Medical strontium applicator source core and preparation method thereof

Abstract

The invention discloses a medical strontium applicator source core and a preparation method thereof. The medical strontium applicator source core comprises a Pd layer, an Ag window, an Ag bottom and an active layer, compared with a traditional silver powder doped strontium carbonate precipitation method, the method for preparing the silver / strontium carbonate powder through the strontium-silver coprecipitation and calcination transformation method has the advantages that the < 90 > Sr recovery rate and the powder uniformity can be remarkably improved; rolling is carried out after sintering, the compression molding difficulty of the source chip is remarkably reduced, the compressed source chip is good in ductility and can be well coated with an active layer, and radioactive contamination in the rolling process is remarkably reduced.

Description

Technical Field

[0001] This invention relates to the field of radioactive source preparation technology, specifically to a strontium source core for a medical plaster and its preparation method. Background Technology

[0002] Strontium-yttrium applicators utilize 90 Sr and 90 A medical device that uses beta rays emitted by gamma rays to treat superficial lesions of the human skin. It achieves a therapeutic effect by controlling the lesions through ionizing radiation. Because beta rays have low energy, their maximum penetration distance in tissues is only 11 mm, and they have minimal impact on normal cells. They are commonly used to treat superficial skin diseases such as keloids, pediatric capillary tumors, chronic eczema, neurodermatitis, and psoriasis.

[0003] Currently, due to domestic 90 Sr raw materials are relatively scarce. Although there is some research on the development of radioactive dressings in China, there are basically no commercialized products, and the dressings used in the domestic market are mainly imported. In recent years, with the development of high-level radioactive waste liquid separation and transmutation technology, it has become possible to extract Sr from high-level radioactive waste liquid. 90 Sr product liquid technology. However, research on the preparation of the radioactive source core for strontium-yttrium patch is not mature and cannot be realized. 90 Effective conversion of Sr product liquid into the radiation source core of the applicator. Summary of the Invention

[0004] The purpose of this invention is to provide a source core for a medical strontium plaster and its preparation method, so as to meet the needs of medical plaster use.

[0005] The technical solution of the present invention is as follows: a medical strontium plaster source core, comprising a Pd layer, an Ag window, an Ag base, and an active layer; wherein the Pd layer is located on the outer layer and wraps the entire source core, while the active layer is located in the middle of the source core, with the Ag window at the top and the Ag base at the bottom.

[0006] A method for preparing a source core for a medical strontium plaster includes the following steps:

[0007] Step 1, Strontium-silver coprecipitation: Mix equal volumes of silver nitrate and strontium nitrate solutions, then... 90 The Sr(NO3)2 product solution was mixed evenly, then oxalic acid solution was added, and ammonia water was added dropwise to adjust the pH to 4-6, resulting in the co-precipitation of silver oxalate and strontium oxalate, which was then dried.

[0008] Step 2, calcination transformation: The co-precipitate is calcined to obtain Ag / SrCO3 powder;

[0009] Step 3, tableting: The calcined and transformed powder is loaded into a mold and pressed into an active layer in a hydraulic press; then silver powder is used for pressing to obtain the source chip;

[0010] Step four, sintering: sintering the source chip at high temperature;

[0011] Step five, rolling: rolling the sintered source chip to a specified thickness in a roller press;

[0012] Step six, electroplating: cutting and electroplating the rolled source chip with a palladium layer to obtain a radioactive source core.

[0013] In the step one, the concentration of silver nitrate in the mixed solution of silver nitrate and strontium nitrate is 5 mol / L, and the concentration of strontium nitrate is 0.2 mol / L; the solubility of the oxalic acid solution is 0.8-1.0 mol / L; the addition amount of oxalic acid is 1.2-1.4 times of the amount required for silver-strontium precipitation; the drying temperature is 90°C, and the drying time is 12-24 h.

[0014] In the step one, the silver oxalate and strontium oxalate co-precipitate obtained after aging is filtered and dried in an oven.

[0015] In the step two, the calcination includes two stages: the first stage is at 150-160°C for 24-48 h, and the second stage is at 260-300°C for 12-24 h.

[0016] In the step three, the pressing of the active layer is in stages, the first stage has a pressing force of 2 t and a pressing time of 100 s, and the second stage has a pressing force of 10 t and a pressing time of 600 s.

[0017] In the step three, the silver powder pressing includes the following steps:

[0018] S1: loading the silver powder into a mold and pressing it by a pressing rod, the pressing is in stages, the first stage has a pressing force of 2 t and a pressing time of 100 s, and the second stage has a pressing force of 10 t and a pressing time of 600 s, to obtain a silver base with grooves;

[0019] S2: placing the prepared active layer sheet in the grooves of the silver base;

[0020] S3: covering the silver base and the active layer sheet with silver powder and pressing it by a pressing rod, the pressing is in stages, the first stage has a pressing force of 2 t and a pressing time of 100 s, and the second stage has a pressing force of 30 t and a pressing time of 600 s, to obtain a source chip.

[0021] In the step four, the sintering temperature is 800-850°C, and the time is 1-3 h.

[0022] In the step five, the feeding amount of the roller gap is 0.05-0.1 mm each time, and the annealing time is 10 min at 600-800°C before each rolling.

[0023] A pressing mold comprises a top cover, a pressing rod, a cavity wall, a base, the cavity wall is located on the base, the cavity wall forms a cavity inside, and the pressing rod is located in the cavity, and the top cover is installed on the top of the pressing rod.

[0024] The significant effect of the present application is that:

[0025] The strontium-yttrium applicator used for the domestic market basically depends on import, and there is no domestic strontium-yttrium applicator product, so a method for preparing a medical Sr applicator source core by using a powder metallurgy method is provided 90 The method fills the domestic blank by preparing a radioactive source core for a medical applicator through strontium-silver co-precipitation, calcination transformation, tabletting, sintering, rolling and electroplating steps;

[0026] Compared with the traditional strontium carbonate precipitation method of doping silver powder, the method of strontium-silver co-precipitation and calcination transformation for preparing silver / strontium carbonate powder can significantly improve 90 Sr recovery rate and powder uniformity;

[0027] The present application adopts a three-in-one pressing method to tablet, and then performs rolling after sintering, thereby significantly reducing the difficulty of forming the source core tablet, the ductility of the pressed source core tablet is good, the active layer can be well coated, and radioactive contamination in the rolling process is significantly reduced.

[0028] The prepared radioactive source core has a surface air absorption dose rate of 85 Gy / h, an irradiation uniformity of more than 97%, excellent sealing performance, lightness, convenience and high safety, and has reached the international advanced level;

[0029] The raw material of the present application is extracted from high-level liquid waste 90 Sr, realizing waste recycling, reducing waste treatment and disposal pressure, and being beneficial to sustainable development. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 : Schematic diagram of a pressing mold

[0031] Figure 2 : Schematic diagram of the structure of the prepared radioactive source core

[0032] In the figure: Pd layer 1, Ag window 2, Ag bottom 3, active layer 4, top cover 5, pressing rod 6, cavity wall 7, base 8. DETAILED DESCRIPTION

[0033] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a variety of ways beyond those described herein without departing from the scope of the present application, and it will be apparent to those skilled in the art that the present application can be practiced with or without these specific details.

[0034] The terminology used in one or more embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of one or more embodiments of this application. The singular forms “a,” “the,” and “the” used in one or more embodiments of this application and in the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” used in one or more embodiments of this application refers to and includes any or all possible combinations of one or more associated listed items.

[0035] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this application, and similarly, second may also be referred to as first.

[0036] The specific technical content of the present invention will now be described with reference to the accompanying drawings;

[0037] A method for preparing a source core for a medical strontium plaster includes the following steps:

[0038] Step 1, Strontium-silver coprecipitation: Mix equal volumes of silver nitrate and strontium nitrate solutions, then... 90 The Sr(NO3)2 product solution was mixed evenly, then oxalic acid solution was added, and ammonia water was added dropwise to adjust the pH to 4-6. After aging, the mixture was filtered to obtain silver oxalate and strontium oxalate coprecipitates, which were then dried in an oven.

[0039] Preferably, in the mixed solution of silver nitrate and strontium nitrate in step one, the concentration of silver nitrate is 5 mol / L and the concentration of strontium nitrate is 0.2 mol / L; the solubility of oxalic acid solution is 0.8–1.0 mol / L; the amount of oxalic acid added is 1.2–1.4 times that required for silver-strontium precipitation; the pH range is 4–6; the drying temperature is 90℃; and the drying time is 12–24 h.

[0040] Step 2, calcination transformation: The coprecipitate is calcined at a certain temperature to transform it into a stable compound, yielding Ag / SrCO3 powder.

[0041] Preferably, the calcination process in step two is segmented, with the first segment being calcination at 150℃~160℃ for 24h~48h, and the second segment being calcination at 260℃~300℃ for 12h~24h.

[0042] Step 3, tableting: The calcined and transformed powder is loaded into a mold and pressed into an active layer in a hydraulic press; silver powder is used for three-in-one pressing to obtain a "sandwich" structure source chip with silver base-active layer-silver window.

[0043] Preferably, the pressing of the active layer is segmented, with the first segment pressing pressure being 2t and the pressing time being 100s, and the second segment pressing pressure being 10t and the pressing time being 600s.

[0044] The preferred three-in-one pressing steps are as follows:

[0045] S1. Silver powder is loaded into a mold, and a pressure bar with a boss is inserted for pressing. The pressing is done in stages. The first stage pressing pressure is 2t and the pressing time is 100s. The second stage pressing pressure is 10t and the pressing time is 600s, resulting in a grooved silver bottom that does not require demolding.

[0046] S2. Place the prepared active sheet in the groove of the silver base described above;

[0047] S3 covers the silver base and active layer with silver powder, and then inserts a flat-bottomed pressure bar for pressing. The pressing is done in segments. The first segment has a pressing pressure of 2t and a pressing time of 100s, and the second segment has a pressing pressure of 30t and a pressing time of 600s, to obtain a three-in-one source chip.

[0048] Step 4, Sintering: The source chip is sintered at a high temperature;

[0049] Preferably, the sintering temperature in step four is 800–850°C, and the time is 1–3 hours.

[0050] Step 5, Rolling: The sintered source core is gradually rolled to the specified thickness in a roller press;

[0051] Preferably, in step five, the feed amount of the roll gap during each rolling is 0.05 to 0.1 mm, and annealing at 600 to 800°C for 10 minutes is required before each rolling.

[0052] Step 6, electroplating: After cutting the rolled source chip, a palladium layer is electroplated to obtain the radiation source core.

[0053] like Figure 2 As shown, the medical strontium patch source core manufactured by the present invention includes a Pd layer 1, an Ag window 2, an Ag base 3, and an active layer 4; wherein the Pd layer 1 is located on the outer layer and wraps the entire source core, while the active layer 4 is located in the middle of the source core, with the Ag window 2 at the top and the Ag base 3 at the bottom.

[0054] like Figure 1 As shown, the pressing mold involved in the medical strontium patch source core manufactured by the present invention includes a top cover 5, a pressing rod 6, a cavity wall 7, and a base 8. The cavity wall 7 is located on the base 8, and a cavity is formed inside the cavity wall 7. The pressing rod 6 is located in the cavity, and the top cover 5 is installed on the top of the pressing rod 6.

[0055] Example 1

[0056] This embodiment provides a method for preparing the radiation source core of an applicator, the specific steps of which are as follows:

[0057] Step 1, Strontium-Silver Co-precipitation: Mix 10 times the volume of 5 mol / L silver nitrate solution with 10 times the volume of strontium product solution until homogeneous. Add 14 times the volume of 0.8 mol / L oxalic acid solution, and slowly add ammonia water dropwise to adjust the pH to 4–6. After stirring thoroughly, age at room temperature for 30 minutes, then filter and wash the precipitate 2–3 times with deionized water. Transfer the precipitate to an oven and dry completely at 90°C.

[0058] Step 2, calcination transformation: The precipitate prepared in Step 1 is transferred to a ceramic boat, placed in a tube furnace, heated at a rate of 5℃ / min, and calcined at 155℃ for 48h, followed by calcination at 260℃ for 12h to obtain Ag / SrCO3 powder.

[0059] Step 3, tableting: Weigh 1g of Ag / SrCO3 powder prepared in step 2 and load it into a φ25mm pressing mold. Press the active layer in a hydraulic press. The first pressing pressure is 2t and the pressing time is 100s. The second pressing pressure is 10t and the pressing time is 600s. Use silver powder to perform three-in-one pressing in a φ30mm pressing mold to obtain the radioactive source chip.

[0060] Step 4, sintering: Transfer the radioactive source chip prepared in step 3 to a muffle furnace and sinter at 800℃ for 2 hours.

[0061] Step 5, Rolling: Measure the thickness of the source chip using a micrometer and set an appropriate roll gap. After annealing at 700℃ for 10 minutes, feed the source chip into a roller press and roll it back and forth five times. After completion, reduce the roll gap by 0.05–0.1 mm, anneal at 700℃ for 10 minutes, and continue rolling. Repeat this step, adjusting the rolling direction of the source chip during this process, so that the rolled source chip is approximately circular, until the source core thickness reaches 0.25 mm.

[0062] Step 6, Electroplating: The source chip rolled in Step 5 is die-cut into a 30mm×30mm square source chip using a die-cutting machine, and then a palladium layer is electroplated. The composition of the electroplating solution is: 10g / L ammonium palladium chloride (calculated as palladium), 150g / L ammonium chloride, pH 9.0, and the electroplating conditions are: constant current 0.1A and electroplating time 60min.

[0063] The three-in-one pressing steps in step three are as follows:

[0064] S1. 3g of silver powder is put into a φ30mm mold, and a pressure rod with a boss is inserted for pressing. The pressing is segmented. The first pressing pressure is 2t and the pressing time is 100s. The second pressing pressure is 10t and the pressing time is 600s, resulting in a grooved silver bottom. No demolding is required.

[0065] S2. Place the prepared active sheet in the groove of the silver base described above;

[0066] S3 covers the silver base and active layer with 1.5g of silver powder, and then loads it into a flat-bottomed press rod for processing. The pressing is done in segments. The first segment pressing pressure is 2t and the pressing time is 100s. The second segment pressing pressure is 300t and the pressing time is 600s, resulting in a three-in-one source chip.

[0067] Example 2

[0068] This embodiment provides a method for preparing the radiation source core of an applicator, the specific steps of which are as follows:

[0069] Step 1, Strontium-Silver Coprecipitation: Mix 10 times the volume of a 5 mol / L silver nitrate and 0.2 mol / L strontium nitrate solution with 10 times the volume of the strontium product solution. Add 12 times the volume of a 1 mol / L oxalic acid solution, and slowly add ammonia water dropwise to adjust the pH to 4–6. After stirring thoroughly, age at room temperature for 30 minutes, then filter. Wash the precipitate 2–3 times with deionized water. Transfer the precipitate to an oven and dry completely at 90°C.

[0070] Step 2, calcination transformation: The precipitate prepared in Step 1 is transferred to a ceramic boat, placed in a tube furnace, heated at a rate of 5℃ / min, and calcined at 160℃ for 48h, followed by calcination at 300℃ for 12h.

[0071] Step 3, tableting: Weigh 1g of Ag / SrCO3 powder prepared in step 2 and load it into a φ25mm pressing mold. Press the active layer in a hydraulic press. The first pressing pressure is 2t and the pressing time is 100s. The second pressing pressure is 10t and the pressing time is 600s. Use silver powder to perform three-in-one pressing in a φ30mm pressing mold to obtain the radioactive source chip.

[0072] Step 4, sintering: Transfer the radioactive source chip prepared in step 3 to a muffle furnace and sinter at 850°C for 1 hour.

[0073] Step 5, Rolling: Measure the thickness of the source chip using a micrometer and set the roll gap. After annealing at 800℃ for 10 minutes, feed the source chip into a roller press and roll it back and forth five times. After completion, reduce the roll gap by 0.05–0.1 mm, anneal at 800℃ for 10 minutes, and continue rolling. Repeat this step, adjusting the rolling direction of the source chip during this process, so that the rolled source chip is approximately circular, until the source core thickness reaches 0.30 mm.

[0074] Step 6, Electroplating: The source chip rolled in Step 5 is die-cut into a 30mm×30mm square source chip using a die-cutting machine, and then a palladium layer is electroplated. The composition of the electroplating solution is: 10g / L ammonium palladium chloride (calculated as palladium), 150g / L ammonium chloride, pH 9.0, and the electroplating conditions are: constant current 0.1A and electroplating time 60min.

[0075] The three-in-one pressing steps in step three are as follows:

[0076] S1. 4.5g of silver powder is put into a φ30mm mold, and a pressure rod with a boss is inserted for pressing. The pressing is segmented. The first pressing pressure is 2t and the pressing time is 100s. The second pressing pressure is 10t and the pressing time is 600s, resulting in a grooved silver bottom. No demolding is required.

[0077] S2. Place the prepared active sheet in the groove of the silver base described above;

[0078] S3 covers the silver base and active layer with 1.5g of silver powder, and then loads it into a flat-bottomed press rod for processing. The pressing is done in segments. The first segment pressing pressure is 2t and the pressing time is 100s. The second segment pressing pressure is 30t and the pressing time is 600s, resulting in a three-in-one source chip.

[0079] Example 3

[0080] This embodiment provides a method for preparing the radiation source core of an applicator, the specific steps of which are as follows:

[0081] Step 1, Strontium-Silver Coprecipitation: Mix 10 times the volume of a 5 mol / L silver nitrate and 0.2 mol / L strontium nitrate solution with 10 times the volume of the strontium product solution. Add 14 times the volume of a 1 mol / L oxalic acid solution, and slowly add ammonia water dropwise to adjust the pH to 6. After stirring thoroughly, age at room temperature for 30 minutes, then filter and wash the precipitate 2-3 times with deionized water. Transfer the precipitate to an oven and dry completely at 90°C.

[0082] Step 2, calcination transformation: The precipitate prepared in Step 1 is transferred to a ceramic boat, placed in a tube furnace, heated at a rate of 5℃ / min, and calcined at 150℃ for 48h, followed by calcination at 260℃ for 12h.

[0083] Step 3, tableting: Weigh 1g of Ag / SrCO3 powder prepared in step 2 and load it into a φ25mm pressing mold. Press the active layer in a hydraulic press. The first pressing pressure is 2t and the pressing time is 100s. The second pressing pressure is 10t and the pressing time is 600s. Use silver powder to perform three-in-one pressing in a φ30mm pressing mold to obtain the radioactive source chip.

[0084] Step 4, sintering: Transfer the radioactive source chip prepared in step 3 to a muffle furnace and sinter at 850°C for 3 hours.

[0085] Step 5, Rolling: Measure the thickness of the source chip using a micrometer and set the roll gap. After annealing at 800℃ for 10 minutes, feed the source chip into a roller press and roll it back and forth five times. After completion, reduce the roll gap by 0.05–0.1 mm, anneal at 850℃ for 10 minutes, and continue rolling. Repeat this step, adjusting the rolling direction of the source chip during this process, so that the rolled source chip is approximately circular, until the source core thickness reaches 0.30 mm.

[0086] Step 6, Electroplating: The source chip rolled in Step 5 is die-cut into a 30mm×30mm square source chip using a die-cutting machine, and then a palladium layer is electroplated. The composition of the electroplating solution is: 10g / L ammonium palladium chloride (calculated as palladium), 150g / L ammonium chloride, pH 9.0, and the electroplating conditions are: constant current 0.1A and electroplating time 60min.

[0087] The three-in-one pressing steps in step three are as follows:

[0088] S1. 4.5g of silver powder is put into a φ30mm mold, and a pressure rod with a boss is inserted for pressing. The pressing is segmented. The first pressing pressure is 2t and the pressing time is 100s. The second pressing pressure is 10t and the pressing time is 600s, resulting in a grooved silver bottom. No demolding is required.

[0089] S2. Place the prepared active sheet in the groove of the silver base described above;

[0090] S3 covers the silver base and active layer with 1.5g of silver powder, and then loads it into a flat-bottomed press rod for processing. The pressing is done in segments. The first segment pressing pressure is 2t and the pressing time is 100s. The second segment pressing pressure is 30t and the pressing time is 600s, resulting in a three-in-one source chip.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0092] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0093] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0094] The preferred embodiments disclosed above are merely illustrative of this application. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this application. These embodiments are selected and specifically described in this application to better explain the principles and practical applications of this application, thereby enabling those skilled in the art to better understand and utilize this application.

Claims

1. A source core for a medical strontium plaster, characterized in that: It includes a Pd layer (1), an Ag window (2), an Ag bottom (3), and an active layer (4); wherein the Pd layer (1) is located on the outer layer and wraps the entire source core, while the active layer (4) is located in the middle of the source core, with the Ag window (2) at the top and the Ag bottom (3) at the bottom.

2. A method for preparing a source core for a medical strontium plaster, characterized in that: Includes the following steps: Step 1, Strontium-silver coprecipitation: Mix equal volumes of silver nitrate and strontium nitrate solutions, then... 90 The Sr(NO3)2 product solution was mixed evenly, then oxalic acid solution was added, and ammonia water was added dropwise to adjust the pH to 4-6, resulting in the co-precipitation of silver oxalate and strontium oxalate, which was then dried. Step 2, calcination transformation: The co-precipitate is calcined to obtain Ag / SrCO3 powder; Step 3, tableting: The calcined and transformed powder is loaded into a mold and pressed into an active layer in a hydraulic press; then silver powder is used for pressing to obtain the source chip; Step 4, Sintering: Sinter the source chip at high temperature; Step 5, Rolling: Roll the sintered source core to the specified thickness in a roller press; Step 6, electroplating: After the rolled source chip is cut, a palladium layer is electroplated to obtain the radiation source core.

3. The method for preparing a source core for a medical strontium plaster according to claim 2, characterized in that: In step one, the concentration of silver nitrate in the mixed solution of silver nitrate and strontium nitrate is 5 mol / L and the concentration of strontium nitrate is 0.2 mol / L; the solubility of oxalic acid solution is 0.8–1.0 mol / L; the amount of oxalic acid added is 1.2–1.4 times that required for silver-strontium precipitation; the drying temperature is 90℃ and the drying time is 12–24 h.

4. The method for preparing a source core for a medical strontium plaster according to claim 2, characterized in that: In step one, after aging, the silver oxalate and strontium oxalate coprecipitate are obtained by filtration and then dried in an oven.

5. The method for preparing a medical strontium plaster source core according to claim 2, characterized in that: In step two, the calcination includes two stages: the first stage is calcination at 150℃~160℃ for 24~48h, and the second stage is calcination at 260℃~300℃ for 12~24h.

6. The method for preparing a source core for a medical strontium plaster according to claim 2, characterized in that: In step three, the pressing of the active layer is segmented. The first segment pressing pressure is 2t and the pressing time is 100s. The second segment pressing pressure is 10t and the pressing time is 600s.

7. The method for preparing a source core for a medical strontium plaster according to claim 6, characterized in that: Step three, silver powder pressing, includes the following steps: S1: The silver powder is loaded into the mold and pressed by the pressure bar. The pressing is done in segments. The first segment pressing pressure is 2t and the pressing time is 100s. The second segment pressing pressure is 10t and the pressing time is 600s, resulting in a grooved silver base. S2: Place the prepared active sheet into the groove of the silver base; S3: Cover the silver base and active layer with silver powder, and press it with a pressure bar. The pressing is done in segments. The first segment pressing pressure is 2t and the pressing time is 100s. The second segment pressing pressure is 30t and the pressing time is 600s to obtain the source chip.

8. The method for preparing a source core for a medical strontium plaster according to claim 2, characterized in that: In step four, the sintering temperature is 800–850℃ and the time is 1–3 hours.

9. The method for preparing a source core for a medical strontium plaster according to claim 2, characterized in that: In step five, the feed amount of the roll gap is 0.05 to 0.1 mm during each rolling, and the rolls are annealed at 600 to 800°C for 10 minutes before each rolling.

10. A pressing mold, characterized in that: It includes a top cover (5), a pressure rod (6), a cavity wall (7), and a base (8). The cavity wall (7) is located on the base (8), and a cavity is formed inside the cavity wall (7). The pressure rod (6) is located in the cavity, and the top cover (5) is installed on the top of the pressure rod (6).

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