RU215049U1 - Device for automated isolation and chemical purification of radionuclides - Google Patents

Abstract

The utility model relates to a device for automated isolation and chemical purification of radionuclides and can be used for the isolation and purification of RN produced by medical proton accelerators of medium energy protons (up to 30 MeV) and medium proton beam currents (up to 200 μA). The device contains a transport pipe connected to the transport terminal, a vacuum gripper for transferring cylindrical targets between the storage stand, the transport terminal and the chemical processes stand equipped with a heating block, containing a chemical cell lowered by means of an actuator onto the target located on the chemical processes stand with a heating block , a radionuclide isolation and purification subsystem, consisting of membrane valves, connecting pipes, a column with a sorbent, pumps, and a reaction vessel with a heating block. Additionally, the device contains two multi-way tap-switch, inert to concentrated inorganic acids and alkalis. The technical result is the possibility of isolating radionuclides using concentrated inorganic acids and alkalis (for example, thallium-201, gallium-67). 1 ill.

Description

The utility model (PM) relates to medical equipment, namely to the means for isolating and purifying radionuclides (RN) produced on solid targets of accelerators and can be used for isolating and purifying RN produced on medical proton accelerators of medium-energy protons (up to 30 MeV) and average proton beam currents (up to 200 μA).

A significant amount of RN used in nuclear medicine ( ^64Cu , ^89Zr , ^67Ga , ^111In , ^123I , ^201Tl , ^68Ge , etc.) are produced by proton irradiation of target substances in a solid state of aggregation. The irradiated target substance can be a galvanic layer, foil, powder, etc.

It should be noted that the principles of RH production in the solid state of aggregation are well studied [Proceedings of the 13th International Workshop on Targetry and Target Chemistry, Roskilde, Denmark, July 26-28, 2010. Proceedings of the 14th International Workshop on Targetry and Target Chemistry, Playa del Carmen, Mexico, August 26-29, 2012. Proceedings of the 15th International Workshop on Targetry and Target Chemistry, Prague, Czech Republic, August 18-21, 2014. Solid Target System with In-Situ Target Dissolution, William Z. Gelbart et al., Instruments, 2019, no. 3, vol. 14. Solid Targetry for Compact Cyclotrons, Jožef Čomor, Bratislava, September 19-21, 2004].

The production of launch vehicles produced using solid-state target devices generally includes the following stages:

1) deposition of the target substance on the substrate (in the case of an electroplated layer) or assembly (in the case of foil or powder);

2) installation and sealing of the target device with the target material to ensure tightness in terms of vacuum from the side of the entry of the beam of accelerated particles and tightness in terms of cooling water from the side of the rear wall;

3) irradiation of the target material;

4) removal of the irradiated device and extraction of the irradiated material;

5) dissolution or sublimation of the target substance and its transformation into a liquid or gaseous state of aggregation;

6) isolation and purification of the target isotope.

However, automating the production of isotopes on solid-state target devices is a difficult task. Traditionally, stages 1-4 in the production of launch vehicles are performed using a significant number of manual operations (including using copying manipulators, when working in protective chambers), which leads to a high labor intensity of the process and, potentially, significant exposure of personnel.

An analysis of the proposed commercial products and research projects shows that the main efforts of specialists developing modern solid-state target devices are aimed at increasing the degree of automation of the process of production and extraction of accumulated launch vehicles.

Closest to the proposed is a system for the automatic production of radioisotopes, described in patent WO2006114433A2, which we have chosen as a prototype. The system is designed to isolate and purify radionuclides produced on solid targets of medium-energy accelerators (up to 30 MeV).

According to the description of the prototype, the system includes 3 blocks: a block for electrolytic deposition of the starting isotope and dissolution of the irradiated starting isotope (1), a target irradiation block (2) mounted on a cyclotron, a block for the extraction and purification of the produced PH (3). Blocks 1 and 2 are connected by a transport pipe for automated transfer of the target between the blocks. Blocks 1 and 3 are connected by a tube to transfer the dissolved target substance to block 3. Blocks 1 and 3 are located inside the protective chambers located in the radiochemical laboratory.

Solid target, according to the description of the prototype, includes a capsule of a cylindrical shape. The target substrate is enclosed in a cylindrical capsule, one of the ends of the capsule is made in the form of a truncated cone. The target substrate is separated from the capsule recess by a thin wall.

The unit for electrolytic deposition of the starting isotope and dissolution of the irradiated starting isotope includes a body part, a vacuum gripper, a vacuum tube, supports for storing targets, a transport terminal, a transport tube, a chemical cell, and a heating unit. The transport pipe is connected to the unit with a transport terminal. The block has stands for placing targets: 4 stands for storing targets and a stand for chemical processes equipped with a heating block. The target is moved between stands by means of a vacuum gripper with a vacuum tube connected by a fitting. A chemical cell is installed on the vertical actuator.

The unit for isolation and purification of the accumulated PH includes a column with an ion exchange resin, two pumps, a reaction vessel with a heating block, membrane valves and vessels for reagents, and a control subsystem.

The work of the prototype is carried out as follows. The solid target is installed in the block for electrolytic deposition of the starting isotope and dissolution of the irradiated starting isotope on a stand with a heating block in such a way that the heater enters the recess of the target. Using a vertical actuator, a chemical cell is lowered onto the target, and a closed container is formed, bounded by the chemical cell and the target substrate. An electrolytic solution containing the starting isotope is fed into the resulting container from the block for the isolation and purification of the accumulated PH by means of pumps through tubes. The platinum electrode built into the chemical cell provides the potential difference necessary for the electrochemical deposition of the starting isotope on the target substrate.

The target with the initial isotope deposited is transferred to the stands for waiting for irradiation or to the transport terminal by means of a vacuum gripper with a fitting, and then through the transport pipe by a stream of compressed air to the target irradiation unit.

After the irradiation is completed, the target comes back from the target irradiation unit to the unit for electrolytic deposition of the starting isotope and dissolution of the irradiated starting isotope, and is transferred to the support for chemical processes using a vacuum gripper with a fitting. Using a vertical actuator, a chemical cell is lowered onto the target, and a closed container is formed, bounded by the chemical cell and the target substrate. Solvents designed to dissolve the target layer containing the accumulated PH are fed into the resulting container from the block for the extraction and purification of the accumulated PH by means of pumps through tubes. The resulting solution containing the accumulated PH is transferred through the tubes to the block for the isolation and purification of the accumulated PH to perform chemical reactions for the isolation and purification of the PH. Chemical isolation and purification reactions include applying a solution containing the generated pH to the sorbent in a column, washing the sorbent with various solutions from reagent vessels, elution of pH from the sorbent into a reaction vessel with a heating block, and evaporation of the eluate in a reaction vessel with a heating block (if necessary) , diluting the dry residue in the reaction vessel with a heating block and transferring the resulting solution from the reaction vessel with a heating block into a container for the intermediate product.

The system described in the mentioned patent allows efficient fully automated production, isolation and purification of PH. However, in our opinion, it is not without a number of shortcomings, namely:

1) the use of membrane valves with elastomer membranes in the liquid flow distribution subsystem in the unit for the extraction and purification of the accumulated pH leads to a sharp decrease in the system resource when using concentrated inorganic acids (for example, concentrated nitric acid) and alkalis used in technologies for isolating a number of popular radionuclides ( for example, thallium-201, gallium-67), which leads to a limitation of the scope of the block.

Thus, the noted drawback leads to low versatility of the prototype system, namely the impossibility of separating radionuclides using concentrated inorganic acids and alkalis (eg, thallium-201, gallium-67).

The technical result of this PM is to enable the isolation of radionuclides using concentrated inorganic acids and alkalis (for example, thallium-201, gallium-67).

This result is achieved by the fact that the device for automated isolation and chemical purification of radionuclides contains a transport pipe connected to the transport terminal, a vacuum gripper for transferring cylindrical targets between the storage stand, the transport terminal and the chemical process stand equipped with a heating block, a chemical cell lowered by means of an actuator to a target located on a chemical process stand with a heating block, a radionuclide extraction and purification subsystem consisting of membrane valves, connecting tubes, a column with a sorbent, pumps and a reaction vessel with a heating block, according to the PM, the device additionally contains two multi-way switching valves, inert to concentrated inorganic acids and alkalis.

Adding 2 multi-way switching valves inert to concentrated inorganic acids and alkalis to the radionuclide extraction and purification subsystem makes it possible to use concentrated inorganic acids (for example, concentrated nitric and hydrochloric acids) and alkalis used in the extraction technologies of a number of popular radionuclides (for example, thallium-201, gallium-67), which expands the scope of the system and allows the device to be used for the isolation and purification of a wide range of RN. The list of possible pH includes, but is not limited to: copper-64, zirconium-89, thallium-201, gallium-67, gallium-68.

It should be noted that all components of the device are made compactly and placed in a single housing. This allows you to place the device in one protective chamber instead of two, thus reducing the cost of the equipment complex and its maintenance.

For a better understanding of the proposed device, we present its diagram.

in fig. 1, where 1 is a transport pipe, 2 is a connecting adapter, 3 is a transport terminal, 4 is a vacuum gripper, 5 is a tube, 6 is a chemical process stand, 7 is a target storage stand, 8 is a second chemical process stand, 9 is a chemical cell , 10 – second chemical cell, 11 – vessels for reagents, 12 – first vessel for intermediate product, 13 – multi-way switching valves, 14 – column with sorbent, 15 – membrane valves, 16 – first pump, 17 – second pump, 18 – reaction vessel with a heating block, 19 - peristaltic pump, 20 - second vessel for intermediate.

The operation of the device is as follows.

The target, which is a cylindrical part with a flat target substrate enclosed inside, is mounted on the second support for chemical processes (8). Using a vertical actuator, the second chemical cell (10) is lowered onto the target, and a closed container is formed, bounded by the second chemical cell and the target substrate. An electrolytic solution containing the starting isotope is fed into the resulting container using a peristaltic pump (19) through the tubes, while the distribution of liquid flows in the closed container is carried out using membrane valves (15). The platinum electrode built into the second chemical cell provides the potential difference necessary for the electrochemical deposition of the starting isotope on the target substrate.

The target with the initial isotope deposited is transferred to the target storage stand (7) or to the transport terminal (3) by means of a vacuum gripper (4) and then through the connecting adapter (2) along the transport pipe (1) with a current of compressed air supplied through the tube (5 ) is transferred to the target irradiation unit. The vacuum gripper is fixed on a vertical actuator, which, in turn, is fixed on a horizontal actuator, which ensures the movement of the vacuum actuator between the supports and the possibility of lifting the target from the supports.

After the irradiation is completed, the target comes back from the target irradiation unit to the device and is transferred to the first stand of chemical processes with a heating unit (6) using a vacuum gripper (4). Using a vertical actuator, a chemical cell (9) is lowered onto the target, and a closed container is formed, bounded by the chemical cell and the target substrate. Solvents are supplied through the tubes from the vessels for reagents (11) through the tubes to dissolve the target layer containing the accumulated pH. If necessary, the dissolution process can be carried out in several stages (2 or more), while the solvent intended for dissolving the target layer is supplied in several portions at certain time intervals, and then portions of the solution containing the accumulated pH are taken from a closed container and placed at the help of the first pump into the first intermediate vessel (12) for accumulation.

Chemical reactions of isolation and purification of RN include applying a solution containing the accumulated RN to the sorbent in a column (14), washing the sorbent with various solvents from vessels for reagents (11), elution of RN from the sorbent into a reaction vessel with a heating block (18), evaporation of the eluate in the reaction vessel with a heating block (18) (if necessary), diluting the dry residue in the reaction vessel with a heating block and transferring the resulting solution from the reaction vessel with a heating block to the second intermediate vessel (20). The distribution of flows of strong inorganic acids occurs with the help of multi-way switching valves (13), the distribution of flows of other necessary liquids and gases occurs with the help of membrane valves (15). The movement of liquids is carried out using the first pump (16), which provides accurate dosing by volume. The intermediate product is packed using the second pump (17), which ensures accurate dosing of the intermediate product by volume, while the distribution of liquid flows occurs using membrane valves (15), the second pump (17) and membrane valves (15) form a packaging subsystem.

Thus, the versatility of the device is achieved due to the possibility of implementing various radiochemical technologies for the separation of produced radionuclides and starting isotopes based on separation by solid-phase extraction using various sorbents.

The essence of the utility model is illustrated by examples.

Example 1

In the technology of copper-64 extraction, the starting isotope is nickel-64, upon irradiation of which with 12-20 MeV protons in the target device of the cyclotron, copper-64 is formed by the reaction ⁶⁴ Ni(p,n) ⁶⁴ Cu. To produce and isolate this radionuclide, the device operates as follows.

The target, which is a cylindrical part with a flat target substrate enclosed inside, is mounted on the second support for chemical processes (8). Using a vertical actuator, the second chemical cell (10) is lowered onto the target, and a closed container is formed, bounded by the second chemical cell and the target substrate. An electrolytic solution containing nickel-64 is fed into the resulting container using a peristaltic pump (19) through the tubes, while the distribution of liquid flows in the closed container is carried out using membrane valves (15). The platinum electrode built into the second chemical cell provides the potential difference necessary for the electrochemical deposition of the starting isotope on the target substrate; nickel-64 is deposited in 6-24 hours at a current between the electrode and the target substrate of 10-100 mA.

The target coated with nickel-64 is transferred to the target storage stand (7) or to the transport terminal (3) by means of a vacuum gripper (4) and then through the connecting adapter (2) through the transport pipe (1) by the current of compressed air supplied through the tube ( 5) is transferred to the target irradiation unit.

After the irradiation is completed, the target comes back from the target irradiation unit to the device and is transferred to the first stand of chemical processes with a heating unit (6) using a vacuum gripper (4). Using a vertical actuator, a chemical cell (9) is lowered onto the target, and a closed container is formed, bounded by the chemical cell and the target substrate. 3 ml of 6M hydrochloric acid is supplied through the tubes from the vessels for reagents (11) by means of the first pump (17) to dissolve the target layer, the dissolution stage takes 30-60 minutes at a heating block temperature of 80-90°C. After the first stage of dissolution, the liquid containing the irradiated nickel-64 and produced copper-64 is transferred to the accumulation vessel (12), the second stage of dissolution, similar to the first one, is performed.

Chemical reactions for isolation and purification of RN include applying a solution containing irradiated nickel-64 and accumulated copper-64 to the Bio-Rad AG-1 X8 sorbent in column (14), washing the sorbent with 5 ml of 6M hydrochloric acid, 5 ml of 4M hydrochloric acid, 2 ml 0.1 M hydrochloric acid from the reagent vessels (11), elution of copper-64 from the sorbent into the reaction vessel with a heating block (18) with 4 ml 0.1 M hydrochloric acid, evaporation of the eluate in the reaction vessel with a heating block (18) 30 -60 min at 95°C, diluting the dry residue in the reaction vessel with a heating block with 4 ml of 0.1 M hydrochloric acid and transferring the resulting solution from the reaction vessel with a heating block to the second vessel for intermediate (20). The distribution of flows of strong inorganic acids occurs with the help of multi-way switching valves (13), the distribution of flows of other necessary liquids and gases occurs with the help of membrane valves (15). The movement of liquids is carried out using the first pump (16), which provides accurate dosing by volume. The intermediate product is packed using the second pump (17), which ensures accurate dosing of the intermediate product by volume, while the distribution of liquid flows occurs using membrane valves (15), the second pump (17) and membrane valves (15) form a packaging subsystem.

Example 2

In the technology of thallium-201 isolation, the starting isotope is thallium-203, upon irradiation of which with 25-30 MeV protons in the target device of the cyclotron, thallium-201 is formed by the reaction ²⁰³ Ni(p,3n) ²⁰¹ Pb → ²⁰¹ Tl. To produce and isolate this radionuclide, the device operates as follows.

The target, which is a cylindrical part with a target substrate enclosed inside, is disposable; the deposition of starting thallium-203 by the electrochemical method is performed in a cold chemistry laboratory.

The target with the applied starting tweezers is placed on the target storage stand (7) or in the transport terminal (3) and then through the connecting adapter (2) through the transport pipe (1) by the current of compressed air supplied through the tube (5) is transferred to the target irradiation unit .

After the irradiation is completed, the target comes back from the target irradiation unit to the device and is transferred to the first stand of chemical processes with a heating unit (6) using a vacuum gripper (4). Using a vertical actuator, a chemical cell (9) is lowered onto the target, and a closed container is formed, bounded by the chemical cell and the target substrate. 5 ml of 0.35 M nitric acid is supplied through the tubes from the vessels for reagents (11) through the tubes to dissolve the target layer, the dissolution stage takes 3-6 minutes at a heating block temperature of 60-70°C. After the first stage of dissolution, the liquid containing irradiated thallium-203 and accumulated lead-201 is transferred to the accumulation vessel (12), the second, third, fourth stages of dissolution, similar to the first, are performed.

Chemical reactions for isolating and purifying RN include adding a solution of 13 mg/ml of iron nitrate and 25% ammonia solution to a collection vessel to form an iron precipitate that binds lead-201, applying the resulting solution containing irradiated thallium-203 and accumulated lead-201 to filter with 10 µm pores in the column (14), washing the filter with 5 ml of deionized water, dissolving the precipitate retained by the filter with 3 ml of 0.35 M nitric acid and collecting the resulting solution in the intermediate vessel (20). The resulting solution containing lead-201 is kept for 20-30 hours for the decomposition of lead-201 into thallium-201, the chemical separation reactions are repeated to separate the thallium-201 from the residues of lead-201.

The distribution of flows of strong inorganic acids occurs with the help of multi-way switching valves (13), the distribution of flows of other necessary liquids and gases occurs with the help of membrane valves (15). The movement of liquids is carried out using the first pump (16), which provides accurate dosing by volume. The intermediate product is packed using the second pump (17), which ensures accurate dosing of the intermediate product by volume, while the distribution of liquid flows occurs using membrane valves (15), the second pump (17) and membrane valves (15) form a packaging subsystem.

The proposed device in comparison with the known has a number of significant advantages:

1) using the device, it is possible to isolate and purify a wide range of PH;

2) it is possible to simultaneously perform the cycles of applying the starting isotope and isolating the accumulated launch vehicle;

3) it is possible to place the device in one cell of the protective box;

4) it is possible to package a solution containing the accumulated radionuclide, which allows it to be divided among several consumers.

The proposed device was developed in the department of cyclotron radiopharmaceuticals of the Federal State Budgetary Institution "RNTsRHT them. ak. A.M. Granov” and was tested during 20 cycles of production and release of PH with a positive result.

Claims (1)

A device for automated separation and chemical purification of radionuclides, including two subsystems: a subsystem for the electrolytic deposition of the starting isotope and dissolution of the irradiated starting isotope and a subsystem for the isolation and purification of the radionuclide, while the subsystem for the electrolytic deposition of the starting isotope and the dissolution of the irradiated starting isotope contains a transport tube, a vacuum gripper for transfer cylindrical targets between a storage stand, a transport terminal and a chemical processes stand equipped with a heating block, a chemical cell lowered by means of an actuator onto a target located on a chemical processes stand with a heating block, membrane valves and pumps, and the radionuclide extraction and purification subsystem is connected to the subsystem electrolytic deposition of the starting isotope and dissolution of the irradiated starting isotope with a tube for transferring the dissolved target substance and contains membrane valves connecting t cuttings, columns with a sorbent, pumps and a reaction vessel with a heating block, characterized in that the subsystem for electrolytic deposition of the starting isotope and dissolution of the irradiated starting isotope and the subsystem for isolating and purifying the radionuclide additionally include two multi-way switching valves that are inert to concentrated inorganic acids and alkalis .

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