Technical Note: an Eclipse Scripting Application Programming Interface-based Tool for Automated Structure Duplication, Cropping, and Ring Generation in Eclipse Treatment Planning System

Introduction: Structure duplication and margin-based cropping are routine but time-consuming steps in inverse treatment planning using the Eclipse treatment planning system (TPS). Manual execution is prone to errors such as accidental overwriting and inconsistent margins. This technical note describes the development of an Eclipse scripting application programming interface (ESAPI)-based tool that automates these tasks within a single workflow. Methods: The in-house script was developed using ESAPI v15.5 on Varian’s T-BOX, with Microsoft Visual Studio 2019 and Eclipse TPS. The graphical user interface was built using Windows Presentation Foundation to allow users to select structures easily. The core logic was written in C#. Development and initial testing were performed on the T-BOX, followed by implementation in the clinical workflow. Results: Cropping time was reduced from several minutes to seconds. The script also eliminated common user errors such as incorrect cropping or overwriting. It allowed multiple structure selection and cropped only overlapping regions, removing the need for manual identification. A maximum of 0.95% variation was found between the volumes of structures created manually and using the script, which is clinically negligible for auxiliary planning structures. Conclusion: This technical note presents a practical ESAPI implementation that demonstrated substantial time savings and improved accuracy, minimizing manual steps and reducing error risk.