Making Adaptive Radiotherapy Routine: A High-Throughput Adaptive–IGRT Clinical Workflow
Abstract
Purpose
Weekly or triggered online adaptive radiotherapy has not been widely adopted in clinical practice because of the time and resource demands. Although the Ethos platform enables CBCT-based online adaptive radiotherapy, daily adaptation may be unnecessary for treatment sites with gradual anatomical changes. This work describes the development and clinical implementation of a high-throughput online adaptive–IGRT workflow using the Ethos platform, in which adaptive replanning is performed weekly. The resulting adaptive plan is converted into a non-adaptive IGRT plan for subsequent fractions until the next adaptive session. The workflow is designed to maximize efficiency in a high-volume clinical environment.
Methods
The workflow comprises three components: Adaptive Simulation, Adaptive-to-IGRT Plan Conversion, and Patient Scheduling. For initial adaptive treatments, HyperSight CBCT images and updated structures are acquired. Fiducial markers coinciding with simulation skin tattoos denote simulation isocenter coordinates during plan conversion. Adaptive-to-IGRT plan conversion is performed in the Ethos treatment planning system by importing adaptive CBCT images, structures, and plans, then switching to IGRT mode. Physics plan checks verify image accuracy, plan integrity, and monitor unit consistency. Adaptive and IGRT fractions are scheduled in ARIA, and a departmental web-based dashboard provides real-time visibility into adaptive scheduling.
Results
Following implementation, adaptive patient volume increased from an average of 6 to 17 patients per day. A total of 79 adaptive-to-IGRT plan conversions were completed for 15 patients across lung, rectum, esophagus, pancreas, and cervix treatment sites. Mean plan conversion time ranged from 25 to 30 minutes, and mean physics plan check time ranged from 15 to 25 minutes. Major failure modes included scheduling deviations, missing fiducial placement, and communication gaps, which were mitigated via role-specific checklists.
Conclusion
This high-throughput adaptive–IGRT workflow enables sustainable integration of weekly or triggered adaptive radiotherapy into busy clinical environments, facilitating routine adaptive practice without excessive clinical burden.