JPWO2012039036A1 - Radionuclide production method and apparatus using accelerator - Google Patents

Abstract

A target substance dissolved in a liquid or mixed with a liquid is introduced into a target container, dried in the target container to reduce the liquid component, and then irradiated with a beam from an accelerator. Radionuclides such as large technetium 99m and molybdenum 99 can be remotely and repeatedly manufactured in one target container.

Description

  The present invention relates to a radionuclide production method and apparatus using an accelerator, and in particular, radionuclides such as technetium 99m and molybdenum 99, which are in great demand as radiopharmaceuticals, can be repeatedly produced remotely in one target container. The present invention relates to a method and an apparatus for producing a radionuclide using an accelerator.

  Technetium 99m (Tc-99m, half-life of 6 hours) used in the nuclear medicine and diagnostic imaging fields worldwide is the leading role of over 70% of the radioisotopes used in nuclear medicine. Molybdenum 99 (Mo-99, half-life 66 hours) is a radioisotope called Tc-99m parental nuclide because Tc-99m is generated with the decay of Mo-99. Devices that can selectively recover the produced Tc-99m by adsorbing Mo-99 onto a support such as alumina are commercially available (Mo-99 / Tc-99m generator).

  As a method for producing technetium 99m using an accelerator, a method of irradiating a charged particle, specifically, a proton (proton) beam to molybdenum 100 (Mo-100), which is isotopically enriched, has been studied. There has not yet been a report at the level (eg, obtained a large amount of radioactivity for medical use or demonstrated a set of devices for it).

The present invention is a method for producing Tc-99m or Mo-99 by ¹⁰⁰ Mo (p, 2n) ^99m Tc or ¹⁰⁰ Mo (p, pn) ⁹⁹ Mo nuclear reaction using charged particles obtained from an accelerator. Therefore, the prior art will be verified for all methods using accelerators. In either case, the yield (radioactivity) at a practical level was not obtained, and the evaluation was completed through the examination or verification of the concept.

  That is, Non-Patent Document 1 estimated the generation amount of Tc-99m and Mo-99 when irradiating Mo-100 with a proton beam of energy range 68 → 8 MeV and Non-Patent Document 2 with 22 → 10 MeV. Is. Although it is written that any nuclide will be obtained in a yield according to energy, there is no description about a specific irradiation method or apparatus configuration. It is a previous paper on the experimental element that explores so-called feasibility, and can be said to be a report investigating physical phenomena.

Lagunas-solar, M.C. et al. (1991) Cyclotron production of NCA 99mTc and 99Mo. An alternative non-reactor supply source of instant 99mTc and 99Mo → 99mTc generators. Appl. Radiat. Beaver, J.E. and Hupf, H.B. (1971) Production of 99mTc on a medical cyclotron: A feasibility study.J. Nucl. Med. 12 (11), 739-741

  It has long been confirmed that Mo-99 and / or Tc-99m are generated in accordance with incident energy by irradiating Mo-100 with a proton beam. However, even now, production using charged particles is not performed. The reason for this is considered to be that there was no manufacturing apparatus capable of handling a large amount of radioactive material generated after irradiation without exposure. Specifically, since molybdenum or a molybdenum compound used as a target material is a solid, there is no means for performing these operations easily during preparation in the target container, extraction after irradiation, and the like. Unlike general work, this work is performed in a large amount of radiation environment, so it is essential to ensure safety against exposure and contamination of workers, but it is extremely difficult to realize. Usually, in the production of radioisotopes using a solid target, measures are taken to reduce exposure by a combination of a remote automated industrial equipment robot or a shield and a manipulator. However, the installation of these facilities / equipment requires a considerable cost, and the manipulator work requires high skill in operation, and the specifications required economically and technically are high.

  Therefore, there is a strong demand for establishing a radioisotope production method using a solid target that is inexpensive and can be easily operated.

  The present invention has been made to achieve the above-described conventional problems, and in order to produce practical technetium 99m and / or molybdenum 99, a specific structure and irradiation process applicable when irradiating molybdenum 100 is performed. The task is to establish an operation method.

  The present inventors tried to solve the problem by dissolving molybdenum, which is a target material, in an appropriate solvent, drying it before irradiation, and changing it from a liquid to a solid. Although it is not impossible to use a liquid target (molybdenum solution) for irradiation, the liquid absorbs the energy of the beam, thereby hindering sufficient nuclear reaction of the molybdenum target. Therefore, the yield of Tc-99m or Mo-99 expected by this method is significantly reduced. According to the present invention, the theoretical nuclear reaction yield can be obtained by removing the liquid from the target material before irradiation and increasing the density of the molybdenum target existing on the incident beam orbit.

The present invention has been made on the basis of the above knowledge, introduced a target substance dissolved in a liquid or mixed with a liquid into a target container,
A method for producing a radionuclide using an accelerator, comprising: drying the target container to reduce a liquid component, and then irradiating a beam from the accelerator.

  Here, the target substance dissolved in the liquid or mixed with the liquid and introduced into the target container can be dried in the target container to precipitate a solid component.

  Moreover, the thickness of the solid component deposited in the target container can be set to 0.1 to 5 mm on the trajectory of the beam incident from the accelerator.

  The drying can be performed by at least one of heating, introduction of a drying gas, and exhaust.

  Moreover, the temperature in the target container at the time of the drying can be set to 100 ° C. or higher.

  Further, the gas used for the drying can be helium, hydrogen or carbon monoxide.

  Further, the gas used for the drying is introduced into the target container so as to pass through the target material which is dissolved in the liquid or mixed with the liquid and introduced into the target container and accumulated below the target container. be able to.

  In addition, after the irradiation of the beam is completed, the liquid can be introduced into the target container, and the target material can be dissolved again in the liquid or mixed with the liquid and taken out of the target container.

  Moreover, the liquid taken out from the target container can be recovered without being discarded.

  Further, the target material may be molybdenum 100, the beam may be a 40-9 MeV proton beam, and the produced radionuclide may be technetium 99m and / or molybdenum 99.

  The target material introduced into the target container can be molybdenum oxide dissolved in ammonia water.

  Moreover, hydrogen peroxide water can be added to the ammonia water.

  Moreover, the temperature at the time of the said drying can be 200-650 degreeC.

  The liquid may be ammonia water and / or hydrogen peroxide water.

In the present invention, when the target material that has been irradiated with the beam from the accelerator is taken out of the target container,
Introducing liquid into the target container;
The present invention provides a method for producing a radionuclide using an accelerator, wherein the target substance is dissolved in the liquid or mixed with the liquid and taken out of the target container.

A target container;
Means for introducing a target substance dissolved or mixed with the liquid into the target container;
Drying means for reducing liquid components by drying in the target container;
Means for irradiating the target container with a beam from an accelerator;
An apparatus for producing a radionuclide using an accelerator is provided.

  Here, the drying means can dry the target substance dissolved in the liquid or mixed with the liquid and introduced into the target container to precipitate a solid component in the target container.

  The drying unit may include at least one of a heating unit, a gas supply unit, and an exhaust unit.

  Further, the target container seals the target container and includes a metal thin film for allowing the beam to pass therethrough, and the metal thin film can be cooled.

A means for introducing a liquid into the target container after the irradiation of the beam;
The apparatus may further comprise means for dissolving the target substance in the liquid again or mixing it with the liquid and taking it out of the target container.

  In addition, it is possible to provide means for collecting the liquid taken out from the target container without discarding it.

  The means for collecting may include a filter provided in the middle of the piping.

The present invention is also a radionuclide production apparatus in which a target material that has been irradiated with a beam from an accelerator is extracted from the target container.
Provided is a radionuclide production apparatus using an accelerator, comprising means for introducing a liquid into the target container, dissolving the target material in the liquid or mixing it with the liquid, and taking it out of the target container. To do.

  The production of Tc-99m using molybdenum as a target, which has not been reported in the past, is made possible by the present invention. Furthermore, since all the processes required for manufacturing can be performed remotely, there is no occupational exposure to those involved in the work, and manufacturing in consideration of health and safety is possible.

  In addition, the target material can be quickly taken out from the target container, and can be repeatedly produced in one target container, and even a radionuclide having a short half-life can be taken out without causing a problem. .

Pipeline diagram showing the configuration of the first embodiment of the present invention Sectional drawing which shows the target container used in 1st Embodiment Flow chart showing the processing procedure of the first embodiment Sectional drawing which follows the IV-IV line | wire of FIG. 5 which shows the target container used in 2nd Embodiment of this invention. Side view seen from the direction of arrow V in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the first embodiment of the present invention, as shown in FIG. 1, a charged particle (here, proton) beam from an accelerator irradiation port 108 which is means for irradiating a beam from an accelerator (not shown) is irradiated, for example, vertically. A target container 110; a target solution (Mo) tank 112 for storing a target material (Mo) dissolved or mixed in a liquid (referred to as a target solution); and a target solution in the Mo tank 112 is pushed out to a pipe 114 to Syringe S1, which is a means for introducing into the target container 110, and a drying means for drying the target container 110 to an extent that does not affect the irradiation of the proton beam and reducing the liquid component to precipitate the solid component. Heater H1, an inert gas for drying (also serving as a pressure source for liquid transportation), for example, helium gas is supplied Because helium (He) tank 116, a flow control meter 118 and vacuum pump (for example, a vacuum pump) for vaporization and exhaust promotion P and a mixed solvent for storing the a recovery solvent for example _{H 2 O 2 + NH 4 OH} ( (H ₂ O ₂ + NH ₄ OH) tank 122 and after completion of the proton beam irradiation, the recovery solvent in the H ₂ O ₂ + NH ₄ OH tank 122 is pushed out to the pipe 114 with a syringe (not shown) or the like, and the target container 110, a valve V3 that is a means for introducing into the interior of the 110, a three-way switching valve V7 that selects the helium gas flow paths V7-a and V7-b, and a closed circuit, and a pipe 126 from the target container 110. , a solution trap 124 to permit the overflow solution from the target vessel 110, for example, silicon from the H ₂ O ₂ + NH ₄ OH tank 122 A recovery solvent introduced by a method (not shown) or the like is introduced into the target container 110 from the solution trap 124 and the pipe 126, and the valve V6 as a means for cleaning the target container 110 and the inside of the target container 110 The valve V1, which is a means for taking out the liquid and collecting it without discarding, is disposed in the middle of the recovery pipe 129 so as not to block the solid content of the recovered substance inside the downstream pipe. A filter 130, a Tc-containing Mo recovery tank 132, valves V1 to V8, and pipes 114, 126, 128, and 129 are provided. Here, the valves other than the valve V7 are one-way open / close valves.

The molybdenum solution used as the target solution is obtained by dissolving or mixing molybdenum oxide (MoO ₃ is desirable) in 10 to 30% ammonia water. In order to promote dissolution, 10 to 30% hydrogen peroxide water may be added. In this case, the solution composition is preferably 25% ammonia water: 30% hydrogen peroxide water = 1: 1 to 1: 2. .

  As shown in detail in FIG. 2, the target container 110 is isolated by the irradiation port 110 </ b> A side and the metal thin film 110 </ b> B, introduces a target solution and irradiates charged particles, and heats and cools the target chamber 110 </ b> C. And a heating / cooling unit 110D provided with a heater H1, and a vacuum diaphragm 110E for flowing a fluid (here, helium gas) for cooling the metal thin film 110B to the irradiation port 110A side of the metal thin film 110B. And a cooling chamber 110F partitioned by the metal thin film 110B. In the figure, 110G is a port to which a pipe 114 and a recovery pipe 129 are connected, 110H is a port to which a pipe 126 having a solution trap 124 is connected, 110I is provided with valves V4 and V5. A port to which the pipe 128 is connected, 110J is a cooling He gas inlet port, 110K is a cooling He gas outlet port, 110L is a cooling water inlet port, and 110M is a cooling water outlet port.

  The target chamber 110C is manufactured to have a cylindrical shape with an inner diameter of 10 to 20 mm and a depth of 20 to 100 mm, for example, and the material can be selected from aluminum, gold, or platinum. Aluminum is preferable as an inexpensive material, but gold or platinum can be selected in consideration of corrosion resistance. The material of the metal thin film 110B that irradiates the target material with the beam from the accelerator is the same, and the thickness thereof is, for example, 10 to 500 μm, particularly 10 to 100 μm, depending on the energy of the beam. preferable. A portion of the flange 110N that requires airtightness is provided with an O-ring 110P made of stainless steel or heat-resistant silicon, and the metal thin film 110B maintains airtightness by the pressing force of the flange 110N. However, these methods are limited. is not.

The target solution described above is introduced from the bottom or side surface of the target container 110. In introducing the solution, a pump or a syringe can be used. The amount of the solution introduced is determined in advance so that the thickness of the deposited molybdenum compound on the beam trajectory is 0.1 to 5 mm. However, in order to obtain a practical yield, it is incident as an example. When the proton beam energy is 18 MeV, the area density of molybdenum is assumed to be about 450 mg / cm ² or more. However, since the required area density strongly depends on the incident energy, there is no limitation.

  As means for drying the solution and reducing the liquid component, heating is performed by providing a heating element, for example, a heater H1, fixed to the outer periphery, for example, the bottom of the target container 110. The set temperature at this time is set to about 100 to 700 ° C. in the target container 110, but 200 to 650 ° C. is more desirable. Furthermore, gas is sent into the target container to promote the release of evaporated water. When the release of moisture ends, precipitation of ammonium molybdate occurs, but the compound decomposes into molybdenum oxide, ammonia gas, and water by further heating. At this time, ammonia gas and water are released together with the introduced gas to the outside of the target container. As a result, only molybdenum oxide crystals exist on the bottom surface of the target container.

  It is desirable to use helium gas as the introduced gas, which is caused by not giving a nuclear reaction product when remaining in the target container. Alternatively, it is also preferable to reduce the molybdenum oxide by introducing hydrogen or carbon monoxide. This is because it is possible to increase the molybdenum content per unit volume of the crystals obtained by reduction and increase the yield of Tc-99m or Mo-99 as a result of increasing the nuclear reaction efficiency. Because it becomes.

  As described above, the target substance introduced as a liquid into the target container is prepared as a solid by dry solidification, so that efficient irradiation is possible. The degree of drying and solidification is at least that which allows the influence of absorption of beam energy by the residual liquid to be allowed.

  Since some of the molybdenum oxide may be volatilized (sublimated) due to heat generated during irradiation, the upper part of the target container is sealed with a metal thin film 110B and cooled with helium gas or the like. As a result, it becomes possible to deposit an excessive sublimate on the thin film, thereby preventing loss of raw materials.

  During irradiation, the target container may be a sealed system or an open system. If it is an open system, it becomes possible to prevent the pressure rise resulting from the heat_generation | fever at the time of irradiation, and irradiation without damaging a target container is attained.

  Here, since the target container 110 is provided with a plurality of entrances / exits, (1) When the solution is injected, the upper hole becomes an exhaust port, so that the pressure does not increase. In addition, (2) at the time of heating and drying, since it is connected to the vacuum pump P of the negative pressure system from the upper hole, it is heated, but it is rather lower than the atmospheric pressure. (3) During irradiation, the temperature rises due to the heat generated by the beam, but the pressure balance is made the same as the atmospheric pressure by providing an expansion chamber that increases or decreases the accommodation volume according to the increase or decrease of the internal pressure in the path following the upper hole. Can keep. Therefore, there is no problem with the soundness of the metal thin film 110B, and at least damage due to pressure does not occur.

  After the irradiation, ammonia water is introduced into the target container, and the molybdenum oxide irradiated for about 5 to 10 minutes is redissolved. If ammonia water + hydrogen peroxide solution mixed solution is introduced instead of introducing ammonia water, molybdenum oxide is more easily dissolved. In order to promote dissolution, warming and mixing by introducing gas are performed.

  As the liquid to be introduced, ammonia water is used at a concentration of 10 to 30% by weight, and hydrogen peroxide water is used at a concentration of 10 to 30% by weight. The amount of the liquid depends on the shape of the target container, but 20 to 20% of the volume. A liquid volume corresponding to 80% is introduced. As the number of solutions increases, the efficiency with which Tc-99m and Mo-99 that may adhere to a wide range of the target container wall surface can be dissolved and recovered increases.

  Next, the molybdenum oxide redissolved solution in which Tc-99m or Mo-99 is dissolved is transferred to the outside of the target container by pumping helium gas or the like. At this time, molybdenum oxide or the like that could not be dissolved in the above-described process may block the recovery pipe. Therefore, by providing a filter 130 immediately after the target container and excluding them, stable solution transfer is possible. Become. The filter 130 provided in the middle of the pipe can be a commercially available product having a hole diameter of 0.22 μm or more, and the hole diameter is not limited unless the pipe is blocked. As a filter material, quartz, polypropylene or Teflon (registered trademark) is particularly desirable, but the material is not limited.

  The recovered solution can then be purified using, for example, an ion exchange resin to obtain the target Tc-99m. At this time, the liquid after passing through the ion exchange resin is collected and used for the next production. Since the composition of the collected liquid is the same component as the liquid prepared before irradiation, it can be used as it is for the next production without requiring special purification.

  Hereinafter, an operation procedure of the embodiment will be described with reference to FIGS. 2 and 3.

[1. Target preparation]
A target solution (ammonia molybdenum oxide) is introduced from the port 110G into the target chamber 110C via the valve V2 → V1 (step 100). At this time, the valve V4 is opened as an exhaust path.

  Next, the target container 110 is heated by the heater H1 provided in the target container, and the solution is dried (step 110). At this time, helium gas is introduced via the valve V7-a and the pipe 114 while controlling the flow rate with the flow rate controller 118, and the drying of the inside of the target chamber is promoted, and exhausted from the port 110I via the valve V5 → the vacuum pump P. . At this time, helium gas can be introduced from the port 110H. However, when the helium gas is introduced from the port 110G, the target material mixed with the liquid and introduced into the target container and accumulated below the target container 10 is collected in the port 110G. It is preferable because clogging can be prevented by flowing back to the pipe 114 and solidifying in the middle of the pipe 114. Although the temperature in the target container 110 at the time of drying is set to 100 to 700 ° C., 250 ° C. or more that is a temperature at which ammonia can be removed as vapor in addition to moisture is particularly preferable.

  After drying for an appropriate time (step 120), the preparation is completed by cooling the target container temperature to about room temperature (step 130). At this time, cooling water may be forced to flow from the port 110L to the port 110M. After preparation is complete, all routes are blocked.

[2. Irradiation]
The proton beam passes through the metal thin film 110B and is irradiated toward the bottom of the target chamber 110C (step 140). Irradiation is performed such that the proton beam energy on the target is in the range of 9 to 40 MeV, but in the production of technetium-99m, 15 to 22 MeV is particularly desirable. In addition, the valve V8 is opened to prevent damage to the target container, particularly the metal thin film 110B, in order to suppress an increase in pressure inside the target container due to heat generated during irradiation. Further, helium gas is allowed to flow from the port 110J to the port 110K to cool the vacuum partition 110E and the metal thin film 110B, while cooling water is also allowed to flow from the port 110L to the port 110M. Cool the bottom of the.

[3. [Recovery]
After irradiation for an appropriate time (for example, several hours), the produced technetium 99m is recovered. 30% ammonia water: 30% hydrogen peroxide solution = 1: 1 solution as a recovery medium is introduced into the target container 110 from the port 110G via the valve V3 → pipe 114 and then helium gas is supplied from the port 110G via the pipe 114. Then, the target is agitated (step 150). The valve V8 is opened as a helium gas exhaust path. Further, the target container 110 is heated by the heater H1. By the above procedure, dissolution of irradiated molybdenum oxide is promoted. At this time, in order to allow the solution to overflow from the target container, a solution trap 124 and / or an auxiliary tank is provided between the valve V8 and the target container 110. Furthermore, an expansion chamber can be provided at the open end of the valve V8.

  After a certain time (for example, 5 to 10 minutes), the valve V8 is closed, and helium gas is supplied from the port 110H to the target container 110 via the valve V7-b → the pipe 126 → the solution trap 124, and the target solution is supplied to the port 110G. Then, the recovery pipe 129 and the filter 130 are passed through the valve V1 and recovered in the Tc-containing Mo recovery tank 132 (step 160).

  Subsequently, in order to recover the residue adhering to the target container and the recovery pipe 129, a 30% ammonia water: 30% hydrogen peroxide solution = 1: 1 solution is supplied from the port 110H via the valve V6 → solution trap 124. Then, it is introduced into the target container 110 (step 170). At this time, the valve V4 is opened as an exhaust path.

  Next, after closing the valve V4, helium gas is supplied via the pipe 126 in the same procedure as described above, and the Tc-containing Mo recovery tank 132 is recovered (step 180).

  As described above, the remote production of technetium 99m is completed by a series of procedures.

  The next manufacturing does not require any special operations other than those shown here, [1. This is achieved by performing [Preparation of Target]. At this time, the solution recovered in the Tc-containing Mo recovery tank 132 can be reused. In this case, the solution that enters the target container is a combination of molybdenum + ammonia water + hydrogen peroxide water, and steps for each component. Although there may be some fluctuations due to the effect of the residual collection at 170, the fluctuation is within the expected range, and the fluctuation is offset by preparation and collection. Sometimes used ones can be reused as they are (no need for washing etc.).

  Next, a second embodiment in which the proton beam from the accelerator is irradiated in the horizontal direction will be described. In the present embodiment, as shown in FIG. 4 (sectional view taken along line IV-IV in FIG. 5) and FIG. 5 (side view seen from the direction of arrow V), the metal thin film 110B is provided obliquely with respect to the beam trajectory. The second embodiment is different from the first embodiment in that a target container 110 ′ that is irradiated with a proton beam from the horizontal direction toward the metal thin film 110B is used. In addition, the target container part in FIG. 4 shows the cross section on the IV-IV line shown in FIG. The shape of the inside of the target container is a cylindrical shape in the first embodiment, but in the second embodiment, it is formed in a conical shape with a flat apex for ease of processing. Since other configurations and operations are the same as those in the first embodiment, the same reference numerals are used for corresponding portions, and descriptions thereof are omitted.

  In the embodiment, the target material is introduced and recovered by a combination of helium gas and an exhaust device (vacuum pump P). However, the means for introducing and discharging the target material is not limited to this. General liquid transporting means such as other pumps and syringes may be used. In addition, liquid transporting means may be installed at a place away from the target containers 110 and 110 'to perform liquid feeding.

In the above embodiment, molybdenum 99 and technetium 99m are manufactured from molybdenum 100. However, the type of target material and the production nuclide, the type of solvent used simultaneously, and the type of beam are not limited. For example, the radionuclide to be produced is _Z ^A Product, the target material is _Z-1 ^A Target (A is the atomic weight, Z is the atomic number), and a proton beam is used. _Z-1 ^A Target (p, x) _Z ^A Product Consider the case of manufacturing using a nuclear reaction. At this time, _Z-1 ^A Target alone, oxide, hydroxide, fluoride, chloride, bromide, iodide, hydrochloride, nitrate, nitrite, sulfate, sulfide, hydride, and their hydration Things are available.

  The solubility in a solvent is not questioned. That is, any solvent can be used as long as it can be suspended in the mobile phase without being dissolved. For example, Mo simple metal (fine powder) does not dissolve in organic solvents such as alcohol and acetone, but can be transferred into the target container by these solvents as a mobile phase, and before irradiation. Since the organic solvent can be easily evaporated, this production purpose is achieved. In this paper, the expression “dissolved in a liquid” includes mixing in the liquid and coexistence of both.

  Further, the ammonia water concentration and the molybdenum oxide concentration are not limited. Furthermore, hydrogen peroxide water may be added as necessary to improve solubility. The hydrogen peroxide concentration at this time does not matter.

  The temperature in the target container at the time of drying is preferably 100 ° C. or higher, and more preferably 200 to 650 ° C. capable of evaporating ammonia, but is not limited thereto. The thickness of the generated crystal is preferably 0.1 to 5 mm on the incident beam trajectory, but is not limited to this.

  The gas used for drying is preferably helium, hydrogen or carbon monoxide, but is not limited thereto.

  For taking out the solution, pressurization and pressure feeding with a pressure body, suction with a syringe, or the like can be used.

  Furthermore, in order to promote the dissolution of molybdenum oxide, a heating device and a gas supply device may be used in combination.

  The number of target containers is not limited to one, and a plurality of target containers may be used so that they can be continuously manufactured by irradiation with beams in order. The irradiation beam is not limited to the proton beam. The target substance is not limited to a solid, and may be in solution.

  The present invention is applicable to the production of radiopharmaceuticals used for diagnostic imaging in fields such as radiology and nuclear medicine.

DESCRIPTION OF SYMBOLS 108 ... Accelerator irradiation port 110, 110 '... Target container 110B ... Metal thin film 110C ... Target chamber 110D ... Heating / cooling part H1 ... Heater 110E ... Vacuum diaphragm 110F ... Coolant 112 ... Target solution (Mo) tank 114, 126, 128 ... conduit 122 ... mixed solvent _{(H 2 O 2 + NH 4} OH) tank 116 ... helium (He) tank P ... vacuum (reduced pressure) pumps 126, 128 ... pipe 129 ... collection piping 130 ... filter 132 ... Tc-containing Mo recovery tank

[0003]
Industrial equipment robots, or radiation reduction measures combining shields and manipulators. However, the installation of these facilities / equipment requires a considerable cost, and the manipulator work requires high skill in operation, and the specifications required economically and technically are high.
[0008]
Therefore, there is a strong demand for establishing a radioisotope production method using a solid target that is inexpensive and can be easily operated.
[0009]
The present invention has been made to achieve the above-described conventional problems, and in order to produce practical technetium 99m and / or molybdenum 99, a specific structure and irradiation process applicable when irradiating molybdenum 100 is performed. The task is to establish an operation method.
Means for Solving the Problems [0010]
The present inventors tried to solve the problem by dissolving molybdenum, which is a target material, in an appropriate solvent, drying it before irradiation, and changing it from a liquid to a solid. Although it is not impossible to use a liquid target (molybdenum solution) for irradiation, the liquid absorbs the energy of the beam and as a result hinders sufficient nuclear reaction of the molybdenum target. Therefore, the yield of Tc-99m or Mo-99 expected by this method is significantly reduced. According to the present invention, the theoretical nuclear reaction yield can be obtained by removing the liquid from the target material before irradiation and increasing the density of the molybdenum target existing on the incident beam orbit.
[0011]
The present invention has been made on the basis of the above knowledge, introduced a target substance dissolved in a liquid or mixed with a liquid into a target container,
An accelerator characterized by introducing a drying gas into the target container, drying a target material dissolved in or mixed with the liquid, reducing a liquid component, and then irradiating a beam from the accelerator. Is a method for producing radionuclides.
[0012]
Here, the target substance dissolved in the liquid or mixed with the liquid and introduced into the target container can be dried in the target container to precipitate a solid component.

[0004]
[0013]
Further, the thickness of the solid component deposited in the target container by the drying can be set to 0.1 to 5 mm on the trajectory of the beam incident from the accelerator.
[0014]
Moreover, the said drying can be performed using heating and / or exhaust_gas | exhaustion together.
[0015]
Moreover, the temperature in the target container at the time of the drying can be set to 100 ° C. or higher.
[0016]
Further, the gas used for the drying can be a gas that does not give a nuclear reaction product when it remains inside the target container.
[0017]
Further, the gas used for the drying is introduced into the target container so as to pass through the target material which is dissolved in the liquid or mixed with the liquid and introduced into the target container and accumulated below the target container. be able to.
[0018]
In addition, after the irradiation of the beam is completed, the liquid can be introduced into the target container, and the target material can be dissolved again in the liquid or mixed with the liquid and taken out of the target container.
[0019]
Moreover, the liquid taken out from the target container can be recovered without being discarded.
[0020]
Further, the target material may be molybdenum 100, the beam may be a 40-9 MeV proton beam, and the produced radionuclide may be technetium 99m and / or molybdenum 99.
[0021]
The target material introduced into the target container can be molybdenum oxide dissolved in ammonia water.
[0022]
Moreover, hydrogen peroxide water can be added to the ammonia water.
[0023]
Moreover, the temperature at the time of the said drying can be 100-700 degreeC.
[0024]
The liquid may be ammonia water and / or hydrogen peroxide water.
[0025]
In the present invention, when the target material that has been irradiated with the beam from the accelerator is taken out of the target container,

[0005]
Introducing liquid into the target container;
The present invention provides a method for producing a radionuclide using an accelerator, wherein the target substance is dissolved in the liquid or mixed with the liquid and taken out of the target container.
[0026]
A target container;
Means for introducing a target substance dissolved or mixed with the liquid into the target container;
A drying means for introducing a drying gas into the target container, drying the target material dissolved in the liquid or mixed with the liquid, and reducing liquid components;
Means for irradiating the target container with a beam from an accelerator;
An apparatus for producing a radionuclide using an accelerator is provided.
[0027]
Here, the drying means can dry the target substance dissolved in the liquid or mixed with the liquid and introduced into the target container to precipitate a solid component in the target container.
[0028]
The drying means can also include a heating means and / or an exhaust means.
[0029]
Further, the target container seals the target container and includes a metal thin film for allowing the beam to pass therethrough, and the metal thin film can be cooled.
[0030]
A means for introducing a liquid into the target container after the irradiation of the beam;
The apparatus may further comprise means for dissolving the target substance in the liquid again or mixing it with the liquid and taking it out of the target container.
[0031]
In addition, it is possible to provide means for collecting the liquid taken out from the target container without discarding it.
[0032]
The means for collecting may include a filter provided in the middle of the piping.

[0006]
[0033]
The present invention is also a radionuclide production apparatus in which a target material that has been irradiated with a beam from an accelerator is extracted from the target container.
Provided is a radionuclide production apparatus using an accelerator, comprising means for introducing a liquid into the target container, dissolving the target material in the liquid or mixing it with the liquid, and taking it out of the target container. To do.
When remaining inside the target container, the gas that does not give a nuclear reaction product can be helium.
The gas used for the drying can be a gas that reduces the target material.
The gas for reducing the target material can be hydrogen or carbon monoxide.
Effect of the Invention [0034]
The production of Tc-99m using molybdenum as a target, which has not been reported in the past, is made possible by the present invention. Furthermore, since all the processes required for manufacturing can be performed remotely, there is no occupational exposure to those involved in the work, and manufacturing in consideration of health and safety is possible.
[0035]
In addition, the target material can be quickly taken out from the target container, and can be repeatedly produced in one target container, and even a radionuclide having a short half-life can be taken out without causing a problem. .
Brief Description of the Drawings [0036]
[FIG. 1] Pipeline diagram showing the configuration of the first embodiment of the present invention [FIG. 2] Cross-sectional view showing the target container used in the first embodiment [FIG. 3] The processing procedure of the first embodiment is shown. Flowchart [FIG. 4] Cross-sectional view taken along line IV-IV in FIG. 5 showing the target container used in the second embodiment of the present invention [FIG. 5] Implementation of the side view seen from the direction of arrow V in FIG. Form to do [0037]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0038]
In the first embodiment of the present invention, as shown in FIG. 1, a charged particle (here, proton) beam from an accelerator irradiation port 108 which is means for irradiating a beam from an accelerator (not shown) is irradiated, for example, vertically. A target container 110; a target solution (Mo) tank 112 for storing a target material (Mo) dissolved or mixed in a liquid (referred to as a target solution); and a target solution in the Mo tank 112 is pushed out to a pipe 114 to In the target container 110

The present invention has been made on the basis of the above knowledge, introduced a target substance dissolved in a liquid or mixed with a liquid into a target container,
A drying gas is introduced into the target container, the target material dissolved in or mixed with the liquid is dried, the liquid component is reduced, and then the beam from the accelerator is applied to the dried target material. Irradiation is a method for producing a radionuclide using an accelerator.

Moreover, the gas utilized for the said drying can be made into an inert gas .

The present invention is also a radionuclide production apparatus in which a target material that has been irradiated with a beam from an accelerator is extracted from the target container.
Provided is a radionuclide production apparatus using an accelerator, comprising means for introducing a liquid into the target container, dissolving the target material in the liquid or mixing it with the liquid, and taking it out of the target container. To do.
The inert gas can be helium.
The gas used for the drying can be a gas that reduces the target material.
The gas for reducing the target material can be hydrogen or carbon monoxide.

Next, the target container 110 is heated by the heater H1 provided in the target container, and the solution is dried (step 110). At this time, helium gas is introduced through the flow path V7-a and the pipe 114 while controlling the flow rate with the flow rate controller 118, and the drying of the target chamber is promoted, and exhausted from the port 110I via the valve V5 → the vacuum pump P. To do. At this time, helium gas can be introduced from the port 110H. However, when the helium gas is introduced from the port 110G, the target material mixed with the liquid and introduced into the target container and accumulated below the target container 10 is collected in the port 110G. It is preferable because clogging can be prevented by flowing back to the pipe 114 and solidifying in the middle thereof. Although the temperature in the target container 110 at the time of drying is set to 100 to 700 ° C., 250 ° C. or more that is a temperature at which ammonia can be removed as vapor in addition to moisture is particularly preferable.

After a certain time (for example, 5 to 10 minutes), the valve V8 is closed and helium gas is supplied from the port 110H to the target container 110 via the flow path V7-b → the pipe 126 → the solution trap 124, and the target solution is supplied to the port The recovery pipe 129 and the filter 130 are passed through the valve V1 through 110G and recovered in the Tc-containing Mo recovery tank 132 (step 160).

DESCRIPTION OF SYMBOLS 108 ... Accelerator irradiation port 110, 110 '... Target container 110B ... Metal thin film 110C ... Target chamber 110D ... Heating-cooling part H1 ... Heater 110E ... Vacuum diaphragm 110F ... Cooling chamber 112 ... Target solution (Mo) tank 114, 126, 128 ... Pipe 122 ... Mixed solvent (H ₂ O ₂ + NH ₄ OH) tank 116 ... Helium (He) tank P ... Vacuum (decompression) pump 129 ... Recovery pipe 130 ... Filter 132 ... Tc-containing Mo recovery tank

Claims (23)

Introducing a target substance dissolved or mixed with a liquid into the target container;
A method for producing a radionuclide using an accelerator, comprising drying the target container to reduce a liquid component and then irradiating a beam from the accelerator.   The radionuclide by an accelerator according to claim 1, wherein the target material dissolved in the liquid or mixed with the liquid and introduced into the target container is dried in the target container to precipitate a solid component. Manufacturing method.   The radionuclide production by the accelerator according to claim 2 or 3, wherein the thickness of the solid component deposited in the target container is 0.1 to 5 mm on the trajectory of the beam incident from the accelerator. Method.   The method for producing a radionuclide using an accelerator according to claim 2, wherein the drying is performed by at least one of heating, introduction of a drying gas, and exhaust.   The method for producing a radionuclide using an accelerator according to claim 5, wherein the temperature in the target container at the time of drying is 100 ° C. or higher.   The method for producing a radionuclide using an accelerator according to claim 4 or 5, wherein the gas used for the drying is helium, hydrogen or carbon monoxide.   Introducing the gas used for the drying into the target container so as to pass through the target material dissolved in the liquid or mixed with the liquid and introduced into the target container and accumulated below the target container; A method for producing a radionuclide using an accelerator according to claim 4 or 5.   8. The liquid is introduced into the inside of the target container after the irradiation of the beam, and the target material is again dissolved in the liquid or mixed with the liquid and taken out of the target container. A method for producing a radionuclide using the accelerator according to any one of the above.   The method for producing a radionuclide using an accelerator according to claim 8, wherein the liquid taken out from the target container is collected without being discarded.   The target material is molybdenum 100, the beam is a 40-9 MeV proton beam, and the produced radionuclide is technetium 99m and / or molybdenum 99. A method for producing a radionuclide with the described accelerator.   The method for producing a radionuclide using an accelerator according to claim 10, wherein the target material introduced into the target container is molybdenum oxide dissolved in ammonia water.   The method for producing a radionuclide using an accelerator according to claim 11, wherein hydrogen peroxide is added to the ammonia water.   The method for producing a radionuclide using an accelerator according to claim 11 or 12, wherein the drying temperature is 200 to 650 ° C.   The method for producing a radionuclide using an accelerator according to claim 8, wherein the liquid is ammonia water and / or hydrogen peroxide water. When the target material that has been irradiated with the beam from the accelerator is taken out of the target container,
Introducing liquid into the target container;
A method for producing a radionuclide using an accelerator, wherein the target substance is dissolved in the liquid or mixed with the liquid and taken out of the target container. A target container;
Means for introducing a target substance dissolved or mixed with the liquid into the target container;
Drying means for reducing liquid components by drying in the target container;
Means for irradiating the target container with a beam from an accelerator;
An apparatus for producing radionuclides using an accelerator.   The said drying means is the said target substance which melt | dissolved in the said liquid or mixed with the liquid, and was introduce | transduced in the said target container, It dries in this target container, The solid component is precipitated, It is characterized by the above-mentioned. Radionuclide production equipment with the described accelerator.   The radionuclide production apparatus using an accelerator according to claim 16 or 17, wherein the drying means includes at least one of a heating means, a gas supply means, and an exhaust means.   17. The radionuclide production apparatus using an accelerator according to claim 16, wherein the target container is provided with a metal thin film for sealing the target container and allowing the beam to pass therethrough, and the metal thin film is cooled. . Means for introducing a liquid into the target container after the irradiation of the beam;
The accelerator according to any one of claims 16 to 19, further comprising means for dissolving the target material in the liquid again or mixing it with the liquid and taking it out of the target container. manufacturing device.   21. The radionuclide production apparatus using an accelerator according to claim 20, further comprising means for collecting the liquid taken out from the target container without discarding.   21. The apparatus for producing a radionuclide using an accelerator according to claim 20, wherein the means for collecting includes a filter provided in the middle of the piping. A radionuclide manufacturing apparatus configured to take out a target material, which has been irradiated with a beam from an accelerator, out of a target container,
An apparatus for producing a radionuclide using an accelerator, comprising means for introducing a liquid into the target container, dissolving the target material in the liquid or mixing it with the liquid, and taking it out of the target container.

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