Comparison of ZnS(Ag) Scintillator and Proportional Counter Tube for Alpha Detection in Thin-Layer Chromatography
(1) <b>Background</b>: Targeted alpha therapy is an emerging field in nuclear medicine driven by two advantages: overcoming resistance in cancer-suffering patients to beta therapies and the practical application of lower activities of <sup>212</sup>Pb- and <sup>225</...
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MDPI AG
2024-12-01
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| author | Marc Pretze Jan Wendrich Holger Hartmann Robert Freudenberg Ralph A. Bundschuh Jörg Kotzerke Enrico Michler |
| author_facet | Marc Pretze Jan Wendrich Holger Hartmann Robert Freudenberg Ralph A. Bundschuh Jörg Kotzerke Enrico Michler |
| author_sort | Marc Pretze |
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| description | (1) <b>Background</b>: Targeted alpha therapy is an emerging field in nuclear medicine driven by two advantages: overcoming resistance in cancer-suffering patients to beta therapies and the practical application of lower activities of <sup>212</sup>Pb- and <sup>225</sup>Ac-labelled peptides to achieve the same doses compared to beta therapy due to the highly cytotoxic nature of alpha particles. However, quality control of the <sup>212</sup>Pb/<sup>225</sup>Ac-radiopharmaceuticals remains a challenge due to the low activity levels used for therapy (100 kBq/kg) and the formation of several free daughter nuclides immediately after the formulation of patient doses; (2) <b>Methods</b>: The routine alpha detection on thin-layer chromatograms (TLC) of <sup>212</sup>Pb- and <sup>225</sup>Ac-labelled peptides using a MiniScanPRO+ scanner combined with an alpha detector head was compared with detection using an AR-2000 scanner equipped with an open proportional counter tube. Measurement time, resolution and validity were compared for both scanners; (3) <b>Results</b>: For <sup>225</sup>Ac, the quality control values of the radiochemical purity (RCP) were within the acceptance criteria 2 h after TLC development, regardless of when the TLC probe was taken. That is, if the TLC probe was taken 24 h after radiosynthesis, the true value of the RCP was not measured until 5 h after TLC development. For <sup>212</sup>Pb-labelled peptides, the probe sampling did not have a high impact on the value of the RCP for the MiniScanPRO+ and AR-2000. A difference was observed when measuring TLC with the AR-2000 in different modes; (4) <b>Conclusions</b>: The MiniScanPRO+ is fast, does not require additional equipment and can also measure the gamma spectrum, which may be important for some radiopharmaceutical production sites and regulatory authorities. The AR-2000 has a better signal-to-noise ratio, and this eliminates the need for additional waiting time after TLC development. |
| format | Article |
| id | doaj-art-400f31f8c8554119bd4cb9007393a477 |
| institution | Kabale University |
| issn | 1424-8247 |
| language | English |
| publishDate | 2024-12-01 |
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| series | Pharmaceuticals |
| spelling | doaj-art-400f31f8c8554119bd4cb9007393a4772025-01-24T13:45:03ZengMDPI AGPharmaceuticals1424-82472024-12-011812610.3390/ph18010026Comparison of ZnS(Ag) Scintillator and Proportional Counter Tube for Alpha Detection in Thin-Layer ChromatographyMarc Pretze0Jan Wendrich1Holger Hartmann2Robert Freudenberg3Ralph A. Bundschuh4Jörg Kotzerke5Enrico Michler6Department of Nuclear Medicine, University Hospital Carl Gustav Carus, Technical University Dresden, Fetscherstr. 74, 01307 Dresden, GermanyEckert & Ziegler Eurotope, 13125 Berlin, GermanyDepartment of Nuclear Medicine, University Hospital Carl Gustav Carus, Technical University Dresden, Fetscherstr. 74, 01307 Dresden, GermanyDepartment of Nuclear Medicine, University Hospital Carl Gustav Carus, Technical University Dresden, Fetscherstr. 74, 01307 Dresden, GermanyDepartment of Nuclear Medicine, University Hospital Carl Gustav Carus, Technical University Dresden, Fetscherstr. 74, 01307 Dresden, GermanyDepartment of Nuclear Medicine, University Hospital Carl Gustav Carus, Technical University Dresden, Fetscherstr. 74, 01307 Dresden, GermanyDepartment of Nuclear Medicine, University Hospital Carl Gustav Carus, Technical University Dresden, Fetscherstr. 74, 01307 Dresden, Germany(1) <b>Background</b>: Targeted alpha therapy is an emerging field in nuclear medicine driven by two advantages: overcoming resistance in cancer-suffering patients to beta therapies and the practical application of lower activities of <sup>212</sup>Pb- and <sup>225</sup>Ac-labelled peptides to achieve the same doses compared to beta therapy due to the highly cytotoxic nature of alpha particles. However, quality control of the <sup>212</sup>Pb/<sup>225</sup>Ac-radiopharmaceuticals remains a challenge due to the low activity levels used for therapy (100 kBq/kg) and the formation of several free daughter nuclides immediately after the formulation of patient doses; (2) <b>Methods</b>: The routine alpha detection on thin-layer chromatograms (TLC) of <sup>212</sup>Pb- and <sup>225</sup>Ac-labelled peptides using a MiniScanPRO+ scanner combined with an alpha detector head was compared with detection using an AR-2000 scanner equipped with an open proportional counter tube. Measurement time, resolution and validity were compared for both scanners; (3) <b>Results</b>: For <sup>225</sup>Ac, the quality control values of the radiochemical purity (RCP) were within the acceptance criteria 2 h after TLC development, regardless of when the TLC probe was taken. That is, if the TLC probe was taken 24 h after radiosynthesis, the true value of the RCP was not measured until 5 h after TLC development. For <sup>212</sup>Pb-labelled peptides, the probe sampling did not have a high impact on the value of the RCP for the MiniScanPRO+ and AR-2000. A difference was observed when measuring TLC with the AR-2000 in different modes; (4) <b>Conclusions</b>: The MiniScanPRO+ is fast, does not require additional equipment and can also measure the gamma spectrum, which may be important for some radiopharmaceutical production sites and regulatory authorities. The AR-2000 has a better signal-to-noise ratio, and this eliminates the need for additional waiting time after TLC development.https://www.mdpi.com/1424-8247/18/1/26<sup>212</sup>Pb<sup>225</sup>AcPSMATATETOCthin-layer chromatography (TLC) |
| spellingShingle | Marc Pretze Jan Wendrich Holger Hartmann Robert Freudenberg Ralph A. Bundschuh Jörg Kotzerke Enrico Michler Comparison of ZnS(Ag) Scintillator and Proportional Counter Tube for Alpha Detection in Thin-Layer Chromatography Pharmaceuticals <sup>212</sup>Pb <sup>225</sup>Ac PSMA TATE TOC thin-layer chromatography (TLC) |
| title | Comparison of ZnS(Ag) Scintillator and Proportional Counter Tube for Alpha Detection in Thin-Layer Chromatography |
| title_full | Comparison of ZnS(Ag) Scintillator and Proportional Counter Tube for Alpha Detection in Thin-Layer Chromatography |
| title_fullStr | Comparison of ZnS(Ag) Scintillator and Proportional Counter Tube for Alpha Detection in Thin-Layer Chromatography |
| title_full_unstemmed | Comparison of ZnS(Ag) Scintillator and Proportional Counter Tube for Alpha Detection in Thin-Layer Chromatography |
| title_short | Comparison of ZnS(Ag) Scintillator and Proportional Counter Tube for Alpha Detection in Thin-Layer Chromatography |
| title_sort | comparison of zns ag scintillator and proportional counter tube for alpha detection in thin layer chromatography |
| topic | <sup>212</sup>Pb <sup>225</sup>Ac PSMA TATE TOC thin-layer chromatography (TLC) |
| url | https://www.mdpi.com/1424-8247/18/1/26 |
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