JP6839567B2 - Reaction vessel - Google Patents

Description

The present disclosure ^{relates to a 99m} Tc reaction vessel ^{for 99m} Tc production.

Currently, in the medical field, diagnostic methods such as POSITRON EMISSION TOMOGRAPHY (PET) and single photon emission computed tomography (SPECT) have become indispensable technologies. These diagnostic methods can diagnose blood flow, detect early malignant tumors, and the like by injecting a drug containing a radioisotope into the body and measuring the radiation emitted by the radioisotope. The radioisotopes used are diverse depending on the purpose, ¹⁹ F is used for PET, and technetium-99 ( ^{99 m} Tc) is mainly used for SPECT.

^99m Tc has a half-life of 6 hours, emits only gamma rays, and can obtain images by SPECT by attaching it to organs, for early detection of diseases such as cancer, myocardial infarction, cerebrovascular accident, and stroke. It is a radioisotope that is indispensable for diagnostic imaging of.

^{Most of the 19} F (half-life: about 2 hours) used in PET is produced domestically. On the other hand, ^{99 m} Tc is produced overseas and has a long half-life of 66 hours. ⁹⁹ Mo is regularly imported, and ^{99 m} Tc produced by beta decay of 99 Mo is extracted in a dedicated processing facility. It is used for diagnostic imaging at each medical facility by manufacturing the drug and delivering this drug to each medical facility.

⁹⁹ Mo is manufactured in nuclear reactors operated by research institutes in five countries: Canada, Belgium, France, the Netherlands and South Africa. Recently, the supply problem of ^{99 Mo due to the aging of nuclear reactors has become apparent.} There is. Therefore, ^{various methods for producing 99} Mo have been studied. At the same time, ^{as a method for extracting 99 m} Tc, a sublimation method that is low in cost and easy to manufacture is being studied.

The sublimation method is the method shown below. First, ^{100 Mo foil is sealed in a container, and 99} Mo is produced by ^{a 100} Mo (γ, n) ⁹⁹ Mo reaction in which the container is irradiated with gamma rays having an energy of 15 to 20 MeV. After that, ^{99 m} Tc is generated by the beta decay of Mo 99, and by flowing high-temperature helium gas mixed with a small amount of oxygen into the container and heating it to a temperature of about 800 ° C., ^{99 m} Tc is produced in a small amount in the atmosphere. It combines with oxygen to form technetium-tetraoxide (TcO ₄ ) and evaporates. Then, this vapor is taken out from the container together with helium gas and dissolved in a sodium hydroxide solution. ^{Further, 99 m} Tc is adsorbed on the aluminum oxide by passing through a container filled with aluminum oxide (Al ₂ O ₃ ^{) which is an adsorbent, and then 99 m} Tc is extracted by flowing physiological saline. Can be done.

The advantage of the sublimation method is that the ¹⁰⁰ Mo foil sealed in the container can be reused semi-permanently without any chemical treatment. Therefore, since it is not necessary to open the container, it is easy to handle ^{100 Mo, and it is expected that 99 m} Tc can be directly generated at each medical facility.

Since high-temperature oxygen may oxidize and deteriorate the container, the use of a ceramic container is being considered.

In addition, since ¹⁰⁰ Mo foil is very expensive, _{the use of MoO 3} powder, which is much cheaper than ¹⁰⁰ Mo foil, is being considered.

Action plan for "Stable supply of technetium preparations in Japan" (July 7, 2011, Public-Private Study Group for Stable Supply of Molybdenum-99 / Technetium-99m) Japan's medical isotope supply shortage problem and medical RI manufacturing technology (December 2014 Report to the Ministry of Education, Culture, Sports, Science and Technology 5-year plan formulation)

^{In order to stably produce technetium-tetraoxide by combining 99 m} Tc and oxygen, it is necessary to keep the gas temperature in the container within a certain range. Therefore, it is necessary to match or approximate the gas temperature introduced into the container with the gas temperature inside the container. However, in order to stably and continuously introduce gas with a temperature that matches or approximates the gas temperature inside the container, a mechanism that heats the gas introduction pipe or a mechanism that heats the gas before introduction is externally used. Had to be provided in.

The present disclosure has been devised in view of the above circumstances, and in a simple configuration, ^{99 m} Tc capable of stably extracting technetium tetroxide while maintaining the temperature inside the container within a certain range. It is an object of the present invention to provide a reaction vessel.

^{The 99 m} Tc reaction vessel of the present disclosure includes a flow path body made of ceramics and having a partition wall inside, and a bottomed tubular body made of ceramics. The flow path body covers the opening of the bottomed tubular body. The flow path body has a first hole connected to the outside and a second hole connected to the bottomed tubular body, and at least the flow path is between the first hole and the second hole. The first hole and the second hole are located so as to sandwich the partition wall, and are external to the flow path body, the bottomed tubular body, or between the flow path body and the bottomed tubular body without passing through the flow path. It has a third hole leading to.

Since the ^{99 m} Tc reaction vessel of the present disclosure can maintain the gas temperature in the vessel within a certain range in a simple configuration, it is possible to stably extract technetium tetroxide.

It is a perspective view which shows an example of the ^{99m Tc reaction vessel of this disclosure.} It is an exploded perspective view which shows an example of the ^{99m Tc reaction vessel of this disclosure.} It is a schematic diagram which shows an example of the heating furnace of ^{the 99m} Tc reaction vessel of this disclosure.

^{Hereinafter, the 99 m} Tc reaction vessel of the present disclosure will be described in detail with reference to the drawings as appropriate.

1 and 2 are ^{a perspective view and an exploded perspective view showing an example of the 99 m} Tc reaction vessel of the present disclosure, and both views also show a pipe for gas introduction and gas discharge.

^{The 99 m} Tc reaction vessel 100 of the present disclosure (hereinafter, may be simply referred to as “container 100”) is made of ceramics, a flow path body 20 having a partition wall 24 inside, and a bottomed tubular body 10 made of ceramics. And have. The flow path body 20 covers the opening 10a of the bottomed tubular body 10.

The flow path body 20 has a first hole 31 connected to the outside and a second hole 32 connected to the bottomed tubular body 10, and at least the flow path 23 is between the first hole 31 and the second hole 32. It has become. The first hole 31 and the second hole 32 are located so as to sandwich the partition wall 24, and are located between the flow path body 20, the bottomed tubular body 10, or between the flow path body 20 and the bottomed tubular body 10. It also has a third hole 33 that connects to the outside without passing through the flow path 23.

Note that FIGS. 1 and 2 show an example in which the first pipe 31a, which is a gas introduction pipe, and the third pipe 33a, which is a gas discharge pipe, are provided. Further, a second pipe 32a for introducing gas from the flow path body 20 into the bottomed tubular body 10 is also illustrated.

In the example of the container 100 shown in FIGS. 1 and 2, as the gas introduction path, the gas is introduced from the first pipe 31a through the first hole 31 of the flow path body 20 into the flow path 23 and toward the second hole 32. It flows through the flow path 23 along the partition wall 24, and then is introduced into the bottomed tubular body 10 through the second hole 32 and the second pipe 32a.

Further, as a gas discharge path, the gas is discharged from the inside of the bottomed tubular body 10 to the outside through the third hole 33 and the third pipe 33a without passing through the flow path 23. It should be noted that the discharge is not always discharged from the third hole 33 as shown in FIGS. 1 and 2, and the upper side surface of the bottomed tubular body 10 and the flow path body 20 and the bottomed tubular shape are discharged. It may be excreted from between the body 10 and the body 10. Further, as shown in FIGS. 1 and 2, when the first hole 31 and the third hole 33 are open on the upper surface of the flow path body 20, the container 100 can be easily handled. it can.

In the container 100 of the present disclosure, the gas is not directly introduced into the bottomed tubular body 10 but is introduced after flowing through the flow path body 20, so that the container 100 can be heated. The gas can be heated by heat. In this way, the gas is not introduced directly into the container 100, but is introduced into the container 100 after the flow path body 20 has flowed through the container 100. Therefore, a mechanism for heating the gas introduction pipe and the gas before the introduction The temperature of the gas to be introduced can be matched with or approximated to the temperature of the gas inside the bottomed tubular body 10 without providing an external mechanism for heating the gas. As a result, a gas having a temperature equal to or close to the gas temperature in the container 100 can be stably and continuously introduced, and the gas temperature in the container 100 is maintained within a certain range. It is possible to stably generate technesium oxide.

If the second pipe 32a for introducing gas from the flow path body 20 into the bottomed tubular body 10 is provided, the bottomed tubular body 10 is more likely to have a second pipe 32a than when the second pipe 32a is provided. It can match or better approximate the internal gas temperature.

Further, in an example of the exploded perspective view shown in FIG. 2, a C-shaped partition wall 24 is shown in constructing the flow path 23 from the first hole 31 to the second hole 32, but the flow path is not limited to this shape. The flow path length from the first hole 31 to the second hole 32 can be set to a desired length depending on the shape and the way of providing the partition wall 24 inside the body 20. Further, in FIGS. 1 and 2, the gas is discharged from the third pipe 33a through the third hole 33 connected to the outside without passing through the flow path 23, but the flow path 23 is connected to the flow path body 20. If the partition wall 24 is arranged so that the gas is discharged after flowing through the flow path body 20 so that the gas is not mixed, the gas to be introduced is the gas temperature inside the bottomed tubular body 10. Can be matched or approximated to.

In the container 100 of the present disclosure, since the bottomed tubular body 10 and the flow path body 20 are made of ceramics, the container 100 is heated to a temperature of about 800 ° C. to contain _{oxygen (O 2).} Even when gas is introduced, deterioration due to oxidation is less likely to occur as compared with a metal container, and the container 100 can be used for a long period of time.

From the viewpoint of making the gas temperature in the container 100 uniform and the container 100 easy to handle, the container 100 of the present disclosure may have a cylindrical shape having a diameter of 10 mm to 100 mm and a height of 50 mm to 200 mm. The wall thickness may be 0.5 mm to 5 mm from the outside by irradiating the sample inside the container 100 with gamma rays having an energy of 15 to 20 MeV from the outside, or from the viewpoint of handling strength.

Further, in the present disclosure, the first bonding layer 41 may be located between the flow path body 20 and the bottomed tubular body 10.

It is generally difficult to integrally mold and fire ceramics having a structure having a flow path 23 and a hollow portion such as a space 10b inside, but as shown in FIG. 2, the first member 21 and the second member 22 If the bottomed tubular body 10 is individually molded and fired, and then joined using a joining material such as glass paste or ceramic paste to be the first joining layer 41 and the second joining layer 42, a flow path is provided inside. Ceramics having a structure having a hollow portion such as 23 and space 10b can be manufactured relatively easily.

When the first bonding layer 41 and the second bonding layer 42 are made of glass, for example, silicon oxide is mixed with various oxides and nitrides to have a melting point of 1200 ° C., although it depends on the heating temperature of the container 100. The glass paste adjusted above may be used.

When the first bonding layer 41 and the second bonding layer 42 are made of ceramics, a ceramic material powder of the same material as the ceramic material suitable for the flow path body 20 and the bottomed tubular body 10 may be used as a paste. Good.

The flow path body 20 may be composed not only of two members of the first member 21 and the second member 22, but also of three or more members joined by a plurality of second joining layers 42. With such a configuration, the length of the flow path in the flow path body 20 can be designed more freely, the heat transfer area to the introduced gas flowing inside can be increased, and better heating can be performed. it can.

Further, in the present disclosure, the ceramic may be a silicon carbide (SiC) material sintered body. Further, if it is a silicon carbide sintered body having a higher thermal conductivity than the thermal conductivity of iron, which is a metal (84 W / (m / K)), for example, a thermal conductivity of 200 W / (m / K). Since the thermal conductivity is good, the heat received from the outside can be efficiently transferred to the inside of the container 100.

Next, the first pipe 31a connected to the first hole 31, the third pipe 33a connected to the third hole 33, and the second pipe 32a connected to the second hole 32 located in the space of the bottomed tubular body 10 will be described. ..

When the first pipe 31a connected to the first hole 31 and the third pipe 33a connected to the third hole 33 are provided, the connection with the pipe from another device can be facilitated. Further, when the second pipe 32a connected to the second hole 32, which is located in the space 10b of the bottomed tubular body 10, is provided, the inside of the bottomed tubular body 10 is more than when it is not provided. Can match or more closely resemble the gas temperature of.

The first pipe 31a, the second pipe 32a, and the third pipe 33a are columnar cylinders, and the length, outer shape, and inner diameter may be determined according to the size of the container 100 and the flow rate of gas.

Further, in the present disclosure, the first pipe 31a and the third pipe 33a are made of an alumina-based sintered body, and the flow path body 20, the bottomed tubular body 10 and the second pipe 32a are made of a silicon carbide sintered body. It may be.

The flow path body 20, the bottomed tubular body 10, and the second tube 32a have a higher thermal conductivity than the thermal conductivity of iron, which is a metal (84 W / (m / K)), for example, a thermal conductivity of 200 W / K. Since the (m / K) silicon carbide sintered body has good thermal conductivity, it is easy to match or approximate the temperature inside the container 100 to the temperature outside when the container 100 is heated from the outside. Therefore, the temperature inside the container 100 can be easily controlled.

Further, when the first pipe 31a and the third pipe 33a are made of an alumina-based sintered body, although alumina is a low-priced ceramic raw material, it has necessary and sufficient practicality in terms of mechanical properties such as strength. Therefore, high reliability can be obtained in connection with pipes from other devices, and it can be manufactured at low cost.

^{Then, according to the 99 m} Tc reaction vessel 100 of the present disclosure ^{, 100} Mo foil or MoO ₃ powder is sealed in this vessel 100, and then set in a heating furnace 200 having a gamma ray irradiation and heating mechanism shown in FIG. After that, the container 100 in a closed state is irradiated with gamma rays having an energy of 15 to 20 MeV to generate ^{99 Mo by a 100} Mo (γ, n) ⁹⁹ Mo reaction. Then, by heating the container 100 to about 800 ° C. while introducing an introduction gas 51 made of helium gas to which a small amount of oxygen is added, it can be taken out as an exhaust gas 52 containing ^{99m Tc.} The gamma ray irradiation to the container 100 and the heating of the container 100 may be performed by using different devices.

Next, an example of the method for producing ^{the 99 m} Tc reaction vessel of the present disclosure will be described.

First, a case where the bottomed tubular body 10, the flow path body 20, the first pipe 31a, the second pipe 32a, and the third pipe 33a are made of a silicon carbide sintered body will be described.

First, a silicon carbide primary raw material having an average particle size of 0.5 to 10 μm and a purity of 99 to 99.8% or more is prepared. Next, a sintering aid such as carbon (C), boron (B), alumina (Al ₂ O ₃ ), and yttria (Y ₂ O ₃ ) is added to the silicon carbide primary raw material to prepare a compounding raw material. Next, water having the same mass or more as that of the compounding raw material is added to form a slurry, which is sized by a crusher such as a ball mill so that the average particle size is 1 μm or less. Next, an appropriate amount of a binder such as polyethylene glycol or polyethylene oxide and a dispersant are added to the slurry in the ball mill, and then the slurry is spray-granulated with a spray dryer to obtain a silicon carbide secondary raw material.

Then, this silicon carbide secondary raw material is molded by a hydrostatic pressure press molding method (rubber press), a powder press molding method, or an extrusion molding method, cut if necessary, and then non-oxidized in a firing furnace. Bake at a temperature of 1800 to 2200 ° C. in the atmosphere. After firing, it is finally finished by grinding to make a bottomed tubular body 10 made of a silicon carbide sintered body having a purity of 99% or more, a flow path body 20, a first pipe 31a, a second pipe 32a, and a third pipe. 33a can be obtained.

Next, a case where the bottomed tubular body 10, the flow path body 20, the first pipe 31a, the second pipe 32a, and the third pipe 33a are made of an alumina-based sintered body will be described.

First, an alumina primary raw material having an average particle size of about 1 μm and a purity of 95% or more is prepared. Next, assuming that this primary raw material is 100% by mass, a sintering aid composed of oxides of calcium (Ca), silicon (Si), and magnesium (Mg) is 1 to 5% by mass, and a binder such as polyvinyl alcohol is 1 by mass. ~ 1.5% by mass, 100% by mass of water as a solvent, 0.5% by mass of a dispersant, put into a container of a stirrer to mix and stir to form a slurry, and then spray granulation with a slurry spray dryer. Alumina secondary raw material is obtained.

Then, this alumina secondary raw material is molded by a hydrostatic press molding (rubber press) method, a powder press molding method, or an extrusion molding method, and if necessary, cutting is performed, and then this is placed in an air atmosphere in a firing furnace. It is fired at a firing temperature of 1550 to 1700 ° C. After firing, it is finally finished by grinding to make a bottomed tubular body 10 made of an alumina-like sintered body having a purity of 95% or more, a flow path body 20, a first pipe 31a, a second pipe 32a, and a third pipe 33a. Can be obtained.

Then, the bottomed tubular body 10 and the flow path body 20, the first pipe 31a, the second pipe 32a, and the third pipe 33a obtained by the above manufacturing method are made of heat-resistant glass paste on each member as shown in FIG. ^{The 99 m} Tc reaction vessel 100 of the present disclosure can be obtained by joining with a ceramic paste or a ceramic paste.

When the container is made of either a silicon carbide sintered body or an alumina-based sintered body, the first bonding layer 41 connecting the bottomed tubular body 10 and the flow path body 20 and the flow path body 20 are formed. The second bonding layer 42 connecting the first member 21 and the second member 22 to be formed is fired after each member is fired and ground to form a desired shape, and then glass paste or ceramic paste is applied to the joint surface. It can be formed by

When the first bonding layer 41 and the second bonding layer 42 are made of glass, the melting point is adjusted to 1200 ° C. or higher by mixing, for example, silicon oxide with various oxides and nitrides, although it depends on the heating temperature of the container. A glass paste may be used.

When the first bonding layer 41 and the second bonding layer 42 are made of ceramics, a ceramic material powder of the same material as the ceramic material suitable for each member to be bonded, water or an organic solvent as a solvent, various binders, and the like. A joining method in which a ceramic paste for joining is prepared by mixing a dispersant, and this is applied to the joining surfaces of the flow path body 20 and the bottomed tubular body 10 molded bodies to join the molded bodies, and then dried and fired. Can also be used.

100: ^99m Tc reaction vessel 10: bottomed tubular body 10a: opening 10b: space 20: flow path body 21: first member 22: second member 23: flow path 24: partition wall 31: first hole 32: first 2 holes 33: 3rd hole 31a: 1st pipe 32a: 2nd pipe 33a: 3rd pipe 41: 1st joint layer 42: 2nd joint layer 51: Introduced gas 52: Exhaust gas 200: Heating furnace

Claims (8)

A flow path body made of ceramics with a partition wall inside,
Equipped with a bottomed tubular body made of ceramics
The flow path body covers the opening of the bottomed tubular body, and the flow path body covers the opening of the bottomed tubular body.
The flow path body has a first hole connected to the outside and a second hole connected to the internal space of the bottomed tubular body, and at least the flow path is between the first hole and the second hole. Yes,
The first hole and the second hole are located so as to sandwich the partition wall.
A third that connects the flow path body, the bottomed tubular body, or between the flow path body and the bottomed tubular body from the internal space of the bottomed tubular body to the outside without passing through the flow path. ^{A 99m} Tc reaction vessel with 3 holes. ^{The 99 m} Tc reaction vessel according to claim 1, wherein the first bonding layer is located between the flow path body and the bottomed tubular body. ^{The 99 m} Tc reaction vessel according to claim 1 or 2, wherein the ceramic is a silicon carbide sintered body. ^{The 99 m} Tc reaction vessel according to any one of claims 1 to 3, wherein the third hole is a hole connected to the lower wall of the flow path body, the inside of the partition wall, and the upper wall of the flow path body. .. ^{The 99 m} Tc reaction vessel according to any one of claims 1 to 4, wherein the flow path body is composed of a first member and a second member. A second bonding layer disposed between the second member and the first member, ^{99m Tc} reaction vessel according to 請Motomeko 5. A first pipe connected to the first hole and a third pipe connected to the third hole, which are located outside the outside,
^{The 99 m} Tc reaction vessel according to any one of claims 1 to 6, further comprising a second tube connected to the second hole, which is located in the internal space of the bottomed tubular body. Said first tube and said third tube consists of alumina sintered body, comprising the channel member, the bottomed cylindrical body and the second pipe carbonization silicon sintered body, according to claim 7 ^99m Tc reaction vessel.

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