SU-E-T-718: Automatic IMRT Plan Quality Control for GYN Cancer Clinical Trials

Purpose: To perform efficient quality control (QC) of intensity-modulated radiotherapy (IMRT) plans of gynecological (GYN) cancer in clinical trials. Methods: Plan QC is a necessary component in clinical trials that requires much time and effort. IMRT plans from the INTERTECC clinical trial for the treatment of intact cervix cancer patients have been used to evaluate a plan QC tool. The CT image, organ and target contours, and the clinical IMRT plan were imported into a GPU-based treatment re-planning system that was originally designed to perform online adaptive radiotherapy. The clinical plan was considered as the reference plan and the re-planning system automatically created a new plan. The objective for re-planning was to reduce dose of organs-at-risk (OARs) and to get a more uniform dose in the PTV with respect to the reference plan. After performing automatic re-planning on each plan, we compared the new and the reference DVH curves in terms of the treatment planning goals specified in the clinical trial protocol. Results: Data from 12 patients was retrospectively analyzed. Results showed that DVH curves of the automatic plan satisfy the specified clinical constraints more frequently than the actual clinical plans. DVH for the PTV of the new plan was in most cases similar to the clinical plans, indicating good quality PTV coverage. In 2 out of the 12 cases the QC tool could achieve a PTV hotspots reduction of 11% and 10% respectively. For most patients, lower doses in OARs were achieved after re-planning, except in those plans where there was overlap between OARs and PTV. Re-planning takes less than 1 min for each case. Conclusion: We have proved the feasibility of efficient IMRT plan QC in clinical trials for patients with GYN cancer. Varian Medical Systems through a Master Research Agreement