Main of probabilistic safety assessment (PSA) of the radiotherapy treatment process with a linear accelerator for medical purposes (linac); Principales resultados del analisis probabilista de seguridad (aps) del proceso de tratamiento de radioterapia con un acelerador lineal de usos medicos (linac)

The radiation safety assessments traditionally have been based on analyzing the lessons you learn of new events that are becoming known. Although these methods are very valuable, their main limitation is that only cover known events and leave without consider other possible failures that have occurred or have not been published, This does not mean they can not occur. Other tools to analyze prospectively the safety, among which found Probabilistic Safety Assessment (PSA). This paper summarizes the project of American Forum of agencies radiological and nuclear regulators aimed at applying the methods of APS treatment process with a linear accelerator. We defined as unintended consequences accidental exposures both single patient and multiple patients. FMEA methodology was used to define events initiators of accidents and methods of event trees and trees failure to identify the accident sequences that may occur. A Once quantified the frequency of occurrence of accidental sequences Analyses of importance in determining the most recent events significant from the point of view of safety. We identified 158 of equipment failure modes and 295 errors human if they occurred would have the potential to cause the accidental exposures defined. We studied 118 of initiating events accident and 120 barriers. We studied 434 accident sequences. The accidental exposure of a single patient were 40 times likely that multiple patients. 100% of the total frequency of accidental exposures on a single patient is caused by human errors . 8% of the total frequency of accidental exposures on multiple patients initiating events may occur by equipment failure (Computerized tomography, treatment planning system, throttle linear) and 92% by human error. As part of the and recommendations of the study presents the events that are more contribution on the reduction of risk of accidental exposure. (author)