Preparation method and application of palladium 103 brachytherapy source core
By acidifying and activating graphite particles, their adsorption performance is improved, solving the problems of self-shielding effect and process complexity in the preparation of palladium-103 brachytherapy source cores. This enables low-cost, high-efficiency industrial production and meets the dosage accuracy requirements for clinical treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SICHUAN FUQING YAOHUA BIOMEDICAL TECHNOLOGY CO LTD
- Filing Date
- 2026-02-03
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies for preparing palladium-103 brachytherapy source cores suffer from problems such as strong self-shielding effect, complex processes, high costs, and difficulty in large-scale production.
By using surface-modified graphite particles and improving their adsorption performance through acidification and/or activation treatment, a complex electroplating process can be replaced to achieve efficient and uniform loading of palladium-103, thus preparing a therapeutic source core that is easy to industrialize and has a lower cost.
It reduces raw material costs, simplifies the process, improves the adsorption rate and activity uniformity of radionuclides, enhances the effective output of therapeutic doses, and is suitable for a variety of clinical treatment needs.
Smart Images
Figure CN122005877A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of radiopharmaceutical and medical device technology, and particularly relates to a method for preparing a palladium-103 brachytherapy source core and its application. Background Technology
[0002] Palladium [Pd-103] brachytherapy source is a radiopharmaceutical used for brachytherapy of tumors. It is mainly used for low-dose-rate permanent implantation therapy, and is particularly suitable for rapidly proliferating tumor types such as prostate cancer, head and neck tumors, and eye tumors. This therapy source typically consists of a biocompatible titanium shell and an internally sealed radioactive source core, with the source core being the core component that enables radiotherapy.
[0003] Currently, the following two methods are mainly used to prepare palladium [Pd-103] brachytherapy source cores: One approach is based on a metal-supported source core, typically using silver wire as the carrier. The preparation method usually involves immersing the silver wire in an alkaline solution containing palladium salts, and adding reducing agents such as sodium thiosulfate and hydrazine, causing palladium ions to be reduced and deposited on the surface of the silver wire, forming a dense palladium metal layer. While this method is relatively simple to operate, it suffers from a significant self-shielding effect. Because the X-rays and gamma rays released by the decay of Pd-103 have low energies (approximately 20-23 keV), while silver has a high atomic number and density, high-energy photons undergo significant absorption and scattering when passing through the silver carrier, leading to a reduction in the effective output dose and thus affecting the therapeutic effect.
[0004] Secondly, there are source cores based on carbon material carriers, currently mainly using high-purity graphite particles prepared through electroplating. This method involves placing high-purity graphite particles as cathodes in an electrolyte containing palladium chloride [Pd-103] and ammonium chloride, and then electroplating palladium metal onto the surface of the graphite particles using conventional DC electroplating technology. While electroplating technology can obtain source cores with high apparent activity (0.5-300 mCi), it faces industrialization bottlenecks: First, the electroplating process is complex, requires sophisticated equipment, and involves handling radioactive electrolytes, easily generating radioactive contamination and posing significant safety risks; second, the electroplating process requires the graphite carrier to have good conductivity, thus demanding extremely high purity of the graphite raw materials, resulting in high raw material costs; third, to meet clinical needs, hundreds to thousands of tiny (0.1-1.0 mm) graphite particles need to be uniformly electroplated simultaneously as cathodes, making the process extremely difficult and challenging to guarantee batch consistency and product uniformity; finally, the resulting palladium metal layer is also quite dense, presenting a certain degree of self-shielding.
[0005] In summary, existing palladium [Pd-103] source core preparation technologies, whether using metal supports or electroplated graphite, suffer from drawbacks such as strong self-shielding effects, complex processes, high costs, and difficulties in large-scale stable production. Therefore, there is an urgent need to develop a novel source core preparation method that can reduce self-shielding effects, simplify the process, lower the stringent requirements for support materials, and adapt to the needs of large-scale industrial production, while ensuring efficient and uniform adsorption of radionuclides. Summary of the Invention
[0006] The purpose of this invention is to provide a method for preparing a palladium-103 brachytherapy source core and its application. By chemically modifying the graphite particles to improve their adsorption performance, a complex electroplating process can be replaced to achieve efficient and uniform loading of palladium-103, thereby obtaining a high-performance, easily industrialized and lower-cost therapy source core.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a palladium-103 brachytherapy source core, comprising surface-modified graphite particles and a radioactive nuclide palladium-103 loaded on the surface of the surface-modified graphite particles. The surface-modified graphite particles are obtained through acidification and / or activation treatment, and the graphite content is greater than 60%. Acidification treatment forms a large number of oxygen-containing functional groups (-COOH, -OH) on the surface of the graphite particles, accompanied by slight surface etching, ultimately achieving regulation of the surface chemical properties, adsorption selectivity, and reactivity of the activated carbon. Activation treatment forms a porous structure in the graphite particles, thereby significantly increasing the specific surface area and adsorption active sites.
[0008] Furthermore, the diameter of the surface-modified graphite particles is 0.1-1.0 mm and the length is 0.5-5.0 mm.
[0009] Secondly, the present invention provides a method for preparing a palladium-103 brachytherapy source core, comprising the following steps: Step 1: Prepare graphite particles; graphite, binder and water are mixed, extruded and dried to obtain the particles.
[0010] Step 2: Acidify and / or activate the graphite particles to obtain surface-modified graphite particles; The acidification treatment involves mixing graphite particles with concentrated nitric acid (1-14.5 mol / L) at a ratio of 10-100 mL of concentrated nitric acid per gram of graphite particles, and treating the mixture at 60-150°C for 2-24 hours, followed by washing and drying. This acidification treatment utilizes the strong oxidizing properties of nitric acid to selectively oxidize the surface of the graphite particles, introducing a large number of oxygen-containing functional groups -OH and -COOH, accompanied by slight surface etching. Ultimately, this process regulates the surface chemical properties, adsorption selectivity, and reactivity of the activated carbon.
[0011] The activation treatment involves mixing graphite particles and an activating agent at a mass ratio of 1:2 to 10:1, and heat-treating at 450-900℃ for 1-4 hours under an inert atmosphere. The activating agent is selected from chlorides, nitrates, or sulfates. The activation treatment modifies the structure of the graphite particles and creates pores through pyrolysis at high temperatures, ultimately forming graphite particles with a high specific surface area. During the activation heating process, the activating agent exerts a strong catalytic effect, lowering the pyrolysis temperature of organic macromolecules in the raw material, promoting the pyrolysis of the material, and generating small molecule hydrocarbons (methane, ethane), CO, CO2, and other gases. When these gases rapidly escape from the interior of the raw material, they form numerous micropores, mesopores, and even macropores, constituting the porous framework of the graphite particles.
[0012] Acidification and activation treatments can be performed individually or in combination, and the order in which they are combined is not limited.
[0013] Step 3: Mix the surface-modified graphite particles with an alkaline solution containing palladium-103 at a radioactive concentration of 50-5000 mCi / mL at a mass-volume ratio of 10-100 mL / g, and perform an adsorption reaction by shaking at 10-40℃ for 1-6 hours. Wash and dry to obtain the source core. The total adsorption rate of radionuclides in the source core can reach more than 90%, and the activity uniformity of a single source core is within ±5%.
[0014] Furthermore, the adhesive may be selected from one or more of polyvinyl alcohol, carboxymethyl cellulose, acrylic resin, clay, and polyvinyl acetate to ensure that the particles have sufficient mechanical strength.
[0015] Furthermore, the alkali in the alkaline solution is selected from one or more of sodium hydroxide, potassium hydroxide, ammonium chloride, sodium carbonate, sodium bicarbonate, and ammonia water.
[0016] Furthermore, the activator may be selected from CaCl2, NaCl, MgCl2, AlCl3, KCl, ZnCl2, MnCl2, FeCl3, FeCl2, Ca(NO3)2, NaNO3, Mg(NO3)2, Al(NO3)3, KNO3, Zn(NO3)2, Mn(NO3)2, Fe(NO3)3, Fe(NO3)2, CaSO4, Na2SO4, MgSO4, Al2(SO4)3, K2SO4, ZnSO4, MnSO4, Fe2(SO4)3, and FeSO4.
[0017] Thirdly, the present invention provides a radiotherapy device comprising a palladium-103 brachytherapy source core as described above, sealed within a biocompatible housing. This device is preferably a brachytherapy product such as a sealed seed source, an afterloading therapy source, or a radioactive patch.
[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) It eliminates the dependence of existing electroplating processes on high-purity, high-conductivity graphite. The graphite content in the basic graphite raw material used is greater than 60%, which meets the requirements and greatly reduces the cost of raw material procurement. At the same time, the simplified adsorption process replaces the complex electroplating equipment and operation, reducing equipment investment and energy consumption.
[0019] (2) The preparation method does not require a complex power supply system, cathode assembly and strict electrolyte management. The source core is prepared by chemical adsorption (room temperature shaking). The process is simple to operate and easy to control. It can achieve uniform preparation from laboratory level (a few particles) to industrial production level (thousands of particles). It has good batch repeatability and great industrialization potential.
[0020] (3) By selectively acidifying (introducing oxygen-containing functional groups) and / or activating (creating pores to increase specific surface area) the graphite particles, their chemical affinity and physical adsorption capacity for palladium [Pd-103] were effectively improved. This method can achieve a total adsorption rate of radionuclides ≥90% and control the activity uniformity of a single source core within ±5%, meeting the core requirements of accurate radiation source dosage in clinical treatment.
[0021] (4) The radioactive nuclide palladium [Pd-103] is distributed in an adsorbed state on the surface and inside the pores of the porous and low-density graphite carrier, which reduces the obstruction and absorption of low-energy rays (20-23keV) by the high-density material, which is conducive to the effective output of the therapeutic dose and improves the utilization efficiency of radiation energy.
[0022] (5) The source core prepared according to the preparation method of the present invention has a size (diameter 0.1-1.0 mm, length 0.5-5.0 mm) and activity range (0.5-100 mCi) that can be flexibly adjusted according to clinical needs. It can be directly used as a core component and encapsulated in medical devices such as sealed seed sources, afterloading therapy sources or radioactive applicators of different specifications. It is suitable for brachytherapy of various diseases such as prostate cancer and head and neck tumors and has a wide market application prospect. Attached Figure Description
[0023] Figure 1 This is a SEM image of the graphite particles prepared in step 1 of Example 2 of the present invention.
[0024] Figure 2 This is a SEM image of graphite particles after activation-acidification treatment in Example 2 of the present invention.
[0025] Figure 3 This is a photograph of the graphite particles prepared in Example 2 of the present invention. Detailed Implementation
[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0027] Example 1
[0028] This embodiment provides a method for preparing a palladium-103 brachytherapy source core, and the palladium-103 brachytherapy source core prepared by the method.
[0029] Its preparation methods include: (1) Preparation of graphite particles: Graphite, clay and water are mixed in a ratio of 3:1:1, stirred by twin screws, and extruded under high pressure into graphite particles with a diameter of 1.0 mm and a length of 2.0 mm. After drying, graphite particles are obtained.
[0030] (2) Acidification of graphite particles: 10 ml of concentrated nitric acid with a concentration of 14.5 mol / L was mixed with 1 g of graphite particles and oxidized at 100℃ for 2 hours. The mixture was washed with purified water and dried at 60℃ for 24 hours under nitrogen protection.
[0031] (3) Activation of graphite particles: 1g of graphite particles from step (2) are mixed with 0.1g of ZnCl2 solid, heated to 600℃ under argon protection, and kept warm for 4 hours to obtain activated graphite particles.
[0032] (4) Adsorption of source core: 0.1 ml of ammonium chloride solution of palladium chloride [Pd-103] with 5000 mCi / mL was mixed with 100 (1000 mg) graphite particles after surface modification, and shaken at 25°C for 3 hours. The residual palladium chloride [Pd-103] solution was recovered for later use. The source core was washed with purified water and dried to obtain a source core with an average activity of 4.75 mCi / particle.
[0033] The palladium-103 brachytherapy source core was tested and found to have a total adsorption rate of 95% for radioactive palladium [Pd-103] and a uniformity of activity of a single source core within ±5%.
[0034] Example 2
[0035] This embodiment provides a method for preparing a palladium-103 brachytherapy source core, and the palladium-103 brachytherapy source core prepared by the method.
[0036] Its preparation methods include: (1) Preparation of graphite particles: Graphite, carboxymethyl cellulose and water are mixed in a ratio of 4:0.1:1, stirred by twin screws, and extruded under high pressure into graphite particles with a diameter of 0.5 mm and a length of 1 mm. After drying, graphite particles are obtained.
[0037] (2) Activation of graphite particles: Mix 5g of graphite particles with 1g of Zn(NO3)2 solid, heat to 900℃ under argon protection, and keep warm for 1 hour to obtain activated graphite particles.
[0038] (3) Acidification of graphite particles: Mix 50 ml of 1 mol / L concentrated nitric acid with 1 g of activated graphite particles, oxidize at 150 °C for 24 hours, wash with purified water, and dry at 100 °C for 2 hours under nitrogen protection.
[0039] (4) Adsorption of source core: 1 ml of ammonia solution of palladium chloride [Pd-103] with 50 (100 mg) surface-modified graphite particles were mixed and shaken at 40 °C for 1 hour. The residual alkaline solution of palladium chloride [Pd-103] was recovered for later use. The source core was washed with purified water and dried to obtain a source core with an activity of 0.98 mCi / particle. Its total adsorption rate of radioactive palladium [Pd-103] was 98%.
[0040] Example 3
[0041] This embodiment provides a method for preparing a palladium-103 brachytherapy source core, and the palladium-103 brachytherapy source core prepared by the method.
[0042] Its preparation methods include: (1) Preparation of graphite particles: Graphite, acrylic resin and water are mixed in a ratio of 5:0.2:0.5, stirred by extrusion, and then extruded by twin screw extruder to form graphite particles with a diameter of 0.1 mm and a length of 0.5 mm. After drying, graphite particles are obtained.
[0043] (2) Acidification of graphite particles: Mix 5 ml of concentrated nitric acid with 4 mol / L with 0.1 g of graphite particles, oxidize at 60 °C for 10 hours, wash with purified water, and dry at 100 °C for 1 hour under nitrogen protection.
[0044] (3) Adsorption of source core: 0.5 ml of sodium bicarbonate solution of palladium chloride [Pd-103] with a concentration of 500 mCi / mL was mixed with 500 (300 mg) surface-modified graphite particles and shaken at 10 °C for 6 hours. The residual alkaline solution of palladium chloride [Pd-103] was recovered for later use. The source core was washed with purified water and dried to obtain a source core with an activity of 0.48 mCi / particle. The total adsorption rate of radioactive palladium [Pd-103] was 96%.
[0045] Example 4
[0046] This embodiment provides a method for preparing a palladium-103 brachytherapy source core, and the palladium-103 brachytherapy source core prepared by the method.
[0047] Its preparation methods include: (1) Preparation of graphite particles: Graphite, polyvinyl alcohol and water are mixed in a ratio of 10:1:1, stirred by twin-screw extrusion, and extruded under high pressure into graphite particles with a diameter of 1.0 mm and a length of 5.0 mm. After drying, graphite particles are obtained.
[0048] (2) Activation of graphite particles: Graphite particles and ZnSO4 are mixed at a mass ratio of 1:2, heated to 450°C under argon protection, and kept at that temperature for 1 hour to obtain activated graphite particles.
[0049] (3) Adsorption of source core: 1 ml of sodium carbonate solution of palladium chloride [Pd-103] with 100 mCi / mL was mixed with 400 (500 mg) surface-modified graphite particles and shaken at 25°C for 4 hours. The residual alkaline solution of palladium chloride [Pd-103] was recovered for later use. The source core was washed with purified water and dried to obtain a source core with an activity of 0.24 mCi / particle and a total adsorption rate of radioactive palladium [Pd-103] of 96%.
[0050] SEM images of the graphite particles prepared in Example 2, as well as the surface-modified graphite particles after activation and acidification treatment, were obtained using a scanning electron microscope, as shown below. Figure 1 and Figure 2As shown, after surface modification, the surface of graphite particles becomes rough and exhibits obvious porous structures, which greatly increases the specific surface area and adsorption active sites. Figure 3 The macroscopic morphology of the prepared graphite particles is shown, exhibiting good uniformity.
[0051] Ten samples were randomly selected for activity measurement, and the results are shown in Table 1: Table 1 Activity Measurements Serial Number Activity (mCi) Serial Number Activity (mCi) 1 0.9757 6 1.0098 2 0.9568 7 0.9645 3 0.9889 8 0.9932 4 1.0056 9 1.0241 5 0.9487 10 0.9761 Data shows that the activity uniformity of a single source core is excellent, with relative deviation controlled within ±5%, fully meeting the stringent clinical requirements for dosage accuracy.
[0052] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A palladium-103 brachytherapy source core, characterized in that, It includes surface-modified graphite particles and a radioactive nuclide palladium-103 loaded on the surface of the surface-modified graphite particles; The surface-modified graphite particles are obtained through acidification and / or activation treatment, and the graphite content is greater than 60%.
2. The palladium-103 brachytherapy source core according to claim 1, characterized in that, The surface-modified graphite particles have a diameter of 0.1-1.0 mm and a length of 0.5-5.0 mm.
3. A method for preparing the palladium-103 brachytherapy source core as described in claim 1 or 2, characterized in that, Includes the following steps: Step 1: Prepare graphite particles; Step 2: Acidify and / or activate the graphite particles to obtain surface-modified graphite particles; Step 3: Mix the surface-modified graphite particles with an alkaline solution containing palladium-103 at a mass-volume ratio of 10-100 mL / g, and perform an adsorption reaction by shaking at 10-40℃ for 1-6 hours. Wash and dry to obtain the source core.
4. The method according to claim 3, characterized in that, In step 1, the graphite particles are obtained by extrusion molding and drying after mixing graphite, binder and water; The adhesive is one or more of polyvinyl alcohol, carboxymethyl cellulose, acrylic resin, clay, and polyvinyl acetate.
5. The method according to claim 3, characterized in that, In step 2, the acidification treatment is as follows: graphite particles are mixed with concentrated nitric acid at a mass-volume ratio of 10-100 mL / g, oxidized at 60-150℃ for 2-24 hours, washed and dried; The concentration range of the concentrated nitric acid is 1-14.5 mol / L; The activation treatment is as follows: graphite particles and activator are mixed at a mass ratio of 1:2-10:1 and heated at 450-900℃ for 1-4 hours under inert gas protection. The activator is selected from one of chloride, nitrate or sulfate.
6. The method according to claim 3, characterized in that, In step 3, the radioactive concentration of palladium-103 in the alkaline solution containing palladium-103 is 50-5000 mCi / mL.
7. The method according to claim 6, characterized in that, The alkali in the alkaline solution is selected from one or more of sodium hydroxide, potassium hydroxide, ammonium chloride, sodium carbonate, sodium bicarbonate, and ammonia water.
8. A radiotherapy device, characterized in that, Contains the palladium-103 brachytherapy source core of claim 1 or 2, sealed within a biocompatible housing; The device is a sealed seed source, a post-loaded therapeutic source, or a radioactive patch.