Observation apparatus and method thereof

Abstract

When conducting technical training and evaluation for endovascular surgery, the behavior of the catheter, particularly the movement of the wire inside the catheter sheath, can be observed more clearly without the use of X-rays. [Solution] An apparatus for observing a vascular model into which a catheter has been inserted, wherein the light-emitting unit comprises a light source and a polarizing element and irradiates a reference irradiation light containing a first polarization toward the object to be observed, the polarizing element has a polarization axis in a first direction and transmits the first polarization that is circularly polarized in the first direction from the light output from the light source, the first polarization is transmitted through the catheter sheath and at least a part of its light component has its polarization state modulated, the light-receiving unit comprises a photodetector and an analyzer, the analyzer has a polarization axis that constitutes circular polarization in a second direction different from the first direction, the photodetector receives the light component of circular polarization in the second direction that has passed through the analyzer from the reference irradiation light that has been irradiated toward the object to be observed and interfered with by the object to be observed, and generates an observation output, the image generation unit receives the observation output and generates an image, and the display displays the image.

Description

Technical Field

[0001] The present invention relates to an observation device and a method for observing a catheter inserted into a blood vessel model.

Background Art

[0002] In the evaluation of catheters inserted into blood vessels, and in the technical training and evaluation of endovascular surgery, it is necessary to observe the state of a blood vessel model and a catheter inserted into the blood vessel model. The evaluation of technical training for endovascular surgery has been carried out by performing X-ray imaging with a catheter inserted into a blood vessel model. From the perspective of avoiding X-ray exposure of the trainer and trainee, an observation device using near-infrared light has been proposed by the present applicant (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the observation device proposed in Patent Document 1, it was possible to observe the behavior of a catheter inserted into a blood vessel model without using X-rays at all. However, trainers who conduct technical training and evaluation of endovascular surgery have a desire to more clearly observe the behavior of the catheter, particularly the movement of wires or the like inside the catheter sheath.

Means for Solving the Problems

[0005] The inventor has intensively studied to solve the above problems and has come up with the idea of using polarization. As described in previous literature, near-infrared light can penetrate vascular models and catheter sheaths. However, when an object to be observed is placed between a first polarizer and a second polarizer, whose polarization axes are mutually orthogonal, and near-infrared light is shone onto the object from the first polarizer side, it is not possible to observe the image of the vascular model or catheter sheath. This is because even if the near-infrared light polarized in the first direction by the first polarizer passes through the vascular model or catheter sheath, it is blocked by the second polarizer.

[0006] However, when the material of the catheter sheath scatters polarized near-infrared light, the polarization direction can be modulated by the scattering, generating a polarization component that can pass through the second polarizer. In this case, a metallic wire inserted into the sheath does not transmit the irradiated light at all, so it appears as a shadow in the image. That is, the part of the sheath where the polarized near-infrared light is scattered is displayed brightly on the screen, and a high brightness contrast is obtained between it and the shadowed wire. Also, when the sheath is placed, for example, in the air or fresh water, the polarization state is maintained in the region surrounding the sheath, so the irradiated light that passes through this region is also blocked by the second polarizer, and this region is displayed darkly. As a result, a high dark-bright-dark contrast is obtained between the wire, the sheath, and the region surrounding the sheath.

[0007] According to the observation device proposed in Patent Document 1, near-infrared light, like X-rays, can penetrate the object being observed, making it possible to obtain a planar image similar to an X-ray image with reduced three-dimensionality. However, when diffuse reflection of the irradiated light occurs at the interface of the blood vessel model or surrounding components, the amount of diffusely reflected light becomes greater than the amount of light transmitted through each component, and it diffuses, blurring the lines of the interface. Therefore, on the display, the image caused by this diffusely reflected light interferes with the image of each component based on the transmitted light, contributing to the blurring of the image of each component that is the original object of observation. Thus, there was a demand to observe the behavior of the catheter, especially the movement of the wire inside the catheter sheath, more clearly when performing technical training for endovascular surgery or evaluating catheters.

[0008] The inventors of this invention diligently conducted research to solve the above problem and came to the realization that this problem could be solved by utilizing polarization. By selectively receiving the polarization component originating from the original material being observed, diffuse reflection at the interface of the material could be substantially eliminated. As a result, when all the received light, including the diffuse reflection, was filtered by a polarizing plate, a clearer image could be obtained. Near-infrared light scattered at the interface of the blood vessel model and surrounding materials can be modulated, generating polarization components according to certain laws. However, even with the polarization components generated in this way, only a small amount can pass through the polarizer on the light-receiving side, and is thought to contribute very little to image formation.

[0009] This invention is based on such knowledge, and one aspect thereof is defined as follows: An observation device for observing a vascular model in which a catheter has been inserted, Observation assembly including light-emitting part and light-receiving part, It comprises an image generation unit and an image display assembly including a display, The light-emitting unit comprises a light source and a polarizing element, and irradiates the object to be observed with reference irradiation light including a first polarization, the polarizing element has a polarization axis in a first direction, and transmits the first polarization that is polarized in the first direction from the light output from the light source, the first polarization passes through the sheath of the catheter, and at least a portion of its light component has its polarization state modulated. The light receiving unit comprises a photodetector and an analyzer, the analyzer having a polarization axis in a direction different from the first direction, the photodetector receives the polarization component that has passed through the analyzer of the reference illumination light (post-illumination light) that has been irradiated onto the object to be observed and interfered with by the object to be observed, and generates an observation output. The image generation unit receives the observation output and generates an image. The aforementioned display is an observation device that displays the aforementioned image.

[0010] According to the observation device defined in this way, when the first polarized light contained in the reference irradiation light passes through the catheter sheath, at least a portion of the polarization component is modulated due to interference such as scattering from the constituent materials of the sheath. For example, if the polarizing element is a polarizing plate that produces linearly polarized light, and the analyzer is a polarizing plate with its polarization axis oriented perpendicular to the polarizing plate, then the first polarized light that passes through the object being observed as is cannot pass through the analyzer, which has a different polarization axis. However, some polarization components whose polarization direction is modulated by the sheath can pass through the analyzer. The polarized components that pass through are received by the photodetector, and an observation output corresponding to the amount of light received is generated. In this specification, "polarization direction" includes the meanings of the "vector direction" of the Jones vector (Jones parameter) and the "vector direction" of the Stokes vector (Stokes parameter), which are used to mathematically represent the overall polarization state.

[0011] In the image generated by the image generation unit based on the observation output, the metallic wire portion (hereinafter sometimes abbreviated as "wire" in this specification) and the sheath portion are displayed with a contrast in brightness. Specifically, the wire portion, which does not transmit any light, is displayed as black, while the sheath portion, where the polarized component that passes through the analyzer due to modulation is received, is displayed as relatively white.

[0012] Polarizing and / or reflective materials are incorporated into the interior or interface of the outer circumferential components of the catheter (circulating fluid, vascular model, immersion fluid, etc.) and the inner circumferential components of the catheter (liquid for continuous flushing, etc.). These materials interfere with all or part of the reference irradiation light containing the first polarization, modulating its polarization state. Some of the polarization components thus modulated will pass through the analyzer. If the amount of polarization components that pass through differs from that originating from the sheath, the inner and outer circumferential parts of the catheter will appear in the image with different brightness than the sheath or wire. Examples of polarizing materials include diffracting materials, liquid crystals, and subrefracting materials.

[0013] The light generated by diffuse reflection of the reference irradiation light at the interface between the catheter and its internal and external components, known as secondary light, is filtered by the analyzer. Although some of its polarized components can pass through, it substantially does not affect the image. Therefore, a clear observation image can be obtained. By making the light transmittance of the inner and outer circumference components of the catheter different from that of the sheath, a difference in brightness can be created between them in the image.

[0014] The inventors have confirmed that the above observation device can clearly distinguish and display the catheter sheath and wire on an image without using X-rays (see Examples). The basic configuration of the observation device described above is as follows: The illumination light irradiated onto the object to be observed is polarized (first polarization), and an image is generated based on the polarization component that can be transmitted through the analyzer in the modulated polarization component when this first polarization is irradiated onto the object to be observed. The inventors thoroughly investigated the principle by which the above configuration, which utilizes polarization, allows for clearer identification of the sheath compared to a configuration that does not use polarization (conventional configuration). As a result, they noticed the following:

[0015] (1) Basic principle of sheath identification If there is a difference between the amount of polarized light component imaged by the light-receiving unit in light originating from the sheath and the amount of polarized light component imaged by the light-receiving unit in light originating from the material surrounding the sheath, the sheath can be displayed in an identifiable manner in the image. The light that can be imaged by the light-receiving unit depends on the correlation between the polarization characteristics of the light and the polarization characteristics of the light-receiving unit (directionality, such as linear polarization or circular polarization). Therefore, the polarization component of the light originating from the sheath that matches the polarization characteristics of the light-receiving unit becomes the source of image generation in that unit. If the light originating from the sheath and the light source from other components (referred to as "reference illumination light" in this specification) are the same, then because the material of the sheath is different from the material of the other components, differences will occur in the polarization components imaged by the light-receiving unit in the light originating from each component. This difference in brightness on the image represents each component. Here, the reference irradiation light irradiated onto the observation target can be polarized as a whole, or a part of it can contain a polarization component. Also, non-polarized light can be used as the reference irradiation light. This is because polarization components may be generated when non-polarized light is reflected by the observation target.

[0016] (2) Polarization components imaged by the light-receiving unit In this specification, "imaged by the light-receiving unit" means that the light-receiving unit provides an output for generating an image. Examples of imaging when the light-receiving unit receives a polarization component having a predetermined polarization characteristic can be given as follows. (2-1) When the wavelength of the polarization component is visible light, a analyzer that allows the polarization component to pass through is used as the light-receiving unit. The polarization component passing through such an analyzer is visible as an output, and thus, an observer can recognize the output image. (2-2) When the wavelength of the polarization component is near-infrared, the light-receiving unit includes an analyzer and a light receiver. The analyzer allows the polarization component to pass through. The light receiver receives the passed polarization component and outputs an observation output corresponding thereto. This observation output serves as an output for generating an image and is sent to an image generation unit for imaging. (2-3) The combination of a polarizer and a light receiver can also be applied to polarization components of visible light. (2-4) For an element (photoelectric conversion element) that directly converts polarization into an electrical signal, the element can be used directly as the light-receiving unit. In this case, the element is designed to be activated and output by a polarization component having a predetermined polarization characteristic. Image generation is possible with this output.

[0017] When a reference illumination light is shone onto the object of observation (a catheter or its surrounding components (such as a vascular model)), light components are obtained through interference with the object. Of these light components, the polarization component that matches the polarization characteristics of the light-receiving unit is the polarization component that is imaged by the light-receiving unit. Specific examples of light components obtained through interference include (A) those obtained when polarized light (first polarization) is transmitted to the object of observation as reference illumination light. In addition, (B) the light obtained when unpolarized light is reflected from the object of observation is also an example of such light components. Furthermore, (C) scattered light, polarization, birefringence (including phase changes of polarization), and photofluorescence (these may be collectively referred to as secondary light in the specification) generated by the object of observation irradiated with the reference illumination light are also examples of such light components. When using reflected or secondary light as described above, it is preferable to use light of a wavelength that does not easily penetrate the sheath as the reference irradiation light in order to avoid the influence of the wire inside the catheter. Alternatively, the influence of unwanted light originating from the wire can be reduced or eliminated by using polarizing elements, lenses, filters, etc.

[0018] (3) Application of visible light By using a light-receiving unit having a predetermined polarization characteristic, reflected light and secondary light derived from an observation target can be utilized. Thus, when the inventor irradiated an observation target with white visible light (wavelength: 380 nm to 700 nm) polarized in the first direction, a sheath was displayed on the screen, and the sheath and the wire could be distinguished. This is presumably because even visible light partially penetrates into the sheath, interferes with the material of the sheath, and emits secondary light containing polarization components. When the polarization characteristic of the light-receiving unit is canceled, that is, when imaging from all the light received by the light-receiving unit is enabled (such as when the analyzer is omitted in the combination of the analyzer and the light receiver), the sheath could not be distinguished and observed when the visible light (white light) polarized in the first direction or the non-polarized visible light (white light) was irradiated to the observation target. Without a light-receiving unit having a polarization characteristic, the polarization component modulated by the sheath and imaged by the light-receiving unit and the light component that could not be imaged by the light-receiving unit originally are received equally, that is, all the light components of the reference irradiation light as the light derived from the sheath are imaged by the light-receiving unit. On the other hand, since all the light components of the reference irradiation light are also imaged by the light-receiving unit for the light derived from the members around the sheath, there is no difference in the amount of light between the two.

[0019] Even when the light-receiving unit is arranged so that the non-polarized white light can be irradiated to the observation target and the reflected light reflected by all or part of the observation target can be received, an image that can distinguish the sheath and the wire is generated. If the members around the sheath have characteristics different from those of the sheath, that is, characteristics that generate polarization or modulate the intensity or direction of polarization, these members can be distinguished from the sheath and displayed on the image even when visible light is used.

[0020] As described above, in the case of visible light, even without using a light receiver or an image generation unit, the sheath can be distinguished from other members and observed by visually observing the polarization component transmitted through the analyzer. In this case, the output of the analyzer can also be projected onto a display using an optical fiber or an optical amplifier.

[0021] (4) Lantern effect As a way to highlight the sheath, which is inherently difficult to detect (display in the image), one might consider increasing the amount of light illuminating the sheath. Of course, this could be achieved by increasing the amount of light illuminating the object being observed, including the sheath, but the output of the light source is limited by issues such as the light source's rating and heat dissipation. Therefore, the inventors considered supplying auxiliary light to the sheath from the surrounding environment (material). If such auxiliary light interferes with the sheath and generates a polarization component that is imaged at the light-receiving unit, the amount of light originating from the sheath will increase, and the sheath in the image will become clearer.

[0022] When the reference illumination light includes a first polarization, it is preferable that the auxiliary light be polarized to the same state as this first polarization. Therefore, a material that causes Rayleigh scattering of the first polarization is dispersed in the surrounding components of the sheath (at least one of the forming material of the blood vessel model, the immersion fluid, and the circulating fluid). This is because Rayleigh-scattered polarization maintains the same polarization state as the polarization before scattering. Examples of materials that cause Rayleigh scattering include aqueous polymers such as PVA and surfactants. When these materials are included in the circulating fluid that circulates within the blood vessel model, their lubricity is improved. The material that generates the auxiliary light is not limited to one that maintains the polarization state of scattered light. It is sufficient if it emits secondary light toward the sheath side by interfering with the irradiated reference light, and this secondary light is modulated by the sheath to generate a polarization component that is imaged at the light-receiving unit. This secondary light is the auxiliary light.

[0023] In this specification, the phenomenon of auxiliary light illuminating the object being observed is referred to as the "lantern effect." This lantern effect is particularly effective when illuminating the object of observation with visible light. Since visible light cannot pass through the sheath, reflected light and secondary light become the source of image generation on the sheath. When using reflected light, the area of ​​the sheath that reflects the reference illumination light is limited. Similarly, when using secondary light, the area of ​​the sheath illuminated by the reference illumination light that serves as the source of generation is also limited. Thus, in either case, it is difficult to obtain sufficient light for post-illumination. Therefore, when visible light as auxiliary light is irradiated from around the sheath to the entire outer surface of the sheath, it becomes possible to emit polarization components that are imaged at the light-receiving part from the entire outer surface of the sheath, which helps to secure sufficient light.

[0024] (5) Light irradiated onto the object of observation (reference irradiation light) The above example is based on the concept that the relative angle between the polarization axis of the polarizing element and the polarization axis of the analyzer is 90 degrees. In this concept, if the intersection angle of the polarization axes is shifted from 90 degrees, some polarization components that have not been modulated in any way from the observed object can pass through the analyzer. As a result, the amount of light that passes through the analyzer from the light originating from the sheath increases, so the sheath appears brighter. On the other hand, the contrast with the wire, which still appears black because it does not transmit light at all, becomes clearer.

[0025] The same applies when the polarizing element and analyzer target elliptic and circularly polarized light, respectively. Furthermore, the same applies when employing polarization states with spatial distribution (for example, polarization distributions dynamically generated by photonic liquid crystals) or polarization states that are mixtures of these. To elaborate on this, it is preferable that the light irradiated onto the object of observation (reference illumination light) contains a first polarization polarized in at least one direction. In other words, the reference illumination light may contain direct light from the light source (unpolarized light component) or a polarization component polarized in a second direction different from the first polarization polarized light.

[0026] When polarized light is generated by reflection from the observation element, it is not necessary to include polarized light in the reference illumination light. However, this does not prevent including one or more types of polarization in the reference illumination light. The wavelength of the reference illumination light is arbitrarily selected according to the characteristics of the object being observed. A light source and a polarizing element are used as the light-emitting part that includes a polarization component in the reference illumination light. The polarizing element has predetermined polarization characteristics (for example, a polarization axis for direct polarization) and polarizes the light from the light source. This makes it possible to illuminate the object being observed with a reference illumination light that includes polarization from the light-emitting part. In addition to using LEDs and bulbs as light sources, ambient light (sunlight or indoor lighting) can also be used as a light source in the case of a visible light source. If the polarization characteristics of a photoelectric element (a device that receives an electrical signal and outputs polarized light) can be designed, this element can be used directly as a light-emitting part. By using optical filters and lenses, it is also possible to generate a reference illumination light that contains only specific wavelengths included in the light source.

[0027] (6) Light that has been irradiated onto the object of observation and subsequently subjected to interference (post-irradiation light) The reference illumination light irradiated onto the object being observed interferes with the object. When viewed from the perspective of the light-receiving unit, the interference consists of (A) light transmitted through the object, (B) light reflected from the object, and (C) secondary light generated by the object (diffusion, polarization, phase change, or fluorescence, etc.). In this specification, these types of light are referred to as "post-irradiation light." The post-irradiation light contains a polarization component that is imaged by the light-receiving unit.

[0028] (7) Adjusting contrast (performing the vascular roadmap method) When the polarization characteristics of the light-receiving unit (for example, the polarization axis direction) are changed, the brightness of each component displayed in the image changes. This is because the polarization components and their intensities contained in the post-irradiation light differ depending on the component. According to the inventors' studies, when the polarization angle of the first polarization contained in the reference irradiation light is set to 90 degrees and the polarization axis of the light-receiving unit is set to 0 degrees, that is, when the relative angle between the polarization axis of the polarizing element and the polarization axis of the light-receiving unit is 90 degrees, an image in which only the structure of the catheter can be recognized (images 1-2) can be generated by adjusting the wavelength and intensity of the reference irradiation light. On the other hand, when the relative angle between the polarization axis of the polarizing element and the polarization axis of the light-receiving unit is set to less than 90 degrees and 45 degrees or more, it becomes possible to generate images of components other than the catheter (images 1-3). By overlaying the first two images, for example, as a video, onto the first three images, a simulation mimicking the vascular roadmap method can be created.

[0029] (8) General concept of the principle of the observation device (1) The principle of the observation device specified in the above situation was explained as follows. If there is a difference between the amount of polarized light component imaged by the light-receiving unit in light originating from the sheath and the amount of polarized light component imaged by the light-receiving unit in light originating from the material surrounding the sheath, the sheath can be displayed in an identifiable manner in the image. In this example, the image was generated based only on the polarization component imaged by the light-receiving unit. However, if there is a difference between the reference illumination light and the polarization component contained in the post-illumination light that is imaged by the light-receiving unit, the sheath can be displayed on the screen in an identifiable manner. That is, the observation output when the reference illumination light is directly received by the light-receiving unit without any interference with the object being observed is used as the reference output, and this is compared with the observation output when the post-illumination light is received by the light-receiving unit. In other words, the observation principle of the observation device specified in the above situation can be understood as determining a reference output in advance and calculating the difference in light intensity between that predetermined reference output and the observed output.

[0030] Based on the above findings, the first aspect of this invention is defined as follows. An observation device for observing a vascular model in which a catheter has been inserted, Equipped with a light-receiving unit, The light-receiving unit has predetermined polarization characteristics and receives a polarization component in the post-irradiation light that matches the predetermined polarization characteristics and images it, wherein the post-irradiation light is a reference irradiation light that is irradiated onto the object to be observed and interfered with by the object to be observed, and includes a polarization component that is imaged by the light-receiving unit, and the polarization component originates from the sheath of the catheter, in an observation device.

[0031] According to the observation apparatus in the first phase as defined above, the polarization component originating from the sheath contained in the post-irradiation light is imaged by the light-receiving unit. On the other hand, by preventing the light originating from the catheter wire from being included in the post-irradiation light, the wire and sheath can be observed with a difference in brightness. Furthermore, the light originating from reflections and scattering at the interfaces of the components constituting the object being observed contains almost no polarization components that are imaged by the light-receiving unit. Consequently, these reflections and scattering have no effect on the image.

[0032] Here, if the reference illumination light is of a wavelength that can penetrate the sheath, the reference illumination light is blocked by the wire when it is transmitted to the object of observation, so the light component originating from the wire is not included in the post-illumination light. If the reference illumination light is of a wavelength that cannot penetrate the sheath, the reference illumination light does not reach the wire, so the polarization component originating from the wire is not included in the post-illumination light.

[0033] The reason why, when observing by reflecting the reference illumination light onto the object being observed, it is possible to prevent the post-illumination light from containing light originating from the wire is as follows: When the reference illumination light can penetrate the sheath and the wire is made of a material that absorbs the reference illumination light, the reference illumination light is blocked by the wire, and therefore the light component originating from the wire is not included in the post-illumination light. When the wire is made of a material with metallic luster, the reference illumination light interferes with the wire and is specularly reflected. In this case, the polarization state included in the reference illumination light is substantially maintained even after reflection. Therefore, by having the reflected light obtained in this way received by the light-receiving unit as post-illumination light, a difference in brightness can be created between the wire and the sheath. In particular, by adjusting the polarization characteristics of the light-receiving unit, it is possible to adjust the amount of polarization component originating from the wire. This allows the brightness of the wire to be adjusted. When the wire has metallic luster and its surface is covered with resin or the like, in addition to the same polarization maintenance as above for reflection from the metallic luster portion inside the resin, for reflection from the surface of the resin or the like, new polarization is generated along with the reflection (s-waves are reflected relatively more strongly than p-waves), and the light resulting from the combination of both is reflected, so by having the reflected light received by the light-receiving unit, a difference in brightness can be created between the wire and the sheath.

[0034] In the observation apparatus of the first phase as defined in this way, if the reference illumination light is visible light, the ambient light of the observation apparatus can be used as the reference illumination light. The post-illumination light obtained by irradiating the object of observation with this light can contain a polarization component that is imaged by the light-receiving unit. Of course, the reference illumination light can also contain a first polarization. To ensure that the reference illumination light contains a first polarization, a light-emitting unit equipped with a light source and a polarizing element is provided. The light source should be capable of outputting visible light and / or near-infrared light, and the polarizing element should be capable of polarizing the light from the light source in any direction, such as linear or circular polarization. By using a plate-shaped polarizing element with a diffraction grating or a photonic liquid crystal, the light of the reference illumination light can be polarized in different directions for each region, or the polarization state can be dynamically changed overall or for each region by controlling the photonic liquid crystal or by giving a built-in waveplate a mechanical rotation function. The reference illumination light generated by such a polarizing element will contain multiple polarizations. Furthermore, by making a part of the polarizing element's plate transparent, the light from the light source can be included in the reference illumination light as is (in an unpolarized state). By using a photoelectric conversion element that outputs polarization, it is also possible to generate a reference illumination light containing polarization components through electrical control (voltage control).

[0035] The polarizing element can be interposed between the light source and the object being observed, or all or part of it may be embedded within the object being observed, or even embedded within a part or multiple region of the object being observed, such as only the lower part of a vascular model. Similarly, the analyzer can be placed outside the object being observed, or all or part of it may be embedded within the object being observed, or even embedded within a part or multiple region of the object being observed, such as only the upper part of a vascular model.

[0036] When the reference illumination light is visible light, an analyzer is used as the light receiving unit, and the output of the analyzer, i.e., the polarization component that has passed through the analyzer, can be visually observed as an image, allowing the observer to directly distinguish and observe the sheath and wire. When the light-receiving unit consists of an analyzer and a photodetector, the light (visible light, near-infrared light) that has passed through the analyzer is received by the photodetector, and the photodetector generates an output (observation output) corresponding to the polarization component of the received light. The analyzer has an area capable of receiving the light component originating from the object being observed in the post-irradiation light, and the photodetector has an array of light-receiving elements corresponding to the area of ​​the analyzer. An optical filter, lens, second polarizing element, and second analyzer can be placed between the object being observed and the analyzer and / or between the analyzer and the photodetector.

[0037] The observation assembly is composed of a light-emitting unit and a light-receiving unit. The observation output from the light-receiving unit is converted into an image by the image generation unit, and this image is displayed on the display. The image generation unit and the display constitute the image display assembly. When the light-receiving unit is composed of a photoelectric element, the output of the photoelectric element is sent to the image generation unit as the observation output. This element receives a polarized component with predetermined polarization characteristics and outputs an electrical signal.

[0038] Based on the above, the second aspect of this invention is defined as follows. In the first phase, using the specified observation apparatus, It further comprises a light-emitting section and an image display assembly, The observation assembly is composed of the light-receiving unit and the light-emitting unit. The light-emitting unit irradiates the reference irradiation light toward the object to be observed, and the reference irradiation light includes a first polarization. The light receiving unit, upon receiving the post-irradiation light, generates an observation output corresponding to the polarization component to be imaged. The image display assembly comprises an image generation unit and a display, the image generation unit generates an image based on the observation output, and the display displays the image.

[0039] The third aspect of this invention is defined as follows: The observation apparatus according to the second paragraph, wherein the image generation unit generates an image based on a comparison between the observation output and the reference output from the light receiving unit that receives the reference illumination light which does not interfere with the object to be observed. According to the third-phase observation apparatus defined in this way, the observation output is compared to the reference output based on the reference illumination light. Therefore, compared to simply generating an image from the observation output alone, disturbances in the observation output due to changes in the observation environment are canceled out, and the generated image becomes more stable. For example, even if ambient light is incident, it is also treated as the reference illumination light.

[0040] In the third observation apparatus, the reference output is the output when the photodetector, with its polarization characteristics removed, receives the reference illumination light that does not interfere with the object being observed. The light-receiving unit has a polarization axis in a direction different from the first direction as its polarization characteristics, and the light-receiving unit can generate an observation output corresponding to the polarization component imaged by the light-receiving unit (fourth aspect). In the fourth phase observation device, the amount of light from a polarized component that has passed through a specific polarization axis provided by the light-receiving unit becomes the observation output, and an image is formed by comparing this with the reference output.

[0041] Furthermore, in the observation device of the third phase, the reference output is the output of the light receiving unit that receives the reference illumination light, which does not interfere with the object of observation, as the post-illumination light. The light-receiving unit generates an observation output corresponding to the polarization direction component of the polarization contained in the received post-irradiation light (fifth phase).

[0042] In the fifth phase observation device, since the light-receiving unit can detect the polarization direction component, the count is set to 1 when the light-receiving unit receives the first polarization in the first direction of the reference illumination light, and to n when the light-receiving unit assumes that there are n polarization directions in the polarization component contained in the post-illumination light, and the observation output is generated based on the comparison result of these two (for example, the difference n-1). This generates an image that reflects the type of polarization component (based on the polarization direction) generated by modulating the first polarization. In other words, the image is generated based on the degree of polarization of the polarization component contained in the post-illumination light relative to the first polarization. Here, an example of detecting n polarization states relative to a reference illumination light with one polarization state is shown. Similar detection can also be performed if the reference illumination light contains the polarization of n polarization states.

[0043] The sheath in the image can be highlighted using the aforementioned lantern effect. The sixth aspect of this invention is an observation device that utilizes this lantern effect, and is defined as follows. The observation object assembly includes the observation object, a circulating fluid that circulates through the blood vessel model, and an immersion fluid in which the observation object is immersed. At least one of the constituent materials of the blood vessel model, the immersion fluid, and the circulating fluid is dispersed with a secondary light generating material that interferes with the reference irradiation light to generate secondary light. The observation apparatus according to the first paragraph, wherein the secondary light interferes with at least the sheath to enhance the polarization component originating from the sheath in the post-irradiation light.

[0044] It is preferable that the polarization direction of the secondary light be the same as that of the first polarization contained in the reference irradiation light. Therefore, the secondary light generating material dispersed in the immersion liquid and the circulating liquid is designed to cause Rayleigh scattering with respect to the reference irradiation light (Phase 7). The secondary light-generating material that produces the Rayleigh scattering can be a water-soluble polymer and / or a surfactant (Phase 8).

[0045] Another technique for highlighting the sheath in an image is to make the light absorption and polarization properties of the material surrounding the blood vessel model different from those of the sheath. Thus, the ninth aspect of this invention is defined as follows. The observation apparatus according to the second paragraph, wherein the immersion fluid and / or the circulating fluid have different light absorption characteristics and / or polarization characteristics with respect to the reference irradiation light than the blood vessel model. The light absorbed here is all or part of the light components of the reference illumination and post-illumination light. Substances that alter the polarization properties can be used, for example, sucrose or maltose, which induce optical rotation.

[0046] The tenth aspect of this invention is defined as follows: The observation apparatus according to the second paragraph, wherein the material forming the blood vessel model exhibits a photoelastic effect with respect to the reference irradiation light, and the light generated by the photoelastic effect is included in the post-irradiation light. Stress is generated in the material forming the blood vessel model, causing a photoelastic effect, and the resulting light becomes part of the post-irradiation light. This light may contain a polarization component that is imaged by the light-receiving unit. Thus, the photoelastic effect can be reflected in the image. A separate light-receiving unit may be provided specifically to receive the light originating from the photoelastic effect.

[0047] The eleventh aspect of this invention is defined as follows: The aforementioned observation assembly further comprises a plate for holding the blood vessel model, The plate transmits the reference irradiation light, The observation device according to the second aspect, wherein the plate has grooves that conform to the shape of the blood vessel model, and the blood vessel model is fitted into the grooves completely or partially without any gaps. Using these plates makes it easy to set up and change vascular models.

[0048] By inducing a photoelastic effect in the material of the circumferential wall of the groove into which the blood vessel model is fitted, the stress generated in the forming material of the blood vessel model can be transmitted to the plate material, where the photoelastic effect can be exerted. Therefore, the twelfth aspect of this invention is defined as follows. The observation apparatus according to the 11th section, wherein the peripheral wall of the groove in the plate is formed of a soft material that produces a photoelastic effect with respect to the reference irradiation light, and the light produced by the photoelastic effect is included in the post-irradiation light.

[0049] In actual catheter surgery, operations are performed to remove blood clots and other debris from within blood vessels. To simulate such operations, the thirteenth aspect of this invention is defined as follows. The observation apparatus according to the second paragraph, wherein in the observation target assembly, the blood vessel model has a movable part that mimics a thrombus or the like placed inside it, and the movable part interferes with the reference irradiation light to modulate its polarization state.

[0050] The observation device of this invention is used as a simulator for catheter surgery. In this use, it is required to display images similar to those of actual catheter surgery. Therefore, the 14th aspect of the observation device of this invention is defined as follows. The observation apparatus described in the second section, wherein the observation assembly is capable of photographing a first part of the object to be observed and a second part different from the first part. To observe different parts of the object being observed, one can move at least one of the light-emitting and light-receiving parts of the object assembly relative to the object, or polarize the optical axis of the reference synchrotron radiation emitted from the light-emitting part.

[0051] In recent years, so-called biplane observation has been performed on catheter operating tables. To simulate such biplane observation, the 15th aspect of the invention is defined as follows. A second observation assembly comprising a second light-emitting unit and a second light-receiving unit is further provided. The observation device according to the 14th section, wherein the second observation assembly observes the part of the object to be observed by the observation assembly from another direction. The observation assembly and the second observation assembly can be made movable relative to the object being observed (Phase 16). Here, the second light-emitting unit and the second light-receiving unit perform the same functions as the light-emitting unit and light-receiving unit of the observation assembly, and supply observation output to the image generation assembly.

[0052] The seventeenth aspect of this invention is defined as follows: The observation apparatus according to the first section, wherein the light receiving unit is positioned at one or more of the following locations: a first position capable of mainly receiving post-irradiation light obtained when the reference irradiation light has passed through the object of observation; a second position capable of mainly receiving post-irradiation light obtained when the reference irradiation light has been reflected by the object of observation; and a third position capable of mainly receiving secondary light generated by the interference of the reference irradiation light with the object of observation. For example, by placing light-receiving elements at multiple locations, the sheath can be observed more reliably. This is because the transmission and reflection properties of the sheath can differ depending on the material.

[0053] The eighteenth aspect of this invention is defined as follows: The assembly to be observed includes a case that holds the immersion liquid. The case constitutes part of the mannequin. The observation device described in the 11th section, wherein the plate is placed inside the case. According to the observation apparatus for the 18th phase as defined in this way, observations can be performed more realistically.

[0054] The 19th aspect of this invention is defined as follows: The observation apparatus according to the second view, wherein the observation object assembly includes a case for holding the immersion liquid, and the peripheral wall of the case includes the light-emitting part. According to the observation apparatus for the 19th phase as defined in this way, the apparatus is simplified.

[0055] The 20th aspect of this invention is defined as follows: The assembly to be observed includes a case that holds the immersion liquid. The observation apparatus according to the second aspect, wherein the light-emitting part is provided with an anti-reflection part for reference illumination light in the case. According to the 20th observation apparatus defined in this way, the influence of the reference illumination light reflected by the object being observed within the case can be eliminated, resulting in a clearer image.

[0056] The 21st aspect of this invention is defined as follows: The observation apparatus according to the 20th aspect, wherein the object to be observed is positioned towards the light-receiving part within the case, the layer of immersion liquid between the object to be observed and the light-emitting part is made thicker than the layer of immersion liquid between the object to be observed and the light-receiving part, and the layer of immersion liquid between the object to be observed and the light-receiving part performs the function of the anti-reflective part. According to the observation apparatus of the 21st phase as defined in this way, the influence of reflected light from the observation target can be eliminated by adjusting the arrangement of the vascular model within the case, resulting in a simple apparatus configuration.

[0057] The 22nd aspect of this invention is defined as follows: The components of the assembly to be observed are fitted with a fluorescent material that emits a polarization component that is imaged by the light-receiving unit. The observation assembly includes a light source that causes the material to fluoresce. The observation apparatus described in the second section. According to the observation apparatus specified in the 22nd phase as defined in this way, observation operations can be facilitated by writing marks or letters on the object of observation with fluorescent paint. The light from the fluorescence contains a polarizing component that is imaged by the light-receiving unit.

[0058] The 23rd aspect of this invention is defined as follows: The assembly to be observed includes a case that holds the immersion liquid. The light is ultraviolet light, and the ultraviolet light from the light source is introduced into the case and emitted from the side wall of the case toward the object to be observed. The observation apparatus described in Section 22. According to the observation apparatus specified in the 23rd phase as defined in this way, visible light or near-infrared light is used as the reference illumination light. Since the light used here is ultraviolet light, it does not disturb the reference illumination light. Furthermore, since the case functions as the light source, the apparatus can be simplified.

[0059] Since the roadmap method is used in actual catheter surgery, it is preferable to mimic the roadmap method in simulations using this observation device. Therefore, the 24th aspect of this invention is defined as follows: The light-receiving unit has a second polarization characteristic state and a third polarization characteristic state in a direction relatively different from the first direction of the first polarization, The aforementioned image display assembly includes an image synthesis unit, The light receiving unit generates an observation output that generates the first and second images when the second polarization characteristic state is reached. When the light receiving unit is in the third polarization characteristic state, it generates an observation output that generates the first to third images. The image synthesis unit synthesizes the first-2 image and the first-3 image, The observation apparatus described in the second section, wherein the display shows the synthesized image. Here, the second and third polarization characteristic states of the light-receiving unit are obtained by adjusting the polarization characteristics of the light-receiving unit itself. Furthermore, they can also be obtained by adjusting the polarization direction of the first polarization of the reference illumination light, either in conjunction with or independently of this adjustment.

[0060] In such a 24th observation device, the 1st and 2nd images are configured to display only the sheath of the catheter and the metallic wire within the sheath. By displaying the vascular model in the aforementioned images 1-3 (Phase 25), it becomes possible to simulate the roadmap method. It is especially preferable to use video for the first and second screens (Phase 26). In addition to the vascular model, catheters can also be displayed on screens 1-3. Furthermore, when using a polarization camera or the like in which polarizing elements are arranged in an array in different states for each pixel, multiple polarization characteristic states can be detected simultaneously in real time without physical manipulation. As a result, the first and second images, the first and third images, and composite images thereof (such as roadmap images or images with unwanted reflected light removed) can be generated easily, freely, and in real time by software processing.

[0061] The 27th aspect of this invention is an observation method using the observation apparatus specified in the first aspect, and is defined as follows. An observation device for observing a vascular model in which a catheter has been inserted, In an observation method using an observation device having a light-receiving section with predetermined polarization characteristics, The steps include irradiating the object to be observed with reference irradiation light, The steps include causing the light receiving unit to receive post-irradiation light generated by the reference irradiation light that has been interfered with by the object being observed, wherein the post-irradiation light includes a polarization component, and the polarization component originates from the sheath of the catheter. An observation method comprising the step of the light-receiving unit generating an output based on a polarization component that matches the polarization characteristics of the polarization component originating from the sheath and is imaged by the light-receiving unit.

[0062] The 28th aspect of this invention is defined as follows: At least one of the constituent materials of the blood vessel model, the lubricating fluid circulating within the blood vessel model, and the immersion fluid in which the blood vessel model is immersed contains a secondary light generating material that interferes with the reference irradiation light to generate secondary light. The observation method according to the 27th section, wherein the polarization component of the post-irradiation light is changed by interfering the secondary light with the sheath.

[0063] The 29th aspect of this invention is defined as follows: The light-receiving unit has a second polarization characteristic state and a third polarization characteristic state in a direction relatively different from the first direction of the first polarization, The observation method according to the 27th section, wherein the contrast between the catheter sheath on which the image is displayed and its surroundings is adjusted by adjusting the second polarization characteristic state and the third polarization characteristic state. According to the 29th observation method defined in this way, the contrast is adjusted by adjusting the second and third polarization characteristic states of the light-receiving unit. Therefore, it is possible to display only the catheter or only the vascular model on the image.

[0064] The 30th aspect of this invention is defined as follows: The steps include generating a contrast-enhanced mode image in which only the sheath of the catheter and the metallic wire within the sheath are displayed in the second polarized light-receiving state, The steps include obtaining a still image mode image in which a blood vessel model is displayed in the third polarized light receiving state, The steps include displaying the still image mode image and the contrast-enhanced image overlaid on each other, The observation method described in the 29th section, including the following.

[0065] The 31st aspect of this invention is defined as follows: A cassette incorporating the vascular model, used in an observation device that irradiates the object to be observed with a reference irradiation light that interferes with the catheter sheath, The aforementioned vascular model, A housing that holds the blood vessel model, A polarizing element is placed between the blood vessel model and the light source. A cassette equipped with [a specific feature / feature]. Using such a cassette makes it easier to set up the object to be observed.

[0066] The 32nd aspect of this invention is defined as follows: A plate for holding a catheter in an observation device that observes a vascular model into which a catheter has been inserted, The plate comprises grooves that conform to the shape of the blood vessel model, and the peripheral walls of the grooves are in complete or partial, gap-free contact with the blood vessel model. Using this plate allows for stable support of the vascular model, facilitating smooth observation.

[0067] The 33rd aspect of this invention is defined as follows: The plate according to the 32nd section, wherein the peripheral wall of the groove is formed of a soft material that exhibits a photoelastic effect. Since the vascular model is fitted snugly into the groove and in contact with it, the deformation of the vascular model imposes stress changes on the soft material of the plate, thereby producing a photoelastic effect. In other words, the degree of deformation of the vascular model when the catheter interferes with it can be observed as a photoelastic effect on the groove wall of the plate that is in contact with the deformed area of ​​the vascular model.

[0068] The 34th aspect of this invention is defined as follows: An observation device for observing a vascular model in which a catheter has been inserted, Observation assembly including light-emitting part and light-receiving part, It comprises an image generation unit and an image display assembly including a display, The light-emitting unit comprises a light source and a polarizing element, and irradiates the object to be observed with reference irradiation light including a first polarization, the polarizing element has a polarization axis in a first direction, and transmits the first polarization that is polarized in the first direction from the light output from the light source, the first polarization passes through the sheath of the catheter, and at least a portion of its light component has its polarization state modulated. The light receiving unit comprises a photodetector and an analyzer, the analyzer having a polarization axis in a second direction different from the first direction, the photodetector receives the light component that has passed through the analyzer of the reference illumination light (post-illumination light) that has been irradiated onto the object to be observed and interfered with by the object to be observed, and generates an observation output. The image generation unit receives the observation output and generates an image. The aforementioned display is an observation device that displays the aforementioned image. [Effects of the Invention]

[0069] The sheath of a real catheter has a multilayer structure of polymer thin films, but the material and thickness of the thin films constituting the sheath are not uniform depending on the type of catheter. Various soft resins such as polyester, polyethylene, polyamide, polyurethane, and silicone rubber are used as materials for the thin films constituting the sheath. In addition, the catheter wire has a complex structure incorporating metal structures such as mesh and radiopaque markers, and mechanical structures such as balloons and coil release mechanisms. For catheters with these characteristics, the present invention makes it possible to clearly photograph the wire inside the sheath without using any X-rays, using typical near-infrared light and visible light, which has been newly found to be usable. As a result, it was possible to obtain observation images that are close to the X-ray observation images obtained during actual surgery using a catheter. [Brief explanation of the drawing]

[0070] [Figure 1] Figure 1 is a block diagram showing the configuration of an observation device according to an embodiment of this invention. [Figure 2] Figure 2 shows a perspective view of the observation apparatus in the embodiment. [Figure 3]Figure 3 is a partial perspective view showing the plate of the assembly being observed. [Figure 4] Figure 4 shows the case containing the plate shown in Figure 3. [Figure 5] Figure 5 shows the photoelastic effect. [Figure 6] Figure 6 shows an image of the object observed using the observation device of the embodiment shown in Figure 2. [Figure 7] Figure 7 is a block diagram showing an observation device of another embodiment. [Figure 8] Figure 8 is a block diagram showing an observation device of another embodiment. [Figure 9] Figure 9 is a block diagram showing an observation device of another embodiment. [Figure 10] Figure 10 is a block diagram showing an observation device of another embodiment. [Figure 11] Figure 11 shows an image of the object observed using the observation device shown in Figure 10. [Figure 12] Figure 12 is a block diagram showing an observation device of another embodiment. [Figure 13] Figure 13 is a block diagram showing an observation device of another embodiment. [Figure 14] Figure 14 is a block diagram showing an observation device of another embodiment. [Figure 15] Figure 15 shows an image of the object observed using the observation device shown in Figure 14. [Figure 16] Figure 16 shows an image of a comparative example. [Figure 17] Figure 16 is a block diagram showing an observation device of another embodiment. [Modes for carrying out the invention]

[0071] The observation device A of this embodiment of the present invention will be described below with reference to Figure 1. This observation device A comprises an observation target assembly 1, an observation assembly 20, and an image generation assembly 30. The observation target assembly 1 comprises a catheter 2, a vascular model 5, circulating fluid 6, immersion fluid 7, and a case 8. Catheter 2 has a sheath 3 made of soft resin into which a light-blocking component (hereinafter referred to as "wire") made of a metal wire 4 is inserted. In catheter technique training, it is necessary to understand the position of the tip of the wire 4 inside the sheath 3. The actual device can be used directly for Catheter 2.

[0072] The blood vessel model 5 is formed to mimic human blood vessels and can be formed, for example, using soft silicone rubber by the so-called lost-wax casting method. For details on the manufacturing method of the blood vessel model, please refer to the description in Japanese Patent Publication No. 3613568. The description in said patent publication is hereby referenced and cited. The constituent materials of the vascular model can be enriched with materials that induce Rayleigh scattering in the near-infrared light, which is the reference irradiation light. Examples of materials that induce Rayleigh scattering include silicone rubber containing silica particles and PVA gel.

[0073] Furthermore, the constituent materials of the blood vessel model may include materials that change the scattering state of near-infrared light passing through the model when stress is applied, thereby producing a photoelastic effect. Examples of such materials include gelatin and polyurethane rubber. Furthermore, a movable part simulating a blood clot can be placed inside the blood vessel model. This movable part can be made from the same material as the blood vessel model, or it may be made from other soft materials.

[0074] This movable part may include at least one of a material that scatters near-infrared light 9 in a polarized state, a material that modulates the polarization state of the near-infrared light 9, and a secondary light-emitting material that receives the near-infrared light 9 and generates secondary light. Materials that alter the scattering state include, in addition to the materials that induce Rayleigh scattering as described above, silica particles or colloids with particle sizes that induce Mie scattering. Materials that modulate the polarization state include cellulose and maltose that induce optical rotation. For secondary light-emitting materials, materials that absorb near-infrared light and exhibit fluorescence, diffraction, birefringence, etc., are selected.

[0075] The circulating fluid 6 is filled into the blood vessel model 5 and preferably flows within the blood vessel model 5 to simulate human blood flow. The circulating fluid 6 makes it easier for the catheter 2 to slide against the inner wall of the vascular model 5, and it is preferable that the resistance when inserting the catheter 2 into the vascular model 5 be equivalent to that when inserting it into a human blood vessel.

[0076] As this circulating fluid 6, a water-soluble polymer can be used, which is dispersed in water and contains a water-soluble polymer having both hydrophilic and hydrophobic groups, and / or a mixture of a polymer having hydrophilic groups and a polymer having hydrophobic groups. For such a circulating fluid, the contents described in PCT / JP2024 / 036297 are referenced and cited herein.

[0077] It is preferable to use a circulating fluid 6 that has different absorption characteristics for near-infrared light 9 than the constituent materials of the blood vessel model. This is to clearly define the boundary between the circulating fluid 6 and the inner casing (inner surface) of the blood vessel model 5. This circulating fluid 6 can contain at least one of the following materials, similar to the constituent materials of the blood vessel model 5: a material that changes the scattering state to near-infrared light 9, a material that modulates the polarization state, and a secondary light-emitting material that receives the irradiated light and emits secondary light. This secondary light acts as auxiliary light and exerts a lantern effect.

[0078] The immersion solution 7 is filled into the case 8, and the blood vessel model 5 is immersed in it. It is preferable to use an immersion solution 7 that has different absorption characteristics for near-infrared light 9 than the constituent materials of the blood vessel model. This is to clearly define the boundary between the circulating fluid 6 and the outer casing (outer surface) of the blood vessel model 5. This immersion solution 7 can contain at least one material that changes the scattering state to near-infrared light 9, a material that modulates the polarization state, and a secondary light-emitting material that receives the irradiated light and emits secondary light, similar to the constituent materials of the blood vessel model 5. This secondary light acts as auxiliary light and exerts a lantern effect. Depending on the observation environment, this immersion solution can be omitted from the observation target assembly 1.

[0079] As shown in Figure 1, the blood vessel model 5 is positioned towards the upper side of case 8. This creates a relatively thick layer of immersion fluid 7 between the bottom wall of case 8 and the blood vessel model 5. By providing this thick layer of immersion fluid 7, near-infrared light reflected by the observation target consisting of the blood vessel model 5 and catheter 2 is absorbed, preventing the reflected near-infrared light from being reflected by the bottom wall of case 8 or the first polarizing plate 23, which will be described later.

[0080] It is preferable that the distance between the vascular model 5 and the interface (upper surface) of the immersion solution 7 be short. This is to prevent the absorption of near-infrared light in the immersion solution 7. Therefore, in case 8, it is preferable to make the distance from the bottom wall to the blood vessel model 5 longer than the distance from the blood vessel model 5 to the surface of the immersion liquid. Additionally, the reflection of near-infrared rays can be prevented by covering the bottom surface of case 8 with a semi-transparent film that is resistant to near-infrared rays. The first polarizing plate 23 may also be equipped with an anti-reflective function.

[0081] The observation assembly 20 comprises a light-emitting unit 20A and a light-receiving unit 20B. The light-emitting unit 20A includes a light intensity adjustment device 21, a near-infrared light source 22, and a first polarizing plate 23. The light-receiving unit 20B includes a second polarizing plate 24 and a near-infrared camera 25. The light intensity adjustment device 21 adjusts the amount of near-infrared light emitted from the near-infrared light source 22. Light intensity can also be adjusted by adjusting the aperture of the near-infrared camera 25.

[0082] Near-infrared light 9 is emitted from the near-infrared light source 22 in the direction of the arrow. This light source 22 is a surface light source and is capable of covering at least a predetermined area of ​​the blood vessel model 5 that is the object of observation. Based on the inventors' experience, the wavelength of the light emitted from the near-infrared light source 22 can be set to 700-1500 nm.

[0083] The first polarizing plate 23, acting as a polarizing element, and the second polarizing plate 24, acting as an analyzer, are both positioned on the optical axis of the near-infrared 9 and have polarization axes in different directions. These can also be given the functions of circular polarization or elliptic polarization. In the example shown in Figure 1, the intersection angle between the polarization axis of the first polarizer 23 and the polarization axis of the second polarizer 24 is set to 90-45 degrees. By adopting this intersection angle, some of the polarization components (first polarization) of the near-infrared 9 polarized by the first polarizer 23 can pass directly through the second polarizer 24, thereby enabling the imaging of the entire object being observed.

[0084] On the other hand, when a portion of the first polarization is modulated by scattering in the observed object, some of the polarization components within it have a polarization direction that matches the polarization axis of the second polarizer 24. Such polarization components reliably pass through the second polarizer 24. Therefore, they are reliably reflected in the image displayed on the display 29.

[0085] The near-infrared camera 25, which acts as a light receiver, is positioned on the optical axis of the near-infrared light 9, which is the reference illumination light. The image generation assembly 30 comprises an image generation unit 31 and a display 33. Data captured by the infrared camera 25 is sent to the image generation unit 31, and a general-purpose image generation program generates image data that can be displayed on the display 33. The near-infrared camera 25 may also have an analyzer integrated into it. The same applies to the visible light camera described later.

[0086] Figure 2 shows the observation apparatus for the embodiment. In the observation apparatus of this embodiment, the near-infrared camera 125 is supported by a support column 126 via a position and orientation adjustment unit 127. A second polarizing plate 124 is attached directly in front of the objective lens of the camera 125. The first polarizing plate is located on the underside of the observation object assembly 101 (not shown in the figure). The camera 125 is connected to an image generation unit (not shown). This image generation unit includes a general-purpose computer device and generates image data based on signals from the camera 125. The generated image data is sent to a display device (not shown) and displayed thereon.

[0087] The observation assembly 101 is roughly composed of a vascular model 105, a case 108, and a plate 110. The catheter is omitted. The catheter will be inserted during the observation. The vascular model 105 is fitted tightly into the peripheral wall of a groove 111 formed on the upper surface of the plate 110. Reference numeral 121 indicates the inlet of a catheter connected to the vascular model 105, and it has a circulating fluid inlet 123 on its side. Reference numeral 125 indicates the outlet of the circulating fluid.

[0088] The plate 110 is supported by a partition plate 113, which is fixed to the inner side wall of the case 108. The partition plate 113 is positioned towards the upper side in the case 108. This ensures a large space between the plate 110 (i.e., the blood vessel model 105) and the bottom wall of the case 108. By filling this space with immersion fluid, near-infrared light reflected by the blood vessel model 105 can be absorbed.

[0089] Figure 3 is a perspective view showing the vascular model 105 mounted on plate 110. The set shown in Figure 3 is housed in case 108, as shown in Figure 4. Figure 5 shows a vascular model with a catheter inserted, fitted into the groove of the model holder (plate). The upper part of Figure 5 shows the state without irradiation of near-infrared light 9 polarized by the first polarizing plate, while the lower part of Figure 5 shows the state with irradiation of near-infrared light 9 polarized by the same polarizing plate.

[0090] Here, the model holder (plate) is made of a soft polymer material consisting of urethane elastomer. As can be seen in the lower diagram, when the catheter compresses the vascular model, it deforms the vascular model, and the walls of the grooves in the model holder (plate) deform accordingly. The stress in this deformed area generates the photoelastic effect.

[0091] The specifications of the observation apparatus used in the example are as follows: Catheter: Stryker Excelsior Microcatheter, Model No.: 1080 Blood vessel model: Made of silicone rubber, provided by Fine Biomedical Co., Ltd. Circulating fluid: Dilute the circulating fluid (model number: BIOACT[A]) provided by Fine Biomedical Co., Ltd. with water 500 times. Immersion solution: Dissolve 0.8 wt% polyvinyl alcohol (manufactured by Kanto Chemical Co., Ltd., model number: Polyvinyl Alcohol 2000) in 100 parts by volume of water. Near-infrared light source: LEDs with a wavelength of 940 Hz are densely arranged in a 200mm x 200mm area. First and second polarizing plates: Near-infrared polarizing plates (Asahi Kasei Corporation wire grid polarizing plates, model number: WGF) Intersection angle of polarization between the first and second polarizers: 30 degrees Near-infrared camera (polarizing camera): Manufactured by Sony Corporation, Model number: XCG-CP510 Image formation software: The image software included with the near-infrared camera is incorporated into the computer that constitutes the image generation unit 31. Display: General-purpose Distance between plate 110 and the bottom wall of the case: 60mm

[0092] The above-mentioned polarization camera (manufactured by Sony Corporation, model number: XCG-CP510) has polarizers (analyzers) arranged in an array in different states for each pixel, allowing for the acquisition of diverse information regarding the polarization state (at least three of the four Stokes parameters necessary to identify the polarization state) in real time. Furthermore, by using software processing, the obtained information regarding the polarization state (Stokes parameters) can be freely numerically calculated (e.g., addition, subtraction, multiplication). As a result, it is possible to extract the intensity and direction of the polarization component, extract the degree of polarization, extract the degree of birefringence (photoelastic effect, i.e., the magnitude of internal stress), detect or remove only the unpolarized component, detect or remove only the reflective component, and even identify the shape of the object being observed. In the applications of the present invention, by using this polarization camera, for example, the above-mentioned contrast adjustment (adjustment of the degree of fusion of interference and non-interference components in the sheath) and procedures associated with the roadmap method can be achieved solely through software processing, without the need for physical means or physical operations.

[0093] Figure 6 shows an example of an image taken with the observation device of the embodiment. From the results in Figure 6, the wire can be clearly seen inside the sheath of catheter 202 using the observation device of the embodiment.

[0094] Figure 7 shows another embodiment of observation apparatus B. Note that in Figure 7, elements identical to those in Figure 1 are denoted by the same reference numerals, and their descriptions are omitted. The image display unit 130 of the observation device B in Figure 7 includes, in addition to the image generation unit 31 and the display 33, a background image storage unit 41, an image synthesis unit 43, an image evaluation unit 45, and a guidance generation unit 47. The background image storage unit 41 stores background images showing bones and other tissues, and these background images can be combined with images obtained by the near-infrared camera 25 by the image synthesis unit 43 and displayed.

[0095] The image evaluation unit 45 evaluates the photoelastic effect shown in Figure 5, for example, using AI. The evaluation results from the image evaluation unit 45 are sent to the guidance generation unit 47. Based on these evaluation results, the guidance generation unit 47 generates guidance in text format, for example, and displays it on the display 33.

[0096] In actual catheter-based endovascular surgery, the administered contrast agent is washed away by the bloodstream, so the blood vessels are only visualized for a few seconds. Furthermore, due to toxicity, there is a limit to the amount of contrast agent that can be used, and it cannot be administered repeatedly. Therefore, a technique (vascular roadmap method) is used in which the vascular visualization image at the moment of contrast agent administration is saved as a still image and superimposed onto an observational image in which only the catheter is visualized.

[0097] The observation device of the present invention can be used to simulate the vascular roadmap method as follows: First, a still image of the vascular model in a visualized state is saved. Then, by changing the observation conditions, the image of the vascular model is made invisible and an image in which only the catheter is visible is saved. These two images are then superimposed. In order to simulate the vascular roadmap method, it is preferable to further equip the observation device of the present invention with hardware interfaces such as a foot pedal or joystick so that various operations associated with the image processing can be performed in a manner similar to that of actual catheter endovascular surgery.

[0098] Figure 8 is a block diagram showing the configuration of observation device C for performing the vascular roadmap method. Elements identical to those in Figure 1 are denoted by the same reference numerals, and their descriptions are omitted. The image generation assembly 230 of this observation device C includes an image generation unit 31, a display 33, and an image synthesis unit 43, as well as an image storage unit 51. In this example, the second polarizing plate 24 is rotated relative to the first polarizing plate 23, changing the relative angle of the polarization axes of both polarizing plates. This changes the observation conditions, and when the relative angle of the polarization axes of both polarizing plates is set to the second angle (second polarization characteristic state) and the third angle (third polarization characteristic state), and further by adjusting the intensity of the light source 22 and the wavelength of the near-infrared light 9, the first and second images, in which only the catheter is visualized, are generated and saved in the image storage unit 51. Similarly, the first to third images, in which the vascular model is visualized, are generated and saved in the image storage unit 51. The first and second images are made into a video, and the image synthesis unit 43 synthesizes these first and second images into the first to third images to perform observation simulating the vascular roadmap method.

[0099] As an alternative method for implementing the roadmap method, a solution that affects the polarization component caused by the circulating fluid can be introduced into the circulating fluid as a contrast agent in order to capture still images that mainly display a vascular model corresponding to the first to third images. Examples of such solutions include solutions that absorb the reference irradiation light (liquids mixed with India ink or aluminum powder, etc.) and solutions that change the polarization state (such as milk, which causes the polarization to disappear due to scattering, or aqueous solutions containing cellulose or maltose (sugar water), which affect optical rotation).

[0100] Another embodiment of the present invention, observation device D, is shown in Figure 9. In Figure 9, elements identical to those in Figure 1 are denoted by the same reference numerals, and their descriptions are omitted. The image display assembly 330 of this observation device D includes, in addition to the display 33, an image generation unit 231, a reference output storage unit 61, and an observation output storage unit 63. The reference output stored by the reference output storage unit 61 is the output data from the near-infrared camera 25 when the second polarizing plate 24 is removed. The observation output stored by the observation output storage unit 63 is the output data from the near-infrared camera 25 of the polarization component that has passed through the second polarizing plate. The reference output may be acquired and stored in advance as a baseline before the start of observation, or it may be acquired each time an observation is performed. The image generation unit 231 compares the reference output and the observation output and, more specifically, calculates the difference in light intensity between the two and sends the result as image data to the display 33.

[0101] Figure 10 shows another embodiment of the observation device E of this invention. In Figure 10, the same reference numerals are used for elements that are the same as those in Figure 1, and their descriptions are omitted. The observation assembly 120 of this observation device E handles visible light (white light). The light-emitting section 120A of the observation assembly 120 comprises a white light source 122A and a first polarizing plate 123 consisting of a polarizing element for visible light. The light-receiving section 120B comprises a visible light camera 125B and a second polarizing plate 124B consisting of a photodetector for visible light. For the observation device E with the above configuration, the specifications of each element were those described above, except for the near-infrared light source, and observation tests were conducted. A point light source was used for the white light source. The observation results are shown in Figure 11.

[0102] Figure 12 shows another embodiment of the observation device F of this invention. In Figure 12, the same reference numerals are used for elements that are the same as those in Figure 1, and their descriptions are omitted. In the observation assembly 220 of this observation device F, polarized near-infrared light 9, which is the reference illumination light from the light-emitting unit 220A, is irradiated obliquely onto the observation target 1, and there is no light-receiving unit 20B at the end of its optical axis. The light component of the post-irradiation light reaching the light-receiving unit 20B is mainly secondary light 9a from the observation target.

[0103] Another embodiment of the present invention, observation device G, is shown in Figure 13. In Figure 13, elements identical to those in Figure 1 are denoted by the same reference numerals, and their descriptions are omitted. In the observation assembly 320 of this observation device G, the light-emitting unit 320A and the light-receiving unit 20B are arranged on the same side. Polarized near-infrared light 9, which is the reference illumination light, is irradiated obliquely from the light-emitting unit onto the observation object 1, and the light-receiving unit 20B is not located at the end of the optical axis. The post-irradiation light that reaches the light-receiving unit 20B is mainly reflected light 309c, and this reflected light 309c contains a polarization component.

[0104] Another embodiment of the present invention, observation device H, is shown in Figure 14. In Figure 14, elements identical to those in Figure 10 are denoted by the same reference numerals, and their descriptions are omitted. In the observation assembly 420 of this observation device H, the light-emitting unit 420A is positioned on the same side as the light-receiving unit 120B, and white light 409 is emitted from the light-emitting unit 420 as a reference illumination light without any polarization. The secondary light 409c, which reaches the light-receiving unit 20B as post-illumination light, includes reflected and scattered light from the observation object. It is known that reflected light contains a polarization component. Secondary light (scattered light and fluorescence) obtained when the white light 409 penetrates into the material of the observation object, especially the sheath 3, and interferes with the material there may also be included in this secondary light.

[0105] Observation tests were conducted using the previously described specifications for each element constituting the observation device H with the above configuration, except for the near-infrared light source. The white light source was a point light source, irradiated from above the observation target at an angle of approximately 45 degrees, without any polarizing plate. The light receiving unit 120B was also positioned above the observation target. A circulating liquid 6 containing a secondary light-emitting material that receives the irradiated light and emits secondary light is arranged around the sheath 3, and it is preferable that this secondary light acts as auxiliary light to produce a lantern effect on the sheath 3. The observation results are shown in Figure 15. Figure 16 shows the image obtained when the second polarizing plate 124B was removed from the observation device. The catheter insertion state into the vascular model is the same as in Figure 15.

[0106] The image generation assemblies for observation device B, observation device C, and observation device D can be applied to other observation devices as well.

[0107] Figure 17 shows an observation apparatus I of another embodiment. In Figure 17, elements identical to those in Figure 2 are denoted by the same reference numerals, and their descriptions are omitted. In this observation device I, two observation assemblies are arranged orthogonally with respect to the observation target assembly 101. The observation assembly comprises a light-emitting section consisting of a near-infrared light source 122 and a first polarizing plate (not shown in the figure), and a light-receiving section consisting of a second polarizing plate 124 and an infrared camera 125. This observation assembly allows the light-receiving section to be moved horizontally.

[0108] The second observation assembly comprises a second light-emitting unit consisting of a near-infrared light source 1122 and a first polarizing plate (not shown in the figure), and a second light-receiving unit consisting of a second polarizing plate 1124 and an infrared camera 1125. This second observation assembly allows the second light-receiving unit to be moved vertically. By moving two observation assemblies in sync, the first part of the target object can be observed from two axial directions. By displaying images based on the observation output of each observation assembly side by side, biplane observation can be simulated. The near-infrared light sources of each light-emitting unit, or either one of them, may be replaced with a white light source. The two light sources are shared, and the resulting light can be emitted from the bottom and sides of the case of the assembly to be observed via a predetermined light-transmitting member.

[0109] This invention is not limited in any way to the embodiments and examples described above. Various modifications that do not depart from the scope of the claims and are easily conceivable by those skilled in the art are also included in this invention.

[0110] The above describes observation devices that utilize polarization. The following points highlight how these new findings can be applied to conventional observation devices that do not utilize polarization, and how they can improve their performance. Furthermore, the basic principle of the conventional X-ray-free observation device disclosed in prior art 1 was the discovery that near-infrared light penetrates the catheter sheath when irradiated onto the observation target. As a result, in the captured image, the catheter wire, which blocks the near-infrared light, appears black, while the sheath appears relatively white (gray) due to the near-infrared light that has passed through it. In this way, even in the conventional type, the sheath and wire can be distinguished by the difference in brightness.

[0111] In the conventional example described above, no polarization was used, and the basic illumination light emitted from the light-emitting unit was transmitted through the object being observed. The post-illumination light obtained after transmission was then observed by the light-receiving unit. As can be understood from the above explanation, the post-illumination light received by the light-receiving unit can also be reflected light or secondary light from the object being observed.

[0112] Therefore, we propose the following observation device as a novel design. That is, (1) An observation device for observing a vascular model in which a catheter has been inserted, Equipped with a light receiving unit for post-irradiation light, In an observation device, the post-irradiation light is a reference irradiation light that is irradiated onto the object to be observed and subjected to interference from the object to be observed. An observation device in which the light receiving unit is positioned at a second position capable of mainly receiving post-irradiation light formed when the reference irradiation light is reflected by the object being observed, and / or at a third position capable of mainly receiving secondary light generated when the reference irradiation light interferes with the object being observed.

[0113] (2) An observation device for observing a vascular model in which a catheter has been inserted, An observation assembly comprising a light-emitting unit and a light-receiving unit. It comprises an image generation assembly that includes an image generation unit and a display, The light-emitting unit emits a reference irradiation light toward the object to be observed. The light receiving unit receives post-irradiation light and outputs an observation output, the post-irradiation light is light generated by the reference light interfering with the observation target, and has a light component originating from the catheter sheath. The image generation unit generates an image according to the observation output. The display is an observation device that displays the image, The observation assembly is an observation device capable of observing a first part of the object to be observed and a second part different from the first part.

[0114] (3) An observation device for observing a vascular model in which a catheter has been inserted, An observation assembly comprising a light-emitting unit and a light-receiving unit. It comprises an image generation assembly that includes an image generation unit and a display, The light-emitting unit emits a reference irradiation light toward the object to be observed. The light receiving unit receives post-irradiation light and outputs an observation output, the post-irradiation light is light generated by the reference light interfering with the observation target, and has a light component originating from the catheter sheath. The image generation unit generates an image according to the observation output. The display is an observation device that displays the image, Furthermore, a second observation assembly including a second light-emitting unit and a second light-receiving unit is provided. The second observation assembly is an observation device for observing the part of the object being observed by the observation assembly from another direction.

[0115] (4) The observation apparatus according to (3), wherein the observation assembly and the second observation assembly are movable relative to the object to be observed.

[0116] (5) The observation apparatus according to (3), wherein the output unit and the second output unit are equipped with a common light source.

[0117] (6) An observation device for observing a vascular model in which a catheter has been inserted, An observation assembly comprising a light-emitting unit and a light-receiving unit. It comprises an image generation assembly that includes an image generation unit and a display, The light-emitting unit emits a reference irradiation light toward the object to be observed. The light receiving unit receives post-irradiation light and outputs an observation output, the post-irradiation light is light generated by the reference light interfering with the observation target, and has a light component originating from the catheter sheath. The image generation unit generates an image according to the observation output. The display is an observation device that displays the image, When the light-emitting unit irradiates with a reference illumination light of the first wavelength, the light-receiving unit generates the first and second images. When the light-emitting unit is irradiated with a reference illumination light of the second wavelength, the light-receiving unit generates the first to third images. The image generation unit generates a composite image of the first-2 image and the first-3 image, The display is an observation device that displays the composite image.

[0118] (7) The images 1-2 above show only the sheath of the catheter and the metallic wire inside the sheath. The observation apparatus described in (6), wherein the blood vessel model is displayed in the 1-3 images.

[0119] (8) The above 1-2 images are a video, as shown in (7) of the observation apparatus.

[0120] The following matters are disclosed below. (1) An observation device for observing a vascular model in which a catheter has been inserted, Equipped with a light-receiving unit, The light-receiving unit has predetermined polarization characteristics and receives a polarization component in the post-irradiation light that matches the predetermined polarization characteristics and images it, wherein the post-irradiation light is a reference irradiation light that is irradiated onto the object to be observed and interfered with by the object to be observed, and includes a polarization component that is imaged by the light-receiving unit, and the polarization component originates from the sheath of the catheter, in an observation device. (2) It further comprises a light-emitting section and an image display assembly, The observation assembly is composed of the light-receiving unit and the light-emitting unit. The light-emitting unit irradiates the reference irradiation light toward the object to be observed, and the reference irradiation light includes a first polarization polarized in a first direction. The light receiving unit, upon receiving the post-irradiation light, generates an observation output corresponding to the polarization component to be imaged. The observation apparatus according to (1), wherein the image display assembly comprises an image generation unit and a display, the image generation unit generates an image based on the observation output, and the display displays the image. (3) The observation apparatus according to (2), wherein the image generation unit generates an image based on a comparison between the reference output from the light receiving unit, which receives the reference illumination light that does not interfere with the object to be observed, and the observation output. (4) The aforementioned reference output is the output when the light receiving unit, with its polarization characteristics removed, receives the reference illumination light that does not interfere with the object being observed in any way. The observation apparatus according to (3), wherein the light receiving unit has a polarization axis in a direction different from the first direction as the polarization characteristic, and the light receiving unit generates an observation output corresponding to the polarization component imaged by the light receiving unit. (5) The aforementioned reference output is the output of the light receiving unit that receives the reference illumination light, which does not interfere with the object being observed, as the post-illumination light. The observation apparatus according to (3), wherein the light receiving unit generates an observation output corresponding to the polarization direction component of the polarization contained in the received post-irradiation light. (6) The observation object assembly includes the observation object, a circulating fluid that circulates through the blood vessel model, and an immersion fluid in which the observation object is immersed. At least one of the constituent materials of the blood vessel model, the immersion fluid, and the circulating fluid is dispersed with a secondary light generating material that interferes with the reference irradiation light to generate secondary light. The observation apparatus according to (2), wherein the secondary light interferes with at least the sheath to enhance the polarization component originating from the sheath in the post-irradiation light. (7) The observation apparatus according to (6), wherein the secondary photogenerating material dispersed in the immersion liquid and the circulating liquid causes Rayleigh scattering with respect to the reference irradiation light. (8) The observation apparatus according to (7), wherein the secondary light-generating material that produces Rayleigh scattering is a water-soluble polymer and / or surfactant. (9) The observation apparatus according to (6), wherein the immersion fluid and / or the circulating fluid have different light absorption characteristics and / or polarization characteristics with respect to the reference irradiation light than the blood vessel model. (10) The observation apparatus according to (2), wherein the material forming the blood vessel model exhibits a photoelastic effect with respect to the reference irradiation light, and the light generated by the photoelastic effect is included in the post-irradiation light. (11) The aforementioned observation assembly further comprises a plate for holding the blood vessel model, The plate transmits the reference irradiation light, The observation apparatus according to (6), wherein the plate has grooves that conform to the shape of the blood vessel model, and the blood vessel model is fitted into the grooves completely or partially without any gaps. (12) The observation apparatus according to (11), wherein the peripheral wall of the groove in the plate is formed of a soft material that produces a photoelastic effect with respect to the reference irradiation light, and the light produced by the photoelastic effect is included in the post-irradiation light. (13) The observation apparatus according to (2), wherein the blood vessel model has a movable part inside it that mimics a thrombus or the like, and the movable part interferes with the reference irradiation light to modulate its polarization state. (14) The observation apparatus according to (2), wherein the observation assembly is capable of photographing a first part of the object to be observed and a second part different from the first part. (15) A second observation assembly comprising a second light-emitting unit and a second light-receiving unit is further provided. The observation apparatus according to (14), wherein the second observation assembly observes the part of the object to be observed by the observation assembly from another direction. (16) The observation apparatus according to (15), wherein the observation assembly and the second observation assembly are movable relative to the object to be observed. (17) The observation apparatus according to (1), wherein the light receiving unit is positioned at one or more of the following locations: a first position capable of mainly receiving post-irradiation light obtained when the reference irradiation light passes through the object of observation; a second position capable of mainly receiving post-irradiation light obtained when the reference irradiation light is reflected by the object of observation; and a third position capable of mainly receiving secondary light generated when the reference irradiation light interferes with the object of observation. (18) The assembly to be observed includes a case that holds the immersion liquid. The case constitutes part of the mannequin. The observation apparatus described in (11), wherein the plate is placed inside the case. (19) The observation apparatus according to (6), wherein the observation object assembly includes a case for holding the immersion liquid, and the peripheral wall of the case includes the light-emitting part. (20) The assembly to be observed includes a case that holds the immersion liquid. The observation apparatus according to (6), wherein the light-emitting part is provided with an anti-reflection part for reference illumination light on the light-emitting part side. (twenty one) The observation apparatus according to (20), wherein the object to be observed is positioned towards the light-receiving part within the case, and the layer of immersion liquid between the object to be observed and the light-emitting part is made thicker than the layer of immersion liquid between the object to be observed and the light-receiving part, and the layer of immersion liquid between the object to be observed and the light-receiving part performs the function of the anti-reflective part. (twenty two) The components of the assembly to be observed are fitted with a fluorescent material that emits a polarization component that is imaged by the light-receiving unit. The light-emitting part of the observation assembly is equipped with a light source that causes the material to fluoresce. (6) The observation apparatus described above. (twenty three) The assembly to be observed includes a case that holds the immersion liquid. The light is ultraviolet light, and the ultraviolet light from the light source is introduced into the case and emitted from the side wall of the case toward the object to be observed. The observation apparatus described in (22). (twenty four) The light-receiving unit has a second polarization characteristic state and a third polarization characteristic state in a direction relatively different from the first direction of the first polarization, The aforementioned image display assembly includes an image synthesis unit, When the light receiving unit is in the second polarization characteristic state, it generates an observation output that generates the first and second images. When the light receiving unit is in the third polarization characteristic state, it generates an observation output that generates the first to third images. The image synthesis unit synthesizes the first-2 image and the first-3 image, The observation apparatus according to (2), wherein the display shows a synthesized image. (twenty five) Images 1 and 2 above are designed to show only the sheath of the catheter and the metallic wire inside the sheath. The observation apparatus according to (24), wherein the vascular model is displayed in the first to third images. (26) The observation apparatus described in (25) shows the first and second screens as video. (27) An observation device for observing a vascular model in which a catheter has been inserted, In an observation method using an observation device having a light-receiving section with predetermined polarization characteristics, The steps include irradiating the object to be observed with reference irradiation light, The steps include causing the light receiving unit to receive post-irradiation light generated by the reference irradiation light that has been interfered with by the object being observed, wherein the post-irradiation light includes a polarization component, and the polarization component originates from the sheath of the catheter. An observation method comprising the step of the light-receiving unit generating an output based on a polarization component that matches the polarization characteristics of the polarization component originating from the sheath and is imaged by the light-receiving unit. (28) At least one of the constituent materials of the blood vessel model, the lubricating fluid circulating within the blood vessel model, and the immersion fluid in which the blood vessel model is immersed contains a secondary light generating material that interferes with the reference irradiation light to generate secondary light. The observation method according to (27), wherein the polarization component of the post-irradiation light is changed by interfering the secondary light with the sheath. (29) The polarization characteristics of the light-receiving section include a second polarization characteristic state and a third polarization characteristic state. The observation method according to (27), wherein the output of the light receiving unit is changed by adjusting the second polarization characteristic state and the third polarization characteristic state, thereby adjusting the contrast between the imaged catheter sheath and its surroundings. (30) The steps include generating a contrast-enhanced mode image in which only the sheath of the catheter and the metallic wire within the sheath are displayed in the second polarization characteristic state, The steps include obtaining a still image mode image in which a blood vessel model is displayed in the third polarization characteristic state, The steps include displaying the still image mode image and the contrast-enhanced image overlaid on each other, The observation method described in (29), including. (31) An observation device for observing a vascular model in which a catheter has been inserted, Observation assembly including light-emitting part and light-receiving part, It comprises an image generation unit and an image display assembly including a display, The light-emitting unit comprises a light source and a polarizing element, and irradiates the object to be observed with reference irradiation light including a first polarization, the polarizing element has a polarization axis in a first direction, and transmits the first polarization that is polarized in the first direction from the light output from the light source, the first polarization passes through the sheath of the catheter, and at least a portion of its light component has its polarization state modulated. The light receiving unit comprises a photodetector and an analyzer, the analyzer having a polarization axis in a second direction different from the first direction, the photodetector receives the light component that has passed through the analyzer of the reference illumination light (post-illumination light) that has been irradiated onto the object to be observed and interfered with by the object to be observed, and generates an observation output. The image generation unit receives the observation output and generates an image. The aforementioned display is an observation device that displays the aforementioned image. [Explanation of Symbols]

[0121] 1.101 Observation Assembly 2 Catheter 3 Sheath 4 wires 5.105 Vascular Model 6 Circulating fluid 7 Immersion liquid 9. Near-infrared 20, 120, 220, 320, 420 Observation Assembly 22, 122 Near-infrared light source 23, 123 First polarizing plate 24, 124 Second polarizer 25, 125 Near-infrared camera 30, 130, 230, 330 Image generation assembly 31 Image generation unit 33 displays 109 white light 122A white light source 125A Visible Light Camera A-I Observation Device

Claims

1. An observation device for observing a vascular model in which a catheter has been inserted, Observation assembly including light-emitting part and light-receiving part, It comprises an image generation unit and an image display assembly including a display, The light-emitting unit comprises a light source and a polarizing element, and irradiates a reference irradiation light including a first polarization toward the object to be observed. The polarizing element has a polarization axis in a first direction and transmits the first polarization, which is circularly polarized in the first direction, from the light output from the light source. The first polarization passes through the sheath of the catheter, and at least a portion of its light component has its polarization state modulated. The light receiving unit comprises a photodetector and an analyzer, the analyzer having a polarization axis that constitutes circular polarization in a second direction different from the first direction, the photodetector receives the circular polarization light component in the second direction that has passed through the analyzer from the reference illumination light (post-illumination light) that has been irradiated onto the object to be observed and interfered with by the object to be observed, and generates an observation output. The image generation unit receives the observation output and generates an image. The aforementioned display is an observation device that displays the aforementioned image.

2. An observation device for observing catheters, Observation assembly including light-emitting part and light-receiving part, It comprises an image generation unit and an image display assembly including a display, The light-emitting unit comprises a light source and a polarizing element, and irradiates a reference irradiation light including a first polarization toward the object to be observed. The polarizing element has a polarization axis in a first direction and transmits the first polarization, which is circularly polarized in the first direction, from the light output from the light source. The first polarization passes through the sheath of the catheter, and at least a portion of its light component has its polarization state modulated. The light receiving unit comprises a photodetector and an analyzer, the analyzer having a polarization axis that constitutes circular polarization in a second direction different from the first direction, the photodetector receives the circular polarization light component in the second direction that has passed through the analyzer from the reference illumination light (post-illumination light) that has been irradiated onto the object to be observed and interfered with by the object to be observed, and generates an observation output. The image generation unit receives the observation output and generates an image. The aforementioned display is an observation device that displays the aforementioned image.

3. An observation method for observing a catheter using an observation device that includes an observation assembly comprising an observation unit including a light-emitting unit equipped with a light source and a polarizing element, a light-receiving unit equipped with a photodetector and an analyzer, and an image display assembly comprising an image generation unit and a display, The light source of the light-emitting unit is directed towards the object to be observed with reference illumination light including the first polarization. The polarizing element has a polarization axis in a first direction and transmits the first polarized light, which is circularly polarized in the first direction, from the light output from the light source, and the first polarized light passes through the sheath of the catheter, and at least a portion of its light component has its polarization state modulated. The analyzer in the light-receiving unit is provided with a polarization axis that constitutes circular polarization in a second direction different from the first direction, and the light receiver receives the circular polarization light component in the second direction that has passed through the analyzer from the reference illumination light (post-illumination light) that has been irradiated onto the object to be observed and interfered with by the object to be observed, and generates an observation output. The image generation unit receives the observation output and generates an image. An observation method for displaying the image on the aforementioned display.

Images