Linguistic approach to support human reliability analysis and validation work in advanced radiotherapy technologies

An integrated methodology, that combines Hierarchical Task Analysis (HTA), Cognitive Task Analysis (CTA) and a modified Human Error Assessment and Reduction Technique (HEART), is proposed to identify safety-relevant human actions in innovative and advanced facilities. It is suggested to use in HEART the concept of linguistic expressions for proportion assessment factors. To prove its applicability, a case study is presented. The validation work has related to safety analyses of accidental events that can involve radiological over-exposure of patients during proton therapy treatments carried out by CATANA (Centro di AdroTerapia Applicazioni Nucleari Avanzate) centre, Italy. CATANA is the first Italian clinical facility that since 2002 used proton beams for ocular melanoma treatments. The results demonstrate the validity of the proposed integrated methodology as well as the versatility of HEART linguistic approach.