A Guideline-Aware AI Agent for Zero-Shot Target Volume Auto-Delineation
This addresses the costly retraining issue for deep learning models in radiotherapy when guidelines change, offering a scalable and interpretable solution for treatment planning.
The paper tackled the problem of automating clinical target volume delineation in radiotherapy without needing retraining for guideline updates, by introducing OncoAgent, a guideline-aware AI agent that achieved zero-shot Dice scores of 0.842 for CTV and 0.880 for planning target volume, comparable to supervised baselines and preferred by physicians in clinical evaluations.
Delineating the clinical target volume (CTV) in radiotherapy involves complex margins constrained by tumor location and anatomical barriers. While deep learning models automate this process, their rigid reliance on expert-annotated data requires costly retraining whenever clinical guidelines update. To overcome this limitation, we introduce OncoAgent, a novel guideline-aware AI agent framework that seamlessly converts textual clinical guidelines into three-dimensional target contours in a training-free manner. Evaluated on esophageal cancer cases, the agent achieves a zero-shot Dice similarity coefficient of 0.842 for the CTV and 0.880 for the planning target volume, demonstrating performance highly comparable to a fully supervised nnU-Net baseline. Notably, in a blinded clinical evaluation, physicians strongly preferred OncoAgent over the supervised baseline, rating it higher in guideline compliance, modification effort, and clinical acceptability. Furthermore, the framework generalizes zero-shot to alternative esophageal guidelines and other anatomical sites (e.g., prostate) without any retraining. Beyond mere volumetric overlap, our agent-based paradigm offers near-instantaneous adaptability to alternative guidelines, providing a scalable and transparent pathway toward interpretability in radiotherapy treatment planning.