Tools for risk assessment in radiation therapy.

Radiotherapy has unquestionable benefits, but it is also associated with unique and specific safety issues. It is the only application of radiation in which humans are intentionally delivered very high doses. Safety in radiotherapy remains heavily dependent on human actions. A step-by-step approach is suggested for the prevention of accidental exposures in radiation therapy: (1) allocation of responsibilities to qualified professionals, and design of a quality and safety programme - no radiotherapy practice should be operated without these key elements; (2) use of the lessons from accidental exposures to test whether the quality and safety programme is sufficiently robust against these types of events -publications by the International Commission on Radiological Protection (ICRP) and the International Atomic Energy Agency provide a collection of lessons to facilitate this step; and (3) find other latent risks by posing the questions 'What else could go wrong?' or 'What other potential hazards might be present?' in a systematic, anticipative manner - methods to do so are described briefly in ICRP Publication 112.