG. 6 shows an image obtained when the first region A1 of the first metal wire 10 was observed with a TEM (transmission electron microscope) "JEM-2100F" (manufactured by JEOL Ltd.). FIG. 6(A) is a line diagram of the first region A1 obtained by the TEM. FIG. 6(B) is a photograph of the first region A1 obtained by the TEM. FIG. 6(A) and FIG. 6(B) show the same image.

[0037] As shown in Figs. 6(A) and (B), surface segregation occurs on the surface of the heat-treated first metal wire 10 with the formation of a titanium oxide coating, forming a layer. The outermost layer is the titanium oxide coating CO1. The thickness T1 of the coating CO1 in the first region A1 of the first metal wire 10 is 100 nm or more. A method for obtaining the thickness T1 of the coating CO1 will be described. An operator observes with a TEM the part of the first region A1 of the first metal wire 10 that is colored to indicate the thinnest coating thickness (yellow in the case of the first metal wire 10 shown in Fig. 5), and obtains the thickness T1 of the coating CO1 by measuring the thickness of the part with a relatively thin coating in the image obtained by the TEM.

[0038] In the first metal wire 10, the thickness T1 of the coating CO1 in the first region A1 is greater than the thickness of the coating in the transition region AT. A method for obtaining the thickness of the coating in the transition region AT will be described. An operator performs TEM observation of the portion of the color representing the thickest coating (white in the case of the first metal wire 10 shown in FIG. 5) and measures the thickness of the relatively thicker portion of the coating in the image obtained by TEM, thereby obtaining the thickness of the coating in the transition region AT.

[0039] In the first metal wire 10, the thickness of the coating in the second region A2 is 10 nm or more and 30 nm or less. Regarding the lower limit of the thickness of the third coating, the worker performs TEM observation of the part of the color representing the thinnest coating thickness (gold in the case of the first metal wire 10 shown in FIG. 5) and measures the thickness of the relatively thin coating part in the image obtained by the TEM. Regarding the upper limit of the thickness of the third coating, the worker performs TEM observation of the part of the color representing the thickest coating thickness (purple in the case of the first metal wire 10 shown in FIG. 5) and measures the thickness of the relatively thick coating part in the image obtained by the TEM.

[0040] In the cross-sectional view of the first metal wire 10 shown in Figures 6(A) and (B), an arbitrary position in the outermost layer (titanium oxide coating CO1) is defined as a first position P1. An arbitrary position in the second outermost layer is defined as a second position P2. In this case, the titanium content at the first position P1 is greater than the titanium content at the second position P2 (titanium: first position P1>second position P2). The nickel (Ni) content at the second position P2 is greater than the nickel content at the first position P1 (nickel: first position P1<second position P2).

[0041] The above-mentioned bias in titanium and nickel is due to the surface segregation of titanium that occurs toward the surface of the first metal wire 10 as a result of heat treatment. In Figures 6(A) and (B), the titanium and nickel contents at the first position P1 and the second position P2 of the first region A1 of the first metal wire 10 have been described. In the transition region AT and the second region A2 of the first metal wire 10, the titanium content is greater than the second position P2, and the nickel content is greater than the first position P1, similar to the first region A1.

[0042] FIG. 7 is an enlarged view of the tip portion 100 of the first metal wire 10. FIG. 7(A) shows a side view of the tip portion 100 as viewed from the Z-axis direction. FIG. 7(B) shows a side view of the tip portion 100 as viewed from the Y-axis direction. In FIG. 7, the coil 40 is omitted. The first portion 11 has a flat shape including a first press portion 111, a transition portion 112, and a second press portion 113. The first press portion 111 is a portion that has been pressed at a first drawing ratio. The first press portion 111 has a relatively wide flat shape. The second press portion 113 is a portion that has been pressed at a second drawing ratio that is smaller than the first drawing ratio. The second press portion 113 is closer to a cylinder than the first press portion 111. The second press portion 113 has an elliptical cylindrical shape. The transition section 112 is a section between the first press section 111 and the second press section 113 where the drawing rate and the outer shape gradually change.

[0043] A coating is formed by heat treatment on the first press section 111, the transition section 112, and the entire second press section 113 except for the base end. In the illustrated example, the tip side of the tip of the first press section 111 is an unheat-treated portion. A tip side transition area AT1 is formed on the base end side of the tip of the first press section 111. A first area A1 is formed between the center and base end of the first press section 111. A base side transition area AT2 is formed between the tip and base end of the transition section 112. A second area A2 is formed on the entire second press section 113 except for the base end. Note that the correspondence between the first area A1, the transition area AT, the second area A2, the first press section 111, the transition section 112, and the second press section 113 is merely an example and may be changed arbitrarily.

[0044] In the tip portion 100 of the first metal wire 10, the coating (first region A1, transition region AT, second region A2) is formed in the thickness direction of the flat shape of the first metal wire 10. In other words, the coating is formed on surfaces 111a, 112a, 113a in the thickness direction of the first metal wire 10. In the tip portion 100 of the first metal wire 10, the coating (first region A1, transition region AT, second region A2) is formed in the width direction of the flat shape of the first metal wire 10. In other words, the coating is formed on surfaces 111b, 112b, 113b in the width direction of the first metal wire 10.

[0045] The distal tip 51 (broken line) is attached to the distal portion 100 of the first metal wire 10, closer to the distal side than the first region A1. Specifically, the distal tip 51 is attached to a distal transition region AT1 provided closer to the distal side than the first region A1. In the illustrated example, the base end of the distal tip 51 is located slightly closer to the distal side than the base end of the distal transition region AT1, but the base end of the distal tip 51 may be located at any position within the range of the distal transition region AT1.

[0046] Fig. 8 is a flow chart showing a method for manufacturing the medical device 1. In step S10, an operator prepares a metal wire made of a nickel-titanium alloy. The metal wire may be made of an alloy of nickel-titanium and another metal. In step S12, an operator presses the tip of the metal wire. In step S12, as described in Figs. 7(A) and (B), pressing is performed multiple times to form a first pressed portion 111, a transition portion 112, and a second pressed portion 113. In step S12, pressing may be performed only once.

[0047] In step S14, the worker performs heat treatment on the first region A1 at a first temperature. The heat treatment is performed by "laser heat treatment" in which a high-power laser is irradiated to the metal wire to heat it. The first temperature may be determined arbitrarily. The heat treatment may be performed by other heat treatment methods (for example, heat treatment using a heating furnace). As a result of step S14, a coating is formed on the first region A1 and the transition region AT (the distal transition region AT1 and the proximal transition region AT2). That is, the coating on the transition region AT (the distal transition region AT1 and the proximal transition region AT2) is formed by the heat of the laser irradiated to the first region A1 being conducted on the metal wire. The degree of heat treatment on the first region A1 is stronger than the degree of heat treatment on the transition region AT. The degree of susceptibility of the first region A1 to bending becomes stronger than that of the transition region AT. Step S14 is a step of forming a coating on the first region A1 and the transition region AT. The colors included in the first color group C1 in the first region A1 and the colors included in the second color group C2 in the transition region AT are developed by the first heat treatment.

[0048] In step S18, the operator performs a heat treatment on the second region A2 at a second temperature. The second region A2 is located on the proximal end side with respect to the first region A1. The second region A2 is located on the proximal end side with respect to the proximal end side transition region AT2. The heat treatment at the second temperature is performed by laser heat treatment. The heat treatment at the second temperature may be carried out by other heat treatment methods (for example, heat treatment using a heating furnace). The second temperature is lower than the first temperature (first temperature > second temperature). The first temperature and the second temperature can be measured by measuring the temperature of the metal wire during the heat treatment using a radiation thermometer. As a result of step S18, a film is formed on the second region A2. As a result of the heat treatment at the second temperature lower than the first temperature, the degree of heat treatment of the second region A2 is weaker than the degree of heat treatment of the first region A1. Consequently, the degree of tendency to have a bend in the second region A2 becomes weaker than that in the first region A1. Step S18 is a step of forming a film on the second region A2. The color of the film in the second region A2 is a color included in the third color group C3. The color of the film in the second region A2 is developed by the second heat treatment.

[0049] In steps S14 and S18, even when the heat treatment is performed with the laser output being the same (output: S14 = S18) or with the magnitude relationship reversed (output: S14 < S18), the relationship of the first temperature > the second temperature holds. This is due to the fact that, among the press-processed metal wires, as a result of irradiating the laser with respect to the XZ plane shown in FIG. 7(B), the irradiation area in step S14 (the areas of the first press part 111 and the transition part 112) is larger than the irradiation area in step S18 (the area of the second press part 113). In the present embodiment, the irradiation diameter of the laser is larger than the width of the first press part 111 in FIG. 7(B).

[0050] In step S22, the operator inspects the colors of the films in the first region A1, the transition region AT, and the second region A2. Specifically, the color of the film is inspected according to the following procedures a1 and a2. Procedures a1 and a2 do not necessarily need to be executed continuously. Specifically, procedure a1 may be executed before step S14. Step S22 is a step of inspecting the colors of the films in the first region A1, the transition region AT, and the second region A2. (a1) The operator determines that the heat treatment of step S14 has been completed normally when the color of the coating in the first region A1 corresponds to any of the colors included in the first color group C1 (FIG. 4) and the color of the coating in the transition region AT corresponds to any of the colors included in the second color group C2 (FIG. 4). The operator determines that the heat treatment of step S14 has not been completed normally when at least one of the following occurs: the color of the coating in the first region A1 does not correspond to any of the colors included in the first color group C1 and the color of the coating in the transition region AT does not correspond to any of the colors included in the second color group C2. (a2) If the color of the coating in the second region A2 corresponds to any of the colors included in the third color group C3 (FIG. 4), the worker determines that the heat treatment in step S18 has been completed normally. If the color of the coating in the second region A2 does not correspond to any of the colors included in the third color group C3, the worker determines that the heat treatment in step S18 has not been completed normally.

[0051] The first metal wire 10 described in FIG. 3 is manufactured by the above steps S10 to S22. The steps S10 to S22 are a method for manufacturing the metal wire 10 for a medical device. The metal wire 10 for a medical device manufactured by the steps S10 to S22 has a coating of a color included in the first color group C1, a coating of a color included in the second color group C2, and a coating of a color included in the third color group C3, which are developed by heat treatment of the metal wire. The metal wire 10 for a medical device manufactured by the steps S10 to S22 has been confirmed to have been normally heat-treated by inspection of each color of the coating (the color included in the first color group C1, the color included in the second color group C2, and the color included in the third color group C3). According to the step S22, when manufacturing a plurality of first metal wires 10, even if a plurality of metal wires having variations in dimensions, surface condition, etc. are used, the amount of heat applied to each metal wire (the degree of heat treatment) can be accurately and easily grasped, so that a first metal wire 10 of stable quality can be obtained.

[0052] In step S24, the worker prepares the coil 40. In step S26, the worker forms the tip tip 51 by joining the tip portion 100 of the first metal wire 10 (specifically, the tip side transition region AT1) and the tip of the coil 40 with any bonding agent, for example, a metal solder such as silver solder, gold solder, zinc, Sn-Ag alloy, or Au-Sn alloy. Since the titanium oxide coating has a property of having low wettability with solder, if the tip tip 51 is formed in the portion (first region A1) where the titanium oxide coating is formed thickly, there is a risk that the tip tip 51 will come off from the first metal wire 10 during use. For this reason, in step S26, it is preferable to form the tip tip 51 on the tip side of the first metal wire 10 relative to the portion (first region A1) where the titanium oxide coating is formed thickly. Furthermore, the portion of the first metal wire 10 where the titanium oxide coating is not formed (unheat-treated portion) has the property of being difficult to bend due to the superelasticity of the first metal wire 10, so if the tip tip 51 is formed on the portion where the titanium oxide coating is not formed (unheat-treated portion), it may be difficult to use. For this reason, in step S26, it is more preferable to form the tip tip 51 on the portion where the titanium oxide coating is relatively thin (the tip side transition region AT1). In step S26, the tip tip 51 may be formed after removing the coating in the tip side transition region AT1. Finally, the operator joins the first metal wire 10 and the second metal wire 20 to form the joint 30.

[0053] The metal wire 10 for medical devices and the medical device 1 including the same have a first region A1, a base-side transition region AT2, and a second region A2, in which the degree of heat treatment, i.e., the degree of tendency to bend, is changed from the distal end to the proximal end, and as described above, the degree of heat treatment (degree of tendency to bend) has a relationship of first region A1>transition region AT>second region A2, and becomes stronger toward the distal end. Therefore, it is possible to provide a medical device 1 that can be given a shape with a larger curvature toward the distal end. As a result, it becomes easier for a doctor to select a desired blood vessel at a branching point of a blood vessel in a procedure using the medical device 1.

[0054] As described above, the metal wire 10 for medical devices of the first embodiment includes the first region A1 and the transition region AT in which the coating colors C1, C2 are different from each other (FIG. 5). Therefore, it is possible to provide a metal wire 10 for medical devices in which the degree of heat treatment, i.e., the degree of tendency to bend, is changed to realize gradual change in physical properties. In addition, since the first region A1 and the transition region AT have different coating colors C1, C2, respectively, the tendency of the metal wire 10 for medical devices to bend can be identified by the appearance (color) of the first metal wire 10.

[0055] Moreover, according to the first embodiment of the metal wire 10 for medical devices, the coating in the transition region AT has a gradation that includes at least two or more colors included in the second color group C2 (FIG. 5). Therefore, even in the transition region AT of the first metal wire 10, the degree of heat treatment, i.e., the degree of tendency to develop a bending tendency, can be changed to realize a gradual change in physical properties. Moreover, the degree of the gradual change in physical properties in the transition region AT can be identified by the appearance of the first metal wire 10 (the color gradation that changes from white to blue).

[0056] Furthermore, according to the first embodiment of the metal wire 10 for medical devices, the second region A2 is provided on the opposite side of the first region A1 as viewed from the transition region AT (specifically, the base end transition region AT2) (FIG. 5). Therefore, it is possible to provide a metal wire 10 for medical devices that realizes a more finely gradual change in physical properties by further changing the degree of heat treatment, i.e., the degree of tendency to bend. In addition, since the second region A2 has a coating color C3 different from that of the first region A1 and the transition region AT, the tendency of the metal wire 10 for medical devices to bend can be identified by the appearance (color) of the first metal wire 10.

[0057] Furthermore, according to the first embodiment of the metal wire 10 for medical devices, the titanium content is high at the first position P1 (in other words, near the surface of the metal wire 10 for medical devices) which is located relatively outward compared to the second position P2, so that the biocompatibility and corrosion resistance of the metal wire 10 for medical devices can be improved. Furthermore, according to the first embodiment of the metal wire 10 for medical devices, the nickel content is low at the first position P1 (in other words, near the surface of the metal wire 10 for medical devices) which is located relatively outward compared to the second position P2, so that the biocompatibility can be improved.

[0058] Furthermore, according to the metal wire 10 for medical devices of the first embodiment, the thickness of the coating in the first region A1 is 100 nm or more, so that the tendency of the metal wire 10 for medical devices to develop a bending habit (shaping performance) can be further improved. Furthermore, according to the metal wire 10 for medical devices of the first embodiment, the thickness of the coating in the first region A1 is greater than the thickness of the coating in the transition region AT, so that the first region A1 can be configured to be more prone to develop a bending habit than the transition region AT. Furthermore, according to the metal wire 10 for medical devices of the first embodiment, the thickness of the coating in the second region A2 is 10 nm or more and 30 nm or less, so that the degree of tendency of the second region A2 to develop a bending habit is smaller than that of the first region A1, so that the metal wire 10 for medical devices that realizes a more finely gradual change in physical properties can be provided.

[0059] Furthermore, according to the medical device 1 of the first embodiment, the distal tip 51 is attached to the distal side of the first region A1 of the metal wire 10 for medical devices, which facilitates the brazing work for forming the distal tip 51 and makes it difficult for the metal wire 10 for medical devices to come off the distal tip 51. As a result, the manufacture of the medical device 1 can be made easier and the safety of the medical device 1 can be improved.

[0060] Furthermore, according to the medical device 1 of the first embodiment, the distal tip 51 is attached to the distal transition region AT1, which facilitates the brazing operation for forming the distal tip 51 and makes it difficult for the metal wire for medical devices 10 to become detached from the distal tip 51. Furthermore, the distal tip 51 is attached to the distal transition region AT1 provided on the distal side of the first region A1, which improves the ease with which the medical device 1 can develop a bending habit (shaping performance).

[0061] Furthermore, according to the manufacturing method of the metal wire 10 for medical devices of the first embodiment, the metal wire is subjected to a heat treatment (step S14) to form the first region A1 and the transition region AT, which are different in color from each other in the coating. Therefore, the metal wire 10 for medical devices, which realizes a gradual change in physical properties, can be manufactured by a single heat treatment.

[0062] Furthermore, according to the manufacturing method of the metal wire 10 for medical devices of the first embodiment, the second region A2 is formed by performing heat treatment (step S18) on the base end side of the metal wire from the first region A1. Therefore, by performing two heat treatments, steps S14 and S18, it is possible to manufacture the metal wire 10 for medical devices which realizes further gradual change in physical properties. In addition, since the temperature (second temperature) of the heat treatment for forming the second region A2 is lower than the temperature (first temperature) of the heat treatment for forming the first region A1 and the transition region AT, it is possible to easily change the thickness of the coating in the first region A1 and the thickness of the coating in the second region A2.

[0063] Furthermore, according to the manufacturing method of the metal wire 10 for medical devices of the first embodiment, since the colors C1, C2 of the coating are different between the first region A1 and the transition region AT, by inspecting the appearance of the metal wire (specifically, the colors of the coating in the first region A1 and the transition region AT), it is possible to easily determine whether the heat treatment in step S14 has been completed normally (step S22). As a result, a metal wire 10 for medical devices with stable quality can be manufactured. Also, by inspecting the appearance of the first metal wire 10 (specifically, the color C3 of the coating in the second region A2), it is possible to easily determine whether the heat treatment in step S18 for forming the second region A2 has been completed normally (step S22). As a result, a metal wire 10 for medical devices with stable quality can be manufactured.

[0064] <Second embodiment> FIG. 9 is a diagram showing an example of the tip portion 100A of the first metal wire 10A of the second embodiment. The medical device 1 may include the first metal wire 10A described below instead of the first metal wire 10 described in the first embodiment. The first metal wire 10A is different from the first embodiment in the color of the coating in the first region A1, the transition region AT, and the second region A2 of the tip portion 100A. FIG. 9(A) is a diagram showing the color of the coating of the tip portion 100A by the type of hatched line. FIG. 9(B) is a photograph of the tip portion 100A. The diagram corresponds to the photograph. Both the diagram and the photograph in FIG. 9 show the width direction of the flat shape of the first metal wire 10A.

[0065] As shown in the figure, the portion 92a is silver, indicating that it is not heat-treated. The portion 92b has a blue coating. The portion 92c has a white coating. The portion 92d has a yellow coating. The portion 92e has a magenta coating. The portion 92f has a green coating. The portion 92g has a magenta coating. The portion 92h has a yellow coating. The portion 92i has a white coating. The portion 92j has a blue coating. The portion 92k has a purple coating. For example, as shown in FIG. 9(B), the portion 92g may be a pale magenta color. The portion 92k may be a golden purple color toward the base end side. For example, as shown in FIG. 9(B), coatings of the same color (yellow and magenta in the illustrated example) may be repeated in the first region A1.

[0066] The center of the tip portion 100A of the first metal wire 10A is a first region A1 having a coating of a color included in the first color group C1 (specifically, green, magenta, and yellow). On the tip side of the first region A1 is a tip transition region AT1 having a coating of a color included in the second color group C2 (specifically, white and blue). On the base side of the first region A1 is a base transition region AT2 having a coating of a color included in the second color group C2 (specifically, white and blue). On the opposite side of the first region A1 from the transition region AT (specifically, the base transition region AT2) is a second region A2 having a coating of a color included in the third color group C3 (specifically, purple).

[0067] In this way, the colors of the coatings in the first region A1, the transition region AT, and the second region A2 of the tip portion 100A of the first metal wire 10A, the order of appearance of the colors, and the combination of colors when there are multiple colors can be changed in various ways. The first region A1 only needs to have a coating of at least one color among the colors included in the first color group C1 described in FIG. 4. The transition region AT only needs to have a coating of at least one color among the colors included in the second color group C2 described in FIG. 4. The second region A2 only needs to have a coating of at least one color among the colors included in the third color group C3 described in FIG. 4. The lengths of the first region A1, the transition region AT, and the second region A2 in the longitudinal direction and the lengths of each portion can also be determined arbitrarily. The metal wire 10A for medical devices of the second embodiment can also achieve the same effects as those of the first embodiment described above.

[0068] <Third embodiment> FIG. 10 is a diagram showing an example of a tip portion 100B of a first metal wire 10B of the third embodiment. The medical device 1 may include a first metal wire 10B described below instead of the first metal wire 10 described in the first embodiment. The first metal wire 10B differs from the first embodiment in the color of the coating in the first region A1, the transition region AT, and the second region A2 of the tip portion 100B. FIG. 10(A) is a diagram showing the color of the coating of the tip portion 100B by the type of hatching line. FIG. 10(B) is a photograph of the tip portion 100B. The diagram corresponds to the photograph. Both the diagram and the photograph in FIG. 10 show the width direction of the flat shape of the first metal wire 10B.

[0069] As shown, portion 93a is silver, indicating that it is not heat-treated. Portion 93b has a blue coating. Portion 93c has a white coating. Portion 93d has a yellow coating. Portion 93e has a magenta coating. Portion 93f has a yellow coating. Portion 93g has a white coating. Portion 93h has a blue coating. Portion 93i has a purple coating. Portion 93j has a gold coating. For example, as shown in FIG. 10(B), portion 93f may be yellow with reddish mottling.

[0070] The center of the tip portion 100B of the first metal wire 10B is a first region A1 having a coating of a color included in the first color group C1 (specifically, reddish purple, yellow). On the tip side of the first region A1 is a tip transition region AT1 having a coating of a color included in the second color group C2 (specifically, white, blue). On the base side of the first region A1 is a base transition region AT2 having a coating of a color included in the second color group C2 (specifically, white, blue). On the opposite side of the first region A1 from the transition region AT (specifically, the base transition region AT2) is a second region A2 having a coating of a color included in the third color group C3 (specifically, purple).

[0071] In this way, the colors of the coatings in the first region A1, the transition region AT, and the second region A2 of the tip portion 100B of the first metal wire 10B, the order of appearance of the colors, and the combination of colors when there are multiple colors can be changed in various ways. In addition, the lengths in the longitudinal direction of the first region A1, the transition region AT, and the second region A2, and the lengths of each portion can also be determined arbitrarily. The metal wire 10B for medical devices of this third embodiment can also achieve the same effects as the first embodiment described above.

[0072] <Fourth embodiment> FIG. 11 is a diagram showing an example of a tip portion 100C of a first metal wire 10C of the fourth embodiment. The medical device 1 may include a first metal wire 10C described below instead of the first metal wire 10 described in the first embodiment. The first metal wire 10C differs from the first embodiment in the color of the coating in the first region A1, the transition region AT, and the second region A2 of the tip portion 100C. FIG. 11(A) is a diagram showing the color of the coating of the tip portion 100C by the type of hatching line. FIG. 11(B) is a photograph of the tip portion 100C. The diagram corresponds to the photograph. Both the diagram and the photograph in FIG. 11 show the width direction of the flat shape of the first metal wire 10C.

[0073] As shown, portion 94a is silver, indicating that it has not been heat-treated. Portion 94b has a blue coating. Portion 94c has a white coating. Portion 94d has a yellow coating. Portion 94e has a magenta coating. Portion 94f has a yellow coating. Portion 94g has a white coating. Portion 94h has a blue coating. Portion 94i has a purple coating. Portion 94j has a gold coating. For example, as shown in FIG. 11(B), portions 94d and 94f may be pale yellow.

[0074] The center of the tip 100C of the first metal wire 10C is a first region A1 having a coating of a color included in the first color group C1 (specifically, reddish purple, yellow). On the tip side of the first region A1 is a tip transition region AT1 having a coating of a color included in the second color group C2 (specifically, white, blue). On the base side of the first region A1 is a base transition region AT2 having a coating of a color included in the second color group C2 (specifically, white, blue). On the opposite side of the first region A1 from the transition region AT (specifically, the base transition region AT2) is a second region A2 having a coating of a color included in the third color group C3 (specifically, purple, gold).

[0075] In this way, the colors of the coatings in the first region A1, the transition region AT, and the second region A2 of the tip portion 100C of the first metal wire 10C, the order of appearance of the colors, and the color combinations when there are multiple colors can be changed in various ways. In addition, the lengths in the longitudinal direction of the first region A1, the transition region AT, and the second region A2, and the lengths of each portion can also be determined arbitrarily. The metal wire 10C for medical devices of the fourth embodiment can also achieve the same effects as the first embodiment described above.

[0076] <Fifth embodiment> FIG. 12 is a diagram showing an example of a tip portion 100D of a first metal wire 10D of the fifth embodiment. The medical device 1 may include a first metal wire 10D described below instead of the first metal wire 10 described in the first embodiment. The first metal wire 10D differs from the first embodiment in the color of the coating in the first region A1, the transition region AT, and the second region A2 of the tip portion 100D. FIG. 12(A) is a diagram showing the color of the coating of the tip portion 100D by the type of hatching line. FIG. 12(B) is a photograph of the tip portion 100D. The diagram corresponds to the photograph. Both the diagram and the photograph in FIG. 12 show the width direction of the flat shape of the first metal wire 10D.

[0077] As shown, portion 95a is silver, indicating that it is not heat-treated. Portion 95b has a blue coating. Portion 95c has a white coating. Portion 95d has a yellow coating. Portion 95e has a magenta coating. Portion 95f has a green coating. Portion 95g has a magenta coating. Portion 95h has a yellow coating. Portion 95i has a white coating. Portion 95j has a blue coating. Portion 95k has a purple coating. Portion 95l has a gold coating. For example, as shown in FIG. 12(B), portions 95d and 95i may be yellowish white. Portion 95f may be pale green.

[0078] The center of the tip 100D of the first metal wire 10D is a first region A1 having a coating of a color included in the first color group C1 (specifically, green, magenta, yellow). On the tip side of the first region A1 is a tip transition region AT1 having a coating of a color included in the second color group C2 (specifically, white, blue). On the base side of the first region A1 is a base transition region AT2 having a coating of a color included in the second color group C2 (specifically, white, blue). On the opposite side of the first region A1 from the transition region AT (specifically, the base transition region AT2) is a second region A2 having a coating of a color included in the third color group C3 (specifically, purple, gold).

[0079] In this way, the colors of the coatings in the first region A1, the transition region AT, and the second region A2 of the tip portion 100D of the first metal wire 10D, the order of appearance of the colors, and the combination of colors when there are multiple colors can be changed in various ways. In addition, the lengths in the longitudinal direction of the first region A1, the transition region AT, and the second region A2, and the lengths of each portion can also be determined arbitrarily. The metal wire 10D for medical devices of this fifth embodiment can also achieve the same effects as the first embodiment described above.

[0080] Sixth Embodiment FIG. 13 is a diagram showing an example of a tip portion 100E of a first metal wire 10E of the sixth embodiment. The medical device 1 may include a first metal wire 10E described below instead of the first metal wire 10 described in the first embodiment. The first metal wire 10E is different from the first embodiment in the color of the coating in the first region A1, the transition region AT, and the second region A2 of the tip portion 100E. FIG. 13(A) is a diagram showing the color of the coating of the tip portion 100E by the type of hatching line. FIG. 13(B) is a photograph of the tip portion 100E. The diagram corresponds to the photograph. Both the diagram and the photograph in FIG. 13 show the width direction of the flat shape of the first metal wire 10E.

[0081] As shown, portion 96a is silver, indicating that it is not heat treated. Portion 96b has a blue coating. Portion 96c has a white coating. Portion 96d has a yellow coating. Portion 96e has a white coating. Portion 96f has a blue coating. Portion 96g has a purple coating. Portion 96h has a gold coating. For example, as shown in FIG. 13(B), portion 96d may be a brownish yellow. Portion 96e may be a dark white.

[0082] The center of the tip portion 100E of the first metal wire 10E is a first region A1 having a coating of a color included in the first color group C1 (specifically, yellow). On the tip side of the first region A1 is a tip transition region AT1 having a coating of a color included in the second color group C2 (specifically, white, blue). On the base side of the first region A1 is a base transition region AT2 having a coating of a color included in the second color group C2 (specifically, white, blue). On the opposite side of the first region A1 from the transition region AT (specifically, the base transition region AT2) is a second region A2 having a coating of a color included in the third color group C3 (specifically, purple, gold).

[0083] In this way, the colors of the coatings in the first region A1, the transition region AT, and the second region A2 of the tip portion 100E of the first metal wire 10E, the order of appearance of the colors, and the combination of colors when there are multiple colors can be changed in various ways. In addition, the lengths in the longitudinal direction of the first region A1, the transition region AT, and the second region A2, and the lengths of each portion can also be determined arbitrarily. The metal wire 10E for medical devices of the sixth embodiment can also achieve the same effects as the first embodiment described above.

[0084] Seventh embodiment FIG. 14 is a diagram showing an example of a tip portion 100F of a first metal wire 10F of the seventh embodiment. The medical device 1 may include a first metal wire 10F described below instead of the first metal wire 10 described in the first embodiment. The first metal wire 10F differs from the first embodiment in the color of the coating in the first region A1, the transition region AT, and the second region A2 of the tip portion 100F. FIG. 14(A) is a diagram showing the color of the coating of the tip portion 100F by the type of hatching line. FIG. 14(B) is a photograph of the tip portion 100F. The diagram corresponds to the photograph. Both the diagram and the photograph in FIG. 14 show the width direction of the flat shape of the first metal wire 10F.

[0085] As shown, portion 97a is silver, indicating that it is not heat-treated. Portion 97b has a blue coating. Portion 97c has a white coating. Portion 97d has a yellow coating. Portion 97e has a magenta coating. Portion 97f has a cyan coating. Portion 97g has a magenta coating. Portion 97h has a green coating. Portion 97i has a magenta coating. Portion 97j has a yellow coating. Portion 97k has a white coating. Portion 97l has a blue coating. Portion 97m has a purple coating. Portion 97n has a gold coating. For example, as shown in FIG. 14(B), the magenta colors of portions 97e and 97g and the cyan color of portion 97f may be mixed together to form a mottled pattern.

[0086] The center of the tip portion 100F of the first metal wire 10F is a first region A1 having a coating of a color included in the first color group C1 (specifically, green, cyan, magenta, yellow). On the tip side of the first region A1 is a tip transition region AT1 having a coating of a color included in the second color group C2 (specifically, white, blue). On the base side of the first region A1 is a base transition region AT2 having a coating of a color included in the second color group C2 (specifically, white, blue). On the opposite side of the first region A1 from the transition region AT (specifically, the base transition region AT2) is a second region A2 having a coating of a color included in the third color group C3 (specifically, purple, gold).

[0087] In this way, the colors of the coatings in the first region A1, the transition region AT, and the second region A2 of the tip portion 100F of the first metal wire 10F, the order of appearance of the colors, and the combination of colors when there are multiple colors can be changed in various ways. In addition, the lengths in the longitudinal direction of the first region A1, the transition region AT, and the second region A2, and the lengths of each portion can also be determined arbitrarily. The metal wire 10F for medical devices of the seventh embodiment can also achieve the same effects as the first embodiment described above.

[0088] Eighth embodiment FIG. 15 is a diagram showing an example of a tip portion 100G of a first metal wire 10G of the eighth embodiment. The medical device 1 may include a first metal wire 10G described below instead of the first metal wire 10 described in the first embodiment. The first metal wire 10G differs from the first embodiment in the color of the coating in the first region A1, the transition region AT, and the second region A2 of the tip portion 100G. FIG. 15(A) is a diagram showing the color of the coating of the tip portion 100G by the type of hatching line. FIG. 15(B) is a photograph of the tip portion 100G. The diagram corresponds to the photograph. Both the diagram and the photograph in FIG. 15 show the thickness direction of the flat shape of the first metal wire 10G.

[0089] As shown in the figure, the portion 98a is silver in color indicating that it has not been heat-treated. The portion 98b has a blue coating. The portion 98c has a white coating. The portion 98d has a yellow coating. The portion 98e has a reddish purple coating. The portion 98f has a green coating. The portion 98g has a reddish purple coating. The portion 98h has a yellow coating. The portion 98i has a white coating. The portion 98j has a blue coating. The portion 98k has a purple coating. The portion 98l has a gold coating. For example, as shown in FIG. 15(B), the portions 98b to 98l may each have a color with a relatively high brightness (a bright color, a pale color).

[0090] The center of the tip 100G of the first metal wire 10G is a first region A1 having a coating of a color included in the first color group C1 (specifically, green, magenta, yellow). On the tip side of the first region A1 is a tip transition region AT1 having a coating of a color included in the second color group C2 (specifically, white, blue). On the base side of the first region A1 is a base transition region AT2 having a coating of a color included in the second color group C2 (specifically, white, blue). On the opposite side of the first region A1 from the transition region AT (specifically, the base transition region AT2) is a second region A2 having a coating of a color included in the third color group C3 (specifically, purple, gold).

[0091] In this way, the colors of the coatings in the first region A1, the transition region AT, and the second region A2 of the tip portion 100G of the first metal wire 10G, the order of appearance of the colors, and the color combinations when there are multiple colors can be changed in various ways. In addition, the lengths in the longitudinal direction of the first region A1, the transition region AT, and the second region A2, and the lengths of each portion can also be determined arbitrarily. The metal wire 10G for medical devices of the eighth embodiment can also achieve the same effects as the first embodiment described above.

[0092] <Ninth embodiment> FIG. 16 is an enlarged view of the tip portion 100H of the first metal wire 10H of the ninth embodiment. The medical device 1H of the ninth embodiment includes the first metal wire 10H described below instead of the first metal wire 10 described in the first embodiment. The first metal wire 10H differs from the first embodiment in that it does not have a tip transition region AT1 and a second region A2. FIG. 16(A) shows a side view of the tip portion 100H as viewed from the Z-axis direction. FIG. 16(B) shows a side view of the tip portion 100H as viewed from the Y-axis direction. Note that the coil 40 is omitted from FIG. 16.

[0093] 16(A) and 16(B), in a medical device 1H, a distal tip 51 (broken line) is attached to a distal portion 100H of a first metal wire 10H, on the distal side of the first region A1. In the illustrated example, the base end of the distal tip 51 is located slightly distal to the tip of the first region A1, but the base end of the distal tip 51 may be located at any position within a range distal to the first region A1.

[0094] Fig. 17 is a flowchart showing a method for manufacturing a medical device 1H according to the ninth embodiment. The difference from the first embodiment shown in Fig. 8 is that step S18 is not performed and step S22H is performed instead of step S22. In step S22H, the operator inspects the color of the coating in the first region A1 and the transition region AT. Specifically, the operator performs only step a1 described in the first embodiment and does not perform step a2.

[0095] In this way, the configuration of the medical device 1H can be modified in various ways, and the first metal wire 10H may have the first region A1 and a transition region AT (proximal transition region AT2) adjacent to the proximal side of the first region A1. The first metal wire 10H may also have the first region A1 and a transition region AT (proximal transition region AT1) located on the distal side of the first region A1. The first metal wire 10H may have the first region A1, the distal transition region AT1, and the proximal transition region AT2. The medical device 1H and the metal wire 10H for a medical device of the ninth embodiment can also achieve the same effects as those of the first embodiment described above. In addition, the metal wire 10H for a medical device of the ninth embodiment does not have the second region A2, so that the step S18 (FIG. 8) of forming the second region A2 can be omitted and the inspection step (FIG. 17: S22H) can be simplified. As a result, the manufacturing costs of the medical device 1H and the metal wire 10H for a medical device can be reduced.

[0096] Tenth embodiment FIG. 18 is an enlarged view of the tip portion 100I of the first metal wire 10I of the tenth embodiment. The medical device 1I of the tenth embodiment includes the first metal wire 10I described below instead of the first metal wire 10 described in the first embodiment. The first metal wire 10I differs from the first embodiment in that it does not have the first pressed portion 111, the transition portion 112, and the second pressed portion 113. FIG. 17(A) shows a side view of the tip portion 100I as viewed from the Z-axis direction. FIG. 18(B) shows a side view of the tip portion 100I as viewed from the Y-axis direction. Note that the coil 40 is omitted from FIG. 17.

[0097] 18(A) and 18(B), a tip portion 100I of a first metal wire 10I is not pressed, and a first portion 11I has a cylindrical shape. In other words, the shape of the first portion 11I when viewed from the Z-axis direction is the same as the shape when viewed from the Y-axis direction.

[0098] Fig. 19 is a flowchart showing a method for manufacturing a medical device 1I according to the tenth embodiment. The difference from the first embodiment shown in Fig. 8 is that steps S12 and S22 are not performed. That is, according to this manufacturing method, the heat treatment is performed without pressing the metal wire. Also, according to this manufacturing method, the colors of the coatings in the first region A1, the transition region AT, and the second region A2 are not inspected.

[0099] In this way, the configuration of the medical device 1I can be modified in various ways, and the tip portion 100I of the first metal wire 10I (first portion 11I of the first metal wire 10I) may be a round wire that is not pressed. The medical device 1I and the metal wire 10I for a medical device of the tenth embodiment can also achieve the same effects as those of the first embodiment described above. Furthermore, according to the metal wire 10I for a medical device of the tenth embodiment, the pressing step S12 (FIG. 8) and the inspection step S22 (FIG. 8) can be omitted, thereby reducing the manufacturing costs of the medical device 1I and the metal wire 10I for a medical device.

[0100] <Eleventh embodiment> Fig. 20 is an enlarged view of the tip portion 100 of the first metal wire 10 of the 11th embodiment. The medical device 1J of the 11th embodiment includes a tip tip 51J, which will be described below, instead of the tip tip 51 described in the first embodiment. The tip tip 51J differs from the first embodiment in the position where it is attached to the first metal wire 10. Fig. 20(A) shows a side view of the tip portion 100 as viewed from the Z-axis direction. Fig. 20(B) shows a side view of the tip portion 100 as viewed from the Y-axis direction. Note that the coil 40 is omitted from Fig. 20.

[0101] 20(A) and (B), the distal tip 51J (broken line) is attached to the distal end portion 100 of the first metal wire 10, further distal than the first region A1 and further distal than the distal transition region AT1. In the illustrated example, the base end of the distal tip 51J is located slightly distal than the tip of the distal transition region AT1.

[0102] In this way, the configuration of the medical device 1J can be modified in various ways, and the distal tip 51J may be provided at any position on the distal portion 100 of the first metal wire 10. In the illustrated example, the distal tip 51J is attached on the distal side of the distal transition region AT1. However, the distal tip 51J may be provided within the first region A1 (for example, at the distal portion of the first region A1). With such a medical device 1J of the eleventh embodiment, the same effects as those of the first embodiment described above can be achieved.

[0103] <Modifications of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0104] [Variation 1] In the above first to eleventh embodiments, the configurations of the medical devices 1, 1H, 1I, and 1J are exemplified. However, the configuration of the medical device 1 can be modified in various ways. For example, the medical device 1 may further include a coating layer formed of a hydrophilic resin or a hydrophobic resin on the surfaces of the first metal wire 10, the second metal wire 20, and the coil 40. For example, the length in the longitudinal direction of the coil 40, in other words, the range in which the coil 40 covers the first metal wire 10, may be changed arbitrarily. For example, the medical device 1 may further include an intermediate joint portion between the distal tip 51 and the base end side joint portion 52 for joining the first metal wire 10 and the coil 40. For example, the shape of the second metal wire 20 can be modified in various ways. In addition, the medical device 1 may not have the second metal wire 20. The medical device 1 may not have the coil 40.

[0105] [Variation 2] In the above first to eleventh embodiments, the configurations of the metal wires 10, 10A to 10I for medical devices are exemplified. However, the configuration of the first metal wire 10 can be modified in various ways. For example, the shape of the first metal wire 10 described in FIG. 3 is merely an example, and various modifications are possible. For example, at least one of the second portion 12, the third portion 13, and the fourth portion 14 may be omitted. The third portion 13 may be cylindrical rather than tapered.

[0106] In the above embodiment, the entire first portion 11 of the first metal wire 10 except for a portion on the base end side corresponds to the "tip portion 100 of the first metal wire 10", but the scope of the tip portion 100 can be changed in various ways. For example, the entire first portion 11 of the first metal wire 10 and a portion on the tip side of the second portion 12 may correspond to the "tip portion 100".

[0107] In the above embodiment, the color patterns of the coating in the first region A1, the transition region AT, and the second region A2 of the tip portion 100 of the first metal wire 10 are illustrated. However, the color patterns of the coating in the first region A1, the transition region AT, and the second region A2 of the tip portion 100 may be changed as desired, as long as a coating of at least one color included in the first color group C1 is formed in the first region A1, a coating of at least one color included in the second color group C2 is formed in the transition region AT, and a coating of at least one color included in the third color group C3 is formed in the second region A2.

[0108] In the above embodiment, the thickness T1 of the coating CO1 in the first region A1 of the first metal wire 10 is 100 nm or more. However, the thickness T1 of the coating CO1 in the first region A1 may be less than 100 nm. In addition, although the thickness T1 of the coating CO1 in the first region A1 is greater than the thickness of the coating in the transition region AT, the thickness T1 may be smaller than the thickness of the coating in the transition region AT or may be the same as the thickness of the coating in the transition region AT.

[0109] In the above embodiment, the thickness of the coating in the second region A2 of the first metal wire 10 is set to be 10 nm or more and 30 nm or less. However, the thickness of the coating in the second region A2 may be less than 10 nm. Also, the thickness of the coating in the second region A2 may be greater than 30 nm.

[0110] The results of the shape test described in FIG. 2 are merely an example. The shape angle when the shape test is performed may be the first area A1=the transition area AT. The shape angle when the shape test is performed may be the first area A1<the transition area AT. The shape angle when the shape test is performed may be the first area A1=the second area A2. The shape angle when the shape test is performed may be the first area A1<the second area A2.

[0111] In the above embodiment, an arbitrary position in the outermost layer (titanium oxide coating CO1) is defined as the first position P1, and an arbitrary position in the second layer from the outside is defined as the second position P2. However, the first position P1 and the second position P2 may be set arbitrarily as long as the first position P1 is outside the second position P2 (on the surface side of the first metal wire 10). In addition, although the titanium content is defined as the first position P1>the second position P2, the first position P1<the second position P2 may be set, or the first position P1=the second position P2 may be set. Furthermore, although the nickel content is defined as the first position P1<the second position P2, the first position P1>the second position P2 may be set, or the first position P1=the second position P2 may be set.

[0112] In the above embodiment, the metal wire 10 for a medical device is exemplified as being incorporated into the medical device 1. However, the metal wire 10 for a medical device may be manufactured alone, in other words, without the second metal wire 20, the coil 40, the distal tip 51, and the base-end joint portion 52.

[0113] [Variation 3] The configurations of the medical device and the metal wire for medical device of the first to eleventh embodiments and the configurations of the medical device and the metal wire for medical device of the above-mentioned modified examples 1 and 2 may be appropriately combined. For example, in the first metal wire 10A to 10G of any of the second to eighth embodiments (different color patterns of the first region A1, the transition region AT, and the second region A2), the configuration of the ninth embodiment (no second region A2, no tip-side transition region AT1) may be combined, the configuration of the tenth embodiment (no pressing, no inspection process) may be combined, or the configuration of the eleventh embodiment (different position of the tip tip 51) may be combined. For example, in the first metal wire 10H of the ninth embodiment (no second region A2, no tip-side transition region AT1), the configuration of the tenth embodiment (no pressing, no inspection process) may be combined, or the configuration of the eleventh embodiment (different position of the tip tip 51) may be combined. For example, in the first metal wire 10I of the tenth embodiment (no pressing, no inspection process), the configuration of the eleventh embodiment (different position of the tip tip 51) may be combined.

[0114] Although the present aspect has been described above based on the embodiment and modified examples, the above-mentioned embodiment of the aspect is intended to facilitate understanding of the present aspect and does not limit the present aspect. The present aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents are included in the present aspect. If a technical feature is not described as essential in this specification, it may be deleted as appropriate. [Explanation of symbols]

[0115] 1,1H,1I,1J…Medical devices 10,10A~10I…Metal wire for medical devices 11,11I…Part 1 12…Part 2 13…Part 3 14…Part 4 15…Part 5 20…Second metal wire 30…Joint part 40…Coil 41…Elemental wire 51,51J…Tip 52…Proximal side joint part 100, 100A~100I...Tip 111…1st Press Section 112...Transition part 113…Second Press Section

Claims

1. A metal wire for a medical device, comprising: a predetermined region having a coating exhibiting at least one color selected from a predetermined color group; A specific region having a coating exhibiting at least one color selected from a specific color group; A metal wire for a medical device comprising:

2. 2. The metal wire for medical devices according to claim 1, The metal wire for a medical device, wherein the predetermined region has a larger shape angle when a shape test is performed than the specific region.

3. The metal wire for medical devices according to claim 1 or 2, further comprising: A metal wire for a medical device comprising a predetermined region adjacent to the specific region and located on the opposite side of the specific region from the specified region, the predetermined region having a coating exhibiting at least one color selected from a predetermined color group.

4. A metal wire for a medical device, comprising: a predetermined region having a coating exhibiting at least one color selected from a predetermined color group; a predetermined region having a coating exhibiting at least one color selected from a predetermined color group; A metal wire for a medical device comprising:

5. The metal wire for medical devices according to claim 4, A metal wire for a medical device, wherein the specified region has a shape angle larger than that of the predetermined region when a shape test is performed.

6. The metal wire for medical devices according to claim 4 or 5, further comprising: A metal wire for a medical device, comprising a specific region between the specified region and the predetermined region, the specific region having a coating exhibiting at least one color selected from a specific color group.

7. The metal wire for medical devices according to any one of claims 1 to 3 or claim 6, The coating in the specific region includes two colors selected from the specific color group.

8. The metal wire for medical devices according to claim 3 or 6, A metal wire for a medical device, wherein, in a cross-sectional view of at least any one of the specified region, the particular region, and the predetermined region, the titanium content at a first position is greater than the titanium content at a second position that is more inward than the first position.

9. The metal wire for a medical device according to any one of claims 3, 6 and 8, A metal wire for a medical device, wherein, in a cross-sectional view of at least any one of the specified region, the particular region, and the predetermined region, the nickel content at a second position is greater than the nickel content at a first position outside the second position.

10. The metal wire for a medical device according to any one of claims 1 to 9, A metal wire for a medical device, wherein the thickness of the coating in the predetermined region is 100 nm or more.

11. The metal wire for a medical device according to any one of claims 1 to 3 or any one of claims 6 to 9, A metal wire for a medical device, wherein the thickness of the coating in the predetermined region is greater than the thickness of the coating in the specific region.

12. The metal wire for a medical device according to any one of claims 3 to 6 or any one of claims 8 to 9, A metal wire for a medical device, wherein the thickness of the coating in the predetermined region is 10 nm or more and 30 nm or less.

13. The metal wire for a medical device according to any one of claims 1 to 12, The metal wire for a medical device has a flat shape, The metal wire for a medical device, wherein the coating is formed along a thickness direction of the flat shape.

14. The metal wire for a medical device according to any one of claims 1 to 13, The metal wire for a medical device has a flat shape, The metal wire for a medical device, wherein the coating is formed along the width direction of the flat shape.

15. 1. A medical device comprising: The metal wire for a medical device according to any one of claims 1 to 14, a tip tip attached to the metal wire for medical devices on the tip side of the predetermined region; A medical device comprising:

16. 16. The medical device of claim 15, The metal wire for a medical device according to any one of claims 1 to 3, any one of claims 6 to 9, or claim 11, The specific region of the metal wire for a medical device includes a distal specific region provided on the distal side of the predetermined region and a proximal specific region provided on the proximal side of the predetermined region, A medical device, wherein the distal tip is attached to the distal specific region.

17. A method for producing a metal wire for a medical device, comprising the steps of: A method for manufacturing a metal wire for a medical device, comprising: forming a coating exhibiting at least one color selected from a predetermined color group in a predetermined region by subjecting the metal wire to heat treatment; and forming a coating exhibiting at least one color selected from a specific color group in a specific region.

18. 18. The method of claim 17, further comprising the steps of: A method for manufacturing a metal wire for a medical device, comprising inspecting the color of the coating in the predetermined area and the color of the coating in the specific area to determine whether the heat treatment has been completed normally.

19. A method for producing a metal wire for a medical device according to claim 17 or 18, comprising the steps of: When the temperature of the heat treatment for forming the predetermined region and the specific region is set to a predetermined temperature, A method for manufacturing a metal wire for a medical device, comprising: forming a coating exhibiting at least one color selected from a predetermined color group in a predetermined region of the metal wire by performing heat treatment at a specific temperature lower than the predetermined temperature on the base end side of the predetermined region of the metal wire.

20. 20. The method of claim 19, further comprising the steps of: A method for manufacturing a metal wire for a medical device, comprising inspecting the color of the coating in the predetermined area to determine whether the heat treatment for forming the predetermined area was completed successfully.

21. A metal wire for a medical device, comprising: A predetermined region having a coating exhibiting at least one color selected from a predetermined color group, and a specific region having a coating exhibiting at least one color selected from a specific color group, The metal wire for a medical device, wherein the coating on the predetermined region and the coating on the specific region are formed by subjecting the metal wire for a medical device to a heat treatment.

22. 22. The metal wire for a medical device according to claim 21, When the temperature of the heat treatment for forming the predetermined region and the specific region is set to a predetermined temperature, A metal wire for a medical device, comprising a predetermined region of the metal wire located on the base end side of the specified region, the predetermined region having a coating exhibiting at least one color selected from a predetermined color group, the predetermined region being formed by heat treatment at a specific temperature lower than the specified temperature.

Images