[Implementation and Effectiveness of Measures to Prevent Recurrence of Incidents Developed through Root Cause Analysis Using Work Flowchart].

Purpose: Incidents are recommended to be analyzed by root cause analysis (RCA). Our institution also conducts RCA for incidents and takes measures to prevent recurrence. The purpose of this study was to evaluate the effectiveness of countermeasures against the root causes analyzed by RCA in order to prevent recurrence of incidents.

Methods: Since the treatment planning CT scanner was replaced, incidents of failure to zero adjustment the coordinates of the bed position occurred four times during a three-month period. The RCA was used to investigate the root causes of these incidents and to formulate measures to prevent recurrence. To evaluate the effectiveness of the recurrence prevention measures, we collected the number of recurrence of incidents during the first year after the effectiveness of the recurrence prevention measures, and used the chi-square test to determine the significant difference in the probability of an incident occurring at a significance level of 5% or less.

Results: The measures to prevent the recurrence of incidents were to double-check that the coordinates of the bed position were adjusted to zero and to simulate operations based on a work flow that incorporated this double-check. During the first year period following the implementation of these recurrence prevention measures, the number of recurrence incidents was zero, and the probability of their occurrence decreased statistically significantly (p<0.05).

Conclusion: Thorough double-checks and work simulation based on the work flow are effective methods for preventing the recurrence of incidents.