“…To obtain this ballistic precision, the volume to be irradiated, the distribution of the dose in the target volumes and organs at risk, the positioning of the patient (and their repositioning at each session), the delivery of the dose as prescribed by the radiation oncologist, etc., must be complied with, whereas the clinical practice of radiotherapy is just-in-time within the departments and changes regularly due to technical progress. Radiotherapy is therefore a complex activity that is not devoid of risks (Bourguignon, 2019;Bulot, 2019aBulot, , 2019bBulot, , 2019c, as evidenced by the occurrence of accidents, particularly that of Epinal in France (IRSN, 2007).…”