Phased Implementation for Coordinate System Conversion of a Multi-Linac Radiation Medicine Department from IEC 60601 to IEC 61217
Abstract
Purpose
IEC 61217 is now the reference coordinate standard for modern linear accelerators, yet many multi-linac departments continue to operate legacy IEC 60601 systems. Converting an active clinic between coordinate standards is non-trivial because treatment plans are not transferable across IEC conventions, creating potential safety and operational risks. We describe a phased, physics-led methodology for converting a five-linac radiation medicine department from IEC 60601 to IEC 61217 while maintaining uninterrupted patient care.
Methods
The transition was implemented over three phases spanning ~16 months. A new linac was commissioned directly under IEC 61217, providing an initial clinical pathway isolated from existing IEC 60601 operations. Importantly, beam commissioning and clinical adoption of a new treatment planning system (RayStation) and QA platform (SunCHECK) were not originally planned as part of the IEC conversion, but enabled a deliberate and safe bifurcation of workflows into two IEC-specific pathways. Sequential conversion of existing linacs was guided by retrospective treatment-site workload analysis to balance capacity and avoid patient replanning. A full IEC conversion simulation on an existing linac was performed to validate rollback feasibility and to develop standardized conversion and QA checklists. Each converted linac underwent comprehensive geometric, dosimetric, imaging, and end-to-end validation prior to clinical release. Staff training, protocol development, and procedural readiness were coordinated with each phase.
Results
Two phases have been completed, converting three linacs to IEC 61217 without clinical downtime, safety incidents, or mid-course replanning. Treatments continued throughout all phases, supported by controlled ramp-down and ramp-up of converted units. Clinical capacity was maintained, and QA data were successfully migrated to a unified platform.
Conclusion
This work demonstrates a safe and feasible approach for transitioning a high-volume, multi-linac clinic from IEC 60601 to IEC 61217. The phased strategy, IEC segregation, and reproducible QA sequences provide a practical framework for departments planning transitions.