An optimized knowledge-based planning method for craniospinal irradiation integrated with auto-contouring

Craniospinal irradiation (CSI) is a complex treatment requiring precise delineation of extended plan target volumes (PTV) and multiple organs at risk (OARs). The process traditionally demands substantial time and expertise from physicians and medical physicists. While artificial intelligence (AI) has shown promise in auto-contouring and auto-planning in other tumors, its application to CSI remains limited due to challenges in model generalizability and outlier sensitivity.

We developed an automated workflow integrating deep learning-based auto-contouring and machine learning-enhanced rapidplan. A DPNUNet-based auto-contouring model was trained on 91 CSI patients to delineate the PTV and OARs. A knowledge-based planning (KBP) model was iteratively refined using machine learning algorithms to exclude dosimetric and geometric outliers. The performance was evaluated by comparing 20 manual plans (MP) and rapidplan (RP) using dosimetric indices.

The auto-contouring model achieved dice coefficients of 0.93 for PTV and > 0.85 for major OARs, reducing contouring time from 1-2 h to 10 min. RP met clinical targets while demonstrating superior OAR sparing. However, RP showed higher PTV hotspots and required more monitor units. The automated workflow reduced the contouring and planning time by 75%, from 6-8 h to 1 h.

The proposed framework maintained clinical plan quality while significantly improving efficiency, demonstrating feasibility for standardized CSI planning.