A Clinical Workflow for Evaluating Dose to Organs at Risk After Biology-Guided Radiation Therapy Delivery

Purpose: To develop a workflow for systemically reviewing the doses received by organs at risk (OARs) in a BgRT treatment session, as a means of monitoring delivery constancy and possibly identifying changes of clinical concern in the patient. Methods: We implemented a workflow consisting of a qualitative review of the reconstructed delivered-dose information provided by the RefleXion system, followed by its quantitative evaluation using in-house software. For the latter we developed a framework for calculating custom OAR dose-volume metrics from the delivered-dose distribution and graphing them. We retrospectively applied our workflow to three select BgRT patient cases to appraise its clinical utility. Results: Our workflow efficiently incorporates existing RefleXion TPS features and in-house software into a process for thoroughly evaluating doses to OARs after BgRT delivery. The spreadsheet we created for graphing the trends of normalized OAR dose-volume metrics readily shows if OAR doses have significantly changed or tolerance limits have been violated, thereby potentially revealing if changes of concern occurred in the targeted region. Our workflow also yields a cumulative delivered-dose record at the end of treatment. Conclusions: We established a post-BgRT dose evaluation workflow which supplements the information provided by RefleXion with calculation and graphing of custom OAR dose-volume metrics. This workflow is now routinely used in our clinic following all BgRT treatments. Future improvements could include increased automation, updating the dose calculation to reflect changes in patient anatomy, incorporation of PET metrics, and consideration of target dose data.