Program Information
Study of the Correlation Between the Anatomic Features of PTV and the Whole Lung DVH in Esophagus Cancer IMRT Plans
Department of Radiation Oncology, Shandong Tumor Hospital, Jinan, China
Presentations
SU-E-T-711 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: To quantitatively detect the correlation between the anatomic features of plan target volume (PTV) and the whole lung dose-volume histogram (DVH) in esophagus cancer (EC) intensity-modulated radiotherapy (IMRT) plans.
Methods: 50 patients with EC underwent IMRT protocol were retrospectively studied. The PTV of EC contained esophagus gross target volume (GTV) and the positive neck lymph nodes. 7 fixed gantry IMRT plans were designed by senior planners for each patient using treatment planning system-Eclipse 10.0 (Varian Medical Systems, Palo Alto, CA). The doses of all organ at risks (OARs) met clinical standard. The valuable morphological parameters of PTV under positive neck lymph nodes, such as the volume, the surface area, the ratio of PTV volume to whole lung volume, the fraction of whole lung volume overlapping with PTV (overlap volume), the length, and the torsion, were extracted. The correlation between every anatomic feature parameter of PTV and the whole lung DVH of EC plans were counted. Finally we acquired a curve about the whole lung doses and every morphological parameter using data fitting.
Results: The morphological parameters of PTV under positive neck lymph nodes can be described quite well. Valuable anatomic feature parameters, such as the ratio of PTV volume to whole lung volume, the overlap volume, and the length, impact the whole lung DVH significantly. With these parameters value increasing, dosimetric parameters (such as V5, V10, V20, V30, V40, the mean dose of whole lung) will raise. Especially, the low-dose regions are more obvious.
Conclusion: The results highlight that the anatomical features parameters of PTV and dosimetric indexes of whole lung DVH can be correlated quantitatively in EC IMRT plans, and which offers a potential use in study and prediction of whole lung doses in EC radiotherapy.
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