Optimization of 44gSc Production Using Cyclotron-irradiated Liquid Target
The positron-emitting radionuclide scandium-44 (44gSc) demonstrates significant potential in tumor diagnosis due to its optimal decay properties (T1/2=4.04 h, =632.0 keV, branching ratio (BR)=94.3%). However, its limited availability has constrained the development of related radiopharmaceuticals....
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Editorial Board of Atomic Energy Science and Technology
2025-06-01
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| Series: | Yuanzineng kexue jishu |
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| author | WANG Yizheng1, 2, 3, MAQBOOL Sahil1, 2, 4, ZHANG Yuxuan2, 3, YANG Wenjiang1, 2, 3, , WEI Long1, 2, 3, 4, |
| author_facet | WANG Yizheng1, 2, 3, MAQBOOL Sahil1, 2, 4, ZHANG Yuxuan2, 3, YANG Wenjiang1, 2, 3, , WEI Long1, 2, 3, 4, |
| author_sort | WANG Yizheng1, 2, 3, MAQBOOL Sahil1, 2, 4, ZHANG Yuxuan2, 3, YANG Wenjiang1, 2, 3, , WEI Long1, 2, 3, 4, |
| collection | DOAJ |
| description | The positron-emitting radionuclide scandium-44 (44gSc) demonstrates significant potential in tumor diagnosis due to its optimal decay properties (T1/2=4.04 h,
=632.0 keV, branching ratio (BR)=94.3%). However, its limited availability has constrained the development of related radiopharmaceuticals. To address this supply limitation, the production of 44gSc via the reaction 44Ca(p,n)44gSc using a medical cyclotron was reported. Numerical simulations were employed to optimize irradiation parameters for maximizing production yield and radionuclidic purity. Subsequently, proton irradiation of a natural-abundance Ca liquid target was utilized to produce 44gSc, and the PET imaging performance of 44gSc was also investigated. To calculate theoretical yield and radionuclidic purity, excitation functions were simulated using TALYS 2.0, ALICE-IPPE, and EMPIRE 3.2 nuclear reaction codes. Based on these calculations, liquid targets containing high-concentration (168 mg/mL) calcium nitrate were irradiated using a GE PETtrace cyclotron. The proton beam was delivered at 14.5 MeV with 7-10 μA intensity for 30-90 min irradiation. After irradiation, the targets were processed through branched DGA resin chromatography for radiochemical purification. Radionuclidic, radiochemical, and chemical purity were assessed using an HPGe detector, TLC scanner, and ICP-OES, respectively. The resulting [44gSc]ScCl3 samples (0.33 MBq injection dose) were evaluated through PET imaging studies in murine models to assess their in vivo performance. Numerical simulations demonstrate that 14.5 MeV is the optimal proton energy for the 44Ca(p,n)44gSc reaction, achieving a theoretical radionuclidic purity of 95.8% at the end-of-bombardment (EOB). The primary impurities consist of 43Sc (2.1%), 44mSc (0.6%), 47Sc (0.2%) and 48Sc (1.3%). The experimental results show that compared to other tested conditions, the 10 μA beam intensity with 50 min of irradiation delivers a higher yield. The production yield at EOB is 2.5 MBq/μAh for 44gSc, representing a 3.4-fold improvement over existing data, and the maximum EOB activity is 20.6 MBq. Chemical purification of Sc3+ achieves a recovery yield of 97.0%, which is comparable to literature values. The radiochemical purity exceeds 99% as verified by TLC. ICP-OES analysis confirms effective removal of metallic contaminants, retaining only 362.4 ppm Ca while maintaining other metal impurities (Zn, Fe, Al, Mn) below 4 ppm. Radiolabeling studies show that Ca2+ exhibits negligible influence on labeling yield. Gamma spectroscopy measurements confirm an EOB radionuclidic purity of 95.8%±1.0%, consistent with simulations. Preliminary PET imaging studies reveal that 44gSc exhibits high radioactivity levels in the cardiac blood pool, indicating strong binding affinity of free Sc3+ to plasma proteins. The PET imaging of 44gSc achieves high quality even at low doses, supporting its potential for medical diagnostic applications.
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| format | Article |
| id | doaj-art-9e6bfc2e4f98423eb9793acc0e1cbcce |
| institution | DOAJ |
| issn | 1000-6931 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Editorial Board of Atomic Energy Science and Technology |
| record_format | Article |
| series | Yuanzineng kexue jishu |
| spelling | doaj-art-9e6bfc2e4f98423eb9793acc0e1cbcce2025-08-20T02:45:28ZengEditorial Board of Atomic Energy Science and TechnologyYuanzineng kexue jishu1000-69312025-06-015961165117510.7538/yzk.2025.youxian.0345Optimization of 44gSc Production Using Cyclotron-irradiated Liquid TargetWANG Yizheng1, 2, 3, MAQBOOL Sahil1, 2, 4, ZHANG Yuxuan2, 3, YANG Wenjiang1, 2, 3, , WEI Long1, 2, 3, 4, 01. Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China 2. CAEA Center of Excellence on Nuclear Technology Applications for Nuclear Detection and Imaging, Beijing 100049, China 3. Jinan Laboratory of Applied Nuclear Science, Jinan 251401, China 4. School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, ChinaThe positron-emitting radionuclide scandium-44 (44gSc) demonstrates significant potential in tumor diagnosis due to its optimal decay properties (T1/2=4.04 h, =632.0 keV, branching ratio (BR)=94.3%). However, its limited availability has constrained the development of related radiopharmaceuticals. To address this supply limitation, the production of 44gSc via the reaction 44Ca(p,n)44gSc using a medical cyclotron was reported. Numerical simulations were employed to optimize irradiation parameters for maximizing production yield and radionuclidic purity. Subsequently, proton irradiation of a natural-abundance Ca liquid target was utilized to produce 44gSc, and the PET imaging performance of 44gSc was also investigated. To calculate theoretical yield and radionuclidic purity, excitation functions were simulated using TALYS 2.0, ALICE-IPPE, and EMPIRE 3.2 nuclear reaction codes. Based on these calculations, liquid targets containing high-concentration (168 mg/mL) calcium nitrate were irradiated using a GE PETtrace cyclotron. The proton beam was delivered at 14.5 MeV with 7-10 μA intensity for 30-90 min irradiation. After irradiation, the targets were processed through branched DGA resin chromatography for radiochemical purification. Radionuclidic, radiochemical, and chemical purity were assessed using an HPGe detector, TLC scanner, and ICP-OES, respectively. The resulting [44gSc]ScCl3 samples (0.33 MBq injection dose) were evaluated through PET imaging studies in murine models to assess their in vivo performance. Numerical simulations demonstrate that 14.5 MeV is the optimal proton energy for the 44Ca(p,n)44gSc reaction, achieving a theoretical radionuclidic purity of 95.8% at the end-of-bombardment (EOB). The primary impurities consist of 43Sc (2.1%), 44mSc (0.6%), 47Sc (0.2%) and 48Sc (1.3%). The experimental results show that compared to other tested conditions, the 10 μA beam intensity with 50 min of irradiation delivers a higher yield. The production yield at EOB is 2.5 MBq/μAh for 44gSc, representing a 3.4-fold improvement over existing data, and the maximum EOB activity is 20.6 MBq. Chemical purification of Sc3+ achieves a recovery yield of 97.0%, which is comparable to literature values. The radiochemical purity exceeds 99% as verified by TLC. ICP-OES analysis confirms effective removal of metallic contaminants, retaining only 362.4 ppm Ca while maintaining other metal impurities (Zn, Fe, Al, Mn) below 4 ppm. Radiolabeling studies show that Ca2+ exhibits negligible influence on labeling yield. Gamma spectroscopy measurements confirm an EOB radionuclidic purity of 95.8%±1.0%, consistent with simulations. Preliminary PET imaging studies reveal that 44gSc exhibits high radioactivity levels in the cardiac blood pool, indicating strong binding affinity of free Sc3+ to plasma proteins. The PET imaging of 44gSc achieves high quality even at low doses, supporting its potential for medical diagnostic applications. scandium-44radionuclide productionmedical radioisotopetheranosticspositron emission tomographyliquid target |
| spellingShingle | WANG Yizheng1, 2, 3, MAQBOOL Sahil1, 2, 4, ZHANG Yuxuan2, 3, YANG Wenjiang1, 2, 3, , WEI Long1, 2, 3, 4, Optimization of 44gSc Production Using Cyclotron-irradiated Liquid Target Yuanzineng kexue jishu scandium-44 radionuclide production medical radioisotope theranostics positron emission tomography liquid target |
| title | Optimization of 44gSc Production Using Cyclotron-irradiated Liquid Target |
| title_full | Optimization of 44gSc Production Using Cyclotron-irradiated Liquid Target |
| title_fullStr | Optimization of 44gSc Production Using Cyclotron-irradiated Liquid Target |
| title_full_unstemmed | Optimization of 44gSc Production Using Cyclotron-irradiated Liquid Target |
| title_short | Optimization of 44gSc Production Using Cyclotron-irradiated Liquid Target |
| title_sort | optimization of 44gsc production using cyclotron irradiated liquid target |
| topic | scandium-44 radionuclide production medical radioisotope theranostics positron emission tomography liquid target |
| work_keys_str_mv | AT wangyizheng123maqboolsahil124zhangyuxuan23yangwenjiang123weilong1234 optimizationof44gscproductionusingcyclotronirradiatedliquidtarget |