AI auto-contouring in radiotherapy

A practical checklist for implementing AI auto-contouring in radiotherapy

Published on June 1, 2026

AI auto-contouring in radiotherapy

Radiotherapy treatment planning requires accurate identification of the target volume and organs at risk (OARs), a task traditionally performed by experienced radiation oncologists. However, manual contouring of OARs is time-consuming and subject to inter-observer variability1. In recent years, the development of deep learning models, particularly convolutional neural networks (CNNs) and U-Net architectures, has driven the introduction of artificial intelligence (AI)-based auto-contouring systems. 

Clinical studies have shown that auto-contouring can significantly reduce the time required for OAR delineation. Urago et al.2 demonstrated a significant reduction in delineation time with auto-contouring, requiring six minutes compared with the three hours needed for manual delineation in head and neck cancer cases. The review by Zafar et al.3reported that auto-segmentation can reduce delineation time by up to 75% compared with manual contouring. A survey of French radiation oncologists found that 35% of users achieved time...

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