Host laboratory: Biological dosimetry laboratory (LDB)
Beginning of the thesis: October 2015
Amélie FreneauSubject description
This work is part of an ongoing IRSN program which aims studying, at the submicrometric scale, relationship between the topology of energy deposition and the initial biological events associated with involved molecular damage. In fact, the questioning of the existence or absence of a causal link between the early radiation-induced effects and late tissue consequences is one of the major issues for understanding the effects of ionizing radiation on the organism. In this context, this thesis will involve to analyze qualitative, quantitative, time related and structural characteristics of signaling and behaviour of DNA damage induced by low energy X rays. It allows to identify specificities associated to damage induced by this type of radiation compared to measured characteristics with X rays of reference (>100keV). This characterization will be carried out, not especially, through the observation by immunofluorescence of nuclear foci (H2Axser139p, 53BP1, DNA-scars…), induced following to exposition to different X rays. According to stochastic energy deposition profile, this evaluation will be done through the analysis of a large number of cell nuclei that were simultaneously submitted to the same ionizing stress in such a way as to understand the probabilistic characteristics of observation, and to link them to the specific physical characteristics of each studied radiation.