2251 - Dosimetric Comparison of Intensity-Modulated Radiotherapy, Helical Tomotherapy, and Intensity-Modulated Radiotherapy Based on Orthogonal Dual-Layer Multileaf Collimator In Cervical Esophageal Cancer Patients with Definitive Chemoradiotherapy
Presenter(s)
Q. Liu1, C. Zheng2, K. Shang3, S. Chen1, J. Ai4, Y. Wang1, J. Wang5, and J. Wang1; 1Department of Radiation Oncology, the Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China, 2Hebei Medical University, Shijiazhuang, China, 3Department of Radiotherapy, the Fourth Hospital of Hebei Medical University, Shijiazhuang, China, 4the Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China, 5Fourth Hospital of Hebei Medical University, Shijiazhuang, China
Purpose/Objective(s): To evaluate the dosimetric differences in target volumes and organs at risk (OARs) among intensity-modulated radiation therapy (IMRT), helical tomotherapy (TOMO), and IMRT based on orthogonal dual-layer multileaf collimator (VenusX planning system) for Cervical Esophageal Cancer (CEC) patients with Definitive Chemoradiotherapy (DCRT).
Materials/Methods: Treatment plans with elective node irradiation (ENI) were designed for 20 patients who pathologically diagnosed with cervical esophageal squamous cell carcinoma using IMRT, TOMO, and VenusX techniques, respectively. Dosimetric parameters, including target conformity index (CI), homogeneity index (HI), and dose-volume metrics for OARs, were compared among the three plans.
Results: Compared to both IMRT and VenusX plans, TOMO demonstrated higher CI and lower HI simultaneously (all P < 0.001). In the high-dose region (D2%, Dmax), TOMO was lower than both IMRT and VenusX plans. In the low-dose region (D98%), TOMO showed higher than the other two groups (all P < 0.001). The TOMO plan achieved significantly lower V60, Dmax, and Dmean of the thyroid when compared to IMRT and VenusX plans (all P < 0.001). Regarding to the mean dose to the brachial plexus and carotid arteries, the VenusX plan was significantly lower than TOMO plan (P = 0.006, and P < 0.001, respectively). Both TOMO and VenusX plans decreased the Dmax of laryngeal cavity when compared to IMRT, besides, VenusX demonstrating an advantage over TOMO (P =0.002). Furthermore, the V20, V25, V30, V35, and V40 of total lungs were significantly reduced in the VenusX plan.
Conclusion: Compared with IMRT plan, TOMO achieved superior target conformity and dose homogeneity. The TOMO plan demonstrated advantages in reducing thyroid irradiation dose, whereas the VenusX plan showed superior performance in reducing the mean dose to the brachial plexus and carotid arteries, constraining laryngeal Dmax, and decreasing the high dose irradiated volume and mean dose of the bilateral lungs.