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Bergeron DE, Cessna JT, Broder BA, Pibida L, Fitzgerald RP, DiGiorgio M, Napoli E, Zimmerman BE. Activity standard and calibrations for 227Th with ingrowing progeny. Appl Radiat Isot 2024; 209:111326. [PMID: 38701595 DOI: 10.1016/j.apradiso.2024.111326] [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: 01/03/2024] [Revised: 03/10/2024] [Accepted: 04/10/2024] [Indexed: 05/05/2024]
Abstract
Thorium-227 was separated from its progeny and standardized for activity by the triple-to-double coincidence ratio (TDCR) method of liquid scintillation counting. Confirmatory liquid scintillation-based measurements were made using efficiency tracing with 3H and live-timed anticoincidence counting (LTAC). The separation time and the efficiency of the separation were confirmed by gamma-ray spectrometry. Calibrations for reentrant pressurized ionization chambers, including commercial radionuclide calibrators, and a well-type NaI(Tl) detector are discussed.
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Affiliation(s)
- Denis E Bergeron
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | - Jeffrey T Cessna
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Brittany A Broder
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Leticia Pibida
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Ryan P Fitzgerald
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Morgan DiGiorgio
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | | | - Brian E Zimmerman
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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Takács MP. Measuring the half-life of 215Po by low-level liquid scintillation counting. Appl Radiat Isot 2023; 193:110674. [PMID: 36682309 DOI: 10.1016/j.apradiso.2023.110674] [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: 05/30/2022] [Revised: 10/27/2022] [Accepted: 01/13/2023] [Indexed: 01/16/2023]
Abstract
The half-life of short-lived 215Po was studied in a new experimental setup by means of liquid scintillation counting. The new value of 1.781 (5) ms was obtained by offline data analysis using the delayed coincidence method. Along with the half-life determination, a careful assessment of uncertainties was carried out. The result was compared with data available from the literature.
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Affiliation(s)
- Marcell P Takács
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany.
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Bergeron DE, Kossert K, Collins SM, Fenwick AJ. Realization and dissemination of activity standards for medically important alpha-emitting radionuclides. Appl Radiat Isot 2022; 184:110161. [DOI: 10.1016/j.apradiso.2022.110161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/16/2022] [Accepted: 02/22/2022] [Indexed: 11/27/2022]
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Bergeron DE, Collins SM, Pibida L, Cessna JT, Fitzgerald R, Zimmerman BE, Ivanov P, Keightley JD, Napoli E. Ra-224 activity, half-life, and 241 keV gamma ray absolute emission intensity: A NIST-NPL bilateral comparison. Appl Radiat Isot 2021; 170:109572. [PMID: 33461017 PMCID: PMC8406413 DOI: 10.1016/j.apradiso.2020.109572] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 12/11/2020] [Accepted: 12/21/2020] [Indexed: 11/23/2022]
Abstract
The national metrology institutes for the United Kingdom (UK) and the United States of America (USA) have compared activity standards for 224Ra, an α-particle emitter of interest as the basis for therapeutic radiopharmaceuticals. Solutions of 224RaCl2 were assayed by absolute methods, including digital coincidence counting and triple-to-double coincidence ratio liquid scintillation counting. Ionization chamber and high-purity germanium (HPGe) γ-ray spectrometry calibrations were compared; further, a solution was shipped between laboratories for a direct comparison by HPGe spectrometry. New determinations of the absolute emission intensity for the 241 keV γ ray (Iγ = 4.011(16) per 100 disintegrations of 224Ra) and of the 224Ra half-life (T1/2 = 3.6313(14) d) are presented and discussed in the context of previous measurements and evaluations.
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Affiliation(s)
- Denis E Bergeron
- Radiation Physics Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.
| | - Sean M Collins
- National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK; Department of Physics, University of Surrey, Stag Hill, Guildford, GU2 7XH, UK
| | - Leticia Pibida
- Radiation Physics Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Jeffrey T Cessna
- Radiation Physics Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Ryan Fitzgerald
- Radiation Physics Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Brian E Zimmerman
- Radiation Physics Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Peter Ivanov
- National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK
| | - John D Keightley
- National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK
| | - Elisa Napoli
- Oncoinvent AS, Oslo, Norway; Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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