Mammosite brachytherapy; a safety approach to quality assurance using IDEFØ diagrams

Introduction: MammoSite High Dose Rate (HDR) brachytherapy is becoming an increasingly widespread procedure delivering radiotherapy to post surgery breast cancer patients. This paper examined the application of risk assessment and its relation to Quality Assurance (QA) and Quality control (QC) procedures. Materials and Methods: IDEFØ diagrams were used to look at the steps in the process. These diagrams were used to identify potential treatment delivery errors and to develop a protocol for QA based on this assessment. The risk assessment identified the risks from this procedure, taking into account the levels of probability of an incident occurring, and the levels of severity of the incident. This study examined how QA and QC protocols can be implemented using a prospective study of risk though IDEFØ diagrams and applying identified hazards to a risk matrix. The probability of occurrence and the levels of severity were applied to hazards and errors identified, and a resulting risk number was calculated from the risk matrix. A number of different QA and QC procedures were then applied to the system to analyze how they affect the calculated risk number. This paper provides an example of good practice for applying systems engineering tools that can be used to strengthen the QA and QC program. These different QA and QC procedures were then applied to the potential errors and hazards to analyze how they affect the risk number. Results and discussion: The use of IDEFØ diagrams showed the steps at a detailed level making them easier to identify hazards. The risk matrix can then be used to improve and analyze on the QA and QC protocol. This methodology for risk assessment is useful for a prospective study of risk.