The traditional approaches to safety in risk activities have been applied to radiotherapy following the occurrence of serious accidents. This strategy is based on the characterization of specific risks and the definition of preventive and protective measures, particularly for the implementation of safety barriers. Evaluating the performance of safety barriers makes it possible, in theory, to determine the level of risk control. This article presents a literature review that highlights the limits of the safety barrier concept. To overcome these limitations, we then introduce the notion of “activities contributing to safety” (ACS). This concept allows us to better take into account the managerial, contextual, organizational and human dimensions of safety and to promote risk control through a more realistic approach.