Activity standardisation of 177Lu

Youcef Nedjadi; Frédéric Juget; M Teresa Durán; Laurent Desorgher; François Bochud; Claude Bailat

doi:10.1016/j.apradiso.2023.110986

Activity standardisation of ¹⁷⁷Lu

Appl Radiat Isot. 2023 Oct:200:110986. doi: 10.1016/j.apradiso.2023.110986. Epub 2023 Aug 16.

Authors

Youcef Nedjadi¹, Frédéric Juget², M Teresa Durán², Laurent Desorgher², François Bochud², Claude Bailat²

Affiliations

¹ Institut de Radiophysique, Lausanne, Switzerland. Electronic address: youcef.nedjadi@chuv.ch.
² Institut de Radiophysique, Lausanne, Switzerland.

PMID: 37597267
DOI: 10.1016/j.apradiso.2023.110986

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.

Keywords: (177)Lu; 4πβ-4πγ coincidence counting; Activity standardisation; Plastic scintillation; TDCR.