The Utilisation of Probabilistic Risk Assessment in Radiation Oncology

The technology in radiation oncology has rapidly evolved over the last number of years. The increased complexity of the technology has brought with it increased risk. Systematic risk assessment techniques are now required to ensure the safe delivery of treatment with these new technologies. The risk assessment methodology proposed here combines portions of Failure Mode and Effect Analysis (FMEA), Fault Tree Analysis (FTA) and human error probability modelling. The radiotherapy treatment process was modelled using the analysis described by Ford et al. [Medical Physics 39, no. 12 (2012): 7272-7290]. The output of the model is graphically represented to demonstrate the interactions and relationships between the individual tasks in the radiotherapy process. The components of each process were critically analysed to ascertain their fault potential. Prostate external beam treatment was used as a case study. The proposed methodology identified 34 error modes with the potential to affect the safe delivery of treatment. This method of risk analysis in radiotherapy is novel. It is highly beneficial in evaluating the effectiveness of the safety system currently in place in Radiotherapy. The human error probability is an estimated value which can vary under different conditions. The use of quantitative human error probability values enables the utilisation of mathematical methods to predict the effect of different interactions.