Risk analysis of the Unity 1.5 T MR‐Linac adapt‐to‐position workflow

Abstract

Background and Purpose: Newer technologies allow for daily treatment adaptation, providing the ability to account for setup variations and organ motion but comes at the cost of increasing the treatment workflow complexity. One such technology is the adapt-to-position (ATP) workflow on the Unity MR-Linac. Prospective risk assessment of a new workflow allows clinics to catch errors before they occur, especially for processes that include novel and unfamiliar steps. Methods: As part of a quality management program, failure modes and effects analysis was performed on the ATP treatment workflow following the recommendations of AAPM's Task Group 100. A multidisciplinary team was formed to identify and evaluate failure modes for all the steps taken during a daily treatment workflow. Failure modes of high severity and overall score were isolated and addressed. Results: Mitigations were determined for high-ranking failure modes and implemented into the clinic. High-ranking failure modes existed in all steps of the workflow. Failure modes were then rescored to evaluate the effectiveness of the mitigations. Conclusion: Failure modes and effects analysis on the Unity MR-Linac highlighted areas in the ATP workflow that could be prone to failures and allowed our clinic to change the process to be more robust.

Optimization of treatment workflow for 0.35T MR‐Linac system

“…Despite the valuable insights offered by these publications, there remains an absence of a universally accepted standard for identifying the threshold at which an RPN score requires attention. In contrast to prior studies that solely relied on either RPN or a risk matrix to assess the risk levels, our novel approach of incorporating a risk matrix alongside RPN considerations demonstrated that RPNs significantly lower than the thresholds proposed in the literature may still indicate a high level of risk and require specific attention 21–23 . Conversely, certain steps with low‐risk levels might yield high RPN values due to their high occurrence rate.…”

“…In contrast to prior studies that solely relied on either RPN or a risk matrix to assess the risk levels, our novel approach of incorporating a risk matrix alongside RPN considerations demonstrated that RPNs significantly lower than the thresholds proposed in the literature may still indicate a high level of risk and require specific attention. [21][22][23] Conversely, certain steps with low-risk levels might yield high RPN values due to their high occurrence rate. The analysis showed that human failures, such as inexperience, inattention, and a lack of thorough checks, are identified as the primary potential causes of these high-risk failure modes.…”