Cs-131 as an experimental tool for the investigation and quantification of the radiotoxicity of intracellular Auger decays in vitro

Pil M. Fredericia*, Mattia Siragusa, Ulli Köster, Gregory Severin, Torsten Groesser, Mikael Jensen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Purpose: In this work, we set out to provide an experimental setup, using Cs-131, with associated dosimetry for studying relative biological effectiveness (RBE) of Auger emitters.
Material and methods: Cs-131 decays by 100% electron capture producing K- (9%) and L- (80%) Auger electrons with mean energies of 26 keV and 3.5 keV, respectively, plus ≈9.4 very low energy electrons (<0.5 keV) per decay. Cs-131 accumulates in the cells through the Na+/K+-ATPase. By this uptake mechanism and the alkali chemistry of Cs+, we argue for its intracellular homogeneous distribution. Cs-131 was added to the cell culture medium of HeLa and V79 Cells. The bio-kinetics of Cs-131 (uptake, release, intracellular distribution) was examined by measuring its intracellular activity concentration over time. Taking advantage of the 100% confluent cellular monolayer, we developed a new and robust dosimetry that is entrusted to a quantity called SC-value.
Results: The SC-values evaluated in the cell nucleus are almost independent of the nuclear size and geometry. We obtained dose-rate controlled RBE-values for intracellular Cs-131 decay. Using the γH2AX assay, the RBE was 1 for HeLa cells. Using the clonogenic cell survival, it was 3.9 for HeLa cells and 3.2 for V79 cells.
Conclusion: This experimental setup and dosimetry provides reliable RBE-values for Auger emitters in various cell lines.
Original languageEnglish
JournalInternational Journal of Radiation Biology
Pages (from-to)1-14
Number of pages14
Publication statusAccepted/In press - 2020


  • Auger emitters
  • RBE
  • Cs-131
  • SC-value
  • Cellular S-value

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