Automated Assessment of Target and OAR Volume Changes to Determine the Optimal Re-Planning Point for Head-and-Neck Patients.
Abstract
Purpose
To evaluate the impact and viability of implementing an automated weekly check tool that tracks daily volume changes of target volumes and organs at risk (OARs) for head and neck treatments, optimizing when to re-scan and re-plan the patient.
Methods
Our clinic implemented the ChartCheck Adaptive (CCA) (Radformation Inc., New York) software to assess day-to-day dose changes for targets and OARs by analyzing volumetric changes to AI-generated contours on daily CBCT scans for head and neck patients. We configured the system to automatically flag cases in which tumor or organ-at-risk volumes exceed predefined change thresholds, enabling physicists to predict when rescans and re-planning are necessary.
Results
Volume changes were assessed for intermediate-risk and low-risk clinical target volumes (CTVs), as well as for right and left parotid OARs. We randomly selected 16 patients (8 with re-sim and 8 without re-sim) to evaluate. On average, the patients that received a re-sim were re-planned at fraction 19 based on physician daily imaging review. The volume changes that were assessed in CCA indicated that significant changes (>10%) in CTVs and parotid volumes are observable between fractions 16 and 21. The target and OAR volume changes after the re-sim were significant enough that when compared to first fraction, the volume changes would exceed the 10% threshold, which is a metric easily trackable by CCA.
Conclusion
This data‑driven approach can replace the labor‑intensive manual review traditionally performed by physicians, which relies on visual assessment of daily images rather than quantitative volumetric and/or dose metrics. This approach allows for replanning resources to be strategically allocated rather than conducting subjective, clinician-determined reviews, thereby improving clinical efficiency. In the future, we aim to analyze dosimetric changes in addition to volume changes as indicators for replanning.