Abstract
This paper highlights and models the most important steps in radiotherapy procedures by identifying possible modes of human errors in them. The most common form of radiotherapy is external beam radiotherapy or teletherapy, where the patient sits or lies on a couch and an external source of radiation is pointed at a particular part of the body. The other form is brachytherapy in which the radiation source is inside the body. An approach based on Bayesian networks was used to model the most relevant steps of teletherapy and brachytherapy. Also, interactions between individuals and between humans and complex systems, considering the dependencies between events and performance shaping factors (including organizational factors) can be realistically modeled. Finally, as a technique for the quantification of Bayesian networks, an expert opinion elicitation procedure was used since there was no available database that could be used. In the case of teletherapy, observing only the stages of prescription, planning and execution, it appears that the step which increases the success probability the most, after consideration of preventive measures is implementation, which is in agreement with cases of errors and accidents reported in the literature. Related to brachytherapy, the most relevant factor was the use of equipment, whose increase in success probability, after consideration of preventive measures was 39.8%, demonstrating the importance of a continuous specific training.
