Streamlining Reirradiation Evaluation: An Esapi-Based Script for Rapid Cumulative Dose Assessment and Consultation Reporting
Abstract
Purpose
With improvements in patient outcomes, re-irradiation is increasingly pursued and is becoming a common occurrence in the clinic. Safe planning requires accurate characterization of cumulative organ-at-risk (OAR) exposure across treatment courses that may differ in fractionation and timing. Eclipse out-of-the-box tools can only sum doses physically without accounting for radiobiologic differences between fractionation regimens and time elapsed since previous treatments. This project aimed to develop and validate a user-friendly Eclipse Scripting API (ESAPI) tool that automates cumulative dose evaluation and generates a standardized physics consultation report to support re-irradiation decision-making.
Methods
An ESAPI script was developed to perform structure-specific equivalent dose in 2 Gy fractions (EQD2) conversion using user-defined α/β and time-forgiveness factors. Default institutional α/β and forgiveness factors are automatically assigned based on organ types. This allows for a 1-click workflow resulting in the automatic generation of a standardized physics consultation report featuring a comparison of relevant dose metrics (e.g., D0.1cc) against institutional EQD2 dose limits. Five clinical re-irradiation cases were retrospectively analyzed to compare script outputs with a conventional MIM-based workflow.
Results
The MIM-based workflow required roughly 1 hour per patient (including data transfer) to complete the re-irradiation physics consultation for an experienced user. In contrast, the ESAPI script natively completed dose accumulation and generated a comprehensive report in <3 minutes. Across all patients, cumulative dose metrics of all OARs were found to have an average difference of less than 0.2 Gy between the script-based approach and the MIM-based workflow. The script handled imports across treatment machines, aiding in reviews of cross-vendor treatments.
Conclusion
A fast, standardized ESAPI tool was developed to automate re-irradiation cumulative dose evaluation and reporting directly in Eclipse. Clinically implemented, the script reduces analysis time, improves consistency, and enhances communication by producing a physics consultation report to support safe re-irradiation planning and review.