Deep learning promoted target volumes delineation of total marrow and total lymphoid irradiation for accelerated radiotherapy: A multi-institutional study

Background and purpose: One of the current roadblocks to the widespread use of Total Marrow Irradiation (TMI) and Total Marrow and Lymphoid Irradiation (TMLI) is the challenging difficulties in tumor target contouring workflow. This study aims to develop a hybrid neural network model that promotes accurate, automatic, and rapid segmentation of multi-class clinical target volumes. Materials and methods: Patients who underwent TMI and TMLI from January 2018 to May 2022 were included. Two independent oncologists manually contoured eight target volumes for patients on CT images. A novel DualEncoder Alignment Network (DEA-Net) was developed and trained using 46 patients from one internal institution and independently evaluated on a total of 39 internal and external patients. Performance was evaluated on accuracy metrics and delineation time. Results: The DEA-Net achieved a mean dice similarity coefficient of 90.1 % +/- 1.8 % for internal testing dataset (23 patients) and 91.1 % +/- 2.5 % for external testing dataset (16 patients). The 95 % Hausdorff distance and average symmetric surface distance were 2.04 +/- 0.62 mm and 0.57 +/- 0.11 mm for internal testing dataset, and 2.17 +/- 0.68 mm, and 0.57 +/- 0.20 mm for external testing dataset, respectively, outperforming most of existing state -of -the -art methods. In addition, the automatic segmentation workflow reduced delineation time by 98 % compared to the conventional manual contouring process (mean 173 +/- 29 s vs. 12168 +/- 1690 s; P < 0.001). Ablation study validate the effectiveness of hybrid structures. Conclusion: The proposed deep learning framework achieved comparable or superior target volume delineation accuracy, significantly accelerating the radiotherapy planning process.