A Practical Framework for Safe Linac Coordinate System Standardization
Abstract
Purpose
Linear accelerator (LINAC) coordinate system conventions have historically evolved heterogeneously, with vendors and institutions adopting mixed non-IEC standards. While clinically functional, this lack of uniformity introduces added complexity and potential risk, particularly in multi‑site clinical environments, where identical treatment geometries may be displayed with different angles across the treatment planning and delivery chain. We report our site-of- practice’s transition to the IEC 61217 standard to improve consistency across treatment planning, delivery, and ancillary systems.
Methods
A structured framework was developed for a controlled weekend conversion to IEC 61217. Preparatory meetings defined scope, tasks, and responsibilities including vendor collaboration. Tasks were distributed among four physicists and one dosimetrist. Key activities included machine configuration update in the record-and-verify (R&V) system, beam model updates, system verification, and conducting QA. Active patient plans were recalculated using the IEC-compliant beam model with custom naming conventions, exported to the R&V system, and corresponding updates were applied to the surface guidance system. During the transition weekend, LINAC coordinate settings were modified and synchronized in the R&V system, followed by comprehensive plan validation and end‑to‑end testing of planning, exporting, imaging, surface guidance system, and treatment delivery workflows using a new clinical case.
Results
For a center operating two LINACs with approximately 60 active patients, the transition, including full verification, was completed over a single weekend without clinical disruption. Total effort included ~25 hours by dosimetry, ~3 hours by engineering/R&V support, and ~35 hours of physics work. No treatment errors or user‑reported issues occurred following implementation.
Conclusion
IEC 61217 standardization is a high-impact process requiring meticulous planning, rigorous QA, and cross‑team collaboration. Our experience demonstrates that IEC 61217 standardization can be achieved safely and efficiently, offering a practical framework for institutions seeking improved consistency and patient safety while minimizing downtime.