Radiobiology consists in studying the molecular and cellular mechanisms activated in response to irradiation. In the domain of ion irradiation, where the clinical applications are promising, many questions are still opened. Answering these questions would help to improve the treatment planning software for hadrontherapy (see ETOILE Center in Lyon).

Because living tissues contain a large proportion of water, the irradiation generates huge free-radical quantities by radiolysis of water. The production of free radicals, referred as to oxidative stress, can damage sensitive molecules (DNA, proteins, …) As a natural defense against this stress, antioxydants are produced by the cells to trap free-radical molecules. Conversely, oxygen in living tissues amplifies the cell radiosensitivity. Fortunatly, these effects tend to disappear for high-energy ion irradiations in aid of a better biologic effect for clinical applications.

To better understand these observations, we developed a simulation of the first microseconds of the oxidative stress. We then adapted our model to include the protective role of anti-oxydants and the sensitive role of oxygen.