%0 Journal Article %T Cs-131 as an experimental tool for the investigation and quantification of the radiotoxicity of intracellular Auger decays in vitro. %A Fredericia PM %A Siragusa M %A Köster U %A Severin G %A Groesser T %A Jensen M %J Int J Radiat Biol %V 99 %N 1 %D 2023 %M 32600084 %F 3.352 %R 10.1080/09553002.2020.1787541 %X 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.
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.
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.
This experimental setup and dosimetry provides reliable RBE-values for Auger emitters in various cell lines.