Method and apparatus for sublimation thermal separation of technetium

Abstract

To constantly produce technetium Tc-99m from molybdenum Mo-99, and easily recover and recycle an expensive molybdenum sample (Mo-100 and Mo-98) with high efficiency in a constant period.SOLUTION: When Tc-99m is thermally separated from Mo-99 of a parent nuclide using a sublimation method, a plurality of sublimation devices 8 in which a sample 10 is arranged in a plurality of stages of sample shelves 14 are inserted into a plurality of tubular furnaces 100 and heated, a new sample 10 is arranged in the uppermost stage or lowermost stage of the sample shelf 14 of one sublimation device for each first predetermined period, the sublimation devices 8 are rotated by only a predetermined angle, the sample shelves 14 are moved downward or upward by one stage for each second predetermined period longer than the first predetermined period, and an oldest sample 10 is taken out from the lowermost stage or uppermost stage of the sample stage 14 of the sublimation devices 8 for each third predetermined period longer than the second predetermined period.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for sublimation thermal separation of technetium, and in particular to a method and apparatus for sublimation thermal separation of technetium that can steadily produce technotium Tc-99m from molybdenum Mo-99 and that can easily recover and reuse expensive molybdenum samples (Mo-100 and Mo-98) with high efficiency at regular intervals. [Background technology]

[0002] Tc-99m is the most commonly used radionuclide in nuclear medicine diagnostics and is obtained by periodic separation (milking) from the radioactive parent nuclide Mo-99. In the conventional method, enriched uranium U-235 is used as a sample in a nuclear reactor, and the highly radioactive Mo-99 produced by its nuclear fission reaction is adsorbed onto a small amount of alumina column, from which Tc-99m is separated.

[0003] On the other hand, Mo-99, which is produced using Mo-100 as a sample in accelerators or nuclear reactors, has a specific activity roughly 1 / 10,000 lower than that of the Mo-99 mentioned above. Furthermore, to obtain Mo-99 with the same radioactivity as when using a U-235 sample, it is necessary to produce it from a large amount of molybdenum sample containing non-radioactive molybdenum. In this case, the method of separating Tc-99m from Mo-99 containing a large amount of non-radioactive molybdenum sample using an alumina column mentioned above cannot be used.

[0004] Therefore, in Patent Document 1, the inventors have proposed a technology for thermally separating and purifying Tc-99m from MoO3 by using an electric furnace in which multiple crucibles are arranged in multiple layers in the vertical direction, melting a molybdenum trioxide (MoO3) sample containing Mo-99 in the crucible while flowing a gas containing humid oxygen through the electric furnace, and performing milking multiple times. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6467574 Summary of the Invention [Problem to be solved by the invention]

[0006] However, this was not necessarily sufficient for practical use.

[0007] The present invention has been made to solve the above-mentioned conventional problems, and aims to improve the technology proposed in Patent Document 1 in a practical manner, with safety, operability, and economy in mind. [Means for solving the problem]

[0008] First, the research content of the present invention will be explained.

[0009] Usually, each piece weighs more than 100g to produce high-strength Mo-99. 100 A MoO3 sample is irradiated with accelerator neutrons generated by an accelerator for, for example, 24 hours at a time (hereinafter referred to as one cycle), and this cycle is repeated six times in a week, with the remaining day (24 hours) of accelerator operation being stopped and used for maintenance of the accelerator, etc. Fresh Mo-99 is produced every day through the above Mo-99 production process. Contains Over 100g of irradiated 100 MoO3 sample (hereinafter also referred to as the irradiated sample or target) Removed from the irradiation chamber.

[0010] The present invention provides: 1) the amount of irradiation exceeding 100 g that is thus taken out daily and placed in a crucible; Examination Effective use of fees To do 2) To separate and extract Tc-99m with high efficiency, and 3) To remove Mo-99 that condenses and crystallizes on the outside of the sample shelf during the above process. As appropriate during the above 6 cycles 3) Separating and extracting Tc-99m, and 4) Producing Mo-99 Use to 100 MoO3 samples are expensive, but are consumed in one cycle. 100 Mo-100 in MoO3 is about one part per million and trace amounts Therefore, for example, irradiated 100Highly efficient recovery of MoO3 As a sample for producing Mo-99 and reuse it for a long time.

[0011] 1. Effective use of irradiated samples (Mo-99 generated) The MoO3 samples irradiated by the accelerator exceed 100g per sample. In order to make the most of the Mo-99 produced, a system is created that can separate the material twice a day for nine days (a total of 18 times), using a tubular electric furnace, for example, with a combination of three three-stage thermal separation devices, and one new (highly radioactive) sample is placed in a rotating system every day, and the old sample (9-day-old sample - 10-11 days old if holidays are taken into account) is removed and replaced.

[0012] Specifically, a new sample is placed on the top position (first shelf) of the sample shelf once every three days (every rotation), and the samples from the first and second shelves are moved down one level, with the oldest sample from the third shelf being removed. After four thermal separations in a single electric furnace fabricated using the same method, the sublimation loss of MoO3 in each shelf was 5%, 3%, and 2% from the top shelf, with the sublimation rate varying by position, and the upper shelves having better Tc-99m separation efficiency. This system positions the highly radioactive samples after irradiation in the area with the highest separation efficiency.

[0013] Table 1 shows an example of the amount of Tc-99m recovered using a manufacturing pattern of one day of irradiation and one day of once-daily irradiation, and Table 2 shows an example of the amount of Tc-99m recovered using a manufacturing pattern of two days of irradiation and one day of once-daily irradiation.

[0014] [Table 1]

[0015] [Table 2]

[0016] 2.Recycling of MoO3 needle-like crystals Irradiated sample When heated and melted at around 830 degrees, it can be separated by four thermal processes. The irradiated sampleApproximately 2-5% of the sample vaporizes, aggregates, and crystallizes on the outside of the sample shelf. As the amount of crystals increases, the amount of Mo-99 in the original sample decreases. After that The separation yield of Tc-99m decreases. To eliminate this sample loss, the MoO3 that has been crystallized once is recrystallized. Original irradiated The device is designed to return the sample to the top, the above By heating at this temperature, it is also possible to separate and recover the Tc-99m formed in the crystals.

[0017] 3. Reuse of MoO3 samples After 9 days of thermal separation, the MoO3 sample containing the attenuated Mo-99 can be melted and solidified in the same type of tubular electric furnace as mentioned above and then irradiated again in the accelerator.

[0018] The present invention was made based on the above research results. , complex Several sublimation devices with irradiated samples placed on several shelves are inserted into several electric furnaces and heated. This is a method for thermally separating the daughter nuclide technetium-99m from the parent nuclide molybdenum-99 by sublimation. New irradiated sample Rise Hana equipment One of The sample is placed on the top or bottom shelf of the After heating, the next irradiated sample is placed on the same top or bottom sample shelf of one of the remaining sublimation apparatuses, and the sample is placed on the support rack of the sublimation apparatus. Rotate by a specified angle and heat , After heating all the irradiated samples placed on the top or bottom sample shelf while rotating the support stand once, The sample shelf is moved downward or upward by one stage, After heating all the irradiated samples placed in the thermal separation device, The above-mentioned problems are solved by a sublimation type thermal separation method for technetium, characterized in that the oldest irradiated sample is removed from the lowest or highest sample shelf of the sublimation device.

[0019] The present invention also provides a sublimation-type thermal separation apparatus for technetium, which uses sublimation to thermally separate a daughter nuclide, technetium-99m, from a parent nuclide, molybdenum-99, the apparatus comprising: a plurality of sublimation apparatuses each having a plurality of sample shelves on which irradiated samples are placed; a plurality of electric furnaces into which the plurality of sublimation apparatuses are inserted; Place Rotate by a fixed angle Support stand and ,before A means for moving the sample shelf downward or upward by one stage. ,one and means for removing the oldest irradiated sample from the lowest or highest sample shelf of the sublimation apparatus. The sublimation device is rotated by the support stand at predetermined angles, and all the irradiated samples arranged on the sample shelves are heated in sequence.The above-mentioned problems are also solved by a sublimation type thermal separation device for technetium characterized by the above. [Effects of the Invention]

[0020] According to the present invention, Parent nuclide From Molybdenum Mo-99 daughter nuclides Technetium Tc-99m can be routinely produced, and expensive isotopically enriched molybdenum samples (Mo-100 and Mo-98) can be produced. After sublimation separation of Tc-99m, It can be easily recovered at a regular interval with high efficiency and can be reused. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is an external view of a sublimation thermal separation device according to the present invention, which comprises, for example, three electric furnaces. [Figure 2] Similarly, a system diagram of the Tc-99m purified solution recovery device (hereafter referred to as the Tc-99m recovery device) that was separated by sublimation heat from the irradiated MoO 3 sample. [Figure 3] A front view, including a partial cross section, showing the overall image of the sublimation thermal separation device and Tc-99m recovery device installed in the cell. [Figure 4] A side view, including a partial cross section, showing the overall image of the sublimation thermal separation device and Tc-99m recovery device installed in the cell. [Figure 5] 1 is a front view, including a partial cross-sectional view, showing the configuration of an embodiment of a sublimation-type thermal separation device according to the present invention; [Figure 6] FIG. 10 is a side view including a partial cross-sectional view showing the configuration of an embodiment of the sublimation type thermal separation device. [Figure 7] FIG. 10 is a plan view showing the configuration of an embodiment of the sublimation type thermal separation device. [Figure 8] Cross-sectional view taken along line VIII-VIII in Figure 5. [Figure 9] Cross-sectional view along line IX-IX in Figure 5 [Figure 10] A cross-sectional view taken along line XX in Figure 5. [Figure 11] (A) Enlarged view of the sublimation device, and (B) BB cross section. [Figure 12] Flowchart showing an embodiment starting from the preparation of MoO 3 samples for neutron irradiation to the final recovery of the Tc-99m melt. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the contents described in the following embodiments. Furthermore, the components in the embodiments described below include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the embodiments described below may be appropriately combined or appropriately selected for use.

[0023] The concept of a triple-unit Tc-99m sublimation thermal separation device according to an embodiment of the present invention is shown in FIG.

[0024] The basic flow of the manufacturing process using this embodiment is a system in which, for example, three electric furnaces 100 (100A, 100B, 100C) with water-cooled jackets 106 and three stages of sample shelves 14 made of, for example, platinum, which are part of the sublimation apparatus 8 shown in detail in Figure 11 below, are connected in parallel, and Tc-99m is independently recovered from each of the electric furnaces 100A, 100B, 100C.

[0025] The basic operations are as follows:

[0026] I. Oxygen O2 gas is supplied by the inlet oxygen gas flow controller 210 at a rate greater than the total flow rate of the three outlet oxygen gas flow controllers 280A, 280B, and 280C, and the excess oxygen gas is bubbled through the water trap 250 before being released from the outlet, preventing the system from becoming pressurized. The water trap 250 moistens the oxygen gas, making it easier for Tc-99m to sublime from the molten MoO3.

[0027] II. The vacuum trap 300 shown in FIG. 1 is operated under a constant reduced pressure by a vacuum pump 340, and oxygen gas is supplied at a constant flow rate (for example, 100 to 200 ml / min) by oxygen gas flow rate controllers 280A, 280B, and 280C independently installed in the electric furnaces 100A, 100B, and 100C. 、M The flow rate and recovery rate are determined by checking the shape of the MoO3 insertion guide tube 38. In addition, the differential pressure within the system is measured using differential pressure gauges 270A, 270B, and 270C, and the clogging condition of the lower MoO3 upper recovery container 18 (see Figure 11), for example made of quartz, is checked to determine the replacement timing of the upper and lower MoO3 upper recovery containers 18.

[0028] In FIG. 1, 220 is a reservoir tank for oxygen (O2) gas, 260A, 260B, and 260C are silica gel tubes disposed on the outlet side of each electric furnace 100A, 100B, and 100C, respectively, 300 is a vacuum trap, 310 is a vacuum gauge, and 222, 224, 282A, 282B, 282C, 302, and 304 are solenoid valves.

[0029] FIG. 2 shows a system diagram of the Tc-99m recovery device (hereinafter simply referred to as the recovery device) 500.

[0030] This recovery device 500 connects three Tc-99m recovery tubes 26 (see Figure 11), made of, for example, quartz, installed in three electric furnaces 100A, 100B, and 100C, within a holder guide 510, and dissolves the Tc-99m captured (>99%) on a gold wire 28 (see Figure 11) within the Tc-99m recovery tube 26 in, for example, a 0.1 M NaOH aqueous solution supplied from a sodium hydroxide (NaOH) aqueous solution container 550 via two stages of traps 560 and 570.

[0031] After treating the 0.1 M NaOH aqueous solution with a cation exchange resin 520, Tc-99m is adsorbed onto an alumina column 540, washed with ultrapure water, and then recovered in a product bottle 670, such as a vial, via a trap 650 and a filter 660 using physiological saline, such as a 0.7% NaCl aqueous solution, supplied from a sodium chloride (NaCl) aqueous solution container 580.

[0032] In the figure, 700 is a vacuum pump, 710 is a reservoir tank, 720 is a vacuum gauge, and 512, 522, 542, 552, 562, 564, 572, 574, 582, 652, 654, 672, 702, 712, 714, 716, 718, and 722 are solenoid valves.

[0033] 3 and 4 show an image of an example of installation of a thermal separation purification device (hereinafter also simply referred to as a thermal separation device) 90 in a cell 900.

[0034] The thermal isolation device 90 is installed in a cell 900 made of, for example, iron, which has sufficient shielding capacity. Irradiated sample 10 and Tc-99m recovery tube 26 (see Figure 11) are handled as follows: As shown in Figure 3 This is done by remote operation from outside the cell 900 using a manipulator 910. The recovery of Tc-99m by the Tc-99m recovery device 500 shown in Figure 2 is also done by remote operation from outside the cell 900, except for the connection of the Tc-99m recovery pipe 26. In Figures 3 and 4, 108 is the electric furnace top plate, and 920 is a lift for lifting it.

[0035] 5 to 10 show the details of the thermal separation device 90, and FIG. 11 shows the details of the sublimation device 8.

[0036] The basic performance and operation of the thermal separation device 90 are as follows.

[0037] (1) Electric furnaces 100A, 100B, and 100C are Kanthal furnaces each equipped with a water-cooled jacket 106. For example, the Kanthal heating element 102 is divided into three zones for the purpose of uniformly heating three levels of crucibles 12, each made of, for example, platinum. The electric furnace temperature is controlled for each zone, with the top two zones operating at a temperature distribution of 830–840°C, normally higher than the melting point of MoO3, 795°C. The bottom zone is operated at 600–650°C, with the temperature set to approximately 700°C for the upper MoO3 collection container 18, approximately 550°C for the joint connecting the Tc-99m collection pipe 26 and the lower MoO3 collection container guide 24, made of, for example, quartz, and the gold wire 28 at or below 300°C. In the figure, reference numeral 104 denotes a heat insulator.

[0038] (2) Electric furnaces 100A, 100B, and 100C are heated to 120°C as shown in FIG. Equal intervals of The sample shelf guide 16 made of platinum is installed. (See Figure 11) Located higher, As shown in Figure 5 The electric furnace 100 is driven up and down by an electric furnace vertical drive motor 110 via an electric furnace vertical drive chain 112, an electric furnace vertical drive bearing 114, and an electric furnace vertical drive shaft 116, and then moves up and down to a MoO3 support frame turntable 118. (See Figure 11) The structure is such that airtightness can be maintained by an O-ring.

[0039] (3) The MoO3 support stand turntable 118 is mounted on a MoO3 support stand rotation circular (LM) guide 120 and is configured to rotate clockwise in 60-degree increments by a MoO3 support stand rotation motor 124 only when the electric furnaces 100A, 100B, and 100C are in their uppermost positions and when the Tc-99m recovery pipe upper support stand 132 is in its lowest position. These and the electric furnace 100 are mounted on a thermal separation (refining) device stand 122.

[0040] (4) The crucible 12 containing the MoO3 target 10 and the upper MoO3 recovery container 18 (see FIG. 11) are replaced and exchanged when the target support turntable 118 is at point X in FIG. 8. As shown in Figure 3 The manipulator 910 is used in the following order (see FIG. 11). a. Remove the sample shelf guide 16. b. Remove the upper MoO3 collection container 18 and the MoO3 upper collection container guide 20 from the sample shelf guide 16. c. Remove the sample shelf 14. d. Remove the crucible 12 from the third row from the top, move the second row to the bottom row, move the first row to the second row, and place a new one in the first row. Irradiated sample Place crucible 12 containing 10. e. The upper and lower MoO3 collection vessels 18 on the MoO3 support stand 34 are swapped. f. Place the sample shelf 14, the MoO3 upper collection container 18, and the MoO3 upper collection container guide 20 on the sample shelf guide 16. g. Place the sample shelf guide 16 on the MoO3 support stand 34.

[0041] (5) The Tc-99m recovery pipe upper support frame 132 shown in Figure 5 is configured to be able to insert the Tc-99m recovery pipe 26 into the electric furnace 100 by moving upward as shown in the side view of Figure 6 from its fixed position (directly below the electric furnace) via the Tc-99m recovery pipe support frame vertical drive motor 136, the Tc-99m recovery pipe support frame vertical drive shaft 128, the Tc-99m recovery pipe support frame vertical drive bearing 130, and the Tc-99m recovery pipe support frame vertical drive chain 134. Airtightness during insertion is ensured by an O-ring on the Tc-99m recovery pipe frame 36 (see Figure 11).

[0042] (6) When inserted, the MoO3 lower recovery container guide 24, the Tc-99m recovery pipe 26, and the Tc-99m recovery pipe connecting pipe 30 are connected, for example, by a transparent ball joint, and the airtightness of the flow path is maintained by the balance between the weight of the crucible 12 etc. from above and the spring 32 from below.

[0043] (7) The oxygen gas containing water vapor flows through the oxygen gas inlet 40 on the side of the Tc-99m recovery tube stand 36, rises primarily through the slit 36a in Figure 11(B), cools the gold wire 28, and exits the MoO3 insertion guide tube 38 through a hole 34a, e.g., 10 mm in diameter, on the side of the MoO3 support stand 34, and rises between the MoO3 support stand 34 and the MoO3 support stand 34. The oxygen gas containing water vapor, heated during this process, enters through a hole 18a on the top of the upper MoO3 recovery container 18, and carries the Tc-99m released from the MoO3 in the crucible 12 to the gold wire 28 for recovery. The sublimated MoO3 is then recovered in the lower MoO3 recovery container 18. The gas that passes through the lower MoO3 recovery container 18 is recovered in the lower MoO3 recovery container 22.

[0044] (8) The Tc-99m recovery tube upper support stand 132 shown in Figure 5 is designed to descend after the manufactured Tc-99m has been recovered into the Tc-99m recovery tube 26, and to be able to move to the right on the Tc-99m recovery tube support stand slide rail 138 by the Tc-99m recovery tube support stand left and right drive shaft 144 (see Figure 10) so that the Tc-99m recovery tube 26 can be removed from the lowest level.

[0045] (9) The Tc-99m recovery tube 26 removed from the electric furnaces 100A, 100B, and 100C is removed by the manipulator 910 shown in Figures 3 and 4, installed in the holder guide 510 shown in Figure 2, and then recovered by the Tc-99m recovery device 500 illustrated in Figure 2.

[0046] (10) When using this thermal separation device 90, the amount of Tc-99m recovered is, as shown in Tables 1 and 2, 1.92 times the amount of radioactivity produced in one day when used once a day, and 2.64 times the amount when used twice a day.

[0047] (11) The amount of MoO3 irradiated per day is in the range of 100 to 150 g, and the crucible 12 to contain it can be a container with a diameter of 70 to 80 mmφ, a height of 20 mm, and a thickness of 1 to 1.5 mmt.

[0048] (12) This thermal separation device 90 is used in a nuclear reactor. 98 Mo(n,γ) 99 Using the Mo reaction Manufactured Ta Neutron irradiated MoO3 sample Using Tc-99m It can also be used in manufacturing. 98 MoO 3 sample The processing amount is approximately 1 kg. In this case, there is no need to rotate the sublimation device or move the crucible.

[0049] (13) The thermal separation device 90 is an electron beam accelerator. 100 Mo(γ,n) 99 Using the Mo reaction Manufactured Ta Gamma irradiated MoO3 sample Using Tc-99m It can also be used in manufacturing.

[0050] In FIG. 6, 150 and 152 are radiation detectors using, for example, cadmium zinc telluride CZT.

[0051] The procedure for producing Tc-99m according to the embodiment is shown in FIG.

[0052] First, in step 1010, the MoO3 target 10 is produced. Specifically, 100 to 150 g of MoO3 is heated and melted at 840°C for 15 minutes, and then rapidly cooled to produce a tablet.

[0053] Next, in step 1020, Placed in the irradiation container MoO3 target with neutrons Specifically, carbon is irradiated with deuterons at 40 MeV and 2 mA. Generated , accelerator neutron of Irradiate (1 day).

[0054] Next, in step 1030, Neutron irradiated MoO3 target outside the neutron irradiation chamber Transfer After that, the target is removed, and then , dismantle the irradiation container.

[0055] Next, in step 1040, a new crucible 12 (e.g., 70-80φ×20h× 1~1.5 mmt) Neutron irradiated MoO3 target Insert.

[0056] Next, in step 1050, the crucible 12 is placed on the sample shelf 14. Specifically, the crucible 12 on the bottom row of the sample shelf 14 is removed, the crucibles 12 on the first and second rows are moved down one row at a time, and a new crucible 12 is placed on the top row.

[0057] Next, in step 1060, the positions of the upper and lower MoO3 upper collection vessels 18 are exchanged. do.

[0058] Next, in step 1070, the sample shelf 14 is gently inserted into the sample shelf guide 16 using a hook or the like.

[0059] Next, in step 1080, the manipulator 910 is used to place the MoO3 upper collection container guide 20 on the sample shelf guide 16.

[0060] Then, in step 1090, the manipulator 910 is used to place the sample shelf guide 16 on the MoO3 support stage 34.

[0061] Next, in step 1100, the MoO3 support stand turntable 118 is rotated clockwise by 60 degrees to move the position of the sample shelf guide 16 from point X shown in Fig. 8, which is determined in consideration of operability with the manipulator 910, to point a, which is directly below the electric furnace 100A in the foreground, as shown in Fig. 8. In Fig. 8, point b is the position directly below the electric furnace 100B, and point c is the position directly below the electric furnace 100C.

[0062] Next, in step 1110 , the electric furnace 100 is lowered, and the Tc-99m recovery pipe stand 36 is raised and inserted into the electric furnace 100 .

[0063] Next, in step 1120, moist oxygen gas is supplied at, for example, 100 to 200 ml / min.

[0064] Next, in step 1130, the electric furnace 100 is heated and the upper, middle and lower crucibles 12 are maintained at 830 to 840° C. for about 30 minutes.

[0065] After about 30 minutes, in step 1140, the electric furnace 100 is cooled to below 600° C. and the Tc-99m recovery pipe rack 36 is lowered.

[0066] Next, in step 1150, the supply of oxygen gas is stopped.

[0067] Next, in step 1160, the Tc-99m recovery tube lower support stand 142 is slid to the right in FIG.

[0068] Next, in step 1170, three of the Tc-99m recovery tubes 26 are removed and placed in the holder guide 510 of the Tc-99m recovery device 500 shown in FIG.

[0069] Next, in step 1180, three new Tc-99m recovery tubes 26 are installed in the Tc-99m recovery tube stand 36, and the Tc-99m recovery tube stand 36 is moved to its fixed position.

[0070] Next, in step 1190, the electric furnace 100 is raised.

[0071] Next, in step 1200, the MoO3 support stand turntable 118 is rotated clockwise by 60 degrees to move the position of the sample shelf guide 16 from point c directly below the electric furnace 100C shown in FIG. 8 to point X.

[0072] Next, in step 1210, the manipulator 910 is used to remove the MoO3 upper collection container guide 20 from the sample shelf guide 16.

[0073] Then, in step 1220, the manipulator 910 is used to remove the sample shelf guide 16 from the MoO3 support pedestal 34.

[0074] Then, in step 1230, steps 1040 through 1220 are repeated in accordance with the present invention.

[0075] Next, in step 1240, the Tc-99m recovery tube 26 is filled with, for example, a 0.1 molar aqueous solution of sodium hydroxide and left for about 5 minutes to dissolve the recovered Tc-99m.

[0076] Then, in step 1250, the sodium hydroxide is removed by passing it through a cation exchange resin (eg, Thermo Scientific Onguard II H) 520 shown in FIG.

[0077] Then, in step 1260, steps 1230 and 1240 are repeated.

[0078] Next, in step 1270, the Tc-99m is adsorbed onto an alumina column (eg, Sep Pak alumina A manufactured by Waters) 540.

[0079] Next, in step 1280, the alumina column 540 is washed with ultrapure water.

[0080] Then, in step 1290, the Tc-99m is eluted using saline supplied from the aqueous NaCl container 580.

[0081] Then, in step 1300, the product is collected in product bottle 670.

[0082] Then, in step 1310, the concentration of Tc-99m is measured to assay for radioactivity.

[0083] After step 1310 is completed, the ordered amount is shipped, for example.

[0084] In this embodiment, the sample is moved from the upper stage to the lower stage, so Tc-99m can be produced efficiently. However, the opposite direction may also be possible in some cases.

[0085] In the embodiment, three electric furnaces are used, and three sample shelves are used. Irradiated MoO 3. Sample container (Crucible in the embodiment)However, the number of electric furnaces, the number of sample shelves, and the number of sample containers are not limited to three. For example, the number of electric furnaces may be two or four or more, the number of sample shelves may be two or four or more, or Irradiated MoO 3 The number of sample containers can be two or four or more.

[0086] Furthermore, the materials for the crucible, sample shelf, sample shelf guide, etc. are not limited to platinum, and the materials for the sample shelf guide, recovery container, recovery container guide, recovery pipe, recovery pipe connecting pipe, insertion guide pipe, etc. are not limited to quartz.

[0087] The electric furnace is not limited to a Kanthal furnace using a Kanthal heating element. [Explanation of symbols]

[0088] 8…Sublimation device 10… Irradiated MoO3 sample 12… Irradiated MoO 3 For samples crucible 14...Sample shelf 16… For fixing crucibles Sample shelf guide 18, 22...MoO3 collection container 20, 24...MoO3 collection container for guide 26...Tc-99m recovery tube 28…Gold wire 30...Tc-99m recovery pipe connection pipe 34...MoO3 support stand 36...Tc-99m recovery pipe stand 38...MoO3 insertion guide tube 90…Thermal separation (purification) equipment 100, 100A, 100B, 100C...electric furnace 106...Water-cooled jacket 110...electric furnace up / down drive motor 118...MoO3 support stand turntable 122...Thermal separation (refining) equipment stand 124...MoO3 support stand rotation motor 126...Tc-99m recovery pipe support base top plate 132, 142...Tc-99m recovery pipe support frame 136...Tc-99m recovery pipe support stand vertical drive motor 138...Tc-99m recovery pipe support frame slide rail 140...Tc-99m recovery pipe support stand slide motor 500...Tc-99m (purified solution) recovery device 510...Holder guide 520...Cation exchange resin 540...Alumina column 670...Product bottle (vial bottle) 900…cell 910...Manipulator

Claims

1. A method for thermally separating a daughter nuclide, technetium-99m, from a parent nuclide, molybdenum-99, by sublimation, by inserting a plurality of sublimation devices, each having irradiated samples arranged on a plurality of sample shelves, into a plurality of electric furnaces and heating the sublimation devices, placing a new irradiated sample on one of the top or bottom sample shelves of the sublimation apparatus and heating it; After the heating is completed, the next irradiated sample is placed on the same top or bottom sample shelf of one of the remaining sublimation apparatuses, and the support stand of the sublimation apparatus is rotated by a predetermined angle and heated; While rotating the support stand once, all the irradiated samples arranged on the top or bottom sample shelf are heated, and then the sample shelf is moved downward or upward by one stage; A method for sublimation-type thermal separation of technetium, characterized in that after heating of all irradiated samples placed in a thermal separation apparatus has been completed, the oldest irradiated sample is removed from the lowest or highest sample shelf of said sublimation apparatus.

2. A sublimation type thermal separation apparatus for technetium for thermally separating daughter nuclide technetium-99m from parent nuclide molybdenum-99 by sublimation, comprising: a plurality of sublimation devices each having a plurality of sample shelves on which irradiated samples are placed; a plurality of electric furnaces into which the plurality of sublimation devices are respectively inserted; a support stand that rotates the sublimation device by a predetermined angle; a means for moving the sample shelf downward or upward by one stage; means for removing the oldest irradiated sample from the bottom or top sample shelf of said sublimation apparatus; and a sublimation type thermal separation device for technetium, characterized in that the sublimation device is rotated by the support stand at predetermined angles to sequentially heat all of the irradiated samples sequentially arranged on a plurality of sample shelves.

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