JP7246638B2 - Organ model, manufacturing method thereof, and training kit for cauterization treatment - Google Patents

Description

TECHNICAL FIELD The present invention relates to an organ model for ablation treatment training in which a simulated tumor is included in a simulated normal part, a manufacturing method thereof, and an ablation treatment training kit including the organ model.

Conventionally, the present applicant has proposed a simulated myocardial muscle having electrical conductivity and mechanical properties similar to those of living tissue and an ablation performance evaluation device for use in evaluating ablation treatment using an ablation catheter (Patent Document 1). reference).

In addition, the present applicant has proposed a device for evaluating ablation by an ablation catheter, which includes a counter electrode plate and a container made of a conductive resin that is placed on the counter electrode plate and contains a liquid used when evaluating the ablation. , and an ablation object made of gel placed in the container, and an ablation catheter evaluation device in which the ablation object contains a thermochromic material and a conductive material (Patent Reference 2).

JP 2017-186474 A JP 2017-143875 A

Tumor ablation treatment using an ablation device equipped with an electrode needle is performed while viewing a tumor site to be ablated on an image obtained by an ultrasonic imaging device.
As a device for training such tumor ablation treatment, it is conceivable to use an evaluation device as described in Patent Document 1 and Patent Document 2.

However, the object to be ablated that constitutes these evaluation devices is a gel molded product of a single composition. , Training (mock treatment) such as puncturing an electrode needle targeting the tumor site cannot be performed.

The present invention has been made based on the circumstances as described above.
A first object of the present invention is to provide an organ model in which a simulated tumor area is included in a simulated normal area, and the simulated tumor area can be distinguished from the simulated normal area on an image obtained by an ultrasonic imaging device. be.
A second object of the present invention is to provide an organ model capable of confirming whether or not appropriate ablation treatment has been performed on a simulated tumor site.
A third object of the present invention is to provide a manufacturing method capable of reliably manufacturing such an organ model.
A fourth object of the present invention is to conduct training such as searching for a simulated tumor in a simulated normal area and puncturing an electrode needle targeting the simulated tumor while viewing images obtained by an ultrasonic imaging device. To provide a cauterization treatment training kit capable of

(1) The organ model of the present invention is an organ model used for training tumor ablation treatment,
A simulated tumor portion is included in the simulated normal portion,
The simulated normal part is made of PVA hydrogel having a radiation crosslinked structure and an electrical resistivity of 95 to 380 Ω cm at 37 ° C.,
The simulated tumor portion has the radiation crosslinked structure, and water-insoluble particles are dispersed in a PVA hydrogel having an electrical resistivity of 95 to 380 Ω·cm at 37°C, and the water-insoluble particles are dispersed. It is characterized by being able to distinguish from the simulated normal part in the image obtained by the ultrasonic imaging device.

According to the organ model having such a configuration, it is possible to distinguish between the simulated tumor portion and the simulated normal portion on the image obtained by the ultrasonic imaging device. It is possible to perform training such as searching and puncturing an electrode needle targeting a simulated tumor site.

(2) In the organ model of the present invention, it is preferred that the water-insoluble particles are made of a polymer.

(3) In the organ model of the present invention, the PVA hydrogel constituting the simulated normal part and the PVA hydrogel constituting the simulated tumor part each have a PVA concentration of 5 to 15% by mass and a NaCl concentration of 0.1. It is preferably ~0.9% by mass.

According to such an organ model, since the PVA concentration of the PVA hydrogel that constitutes the simulated normal part and the simulated tumor part is 5 to 15% by mass, handling at the time of production is good, and the organ model is immersed in saline. Even when it is compressed, syneresis (shrinkage) and water absorption (expansion) are unlikely to occur, and the organ model has excellent morphological stability.

In addition, since the NaCl concentration of the PVA hydrogel constituting the simulated normal area and the simulated tumor area is 0.1 to 0.9% by mass, appropriate electrical conductivity can be maintained.

(4) In the organ model of (3) above, it is preferable that the PVA hydrogel constituting the simulated normal portion and the PVA hydrogel constituting the simulated tumor portion have approximately the same NaCl concentration.

Such an organ model can prevent NaCl from migrating between the simulated normal area and the simulated tumor area.

(5) In the organ model of the present invention, the simulated normal portion and the simulated tumor portion are respectively colored in different colors, and a coloring agent that discolors or decolors by heating to a predetermined temperature or higher. is preferably contained.

By observing the cross section of such an organ model, it is possible to visually distinguish between the simulated normal portion and the simulated tumor portion, which are colored in different colors.
In addition, since the colorant contained in each of the simulated normal area and the simulated tumor area changes color or decolors when heated to a predetermined temperature or higher, the simulated tumor area is targeted for cauterization, and then the cross section of the organ model is cut. By observing, the shape and size of the discolored or decolored cauterized region can be confirmed.
In addition, by confirming the presence or absence of a portion that has not been discolored or decolored in the simulated tumor area after cauterization, it is possible to confirm the presence or absence of an unburned portion in the simulated tumor area.

(6) In the organ model of the present invention, preferably, the simulated tumor site contains celluloses and/or aminopolysaccharides as the water-insoluble particles.

(7) In the organ model of the present invention, at least one selected from cellulose, chitin and chitosan is preferably contained in the simulated tumor site as the water-insoluble particles.

(8) In the organ model of (6) or (7) above, it is preferable that the content of the water-insoluble particles in the simulated tumor area is 1 to 20% by mass.

(9) In the organ model of (6) or (7) above, it is particularly preferred that the content of the water-insoluble particles in the simulated tumor site is 3 to 5% by mass.

(10) In the organ model of the present invention, the simulated normal part has a compressive elastic modulus of 20 to 300 kPa at 37 ° C.,
The simulated tumor portion has a compression modulus of 100 to 900 kPa at 37°C,
It is preferable that the compressive elastic modulus of the simulated tumor portion is higher than the compressive elastic modulus of the simulated normal portion by 80 kPa or more.

According to such an organ model, when the electrode needle is punctured, a sensation similar to that of puncturing a living organ can be obtained.
In addition, in this organ model, the compressive elasticity modulus of the simulated tumor portion is higher than that of the simulated normal portion. In the training using , the existence of the simulated tumor can be grasped by the sensation transmitted to the finger through the electrode needle.

(11) The production method of the present invention is a method of producing the organ model of the present invention,
a first step of preparing an aqueous PVA solution having a PVA concentration of 5 to 15% by mass and a NaCl concentration of 0.1 to 0.9% by mass;
A water-insoluble particle dispersion having a PVA concentration of 5 to 15% by mass, an NaCl concentration of 0.1 to 0.9% by mass, and a concentration of the water-insoluble particles of 1 to 20% by mass is prepared, and this water-insoluble particle dispersion is prepared. a second step of irradiating the liquid with radiation of 30 kGy or more to form the simulated tumor site;
The simulated tumor area obtained in the second step is put into the PVA aqueous solution obtained in the first step, and the PVA aqueous solution containing the simulated tumor area is irradiated with radiation of 30 kGy or more. a third step of forming the simulated normal portion by
characterized by comprising

According to such a production method, the irradiation of 30 kGy or more of radiation in the second step causes a sufficient cross-linking reaction of PVA in the water-insoluble particle dispersion to form a simulated tumor site having a radiation cross-linked structure. The radiation irradiation of 30 kGy or more in the process causes a sufficient cross-linking reaction of PVA in the PVA aqueous solution to form a simulated normal part having a radiation cross-linked structure, whereby the simulated tumor part is included in the simulated normal part. The organ model of the present invention can be reliably manufactured.

(12) The ablation therapy training kit of the present invention comprises the organ model of the present invention,
a conductive container containing the organ model and saline;
a counter electrode plate arranged on the lower side of the container;
an ablation device having an electrode needle and a high frequency generator;
and an ultrasonic imaging device capable of capturing an image inside the organ model.

According to the organ model of the present invention, it is possible to distinguish between the simulated tumor portion and the simulated normal portion on the image obtained by the ultrasonic imaging device. It is possible to perform training such as puncturing an electrode needle targeting a simulated tumor site.
In addition, according to the organ model in which the simulated normal area and the simulated tumor area each contain the above-described coloring agent, the simulated tumor area is targeted for ablation, and then the section of the organ model is observed to determine the ablation area. It is possible to confirm the shape, size, presence or absence of unburned portions in the simulated tumor area, etc., and it is possible to confirm whether or not appropriate ablation treatment has been performed on the simulated tumor area.
According to the manufacturing method of the present invention, the organ model of the present invention can be reliably manufactured.
According to the ablation treatment training kit of the present invention, training such as searching for a simulated tumor part in a simulated normal part and puncturing the simulated tumor part with an electrode needle while viewing an image obtained by an ultrasonic imaging device is performed. It can be performed.

1 is a schematic diagram showing the structure of an organ model according to one embodiment of the present invention; FIG. 1 is a schematic diagram showing the structure of a cauterization treatment training kit of the present invention. FIG. 4 is an image captured by an ultrasonic imaging device of a state in which a simulated tumor portion of an organ model according to an embodiment of the present invention is punctured with an electrode needle. 3B is an explanatory diagram of the image shown in FIG. 3A; FIG. It is a cross-sectional photograph of the organ model after training of cauterization treatment. FIG. 4B is an explanatory diagram of the photograph shown in FIG. 4A; It is a cross-sectional photograph of the organ model after training of cauterization treatment. FIG. 5B is an explanatory view of the photograph shown in FIG. 5A; 1 is an image of an organ model of Example 1 having a simulated tumor portion in which cellulose (1% by mass) is dispersed, taken with an ultrasonic imaging device. FIG. 10 is an image of the organ model of Example 2 having a simulated tumor portion in which cellulose (3% by mass) is dispersed, taken by an ultrasonic imaging device. FIG. FIG. 10 is an image of the organ model of Example 3 having a simulated tumor portion in which cellulose (5% by mass) is dispersed, taken by an ultrasonic imaging device. FIG. FIG. 10 is an image of the organ model of Example 4 having a simulated tumor portion in which cellulose (10% by mass) is dispersed, taken by an ultrasonic imaging device. FIG. FIG. 10 is an image of the organ model of Example 5 having a simulated tumor part in which cellulose (20% by mass) is dispersed, taken by an ultrasonic imaging device. FIG. 10 is an image of the organ model of Example 6 having a simulated tumor portion in which chitin (3% by mass) is dispersed, taken by an ultrasonic imaging device. FIG. 10 is an image of the organ model of Example 7 having a simulated tumor portion in which chitosan (3% by mass) is dispersed, taken by an ultrasonic imaging device. FIG. FIG. 10 is an image of the organ model of Example 8 having a simulated tumor portion in which barium sulfate (3% by mass) is dispersed, taken by an ultrasonic imaging device. FIG. FIG. 10 is an image of the organ model of Example 9 having a simulated tumor portion in which chitin (5% by mass) is dispersed, taken by an ultrasonic imaging device. FIG. 10 is an image of the organ model of Example 10 having a simulated tumor portion in which chitosan (5% by mass) is dispersed, taken by an ultrasonic imaging device. FIG. 11 is an image of the organ model of Example 11 having a simulated tumor portion in which barium sulfate (5% by mass) is dispersed, taken by an ultrasonic imaging device. FIG.

<Organ model>
The organ model of the present invention is incorporated into a training kit for ablation treatment, which will be described later, and used for training in ablation treatment of tumors.

The organ model 10 of the present invention shown in FIG. The simulated tumor portion 12 cannot be confirmed from above.

The simulated normal part 11 constituting the organ model 10 of the present invention is made of PVA hydrogel having a radiation-crosslinked structure and an electrical resistivity of 95 to 380 Ω·cm at 37°C.
The simulated tumor portion 12 that is included in the simulated normal portion 11 and constitutes the organ model 10 has a radiation-crosslinked structure and has an electric resistivity of 95 to 380 Ω·cm at 37°C. water-insoluble particles are dispersed.

The term "radiation-crosslinked structure" as used herein refers to a structure in which PVA molecular chains are bonded without intervening a cross-linking agent, and water-soluble PVA molecules are irradiated with radiation to cross-link in the absence of a cross-linking agent. It is formed by

The PVA hydrogel constituting the simulated normal portion 11 and the simulated tumor portion 12 preferably maintains a gel state in a temperature range of at least 25 to 100°C.

An organ model composed of PVA hydrogel, which cannot maintain a gel state at 100° C., may melt at the heating temperature during cauterization and become unable to maintain its shape.

The electric resistivity at 37° C. of the PVA hydrogel constituting the simulated normal portion 11 and the simulated tumor portion 12 is 95 to 380 Ω·cm, preferably 120 to 285 Ω·cm.

When an organ model composed of PVA hydrogel with an electrical resistivity of less than 95 Ω·cm is immersed in saline and cauterized, an excessive current flows through the organ model, causing the internal temperature to rise excessively. However, since the cauterization is performed, it may not be possible to perform treatment simulating a clinical environment.

On the other hand, when an organ model composed of PVA hydrogel with an electrical resistivity exceeding 380 Ω·cm is immersed in saline and cauterized, the current flowing through the specimen becomes too small, and the internal temperature is sufficiently raised. and the desired ablation cannot be performed.

The PVA concentration in the PVA hydrogel constituting the simulated normal portion 11 and the simulated tumor portion 12 is preferably 5-15% by mass, more preferably 7-10% by mass.

A PVA hydrogel having a PVA concentration of less than 5% by mass cannot absorb and retain sufficient water, and syneresis occurs when an organ model composed of such a PVA hydrogel is immersed in saline. may shrink.

On the other hand, a PVA hydrogel with a PVA concentration of more than 15% by mass is difficult to handle due to the excessive viscosity of the PVA aqueous solution for preparing it. Moreover, when an organ model made of such a PVA hydrogel is immersed in saline, it may absorb the saline and swell.

The PVA hydrogel constituting the simulated normal portion 11 and the PVA hydrogel constituting the simulated tumor portion 12 may have different PVA concentrations, but preferably have the same PVA concentration. .

The NaCl concentration in the PVA hydrogel constituting the simulated normal portion 11 and the simulated tumor portion 12 is preferably 0.1 to 0.9% by mass, more preferably 0.1 to 0.5% by mass.

A PVA hydrogel having a NaCl concentration of less than 0.1% by mass tends to have an excessive electrical resistivity (37° C.).
On the other hand, PVA hydrogels with a NaCl concentration of more than 0.9% by mass tend to have an excessively low electrical resistivity (37° C.).

The PVA hydrogel forming the simulated normal portion 11 and the PVA hydrogel forming the simulated tumor portion 12 may have different NaCl concentrations, but preferably have the same NaCl concentration. .

The simulated tumor portion 12 constituting the organ model 10 of the present invention is formed by dispersing water-insoluble particles in the PVA hydrogel described above.
Since the water-insoluble particles are dispersed, the simulated tumor portion 12 can be distinguished from the simulated normal portion 11 on the image by the ultrasonic imaging device.
As a result, the simulated tumor portion 12 can be searched for in the simulated normal portion 11 while viewing the image obtained by the ultrasonic imaging device, or the electrode needle can be used to target the simulated tumor portion 12 as shown in FIG. 3 (FIGS. 3A and 3B). Training such as puncturing 41 can be performed.

Examples of the water-insoluble particles forming the simulated tumor portion 12 include particles that are dispersed so that they can be distinguished from the simulated normal portion 11 on an image obtained by an ultrasonic imaging device.
Polymers, particularly organic polymers such as polysaccharides, are preferred as constituents of the water-insoluble particles. The weight average molecular weight (Mw) of the polymer constituting the water-insoluble particles is preferably 10,000 or more and 10,000,000 or less.
Specific examples of water-insoluble particles include those composed of celluloses such as cellulose, aminopolysaccharides such as chitin and chitosan, inorganic compounds such as barium sulfate, and the like. can be used in combination.

The content of the water-insoluble particles in the simulated tumor portion 12 is preferably 1 to 20% by mass, more preferably 1 to 10% by mass, and particularly preferably 3 to 5% by mass.

The compression elastic modulus of the simulated normal part 11 (PVA hydrogel) constituting the organ model 10 of the present invention at 37° C. is preferably 20 to 300 kPa, more preferably 30 to 200 kPa.

This compressive elastic modulus is approximately the same as the compressive elastic modulus of living tissue, and according to the organ model 10 having such a simulated normal portion 11, when the electrode needle is punctured into the organ model 10, when the organ of the living body is punctured, the You can get a feeling close to

The compression elastic modulus at 37° C. of the simulated tumor portion 12 (dispersion of water-insoluble particles) constituting the organ model 10 of the present invention is preferably 100 to 900 kPa, more preferably 150 to 500 kPa.
The compressive elastic modulus of the simulated tumor portion 12 is preferably higher than the compressive elastic modulus of the simulated tumor portion 11 by 80 kPa or more.

The organ model 10, in which the compression modulus of the simulated tumor portion 12 is higher than that of the simulated normal portion 11, simulates a living organ in which the tumor site is harder than the normal tissue, and this organ model 10 is used. In the training that is performed after the training, the presence of the simulated tumor site 12 can be grasped by the sensation transmitted to the finger through the electrode needle.

In the organ model 10 of the present invention, the simulated normal portion 11 and the simulated tumor portion 12 are respectively colored in different colors, and contain a coloring agent that changes or decolors when heated to a predetermined temperature or higher. It is preferable that

Here, the temperature at which the colorant changes color or disappears is preferably 40° C. or higher, more preferably 55° C. or higher.

Since the simulated normal portion 11 and the simulated tumor portion 12 are colored in different colors by the coloring agent contained therein, the simulated normal portion 11 and the simulated tumor portion 12 can be distinguished from each other when the cross section of the organ model 10 is observed. It can be identified visually.

In addition, since the coloring agent contained in the simulated normal portion 11 and the simulated tumor portion 12 is heated to a predetermined temperature or higher, it is discolored or decolored. ), by observing the cross section of the organ model 10, the shape and size of the cauterized region (discolored or decolored region) can be confirmed.

The area discolored white in FIG. 4A and indicated by reference numeral 15 in FIG. 4B is the ablation area. In the example shown in FIG. 4 (FIGS. 4A and 4B), the entire simulated tumor area is ablated (in FIG. 4B, the ablated simulated tumor area is indicated by reference numeral 12′), and the ablation treatment is complete. It was confirmed that

In addition, by confirming the presence or absence of a portion that has not been discolored or decolored in the simulated tumor portion 12 after cauterization, it is possible to confirm the presence or absence of an unburned portion in the simulated tumor portion 12 .

The area discolored white in FIG. 5A and indicated by reference numeral 15 in FIG. 5B is the ablation area. In the example shown in FIG. 5 (FIGS. 5A and 5B), an unburned part is found in a part of the simulated tumor (in FIG. 12), confirming that the ablation treatment was incomplete.

Although one example of the organ model of the present invention has been shown above, the organ model of the present invention is not limited to these, and various modifications are possible. For example, a plurality of simulated tumor areas may be included in the simulated normal area.
Moreover, it is not an essential requirement that the entire simulated tumor portion 12 is embedded in the simulated normal portion 11 as in the organ model 10 shown in FIG. The organ model of the present invention also includes an embodiment in which the organ model is buried inside and the remainder of the simulated tumor portion exists outside the simulated normal portion.

<Method for producing an organ model>
The method for producing an organ model of the present invention comprises a first step of preparing an aqueous PVA solution having a PVA concentration of 5 to 15% by mass and a NaCl concentration of 0.1 to 0.9% by mass;
Water-insoluble particles are dispersed in a PVA aqueous solution having a PVA concentration of 5 to 15% by mass and an NaCl concentration of 0.1 to 0.9% by mass, and the concentration of the water-insoluble particles is 1 to 20% by mass. a second step of preparing a particle dispersion and irradiating the water-insoluble particle dispersion with radiation of 30 kGy or more to form a simulated tumor site;
The simulated tumor area obtained in the second step is added to the PVA aqueous solution obtained in the first step, and the PVA aqueous solution containing the simulated tumor area is irradiated with radiation of 30 kGy or more to produce a simulated normal area. and a third step of forming

The first step is a step of preparing a PVA aqueous solution for forming a simulated normal part.
The PVA concentration of the PVA aqueous solution prepared in the first step is 5 to 15% by mass, preferably 7 to 10% by mass.
If the PVA concentration of the PVA aqueous solution is less than 5% by mass, a hydrogel capable of absorbing and retaining sufficient water (PVA hydrogel having a PVA concentration of 5% by mass or more) cannot be obtained.
On the other hand, when the PVA concentration of the PVA aqueous solution exceeds 15% by mass, the viscosity becomes excessively high, making it difficult to handle for producing a hydrogel. In addition, when immersing an organ model composed of a hydrogel obtained using a PVA aqueous solution with a PVA concentration exceeding 15% by mass (PVA hydrogel having a PVA concentration exceeding 15% by mass) in a saline solution, the saline solution It absorbs and expands easily.

The NaCl concentration of the aqueous PVA solution prepared in the first step is 0.1 to 0.9% by mass, preferably 0.1 to 0.3% by mass.
If the NaCl concentration of the PVA aqueous solution is less than 0.1% by mass, the obtained hydrogel tends to have an excessive electrical resistivity (37° C.).
On the other hand, when the NaCl concentration of the PVA aqueous solution exceeds 0.9% by mass, the electric resistivity (37° C.) of the resulting hydrogel tends to be too small.

The second step is a step of dispersing water-insoluble particles in an aqueous solution of PVA to prepare a water-insoluble particle dispersion, and irradiating radiation to form a simulated tumor site.
The aqueous PVA solution that serves as a dispersion medium for the water-insoluble particles in the second step is the same as the aqueous PVA solution obtained in the first step. A water-insoluble particle dispersion is prepared which is 20% by weight.
Here, as the water-insoluble particles, celluloses such as the cellulose described above, aminopolysaccharides such as chitin and chitosan, inorganic compounds such as barium sulfate, and the like can be used.
Next, the water-insoluble particle dispersion is irradiated with radiation of 30 kGy or more to crosslink the PVA to form a simulated tumor site.
Here, the type of radiation is not particularly limited as long as it is ionizing radiation such as γ-rays, electron beams, and X-rays, and γ-rays with high penetrating power are particularly preferred.
The dose of radiation applied to the PVA aqueous solution is 30 kGy or more, preferably 30 to 50 kGy. When the irradiation dose is less than 30 kGy, the obtained hydrogel does not have a sufficient crosslink density, and the simulated tumor portion composed of such a hydrogel does not have a sufficient compressive elastic modulus (hardness). shall not have

In the third step, the simulated tumor area obtained in the second step is put into the PVA aqueous solution obtained in the first step, and the PVA aqueous solution containing the simulated tumor area is irradiated with radiation to simulate. This is the step of forming a normal part.
Here, the type of radiation is not particularly limited as long as it is ionizing radiation such as γ-rays, electron beams, and X-rays, and γ-rays with high penetrating power are particularly preferred.
The dose of radiation applied to the PVA aqueous solution is 30 kGy or more, preferably 30 to 50 kGy. When the irradiation dose is less than 30 kGy, the obtained hydrogel does not have a sufficient crosslink density, and the simulated normal part composed of such a hydrogel has a sufficient compressive elastic modulus (hardness). shall not have

<Ablation treatment training kit>
The cauterization treatment training kit 100 of the present invention shown in FIG. a counter electrode plate 30, an ablation device 40 having an electrode needle 41 and a high frequency generator 42, and an ultrasonic imaging device 50 having an ultrasonic probe 51.

The container 20 is made of a conductive material such as conductive silicone rubber.
The electrical resistivity of the conductive material forming the container 20 is approximately the same as the electrical resistivity of the organ model 10 (95 to 380 Ω·cm at 37° C.). A saline solution 60 is contained in the container 20 . The NaCl concentration in the saline solution 60 is 0.1 to 1.5% by mass, and a preferred example is 0.18% by mass.
If the NaCl concentration is too low, the electrical conductivity of the sample becomes lower than that of blood, the amount of current flowing through the sample increases, and the amount of Joule heat generated becomes excessive.
On the other hand, if the NaCl concentration is too high, the electrical conductivity of the sample becomes higher than that of blood, the amount of current flowing through the sample becomes small, and the amount of Joule heat generated becomes too small.
A counter electrode plate 30 is arranged below the container 20 .
The cauterization device 40 has an electrode needle 41 and a high frequency generator 42 . A high-frequency current can be passed between the tip of the electrode needle 41 and the counter electrode plate 30 by the high-frequency generator 42 .
By pressing an ultrasonic probe 51 constituting an ultrasonic imaging device 50 against the surface of the organ model 10, an image of the inside of the organ model 10 (including the simulated tumor portion 12) can be captured.

According to the ablation therapy training kit 100 of the present invention, the simulated normal part 11 and the simulated tumor part 12 can be distinguished on the image captured by the ultrasonic imaging device 50 . While viewing the image, training such as searching for the simulated tumor portion 12 included in the simulated normal portion 11 and puncturing the simulated tumor portion 12 with the electrode needle 41 can be performed.

<Example 1>
(1) First step:
A PVA aqueous solution having a PVA concentration of 8% by mass and an NaCl concentration of 0.15% by mass was prepared by dissolving the PVA melt in saline.

(2) Second step:
A PVA aqueous solution having a PVA concentration of 8% by mass and a NaCl concentration of 0.15% by mass was prepared in the same manner as in (1) above, and cellulose particles were dispersed as water-insoluble particles in the PVA aqueous solution so that the cellulose content was 1. % by weight of water-insoluble particle dispersions were prepared.
By irradiating this water-insoluble particle dispersion liquid with gamma rays (radiation rate = 2 kGy/h) from cobalt 60 for 20 hours (dose = 40 kGy), the cellulose particles are dispersed in the PVA hydrogel. A cylindrical simulated tumor portion with a diameter of 20 mm and a height of 15 mm was obtained.

(3) Third step:
The simulated tumor area obtained in the second step was put into the PVA aqueous solution obtained in the first step, and the PVA aqueous solution containing the simulated tumor area was irradiated with γ rays from cobalt 60 (radiation rate = 1 kGy). / h) for 40 hours (dose = 40 kGy) to form a columnar 50 mm in diameter and 50 mm in height in which the simulated tumor portion 12 is included in the simulated normal portion 11 as shown in FIG. An organ model 10 (organ model of the present invention) was produced.

<Examples 2 to 11>
According to the formulation shown in Table 1 below, an organ model of the present invention was obtained in the same manner as in Example 1, except that the type and/or amount of dispersion of the water-insoluble particles used in the second step was changed.

<Experimental Example 1 (measurement of compression modulus)>
(1) A cylindrical test piece with a diameter of 20 mm and a height of 15 mm was cut out from each of the simulated normal parts of the organ models obtained in Examples 1-11.
Using a "creep meter RE2-3305B" (manufactured by Yamaden Co., Ltd.) as a compression test device, each of the obtained test pieces was axially compressed at a compression rate of 3 mm/min at a temperature of 37 ° C. , when compressed by 1.2 mm (compression rate = 1.2/15 = 8%), the elastic modulus was measured. The results are also shown in Table 1 below.

(2) Each of the simulated tumor sites obtained in the second step of Examples 1 to 11 was used as a test piece, and the compression modulus (compression modulus = 8%) of each of these was measured in the same manner as in (1) above. It was measured.
The results are also shown in Table 1 below.

<Experimental Example 2 (distinguishability between simulated normal area and simulated tumor area)>
Using each of the organ models obtained in Examples 1 to 11, a training kit for ablation therapy having the configuration shown in FIG. 2 was manufactured.
An organ model 10 is placed in a conductive container 20 to contain a saline solution 60, and an ultrasonic probe 51 of an ultrasonic imaging device 50 is pressed against the upper surface of the organ model 10 to obtain an internal image of the organ model 10. A photograph was taken, and it was confirmed whether or not the simulated tumor portion 12 included in the simulated normal portion 11 could be identified on the image.
The results are shown in FIGS. 6A-6K and Table 1 below.

In Table 1, the distinguishability evaluation criteria are as follows.
◎: The entire simulated tumor area can be identified as white ○: Most of the simulated tumor area can be identified as white △: The boundary between the simulated normal area and the simulated tumor area can be identified ×: The simulated normal area and the simulated tumor area cannot be distinguished

As shown in FIGS. 6A to 6E, the simulated tumor portion 12 having a cellulose content of 1 to 20% by mass, particularly 3 to 5% by mass, can be clearly distinguished from its surroundings (simulated normal portion 11). It is possible to perform training in which the simulated tumor site 12 is targeted and punctured with an electrode needle.

As shown in FIGS. 6F to 6K, the simulated tumor portion 12 in which any type of water-insoluble particles are dispersed can be clearly distinguished from its surroundings (simulated normal portion 11). Training for puncturing the electrode needle can be performed by targeting the portion 12 .

REFERENCE SIGNS LIST 100 ablation therapy training kit 10 organ model 11 simulated normal part 12 simulated tumor part 15 ablation region 20 conductive container 30 return electrode 40 ablation device 41 electrode needle 42 high frequency generator 50 ultrasonic imaging device 51 ultrasonic probe 60 saline solution

Claims (12)

An organ model for use in training tumor ablation therapy, comprising:
A simulated tumor portion is included in the simulated normal portion,
The simulated normal part is made of PVA hydrogel having a radiation crosslinked structure and an electrical resistivity of 95 to 380 Ω cm at 37 ° C.,
The simulated tumor portion has the radiation crosslinked structure, and water-insoluble particles are dispersed in a PVA hydrogel having an electrical resistivity of 95 to 380 Ω·cm at 37°C, and the water-insoluble particles are dispersed. An organ model characterized by being capable of being distinguished from the simulated normal part in an image obtained by an ultrasonic imaging device, because the organ model can be distinguished from the simulated normal part. The organ model according to claim 1, wherein said water-insoluble particles are made of a polymer. The PVA hydrogel constituting the simulated normal part and the PVA hydrogel constituting the simulated tumor part each have a PVA concentration of 5 to 15% by mass and an NaCl concentration of 0.1 to 0.9% by mass. The organ model according to claim 1 or 2. 4. The organ model according to claim 3, wherein the PVA hydrogel forming the simulated normal portion and the PVA hydrogel forming the simulated tumor portion have approximately the same NaCl concentration. The simulated normal area and the simulated tumor area are colored in different colors and contain a coloring agent that discolors or decolors when heated to a predetermined temperature or higher. The organ model according to any one of claims 1-4. The organ model according to any one of claims 1 to 5, wherein the simulated tumor site contains celluloses and/or aminopolysaccharides as the water-insoluble particles. 7. The organ model according to any one of claims 1 to 6, wherein at least one selected from cellulose, chitin and chitosan is contained in the simulated tumor site as the water-insoluble particles. 8. The organ model according to claim 6, wherein the content of said water-insoluble particles in said simulated tumor site is 1 to 20% by mass. 9. The organ model according to any one of claims 6 to 8, wherein the content of said water-insoluble particles in said simulated tumor site is 3 to 5% by mass. The simulated normal part has a compression modulus of 20 to 300 kPa at 37 ° C.,
The simulated tumor portion has a compression modulus of 100 to 900 kPa at 37°C,
The organ model according to any one of claims 1 to 9, wherein the compressive elastic modulus of the simulated tumor portion is 80 kPa or more higher than the compressive elastic modulus of the simulated normal portion. A method for producing the organ model according to any one of claims 1 to 10,
a first step of preparing an aqueous PVA solution having a PVA concentration of 5 to 15% by mass and a NaCl concentration of 0.1 to 0.9% by mass;
A water-insoluble particle dispersion having a PVA concentration of 5 to 15% by mass, an NaCl concentration of 0.1 to 0.9% by mass, and a concentration of the water-insoluble particles of 1 to 20% by mass is prepared, and this water-insoluble particle dispersion is prepared. a second step of irradiating the liquid with radiation of 30 kGy or more to form the simulated tumor site;
The simulated tumor area obtained in the second step is put into the PVA aqueous solution obtained in the first step, and the PVA aqueous solution containing the simulated tumor area is irradiated with radiation of 30 kGy or more. a third step of forming the simulated normal portion by
A method for producing an organ model, comprising: an organ model according to any one of claims 1 to 10;
a conductive container containing the organ model and saline;
a counter electrode plate arranged on the lower side of the container;
an ablation device having an electrode needle and a high frequency generator;
and an ultrasonic imaging device capable of capturing an image inside the organ model.

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