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Process Failure Modes and Effects Analysis On Human Errors Using a Novel Linac with Simplified Workflow

J Johnson

J Johnson*, T Netherton , Y Li , P Nitsch , S Gao , P Balter , A Klopp , L Court , The University of Texas MD Anderson Cancer Center, Houston, TX


TH-AB-FS1-12 (Thursday, August 3, 2017) 7:30 AM - 9:30 AM Room: Four Seasons 1

Purpose: We performed a prospective risk analysis to identify the highest potential failures that would impact patient safety on a prototype radiotherapy machine redesigned to streamline daily image guidance and treatment delivery.

Methods: We determined the process maps for machine performance check (MPC), daily machine quality assurance (DMQA), and patient treatment delivery (PTD). A hybrid of process Failure Modes and Effects Analysis (FMEA) and Systematic Human Error Reduction and Prediction Approach (SHERPA) related to human factors (HF) engineering was used to identify potential failure modes (FMs) and their potential causes of failure relating to the task: action, retrieval, checking, selection, and communication. Each cause was scored for its likelihood for occurrence (O), severity (S), and lack of detectability (D) without quality control in place, using a scale of 1 (low) to 3 (high) each. The risk profile number (RPN) was calculated (=O*S*D). FM of RPN ≥ 18 or S ≥ 3 were identified as high risk.

Results: The team identified 10 steps for MPC with 19 FMs, including action (8) tasks; 22 steps for DMQA with 23 FMs, including action (13), selection (7) and checking (2) tasks; and 37 steps for PTD with 50 FMs, including action (25), selection (9), checking (4), retrieval (3) and communication (3) tasks. Some FMs (action tasks) with S ≥ 3 for MPC (4), DMQA (4) and PTD (5) relate to operational training; others (selection, checking tasks) for DMQA (3) and PTD (8) concern procedures and organizational strategies. FMs with RPN ≥ 18 for PTD (3) link procedures and organizational with patient selection and shift checking tasks.

Conclusion: Several risks remain related to operational training (action tasks). Even with the streamlined workflow, clinical training and organizational (cultural) strategies are crucial for quality and safe delivery of patient care.

Funding Support, Disclosures, and Conflict of Interest: This work was funded by Varian Medical Systems.

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