Multiparametric radiobiological assays show that variation of X-ray energy strongly impacts relative biological effectiveness: comparison between 220 kV and 4 MV

Vincent Paget (1) , Mariam Ben Kacem (1) , Morgane dos Santos (2) , Mohamed Amine Benadjaoud (1) , Frédéric Soysouvanh (1) , Valerie Buard (1) , Georges Tarlet (1) , Aurelie Vaurijoux (2) , Gaetan Gruel (2) , Agnes Francois (1) , Olivier Guipaud (1) , Fabien Milliat (1)

1 IRSN/PSE-SANTE/SERAMED/LRMed - Laboratoire de Radiobiologie des expositions médicales
2 IRSN/PSE-SANTE/SERAMED/LRAcc - Laboratoire de Radiobiologie des expositions accidentelles

Based on classic clonogenic assay, it is accepted by the scientific community that, whatever the energy, the relative biological effectiveness of X-rays is equal to 1. However, although X-ray beams are widely used in diagnosis, interventional medicine and radiotherapy, comparisons of their energies are scarce. We therefore assessed in vitro the effects of low- and high-energy X-rays using Human umbilical vein endothelial cells (HUVECs) by performing clonogenic assay, measuring viability/mortality, counting γ-H2AX foci, studying cell proliferation and cellular senescence by flow cytometry and by performing gene analysis on custom arrays. Taken together, excepted for γ-H2AX foci counts, these experiments systematically show more adverse effects of high energy X-rays, while the relative biological effectiveness of photons is around 1, whatever the quality of the X-ray beam. These results strongly suggest that multiparametric analysis should be considered in support of clonogenic assay.

Domaines: Sciences du Vivant [q-bio]

Vincent Paget, Mariam Ben Kacem, Morgane dos Santos, Mohamed Amine Benadjaoud, Frédéric Soysouvanh, et al.. Multiparametric radiobiological assays show that variation of X-ray energy strongly impacts relative biological effectiveness: comparison between 220 kV and 4 MV. Scientific Reports, 2019, 9, pp.14328. ⟨10.1038/s41598-019-50908-4⟩. ⟨hal-02345044⟩