JP2006113520A - Stress observing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-dimensional model capable of reproducing dynamic characteristics of body cavity portions such as a blood vessel. <P>SOLUTION: A membranous model having thereinside cavities reproducing body cavities, such as a blood vessel, formed on the basis of tomogram data of a test subject is buried in a base material with physical properties analogous to those of biotissue. As the base material, use is made of a flexible elastic material, such as silicone gel. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stress observation apparatus. More particularly, the present invention relates to an apparatus for observing the stress of a three-dimensional model that reproduces a body cavity such as a blood vessel of a subject.

The present inventors have proposed a block-shaped three-dimensional model that reproduces a body cavity such as a blood vessel of a subject (Non-Patent Document 1). This three-dimensional model is formed by layering a body cavity model such as a blood vessel based on tomographic image data of the subject, surrounding the body cavity model with a three-dimensional model molding material, curing the three-dimensional model molding material, and then removing the body cavity model Can be obtained.
Furthermore, a film-like three-dimensional model (Non-Patent Document 2) is proposed.
Further, refer to Patent Documents 1 to 5 as documents related to the present invention.

JP 2003-11237 A JP-A-11-73096 WO 03/096309 A1 JP-A-10-33253 Japanese Patent Laid-Open No. 3-111726 A medical model for surgical trials that reproduces the cerebral vascular lumen, Proceedings of the 20th Annual Conference of the Robotics Society of Japan, 2002. Research on surgical simulator based on biological information for intravascular surgery, Proceedings of Lecture Meeting on Robotics and Mechatronics, 2003

According to each of the above three-dimensional models, a complicated and delicate three-dimensional shape of a body cavity such as a cerebral blood vessel is accurately reproduced, which is suitable for confirmation of an affected area or a catheter insertion simulation. However, in the block-shaped three-dimensional model, the vascular shape inside the model is constrained because the vascular membrane structure and the structure around the vascular region are not reproduced individually. It cannot express the dynamic deformation of blood vessels that is sometimes recognized.
In addition, the membranous solid model is inconvenient because it is inferior in shape retention.
In this specification, the membranous three-dimensional model is sometimes expressed as “a membranous model” and “an observation object having a hollow portion”.

1st aspect of this invention was made | formed to solve the said subject, The structure is
A membranous model that reproduces body cavities such as blood vessels inside,
A translucent base material surrounding the membranous model, having elasticity and adhesiveness to the membranous model;
A three-dimensional model comprising

  According to the three-dimensional model configured as described above, the membrane structure of the biological blood vessel and the structure of the soft tissue around the blood vessel are individually reproduced including physical characteristics. As a result, a model of a film-like structure having flexibility such as a blood vessel is embedded in the base material having the elastic characteristics of the tissue surrounding the blood vessel. For this reason, in a medical instrument or fluid insertion simulation, a blood vessel model having a film-like structure inside a three-dimensional model can be flexibly deformed in the same manner as a blood vessel in a living body, and the deformation characteristics of a living blood vessel are reproduced. It becomes a suitable thing.

Hereinafter, each component of the invention will be described in detail.
(Membrane model)
The membranous model is formed as follows.
The subject is the whole or part of the human body, but animals and plants can be the target of tomography. It does not exclude corpses.
The tomographic image data refers to data that is the basis for executing additive manufacturing. In general, three-dimensional shape data is constructed from tomographic data obtained by an X-ray CT apparatus, an MRI apparatus, an ultrasonic apparatus, etc., and the three-dimensional shape data is decomposed into two-dimensional data to obtain tomographic image data.
Hereinafter, an example of tomographic image data generation will be described.

  Here, a case will be described in which a plurality of two-dimensional images obtained by imaging at equal intervals while being translated in the body axis direction are used as input data (tomographic data), but obtained by other imaging methods. Even when a two-dimensional image or a three-dimensional image is used as an input image, three-dimensional shape data of the cavity can be obtained by performing the same processing. Each input two-dimensional image is first accurately stacked based on the shooting interval at the time of shooting. Next, by specifying a threshold for the image density value on each two-dimensional image, only the cavity region that is the target of the body cavity model is extracted from each two-dimensional image, while other regions are stacked. Delete from the two-dimensional image. As a result, the three-dimensional shape of the portion corresponding to the cavity region is given in the form of a stack of two-dimensional images, and the contour line of each two-dimensional image is interpolated three-dimensionally and reconstructed as a three-dimensional curved surface. Three-dimensional shape data of the target cavity is generated. In this case, the cavity region is first extracted from the input image by designating a threshold value for the density value, but separately from this method, by specifying a specific density value that gives the cavity surface. It is also possible to directly generate a three-dimensional curved surface by extracting the cavity surface from the input image and performing three-dimensional interpolation. Further, the input images may be stacked after performing region extraction by specifying a threshold value (or surface extraction by specifying a specific density value). The generation of the three-dimensional curved surface may be performed by polygon approximation.

  The three-dimensional shape data can be modified or changed during or after the generation of the three-dimensional shape data. For example, adding a structure that does not exist in the tomographic data, adding a support structure called a support, removing a part of the structure in the tomographic data, or changing the shape of the cavity Thus, the shape of the cavity formed inside the three-dimensional model can be freely modified or changed. Furthermore, it is also possible to provide a non-layered modeling region inside the cavity, and in the case where a body cavity model having a non-layered modeling region provided with a non-layered modeling region is explained, Three-dimensional shape data in which the layered modeling region is provided inside the cavity is generated. In addition, you may perform these processes in the additive manufacturing system or the software corresponding to an additive manufacturing system.

Next, the generated three-dimensional shape data of the cavity is converted into a format corresponding to the additive manufacturing system used for the additive manufacturing of the body cavity model as necessary, and used for the additive manufacturing system or the additive manufacturing system to be used. Send to compatible software.
The additive manufacturing system (or software that supports additive manufacturing systems) supports the setting of various setting items such as the placement of the body cavity model and the stacking direction during additive manufacturing as well as the purpose of maintaining the shape during additive manufacturing. (Support structure) is added to the place where support is required (if it is not necessary, it is not necessary to add it). Finally, slice data (tomographic image data) that is directly used for additive manufacturing is generated by slicing the modeling data obtained in this way based on the modeling thickness at the time of additive manufacturing. In contrast to the above procedure, support may be added after slice data is generated. Moreover, when the slice data is automatically generated by the additive manufacturing system (or software corresponding to the additive manufacturing system) used, this procedure can be omitted. However, even in this case, the layered modeling thickness may be set. The same applies to the addition of the support. When the support is automatically generated by the additive manufacturing system (or software corresponding to the additive manufacturing system), it is not necessary to generate the support manually (may be generated manually). ).

  In the above example, the 3D shape data is constructed from the tomographic data. However, when the 3D shape data is given as the data from the beginning, it is decomposed into 2D and used in the next additive manufacturing process. Image data can be obtained.

  In this invention, a body cavity such as a blood vessel is targeted, and the body cavity is a cavity located in various organs (skeletal, muscle, circulatory, respiratory, digestive, urogenital, endocrine, nerve, sensory organs, etc.) And a cavity formed by a geometric arrangement of these organs and body walls. Therefore, the lumens of organs such as heart lumen, stomach lumen, intestinal lumen, uterine lumen, blood vessel lumen, ureter lumen, oral cavity, nasal cavity, strait, middle ear A cavity, a body cavity, a joint cavity, a pericardial cavity, and the like are included in the “body cavity”.

The body cavity is formed from the tomographic image data.
Although the formation method is not particularly limited, layered modeling is preferable. Here, the layered structure means that a thin layer is formed based on the tomographic image data, and this is sequentially repeated to obtain a desired shape. That is, based on the tomographic image data of the subject, the cavity region of the subject is extracted and a body cavity model corresponding to the cavity region is layered.
The layered body cavity model must be decomposed and removed in a later process. In order to facilitate the removal, it is preferable that the material used for additive manufacturing is a material having a low melting point or a material that is easily dissolved in a solvent. As such a material, a low-melting-point thermosetting resin or wax can be used. A photo-curable resin widely used in so-called stereolithography (included in layered modeling) can be used if it can be easily decomposed.

If the body cavity model has a strength that can withstand external force such as pressure applied from the outside when surrounded by the membrane model molding material in the next step, the inside of the body cavity model can be thinned with a hollow structure. it can. This not only reduces the time required for layered modeling and the cost associated with modeling, but also simplifies elution of the body cavity model in the subsequent elution process.
Specific examples of the additive manufacturing method include a powder sintering method, a molten resin ejection method, a molten resin extrusion method, and the like.

The body cavity model created by additive manufacturing can be subjected to various processes (removal processing and additional processing) such as surface polishing and surface coating after additive manufacturing, which allows the body cavity model to be It is possible to modify or change the shape. As a part of these processes, when a support that needs to be removed after the layered modeling is added in the production of the body cavity model, the support is removed.
By coating the surface of the body cavity model with another material, it is possible to prevent some or all of the components of the body cavity model material from diffusing into the membranous model molding material. In addition, the diffusion can be prevented by physically treating the surface of the body cavity model (heat treatment, high frequency treatment, etc.) or chemically treating the surface.

  It is preferable to smooth the level difference on the surface of the body cavity model by surface treatment. Thereby, the surface of the lumen of the membranous model becomes smooth, and the surface of the body cavity such as an actual blood vessel can be reproduced. Examples of the surface treatment include contacting the surface of the body cavity model with a solvent, heating to melt the surface, coating, and using these in combination.

  A part or all of the body cavity model is thinly surrounded by a film-shaped model molding material, and this is cured by polymerization or vulcanization. A membranous model is formed by removing the body cavity model.

The membranous model molding material is appropriately selected according to the use of the model. For example, in addition to elastomers such as silicone rubber (silicone elastomer) and thermosetting polyurethane elastomer, thermosetting resins such as silicone resin, epoxy resin, polyurethane, unsaturated polyester, phenolic resin, urea resin, and polymethyl methacrylate These thermoplastic resins can be used alone or in combination. These materials are thinly laminated on the surface of the body cavity model by a method such as application, spraying, or dipping, and then vulcanized or cured by a known method.
When the target of the membranous model is a cerebral blood vessel model, it is preferable to employ a material that is transparent and has elasticity and flexibility close to a living tissue. An example of such a material is silicone rubber. In addition, since silicone rubber has contact characteristics equivalent to those of living tissue, a medical instrument such as a catheter is inserted to be suitable for a trial of surgery. Urethane resins and urethane elastomers can also be suitably used.
The membranous model forming material can be formed from a plurality of layers. The thickness can also be set arbitrarily.

(Base material)
The base material is made of a translucent material, so that the deformation of the film model can be observed.
A base material shall have elasticity. Preferably, the elastic modulus is low elasticity of 2.0 kPa to 100 kPa. More preferably, the substrate has sufficient elongation. Thereby, even if a membranous model changes greatly, a substrate does not peel from a membranous model. For example, when no load is set to 1, it is preferable that the substrate has an elongation ratio of 2 to 15 times that when no addition is applied when the substrate is pulled in a state in which adhesion to the film model is ensured. Here, the elongation percentage refers to the maximum amount of deformation that the base material can return to. In addition, it is preferable that the speed at which the base material is restored when the load is removed from the base material deformed by applying a load is relatively moderate. For example, the loss coefficient tan δ (at 1 Hz), which is a viscoelastic parameter, can be set to 0.2 to 2.0.
As a result, the base material has characteristics similar to or close to those of the tissue existing around the blood vessel or the like, and the deformation of the membranous model is performed in an environment that is closer to reality. That is, the insertion feeling of a catheter or the like can be realistically reproduced.
A base material shall have adhesiveness with respect to a membranous model. Thereby, even if a catheter or the like is inserted into the membranous model and the membranous model is deformed, no deviation occurs between the base material and the membranous model. If there is a difference between the two, the stress applied to the membranous model will change, which may hinder, for example, a catheter insertion simulation, and may cause discomfort during the insertion.
When a cerebral blood vessel model is targeted as a membranous model, the adhesion (adhesive strength) between the substrate and the membranous model is preferably 1 kPa to 20 kPa.
In this embodiment, silicone gel and glycerin gel are used as the base material, but the material is not particularly limited. In addition, if a casing can ensure airtightness, a highly viscous liquid can also be used as a base material. This is particularly suitable as a base material for a membranous model that reproduces a blood vessel surrounded by a living tissue having no elasticity. A suitable base material can also be prepared by mixing these plural kinds of fluids and further mixing an adhesive agent thereto.
When gel is used as the material of the base material, the base material can be brought closer to a living tissue by using a plurality of materials having different physical properties.
In order to observe the dynamic behavior of the membranous model, the base material is preferably translucent. In order to clarify the boundary between the membranous model and the substrate, at least one of the membranous model and the substrate can be colored. Further, it is preferable that the refractive index of the material of the film model and the refractive index of the material of the base material are substantially equal so that the dynamic behavior of the film model can be observed more accurately.
The entire membranous model need not be embedded in the substrate. That is, a part of the membranous model may be located in the gap (see FIG. 8). Further, a part of the membranous model may be in a solid substrate (having dissimilar physical properties to living tissue) or in a fluid.

(casing)
A casing accommodates a base material and can take arbitrary shapes. The whole or a part thereof is formed of a translucent material so that the dynamic behavior of the membranous model can be observed. Such a casing can be formed of a light-transmitting synthetic resin (such as an acrylic plate) or a glass plate.
The casing has a hole communicating with the cavity of the membranous model. A catheter can be inserted through this hole.
The three-dimensional model is preferably translucent as a whole. From the viewpoint of observing the insertion state of the catheter, it is sufficient that at least the inside of the membranous model can be visually recognized.
Provide a sufficient distance between the casing and the membranous model. As a result, a sufficient margin (thickness) is secured for the elastic base material, and when an external force is applied to the membranous model by insertion of a catheter or the like, the membranous model can be freely deformed according to the external force. This margin can be arbitrarily selected according to the object, application, etc. of the three-dimensional model, but is preferably set to 10 to 100 times or more the film thickness of the membranous model, for example.

(Method for manufacturing a three-dimensional model)
The core in a state where the body cavity model is covered with the membranous model is set in the casing, and the base material is injected into the casing for gelation. Thereafter, when the body cavity model is removed, the membranous model remains in the base material.

  Alternatively, the body cavity model is removed prior to the injection of the base material, and after obtaining the membranous model, the membranous model is set in the casing, and then the base material is injected into the casing. The state in which the membranous model is buried in the substrate can also be realized by gelling.

  The method of removing the body cavity model is appropriately selected according to the modeling material of the body cavity model, and is not particularly limited as long as other materials of the three-dimensional model are not affected. As a method for removing the body cavity model, (a) a heat melting method that melts by heating, (b) a solvent dissolution method that dissolves by a solvent, (c) a hybrid method that combines melting by heating and dissolution by a solvent, etc. be able to. By these methods, the body cavity model is selectively fluidized and eluted out of the three-dimensional model to remove it.

(Diffusion removal process)
Some of the components of the material of the body cavity model may diffuse into the membranous model, causing the membranous model to become cloudy and reducing its visibility. In order to remove this fogging, it is preferable to reheat the sample after removing the body cavity model. This heating can also be performed during the removal of the body cavity model.

The three-dimensional model of the present invention can also be formed as follows.
The body cavity model is embedded as a core in a gel-like base material, and the body cavity model is removed. Thereby, the cavity which reproduced the body cavity in the base material is formed. Thereafter, a film-form model forming material is attached to the peripheral wall of the cavity and cured by polymerization or vulcanization. By flowing the membranous model forming material into the cavity of the base material, or by dipping the base material into the membranous model forming material, the membranous model forming material can be attached to the peripheral wall of the body cavity of the base material.

Further, the peripheral wall of the cavity can be hydrophilized instead of attaching the membranous model forming material to the peripheral wall of the cavity. Thereby, when water or an aqueous solution is filled in the cavity of the three-dimensional model, a water film is formed on the peripheral wall, and the insertion resistance of the catheter is alleviated. That is, this water film corresponds to the membranous model.
Similarly, when the peripheral wall of the cavity is subjected to a hydrophobic treatment (lipophilic treatment), when the cavity is filled with oil, an oil film is formed on the peripheral wall and the insertion resistance of the catheter is reduced. That is, this oil film corresponds to a film model.

  The peripheral wall of the cavity is made hydrophilic or hydrophobic by a known method. For example, when silicone gel is employed as the substrate, the peripheral wall of the cavity can be hydrophilized by forming a film having a polar group such as a surfactant on the peripheral wall. Similarly, by forming an oily film such as oil or wax on the peripheral wall of the cavity, the peripheral wall of the cavity can be hydrophobized.

The present inventors have found that the internal stress of the membranous model can be observed by the photoelastic effect. That is, according to another aspect of the present invention, in the three-dimensional model of the first aspect described above, the membranous model is made of a light-transmitting material, and when an external force is applied to the model, The internal stress is not substantially generated, and the first internal stress is generated in the direction along the surface,
The substrate is made of a material that does not substantially generate internal stress,
Used for observation of photoelastic effect.

According to the three-dimensional model configured as described above, even if the membranous model has a three-dimensional shape, the photoelastic effect generated there is exclusively the first internal stress (the direction along the surface of the peripheral wall of the membranous model). The stress on the peripheral wall can be specified from the observed photoelastic effect (wavelength of light).
This stress observation apparatus is effective for observing the physical characteristics of the surrounding area of the cavity when the observation target is a membranous model (a translucent model having a cavity that reproduces a body cavity). That is, when stress is applied to the peripheral wall of the membranous model in a catheter or liquid insertion simulation, a photoelastic effect is generated and the stress state can be observed. Thereby, it is possible to simulate the influence on the living tissue when a catheter or liquid is inserted into a body cavity such as a blood vessel.

In the above description, the peripheral wall is a thin film made of an elastic material. When an external force is applied to the peripheral wall, the peripheral wall is not constrained in the thickness direction, and forced displacement occurs only in the direction along the surface. Thereby, the stress generated in the peripheral wall is only the first internal stress, and the stress of the film-shaped peripheral wall can be specified from the photoelastic effect. Of course, the peripheral wall has translucency in order to obtain a photoelastic effect.
The thickness of the peripheral wall is not particularly limited as long as the above characteristics can be maintained. However, according to the study by the present inventors, it is preferably 0.1 to 5.0 mm. More preferably, it is 0.1-1.0 mm.
Moreover, in order not to generate stress in the thickness direction on the peripheral wall, the peripheral wall is not physically restricted from the thickness direction. Specifically, the outside of the peripheral wall is in contact with the easily deformable base material of gel or fluid (water, etc.) directly or through a space, and the base material is deformed in the thickness direction. Shall not receive substantial resistance. In order not to give physical resistance to the peripheral wall, the substrate needs a predetermined margin (thickness). Since the base material is easily deformed, the periphery thereof is surrounded by a casing in order to secure the predetermined margin. Moreover, it is preferable that there is high adhesion between the molding material for the peripheral wall and the molding material for the base material. This is because if a slip occurs between the two, frictional resistance is generated, and irregular internal resistance may occur. Examples of the material for forming the peripheral wall include urethane resin or urethane elastomer, and examples of the material for forming the base material include silicone gel.
In addition, if a photoelastic effect is generated from the substrate, it is not preferable because noise of the photoelastic effect of the peripheral wall is generated. Therefore, the base material is preferably made of a material that does not substantially generate internal stress such as gel or fluid (water or the like).
An arbitrary object can be inserted into the inside of the peripheral wall, that is, the hollow portion when observing the photoelastic effect. For example, in the case of a membranous model, a catheter or a liquid can be inserted.

  The peripheral wall of the hollow portion is preferably formed in an annular cross section having substantially the same thickness. Thereby, the same photoelastic effect (wavelength of light) can be obtained no matter what direction the peripheral wall is observed. In addition, since the width of the material related to the first internal stress is constant in the peripheral wall, the stress can be easily specified.

In order to observe the stress state of the membranous model by photoelasticity, at least a portion where the stress state needs to be observed is formed of an isotropic material in the membranous model. The membranous model is assumed to be translucent.
Examples of such photoelastic materials include thermosetting of silicone resins, epoxy resins, polyurethanes, unsaturated polyesters, phenol resins, urea resins, etc., in addition to elastomers such as silicone rubber (silicone elastomer) and thermosetting polyurethane elastomers. A thermoplastic resin such as polymethyl methacrylate can be used singly or in combination.
When a catheter or liquid is inserted into a cavity of the membranous model, at least the peripheral wall needs to be formed of an elastically deformable material so that the stress state on the peripheral wall can be observed as a photoelastic effect. Of course, the membranous model can be formed of a material that is elastically deformable as a whole.
As a material for forming such a membranous model, it is easy to deform with insertion of a catheter or the like (that is, the longitudinal elastic modulus is small), and a large change in photoelastic effect can be observed even with slight deformation (that is, the photoelastic coefficient is Large) material is preferred. An example of such a material is a polyurethane elastomer. In addition, a polysaccharide gelling agent such as gelatin (vegetable orange), vegetable orange, carrageenan, locust bean gum may be employed.
The substrate is formed from a material that does not cause internal stress. In order to reproduce a living tissue, appropriate elasticity and adhesion to a membranous model are required.
The most preferable combination of the membranous model and the base material is that the membranous model is formed of a polyurethane elastomer and a silicone gel is adopted as the base material.

(Photoelastic effect)
The photoelastic effect means that when an internal stress occurs in a translucent material, it temporarily has birefringence, and the refractive index differs in the direction of the maximum principal stress and the minimum principal stress. It means to proceed in a divided manner. An interference fringe is generated by the phase difference between the two waves, and the state of the internal stress of the translucent material can be known by observing the interference fringe.
In order to generate this photoelastic effect, as shown in FIG. 1, light from a light source is polarized through a first polarizing plate (polarizing filter), and this linearly polarized light is passed through a three-dimensional model. If an internal stress is generated in the three-dimensional model, birefringence occurs according to the strength of the internal stress, and a maximum main stress (acosφsinωt) and a minimum main stress (acosφsin (ωt−A)) are generated. Since these lights have different speeds, a phase difference is generated, and interference fringes appear when observed through the second polarizing plate (polarizing filter). The polarization direction of the second polarizing plate is substantially perpendicular to the changing direction of the first polarizing plate.
As a method for observing the photoelastic effect generated in light transmitted through the three-dimensional model by interposing a three-dimensional model between a pair of polarizing plates, an orthogonal Nicol method, a parallel Nicol method, a sensitive color method, and the like are known. Further, as a method for detecting the photoelastic effect by interposing a quarter polarizing plate between the polarizing plate and the three-dimensional model, a circular polarization method, a senalmon method, and the like are known.

  In this invention, as shown in FIG. 2B, the observation object 100 has a hollow portion 101, and the peripheral region 103 of the hollow portion 101 is made of an elastic material having a photoelastic effect (thickness: 0.1 to 5). 0.0 mm). The surrounding region 103 is surrounded by a translucent substrate 105 such as gel. The base material 105 is easily deformable and does not substantially exhibit a photoelastic effect. In addition, by ensuring a sufficient thickness (margin) in the base material 105, resistance to deformation of the surrounding region 103 is eliminated. The thickness of the base material 105 is arbitrarily selected depending on the material, but it is preferably 10 times or more, preferably 100 times or more the thickness of the surrounding region 103. Since the thick base material 105 is easily deformed, it is preferable to cover it with a translucent case 107. The shape of the case 107 is arbitrary.

  In the observation target 100 of FIG. 2B, when an external force (corresponding to a catheter) is applied as indicated by an arrow in the drawing, the surrounding region 103 is deformed. At this time, the internal stress σ3 in the thickness direction of the surrounding region 103 hardly occurs in the deformed portion. This is because there is substantially no repulsive force from the substrate 105 to the external force. Therefore, only the internal stress σp (first internal stress) in the direction substantially along the surface of the surrounding region 103 is generated in the deformed portion.

  When polarized light is transmitted through the observation target 100, a photoelastic effect caused by the first internal stress σp is generated, and light having a wavelength corresponding to the magnitude of the first internal stress σp is observed.

  The inventors of the present invention have made extensive studies on a method for identifying the first internal stress σp by utilizing the wavelength generated in the incident light due to the photoelastic effect, in other words, the color change of the observed light. As a result, the internal stress σp on the surrounding region 103 is divided into a portion (contour region) existing in the contour region of the hollow portion 101 at the time of observation and a portion (front region) existing in front of the hollow portion 101 at the time of observation. It was found that they could be identified by different methods.

(Stress observation method of the contour region)
When observing the contour region in the surrounding region 103, the direction of the first internal stress σp is parallel to the observation direction, that is, the direction of incident light, so that the material of the surrounding region 103 is wide in the direction of the internal stress σp. Will exist. In this case, the photoelastic effect caused by the first internal stress σp observed in the contour region is the sum of wavelength changes on the material existing in the width W. Therefore, as shown in FIG. 2B, the wavelength change of the specific region 1031 (unit region) having the unit width w can be obtained by dividing the wavelength change obtained from the observed photoelastic effect by the width W.

Here, if the peripheral region 103 is formed in an annular shape with substantially the same thickness, the width W is fixed, so that the wavelength change of the unit region can be obtained from the observed photoelastic effect. Thus, the internal stress of the contour region can be easily obtained. Specifically, if a conversion table (indicating the relationship between the wavelength (color) of observation light and the internal stress of the unit region) corresponding to the inner or outer diameter of the surrounding region is prepared, the observed photoelastic effect The internal stress generated in the unit region can be grasped from the wavelength (color) of the light.
If there is three-dimensional data representing the surrounding area 103, the width W of the surrounding area can be specified from the data.

Next, a three-dimensional analysis method of internal stress in the contour region of the membranous model will be described.
FIG. 3 is a schematic diagram for explaining this analysis method. The internal stress σp (vector or tensor) is described by the internal principal stresses σ1 and σ2 which are constituent elements in the plane stress problem of the present invention. Then, for each point 108 on the contour region 107 of the membranous model obtained in accordance with each observation direction (that is, each point on the peripheral wall defining the membranous model), the observation direction, that is, the incident direction of polarized light Assuming a tangential plane parallel to, the internal stresses obtained by this method, that is, the internal principal stresses σ1 and σ2 are defined as stresses on the tangential plane and are orthogonal to the tangential plane. Accordingly, these internal principal stresses σ1 and σ2 are in the direction along the surface of the film model, and correspond to the first internal stress defined in this specification. Note that the internal stress in the thickness direction of the membranous model is negligible due to the characteristics of the present invention.
The phase difference R that causes the photoelastic effect is expressed by the following equation.
R = α (σ1cos ² θ + σ2sin ² θ) D
(Where D is the length of polarized light passage)

Therefore, the observed photoelastic effect includes the influence of the internal principal stresses σ1 and σ2.

上記式を解くに当たり、偏光を３つの異なる入射角度で入射し、そのときの偏光の通過長さをＤ１，Ｄ２、Ｄ３とする。観察された光弾性効果より位相差Ｒ１，Ｒ２及びＲ３を求める。なお、Ｒ２はθ＝９０度のときの位相差である。
上記式を解くことにより、内部主応力σ１及びσ２を独立かつ容易に求めることができる。 Accordingly, as a result of intensive studies to independently determine the internal principal stresses σ1 and σ2, the present inventors have found that the values of the internal principal stresses σ1 and σ2 can be obtained by solving the following equations.

In solving the above equation, the polarized light is incident at three different incident angles, and the polarization passing lengths at that time are denoted by D1, D2, and D3. The phase differences R1, R2 and R3 are determined from the observed photoelastic effect. R2 is a phase difference when θ = 90 degrees.
By solving the above equation, the internal principal stresses σ1 and σ2 can be obtained independently and easily.

(Stress observation method for the front region)
When the polarized light is projected from behind the observation object 100 and the photoelastic effect is observed in front of the observation object 100, the wavelength (color) change observed in the front region is the cavity shown in FIG. 2A. The sum of the photoelastic effect on the film (cavity back membrane) existing on the back surface of 101 and the photoelastic effect on the film (cavity pre-film) existing on the front surface of the cavity 101 is the sum of the front region (ie, cavity) It is not possible to determine the wavelength change on the front film independently.

Therefore, the present inventors have intensively studied to obtain the wavelength change on the front region independently, and as a result, found that the wavelength change on the front region can be obtained by the following method.
That is, in this case, the polarized light is projected from the front of the observation target 100, the light transmitted through the pre-cavity film is reflected on the front surface of the cavity 101, and is transmitted through the pre-cavity film again to the front. By observing the returned light in front of the observation object 100, the wavelength change on the front region can be obtained independently,
Such reflection at the front surface of the cavity 101 is such that the interior of the cavity 101 is filled with a highly reflective liquid or a liquid mixed with a highly reflective material, or the surface of the cavity 101 (at least the front surface). This can be realized by forming a layer made of a highly reflective material.

In this case, the photoelastic effect caused by the first internal stress σp observed in the contour region is twice the sum of the wavelength changes on the film thickness of the precavity film. Therefore, the wavelength change with respect to the unit width w ′ within the film thickness can be obtained by dividing the wavelength change obtained from the observed photoelastic effect by the width W ′ twice the film thickness.

More precisely, since the front region has a curved surface, the film thickness in the observation direction differs at each point on the curved surface, but here the surrounding region 103 is formed in an annular shape with substantially the same thickness. If so, since the distribution of the width W ′ is fixed, it is possible to immediately determine the wavelength change of the unit width w ′ from the observed photoelastic effect, thereby easily reducing the internal stress in the front region. Can be sought. Specifically, if a conversion table corresponding to the position in the front region (indicating the relationship between the wavelength (color) of the observation light and the internal stress in the unit region) is prepared, the observed photoelastic effect can be obtained. The internal stress generated in the unit region can be grasped from the wavelength (color) of light.
If there is three-dimensional data representing the surrounding area 103, the width W ′ at each point in the front area can be specified from the data.

Next, a three-dimensional analysis method of internal stress in the front region of the membranous model will be described.
FIG. 23 is a schematic diagram for explaining this analysis method. Assuming a tangential plane for each point 110 on the front surface region 109 of the film model obtained in accordance with each observation direction (that is, each point on the peripheral wall forming the front surface of the film model), this method is used. Internal principal stresses (constituent elements of internal stress σp (vector or tensor)) σ1 and σ2 are defined as stresses on the tangent plane and are orthogonal on the tangential plane. Accordingly, these internal principal stresses σ1 and σ2 are in the direction along the surface of the film model, and correspond to the first internal stress defined in this specification. Note that the internal stress in the thickness direction of the membranous model is negligible due to the characteristics of the present invention.

The front region 109 has a curved surface because it exists on the surface of the cavity 101, and the photoelastic effect is observed on the curved surface. When the photoelastic distribution on the curved surface is projected onto a plane, the phase difference R at each point on the plane is expressed by the following equation.
R = α (σ1-σ2) D
(Where D is the length of polarization passing at each point)
Therefore, the observed photoelastic effect includes the influence of the internal principal stresses σ1 and σ2, but in this case, the internal principal stresses σ1 and σ2 are in a plane perpendicular to the observation direction. By adjusting the direction of the polarizing plate for detecting the photoelastic effect, one can be optically erased, and the values of the internal principal stresses σ1 and σ2 can be obtained.

Another aspect of the present invention will be described.
An observation object having a hollow portion, and a peripheral region of the hollow portion is a thin film formed of a light-transmitting elastic material, and when an external force is applied to the peripheral region, the thickness direction is substantially reduced. An observation object in which the first internal stress is generated in the direction along the surface without generating the internal stress,
Means for detecting a photoelastic effect generated in light passing through a surrounding region of the observation target;
And the photoelastic effect is caused solely by the first internal stress.

According to the stress observation apparatus configured as described above, even if the surrounding region of the hollow portion has a three-dimensional shape, the photoelastic effect generated there is exclusively the first internal stress (along the surface of the surrounding region). The stress in the surrounding region can be specified from the observed photoelastic effect (wavelength of light).
This stress observation apparatus is effective for observing the physical characteristics of the surrounding area of the cavity when the observation target is a three-dimensional model (a translucent model having a cavity that reproduces a body cavity). That is, when stress is applied to the area around the cavity of the three-dimensional model in the catheter or liquid insertion simulation, a photoelastic effect is generated and the stress state can be observed. Thereby, it is possible to simulate the influence on the living tissue when a catheter or liquid is inserted into a body cavity such as a blood vessel.

In the above, the surrounding region is a thin film made of an elastic material, and when an external force is applied to the thin film, the surrounding region is not restricted in the thickness direction but forced displacement occurs only in the direction along the surface. Thereby, the stress generated in the surrounding region is only the first internal stress, and the stress in the film-like surrounding region can be specified from the photoelastic effect. Of course, in order to obtain a photoelastic effect, the surrounding region has translucency.
The thickness of the surrounding region is not particularly limited as long as the above characteristics can be maintained. However, according to the study by the present inventors, it is preferably 0.1 to 5.0 mm. More preferably, it is 0.1-1.0 mm.
Further, in order not to generate stress in the thickness direction in the surrounding area, the surrounding area is not physically restricted from the thickness direction. Specifically, the outside of the surrounding area is in contact with a readily deformable substrate of gel, fluid (water, etc.) or through a space, and the surrounding area is deformed in the thickness direction. It shall not receive substantial resistance from the substrate. In order not to give physical resistance to the surrounding area, the substrate needs a predetermined margin (thickness). Since the base material is easily deformed, the periphery thereof is surrounded by a casing in order to secure the predetermined margin. Moreover, it is preferable that there is high adhesion between the molding material in the surrounding region and the molding material of the base material. This is because if a slip occurs between the two, frictional resistance is generated, and irregular internal resistance may occur. A urethane resin or urethane elastomer can be used as a material for forming the surrounding region, and a silicone gel can be used as a material for forming a base material.
Further, if a photoelastic effect is generated from the base material, it is not preferable because noise of the photoelastic effect in the surrounding area is generated. Therefore, the base material is preferably made of a material that does not substantially generate internal stress such as gel or fluid (water or the like).
An arbitrary object can be inserted into the inside of the surrounding area, that is, the hollow portion when observing the photoelastic effect. For example, in the case of a three-dimensional model, a catheter or liquid can be inserted.

  The peripheral region of the hollow part is preferably formed in an annular cross section having substantially the same thickness. As a result, the same photoelastic effect (the wavelength of light) can be obtained regardless of the direction in which the surrounding region is observed. In addition, since the width of the material related to the first internal stress is constant in the surrounding area (the width can be specified from the diameter of the surrounding area), the stress of the unit area (having the unit width) of the surrounding area can be easily It becomes possible to specify.

Another aspect of the present invention is defined as follows. That is,
Obtaining a photoelastic effect caused by the first internal stress by the detecting means;
Means for obtaining a width in the direction of occurrence of the first internal stress in the surrounding area, and means for calculating a stress in the unit area of the surrounding area from the obtained photoelastic effect and the width of the surrounding area are further provided. .

  According to the stress observation apparatus configured as described above, since the width in the direction in which the first internal stress is generated in the surrounding region is obtained, the photoelastic effect (change in the wavelength of light) acquired by the detection unit is calculated using the width. By dividing, it becomes possible to specify the wavelength change of the unit region (having the unit width) in the surrounding region. Thereby, the stress state generated in the surrounding area can be specified more accurately.

Another aspect of the present invention is defined as follows. That is,
At least a part of the peripheral area of the cavity that reproduces the body cavity is formed of a film-like elastic material having a photoelastic effect, and the periphery of the film-like elastic material is formed from a gel that does not substantially produce a photoelastic effect. A translucent three-dimensional model surrounded by a substantially non-resistant substrate with respect to the thickness direction of the surrounding region;
Means for detecting a photoelastic effect generated in light passing through the three-dimensional model;
A solid model stress observation device.

  According to the stress observation apparatus configured as described above, the periphery of the film-like elastic material is surrounded by the gel-like base material. Therefore, in the three-dimensional model, the photoelastic effect is generated exclusively from the elastic material portion, and the photoelastic effect is not generated from the gel-like base portion. Therefore, the stress state of the film-like elastic material can be accurately observed.

According to yet another aspect, a primary model of the surrounding region of the body cavity is created by additive manufacturing,
Forming a female mold by surrounding the primary model with a mold material;
Removing the primary model from the female mold;
Injecting polyurethane elastomer into the female mold cavity and curing it,
Remove the female mold to obtain a membrane model made of polyurethane elastomer,
A three-dimensional model suitable for observing the photoelastic effect is manufactured by surrounding the film-shaped model with a base material made of silicone gel and having substantially no resistance in the thickness direction of the film-shaped model.

(First embodiment)
In order to obtain three-dimensional data related to the shape of the cerebral blood vessel to be modeled and the cerebral artery, which is the affected part, 0.35 × Imaging was performed with a helical scan type X-ray CT apparatus having a spatial resolution of 0.35 × 0.5 mm. The three-dimensional data obtained by photographing is a two-dimensional image of 256 gradations having a resolution of 512 × 512 and arranged at equal intervals in the body axis direction (tomographic imaging) for delivery to the three-dimensional CAD software. Then, the image data corresponding to each two-dimensional image was stored in a 5.25 inch magneto-optical disk by a drive built in the X-ray CT apparatus in the order corresponding to the imaging direction.

Next, the 5.25 inch magneto-optical drive externally connected to the personal computer is used to capture the image data into a storage device inside the computer, and from this image data, it is necessary for additive manufacturing using commercially available 3D CAD software. 3D shape data in the STL format (a format in which a 3D curved surface is expressed as an aggregate of triangular patches) is generated. In this conversion, the input two-dimensional image is layered based on the imaging interval to construct a three-dimensional scalar field with the density value as a scalar quantity, and a specific density that gives the intravascular surface on the scalar field By specifying a value, after constructing the three-dimensional shape data of the blood vessel lumen as an isosurface (boundary surface of a specific scalar value), rendering of the triangular polygon approximation is performed on the constructed isosurface.
At this stage, additional data is added to the three-dimensional shape data, and the guide portion 13 is bulged from the end of the body cavity model. As shown in FIG. 4, the guide portion 13 is a hollow columnar member. By providing the hollow portion 31, the layered modeling time is shortened. The tip of the guide portion 13 has an enlarged diameter, and this portion is exposed on the surface of the three-dimensional model, thereby forming a large-diameter opening 25 (see FIG. 7).

The generated three-dimensional shape data in STL format is then transferred to a molten resin injection type additive manufacturing system to determine the model placement, stacking direction, and stacking thickness in the modeling system, and support the model at the same time. Was added.
A lot of slice data was generated by slicing the layered modeling data generated in this way to a predetermined layered modeling thickness (13 μm) on a computer. And based on each slice data obtained in this way, a modeling material (melting point: about 100 degrees, easily dissolved in acetone) mainly composed of p-toluenesulfonamide and p-ethylbenzenesulfonamide is heated. Laminated modeling was performed by laminating and forming one layer of a cured resin layer with a specified thickness having a shape that matches each slice data by being melted and ejected. By removing the support after the formation of the final layer, a layered modeling model (body cavity model 12) of the cerebral vascular lumen region was created.
Further, the surface of the body cavity model 12 is processed and smoothed.

A silicone rubber layer 15 having a thickness of about 1 mm was formed on the entire surface of the body cavity model 12 (see FIG. 6). The silicone rubber layer 15 is obtained by drying the body cavity model 12 dipped from the body cavity model 12 and rotating the body cavity model. This silicone rubber layer becomes a membranous model.
In this embodiment, the entire surface of the body cavity model 12 is covered with the silicone rubber layer 15, but a desired portion of the body cavity model 12 may be partially covered with the silicone rubber layer 15.

A core 11 formed by covering the body cavity model 12 with a film model composed of a silicone rubber layer 15 is set in a rectangular casing 24. The casing 24 is made of a transparent acrylic plate. The material of the base material 22 is injected into the casing and gelled.
As a material for the substrate 22, a two-component mixed silicone gel was used. This silicone gel is transparent and has physical properties very close to the soft tissue surrounding the blood vessels. A condensation polymerization type silicone gel can also be used.

The physical properties of the material of the base material 22 are adjusted so as to match the physical properties of surrounding tissues such as blood vessels that are the targets of the membranous model.
In this embodiment, the penetration, fluidity, adhesiveness, stress relaxation, etc. are used as indicators, and finally the physical properties are brought closer to the living tissue by the operator's hand (catheter insertion feeling). Yes.
In the case of silicone gel, the physical properties can be adjusted by blending silicone oil as well as preparing the polymer skeleton.
In this example, a silicone elastomer (Asahi Kasei Wacker Silicone Co., Ltd., trade name: RT601) is selected as the molding material of the film model, and a silicone gel (Asahi Kasei Wacker Silicone Co., Ltd., trade name: SilGel612) is selected as the base material. did. This silicone gel has a longitudinal elastic modulus of about 5.0 kPa, a loss coefficient tan δ (viscoelastic parameter) of about 1.0, and has an elongation of about 1000%. Moreover, the adhesive force (adhesive strength) with respect to a silicone elastomer is about 8 kPa.

  In addition to silicone gel, glycerin gel can also be used. This glycerin gel is obtained as follows. That is, gelatin is immersed in water, glycerin and carboxylic acid are added thereto, and the mixture is dissolved by heating. Filtration while the temperature is high, and when it reaches a temperature that does not affect the core, it is poured into the casing and allowed to cool.

Thereafter, the body cavity model 12 in the core 11 is removed. A hybrid method was adopted as a removal method. That is, the sample is heated to cause the body cavity model material to flow out of the opening 25, and acetone is injected into the cavity to dissolve and remove the body cavity model material.
Thereafter, the sample was heated in a constant temperature layer set at 120 ° C. for about 1 hour to remove the cloudiness of the membranous model (silicone rubber layer 15).

  As shown in FIGS. 7 and 8, the three-dimensional model 21 thus obtained has a configuration in which the film model 15 is embedded in a base material 22 made of silicone gel. Since the silicone gel has physical properties close to those of living tissue, the membranous model 15 exhibits dynamic behavior equivalent to that of blood vessels.

(Second embodiment)
FIG. 9 shows a three-dimensional model 41 of another embodiment. In addition, the same code | symbol is attached | subjected to the element same as FIG. 7, and the description is abbreviate | omitted.
In this example, the base materials 42, 43, and 44 having different physical properties depending on each part of the brain are laminated so as to correspond to the actual brain tissue. The base material 42 corresponds to the physical characteristics of the subarachnoid space around the cerebral artery part, the base material 43 corresponds to the physical characteristics of the soft tissue around the traffic artery part, and the base material 44 corresponds to the cavernous vein tube around the carotid artery part. Corresponds to the physical properties of
The other base materials 46 and 47 were the same as those shown in FIG. Moreover, the base material of the said other parts 46 and 47 can also make this other than a gel (solid etc.).

(Third embodiment)
FIG. 8 shows a three-dimensional model 51 of another embodiment.
In the three-dimensional model 51, a gap 53 is provided in the base material 52, and a part of the membranous model 55 exists in the gap 53. The void 53 corresponds to the subarachnoid space.
The gap portion 53 covers the core (body cavity model + membrane model) with a cover corresponding to the gap portion 53, and a base material 52 made of silicone gel is filled therearound. The configuration shown in FIG. 9 can be obtained by removing the body cavity model and the cover.
FIG. 11 is a cross-sectional view taken along the line CC of FIG. 10 and shows that the membranous model 55 is embedded in the base material 51 made of silicone gel.
Note that the gap 53 may be filled with a material having physical properties different from those of the base material 52 (preferably having physical properties equal to the biological tissue constituting the subarachnoid space (gel or the like)). This filler material preferably has a refractive index substantially equal to that of the substrate 52.
The shape of the gap can be arbitrarily formed.

FIG. 12 shows the configuration of a stress observation apparatus 60 according to an embodiment of the present invention.
The stress observation device 60 of this embodiment is generally composed of a light source 61, a pair of polarizing plates 62 and 63, the three-dimensional model 21 shown in FIG.
The light source 61 is preferably a white light source. Sunlight can also be used as a light source. It is also possible to use a monochromatic light source. The first polarizing plates 62 and 63 have polarization directions orthogonal to each other. Thereby, as explained in FIG. 1, the photoelastic effect caused by the internal stress of the three-dimensional model 21 in the contour region can be observed on the second polarizing plate 63 side.
For example, when a catheter is inserted into a cavity of the three-dimensional model 21, if the catheter interferes with the peripheral wall of the cavity, stress is generated in the peripheral wall of the cavity and a photoelastic effect (interference fringe) appears there. In addition, the stress state in the region around the aneurysm accompanying the deformation of the aneurysm during coil embolization can be simulated from the photoelastic effect.
In this three-dimensional model, the membranous model is formed of a polyurethane elastomer, and silicone gel is used for the equipment. Thereby, the internal stress change of the membranous model can be observed as a photoelastic effect.

  In this embodiment, the light source 61, the first polarizing plate 62, the three-dimensional model 21, and the second polarizing plate 63 are arranged on a straight line. However, the second polarizing plate 63 is shifted (that is, from the straight line). Can be shifted). This is because light diffusely reflects in the cavity of the three-dimensional model 21, and the photoelastic effect may be observed more clearly if the second polarizing plate 63 is shifted in the shape of the cavity.

19 is a stress observation device 360 of another embodiment related to the stress observation device 60 shown in FIG. 12 (the same elements as those shown in FIG. 12 are denoted by the same reference numerals and the description thereof is omitted). Indicates. In this embodiment, the light source 61 and the first polarizing plate 62, and the second polarizing plate 63 and the light receiving unit 70 are moved as one set to one side of the three-dimensional model 21 and arranged in parallel. Thereby, the photoelastic effect resulting from the internal stress on the front region of the three-dimensional model 21 can be observed on the second polarizing plate 63 side.
The light emitted from the light source 61 passes through the first polarizing plate 62 and enters the three-dimensional model 21, and further passes through the film portion of the three-dimensional model 21 (film model), and then the void in the film model. The light is reflected on the surface, passes through the film portion of the three-dimensional model 21 (film model) again, and is observed by the light receiving unit 70 via the polarizing plate 63 and the second ¼ polarizing plate 83. According to this method, the photoelastic effect on the projection surface by the light source 61 on the surface of the space can be observed. In this embodiment, the inside of the void is filled with a highly reflective liquid or a liquid mixed with a highly reflective material, or a layer made of a highly reflective material is formed on the surface of the void. Thus, the incident light from the light source 61 is reflected on the surface of the gap.

In these two embodiments (the stress observation device 60 shown in FIG. 12 and the stress observation device 360 shown in FIG. 19), the light receiving unit 70 includes an imaging device 71 composed of a CCD or the like and a photoelasticity imaged by the imaging device 71. The image processing apparatus 70 which processes the image of an effect, the display 75 which outputs the process result of the image processing part 70, and the printer 77 are provided.
The image processing apparatus 73 performs the following processing (see FIG. 13).
First, an image in an initial state where no external force is applied to the three-dimensional model 21 is captured as a background image (step 1). When the three-dimensional model 21 is formed of a material having a high photoelastic coefficient, a photoelastic effect may be generated by its own weight. Therefore, after capturing an interference fringe image due to the photoelastic effect when light is applied from the light source 61 and an external force is applied (for example, when a catheter is inserted) (step 3), the background image is differentially processed (step 3). Step 5).

When the three-dimensional model 21 is formed of a material having a high photoelastic coefficient, fine interference fringes appear in a repetitive pattern depending on the internal stress. The image processing device 73 digitizes the internal stress by counting the number of the patterns per unit area (step 7). Then, in the image relating to the shape of the three-dimensional model 21 obtained through the second polarizing plate 63, the portion corresponding to the internal stress is given a color corresponding to the numerical value and is externally displayed (step 9).
In this embodiment, the interference fringes due to the photoelastic effect are image-processed by the light receiving unit 70, but the observer may observe the interference fringes directly or via the imaging device 71.

FIG. 14 shows a stress observation apparatus 80 according to another embodiment. Elements that are the same as those shown in FIG. 12 are given the same reference numerals, and descriptions thereof are omitted.
In this embodiment, a first 1/4 polarizing plate 82 is interposed between the first polarizing plate 62 and the three-dimensional model 21, and a second 1/2 is provided between the three-dimensional model 21 and the second polarizing plate 63. Four polarizing plates 83 are interposed. Thereby, the photoelastic effect in the outline region can be observed by a circular polarization method. According to the observation of the photoelastic effect based on the circular polarization method, since the influence of the relative direction between the polarizing plate and the internal principal stress does not appear in the interference fringes, the attitude control of the three-dimensional model is facilitated.
In the stress observation apparatus 380 of another embodiment shown in FIG. 20 (the same elements as those shown in FIG. 12 are given the same reference numerals and the description thereof is omitted), the light source 61 and the first polarizing plate 62, In addition, the second polarizing plate 63 and the light receiving unit 70 are set as a pair and arranged in parallel on one side of the three-dimensional model 21, and the first quarter polarizing plate 82 is also connected to the first polarizing plate 62 and the three-dimensional model 21. The second quarter polarizing plate 83 is interposed between the three-dimensional model 21 and the second polarizing plate 63. Thereby, the photoelastic effect resulting from the internal stress on the front region of the three-dimensional model 21 can be observed on the second polarizing plate 63 side by the circular polarization method.
In this embodiment, light emitted from the light source 61 passes through the first polarizing plate 62 and the first ¼ polarizing plate 82 and enters the three-dimensional model 21, and the three-dimensional model 21 (film model) After further passing through the film part, it is reflected by the surface of the void in the film model, passes through the film part of the three-dimensional model 21 (film model) again, and the polarizing plate 63 and the second quarter polarizing plate 83. And is observed by the light receiving unit 70. According to this method, the photoelastic effect on the projection surface by the light source 61 on the surface of the space can be observed without being affected by the stress direction. In this embodiment, the inside of the void is filled with a highly reflective liquid or a liquid mixed with a highly reflective material, or a layer made of a highly reflective material is formed on the surface of the void. Thus, the incident light from the light source 61 is reflected on the surface of the gap.

FIG. 15 shows a stress observation apparatus 90 according to another embodiment. Elements that are the same as those shown in FIG. 12 are given the same reference numerals, and descriptions thereof are omitted.
In this embodiment, the three-dimensional model 21 is held on the rotation / tilting stage 91 so that the three-dimensional model 21 can be rotated and / or tilted. Thereby, the incident direction of light with respect to the three-dimensional model 21 is changed, and the stress distribution in the contour region of the three-dimensional model 21 can be observed three-dimensionally. Therefore, the simulation in the three-dimensional model can be performed in more detail.
Note that the rotation / tilting stage 91 can also be applied to the three-dimensional model 21 in the example of FIG.
In this embodiment, the three-dimensional model 21 is rotated and / or inclined, but the same action and effect can be obtained even if the surrounding elements are rotated and / or inclined while the posture of the three-dimensional model 21 is fixed. .
Further, the stress observation apparatus 390 of the other embodiment shown in FIG. 21 (the same elements as those shown in FIG. 12 are denoted by the same reference numerals and the description thereof is omitted) is the stress observation apparatus 90 shown in FIG. Similarly, the three-dimensional model 21 is held on the rotation / tilting stage 91 so that the three-dimensional model 21 can be rotated and / or tilted. According to this apparatus, the stress distribution in the front region of the three-dimensional model 21 can be observed three-dimensionally by changing the incident direction of light with respect to the three-dimensional model 21. In this embodiment, the three-dimensional model 21 is rotated and / or inclined, but the same action and effect can be obtained even if the surrounding elements are rotated and / or inclined while the posture of the three-dimensional model 21 is fixed. .

FIG. 16 shows a configuration of a stress observation apparatus 200 according to another embodiment. The same elements as those in FIG. 12 are denoted by the same reference numerals, and the description thereof is omitted.
The image processing apparatus 273 of the stress observation apparatus 200 that enables the stress distribution in the contour area includes data (surrounding area data) 205 representing the surrounding area 103 shown in FIG.
Further, the stress observation apparatus 400 of the other embodiment shown in FIG. 22 (the same elements as those shown in FIG. 12 are denoted by the same reference numerals and the description thereof is omitted) is the stress observation apparatus 200 shown in FIG. 2 includes data (surrounding area data) 205 representing the surrounding area 103 shown in FIG. 2, and enables stress distribution in the front area.
In these two examples (that is, the stress observation device 200 shown in FIG. 16 and the stress observation device 400 shown in FIG. 22), an image including the photoelastic effect imaged by the imaging device 71 is taken into the image memory 201. save. The position specifying device 203 analyzes the captured image and associates it with the surrounding area data 205. Thereby, the position and observation direction of the obtained photoelastic effect are specified. For example, a marker is provided in the three-dimensional model, and the captured image and the surrounding area data can be associated with each other based on the position of the marker. The internal stress calculation device 207 obtains the surrounding region material width W (see FIG. 2) in the first internal stress direction that causes the photoelastic effect from the surrounding region data 205. Then, by dividing the value of the photoelastic effect (apparent internal stress) obtained by the imaging device by the material width W, the internal stress in the unit region of the surrounding region is calculated.

  Thereby, the process of step 200 shown in FIG. 17 is completed. That is, the internal stress quantified in step 7 is corrected based on the width W of the surrounding area, and the internal stress can be specified for each unit area of the surrounding area. In FIG. 17, the same steps as those in FIG. 13 are denoted by the same elements, and the description thereof is omitted.

FIG. 18 shows a method for manufacturing a film model suitable for observing the photoelastic effect.
A body cavity model is prepared in Process I, and PVA is coated on the entire surface of the body cavity model by a dipping method (Process II). In process III, the polyurethane elastomer is coated on the sample obtained in process II by dipping. Thereafter, in consideration of the affinity with the polyurethane elastomer film, PVA is coated twice by a dipping method (processes V and VI). Thereby, the polyurethane elastomer film is completely covered with the PVA film from above and below.
Thereafter, the body cavity model is selectively dissolved and eluted by immersion in an organic solvent (process VII), and finally PVA is dissolved in water (process VIII) to obtain a film model made of polyurethane elastomer.
Thus, the surface of the body cavity model is coated with a water-soluble material film, a polyurethane elastomer layer is formed on the surface of the film, the surface of the polyurethane elastomer layer is coated with a water-soluble material layer, and the body cavity model is coated with an organic solvent. Dissolve and then. By dissolving the water-soluble material film with water to obtain a film model made of polyurethane elastomer, all the steps can be performed by the dipping method. Therefore, the manufacturing method is simplified, and as a result, the manufacturing cost can be reduced.

  The present invention is not limited to the description of the embodiments and examples of the invention described above. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

The following matters are disclosed below.
(1)
A membranous model made of a light-transmitting material and having a cavity inside that reproduces a body cavity such as a blood vessel formed based on tomographic image data of the subject,
A substrate surrounding the membranous model;
A three-dimensional model comprising: a translucent casing for housing the base material.
(2) The solid model according to (1), wherein the film model and the base material have substantially the same refractive index.
(3) The three-dimensional model according to (1) or (2), wherein the substrate is made of silicone gel or glycerin gel.
(4) A membranous model having a cavity that reproduces a body cavity such as a blood vessel formed on the basis of tomographic image data of the subject is embedded in a gel-like substrate, and the cavity of the membranous model is visually recognized. A three-dimensional model characterized by being able to.
(5) The three-dimensional model according to (4), wherein the base material is made of silicone gel or glycerin gel.
(6) A cavity that reproduces a body cavity is provided on a base material made of a light-transmitting gel-like first material, and a light-transmitting second material is formed in a film shape on the peripheral wall of the cavity. A three-dimensional model characterized by this.
(7) The three-dimensional model according to (6), wherein the first material is silicone gel or glycerin gel.
(8) A three-dimensional body characterized in that a cavity that reproduces a body cavity is provided on a base material made of a light-transmitting gel-like first material, and the peripheral wall of the cavity is subjected to a hydrophilic treatment or a hydrophobic treatment. model.
(9) Laminating a body cavity model such as a blood vessel based on tomographic image data of the subject;
Surrounding the body cavity model with a model molding material in the form of a membrane to form a core;
Setting the core in a casing, injecting a base material into the casing and gelling;
Removing the body cavity model after the substrate material has gelled;
The manufacturing method of the solid model characterized by including.
(10) formed of a translucent gel-like first material, forming a base material having therein a cavity that reproduces a body cavity such as a blood vessel formed based on tomographic image data of the subject;
A method for producing a three-dimensional model, comprising forming a translucent second material in a film shape on the inner peripheral surface of the cavity.
(11) formed of a translucent gel-like first material, forming a base material having therein a cavity that reproduces a body cavity such as a blood vessel formed based on tomographic image data of the subject;
A method for producing a three-dimensional model, wherein the inner peripheral surface of the cavity is subjected to a hydrophilic treatment or a hydrophobic treatment.

FIG. 1 is an explanatory diagram of the photoelastic effect. FIG. 2 is a conceptual diagram showing the operation of the present invention. FIG. 3 is a schematic diagram showing the relationship between internal stress and incident light. FIG. 4 is a perspective view showing the core 11 of the embodiment. FIG. 5 is a perspective view showing the guide portion. FIG. 6 is a cross-sectional view taken along line AA in FIG. 2 and shows the configuration of the core. FIG. 7 shows a three-dimensional model of the embodiment of the present invention. FIG. 8 is a cross-sectional view taken along the line BB of FIG. 7 and shows a state in which the membranous model is embedded in the base material. FIG. 9 shows a three-dimensional model of another embodiment. 10 shows a three-dimensional model of another embodiment. FIG. 8 is a cross-sectional view taken along the line CC of FIG. 10 and shows a state in which the membranous model is embedded in the base material. FIG. 12 is a schematic diagram showing the configuration of the stress observation apparatus according to the embodiment of the present invention. FIG. 13 is a flowchart illustrating the operation of the light receiving unit of the stress observation apparatus according to the embodiment. FIG. 14 is a schematic diagram showing the configuration of a stress observation apparatus according to another embodiment of the present invention. FIG. 15 is a schematic diagram showing the configuration of a stress observation apparatus according to another embodiment of the present invention. FIG. 16 is a schematic diagram showing the configuration of a stress observation apparatus according to another embodiment of the present invention. FIG. 17 is a flowchart showing the operation of the stress observation apparatus. FIG. 18 is a flowchart showing a method for manufacturing a membranous model suitable for photoelastic observation. FIG. 19 is a schematic diagram showing the configuration of a stress observation apparatus according to another embodiment of the present invention. FIG. 20 is a schematic diagram showing the configuration of a stress observation apparatus according to another embodiment of the present invention. FIG. 21 is a schematic diagram showing the configuration of a stress observation apparatus according to another embodiment of the present invention. FIG. 22 is a schematic diagram showing a configuration of a stress observation apparatus according to another embodiment of the present invention. FIG. 23 is a conceptual diagram showing the operation of the present invention.

Explanation of symbols

11 Core 12 Body cavity model 15, 55 Silicone rubber layer (film model)
21, 41, 51 Solid model 22, 42, 43, 44, 46, 47, 52

Claims (1)

Create a primary model of the surrounding area of the body cavity by additive manufacturing,
Forming a female mold by surrounding the primary model with a mold material;
Removing the primary model from the female mold;
Injecting polyurethane elastomer into the female mold cavity and curing it,
Remove the female mold to obtain a membrane model made of polyurethane elastomer,
A three-dimensional model suitable for observing the photoelastic effect, characterized in that the film model is surrounded by a base material made of silicone gel and substantially non-resistant in the thickness direction of the film model. Production method.

Images