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Nedjadi Y, Durán MT, Juget F, Bochud F, Veicht M, Schumann D, Mihalcea I, Kossert K, Bailat C. Activity standardisation of 32Si at IRA-METAS. Appl Radiat Isot 2023; 202:111041. [PMID: 37776633 DOI: 10.1016/j.apradiso.2023.111041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/22/2023] [Accepted: 09/22/2023] [Indexed: 10/02/2023]
Abstract
This work explores the primary activity standardisation of 32Si as part of the SINCHRON project that aims at filling the geochronological dating gap by making a new precise measurement of the half-life of this nuclide. The stability of some of the radioactive test solutions, providing 32Si as hexafluorosilicic acid (H232SiF6), was monitored over long periods, pointing to the adequate sample composition and vial type to ensure stability. These solutions were standardised using liquid scintillation counting with the triple to double coincidence ratio (TDCR) technique and the CIEMAT-NIST efficiency tracing (CNET) method. Complementary backup measurements, using 4πβ-γ coincidence counting with 60Co as a tracer, were performed with both liquid and plastic scintillation for beta detection. While 60Co coincidence tracing with a liquid scintillator predicted activities in agreement with the TDCR and CNET determinations, using plastic scintillation turned out to be unfeasible as the addition of lanthanum nitrate and ammonia to fix the silicon during the drying process generated large crystals that compromised the linearity of the efficiency function.
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Affiliation(s)
| | | | | | | | - Mario Veicht
- Laboratory of Radiochemistry, Paul Scherrer Institut, Villigen-PSI, Switzerland
| | - Dorothea Schumann
- Laboratory of Radiochemistry, Paul Scherrer Institut, Villigen-PSI, Switzerland
| | - Ionut Mihalcea
- Laboratory of Radiochemistry, Paul Scherrer Institut, Villigen-PSI, Switzerland
| | - Karsten Kossert
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
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Nedjadi Y, Juget F, Durán MT, Desorgher L, Bochud F, Bailat C. Activity standardisation of 177Lu. Appl Radiat Isot 2023; 200:110986. [PMID: 37597267 DOI: 10.1016/j.apradiso.2023.110986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 08/08/2023] [Accepted: 08/14/2023] [Indexed: 08/21/2023]
Abstract
177Lu decays through low-energy β-- and γ-emissions in addition to conversion and Auger electrons. To support the use of this radiopharmaceutical in Switzerland, a 177Lu solution was standardised using the β-γ coincidence technique, as well as the TDCR method. The solution had no 177mLu impurity. Primary coincidence measurements, with plastic scintillators for beta detection, were carried out using both analogue and digital electronics. TDCR measurements using only defocusing were also made. Monte Carlo calculations were used to compute the detection efficiency. The coincidence measurements with both analogue and digital electronics are compatible within one standard uncertainty, but they are lower than (and discrepant with) the TDCR measurements. An ampoule of this solution was submitted to the BIPM as a contribution to the Système International de Référence.
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Determination of the gamma and X-ray emission intensities of erbium-169. Appl Radiat Isot 2021; 176:109823. [PMID: 34175545 DOI: 10.1016/j.apradiso.2021.109823] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 05/07/2021] [Accepted: 06/06/2021] [Indexed: 11/21/2022]
Abstract
The gamma and X-ray emission intensities of 169Er were determined using radionuclidically pure 169Er. The activity of the 169Er source was standardized by the triple-to-double-coincidence ratio technique. Three independent measurements were performed to measure the emission intensities using calibrated high-purity germanium spectrometers. The efficiencies were computed with the Monte Carlo method and validated using several experimental measurements. Final results present a large uncertainty reduction compared to previous evaluations. The emission intensities per decay of 169Er are reported as 1.401(40).10-5 for the 109.8 keV line and 1.513(19).10-6 for the 118.2 keV line. The values obtained for the X-ray lines show large discrepancies with the reference values.
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Talip Z, Borgna F, Müller C, Ulrich J, Duchemin C, Ramos JP, Stora T, Köster U, Nedjadi Y, Gadelshin V, Fedosseev VN, Juget F, Bailat C, Fankhauser A, Wilkins SG, Lambert L, Marsh B, Fedorov D, Chevallay E, Fernier P, Schibli R, van der Meulen NP. Production of Mass-Separated Erbium-169 Towards the First Preclinical in vitro Investigations. Front Med (Lausanne) 2021; 8:643175. [PMID: 33968955 PMCID: PMC8100037 DOI: 10.3389/fmed.2021.643175] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/22/2021] [Indexed: 01/08/2023] Open
Abstract
The β--particle-emitting erbium-169 is a potential radionuclide toward therapy of metastasized cancer diseases. It can be produced in nuclear research reactors, irradiating isotopically-enriched 168Er2O3. This path, however, is not suitable for receptor-targeted radionuclide therapy, where high specific molar activities are required. In this study, an electromagnetic isotope separation technique was applied after neutron irradiation to boost the specific activity by separating 169Er from 168Er targets. The separation efficiency increased up to 0.5% using resonant laser ionization. A subsequent chemical purification process was developed as well as activity standardization of the radionuclidically pure 169Er. The quality of the 169Er product permitted radiolabeling and pre-clinical studies. A preliminary in vitro experiment was accomplished, using a 169Er-PSMA-617, to show the potential of 169Er to reduce tumor cell viability.
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Affiliation(s)
- Zeynep Talip
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen, Switzerland
| | - Francesca Borgna
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen, Switzerland
| | - Cristina Müller
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen, Switzerland
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Jiri Ulrich
- Laboratory of Radiochemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Charlotte Duchemin
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
- Institute for Nuclear and Radiation Physics, Catholic University of Leuven, Leuven, Belgium
| | - Joao P. Ramos
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
- Institute for Nuclear and Radiation Physics, Catholic University of Leuven, Leuven, Belgium
| | - Thierry Stora
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | | | - Youcef Nedjadi
- Institute of Radiation Physics, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Vadim Gadelshin
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
- Institute of Physics, Johannes Gutenberg University, Mainz, Germany
- Institute of Physics and Technology, Ural Federal University, Yekaterinburg, Russia
| | | | - Frederic Juget
- Institute of Radiation Physics, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Adelheid Fankhauser
- Analytic Radioactive Materials, Paul Scherrer Institute, Villigen, Switzerland
| | - Shane G. Wilkins
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - Laura Lambert
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - Bruce Marsh
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - Dmitry Fedorov
- Petersburg Nuclear Physics Institute, National Research Center Kurchatov Institute, Gatchina, Russia
| | - Eric Chevallay
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - Pascal Fernier
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - Roger Schibli
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen, Switzerland
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Nicholas P. van der Meulen
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen, Switzerland
- Laboratory of Radiochemistry, Paul Scherrer Institute, Villigen, Switzerland
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Nedjadi Y, Juget F, Desorgher L, Durán MT, Bochud F, Müller C, Talip Z, van der Meulen NP, Bailat C. Activity standardisation of 161Tb. Appl Radiat Isot 2020; 166:109411. [PMID: 32961523 DOI: 10.1016/j.apradiso.2020.109411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/18/2020] [Accepted: 09/04/2020] [Indexed: 01/16/2023]
Abstract
161Tb, which emits low-energy β-- and γ-particles in addition to conversion and Auger electrons, has aroused increased interest for medical imaging and therapy. To support the use of this radionuclide, a161Tb solution was standardised using the β-γ coincidence technique, as well as the TDCR method. The solution had 4.5·10-3% of 160Tb impurities. Primary coincidence measurements, with plastic or liquid scintillators for beta detection, were carried out using both analogue and digital electronics. TDCR measurements using defocusing, grey filtering and quenching for varying the efficiency were also made. Monte Carlo calculations were used to compute the detection efficiency. The coincidence measurements with analogue electronics and the TDCR show a good consistency, and are compatible with the digital coincidence results within uncertainties. An ampoule of this solution was submitted to the BIPM as a contribution to the international reference system.
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Affiliation(s)
| | | | | | | | | | - Cristina Müller
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Zeynep Talip
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Nicholas P van der Meulen
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland; Laboratory of Radiochemistry, Paul Scherrer Institute, Villigen-PSI, Switzerland
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