Retrospective Study on the Prediction of Radiation-induced Brain Injury in Patients With Nasopharyngeal Carcinoma

All patients were staged according to the 8th edition of the TNM classification by the American Joint Committee on Cancer/Union for International Cancer Control and received a standardized treatment regimen including IMRT and concurrent or adjuvant chemotherapy. Inverse IMRT treatment planning was performed on a Varian Inspiration Platform (version 10.0), using the simultaneous integrated boost technique. The prescribed doses were 68-75 Gy to the PTV of the GTVnx in 32-34 fractions; 64-75 Gy to the PTV of the GTVnd in 32-34 fractions; 60 Gy to the PTV of CTV1 in 32 fractions; and 50 Gy to the PTV of CTV2 in 28 fractions. All patients were given one fraction daily 5 days a week. The dose-volume-histograms (DVHs) of the organs at risk were evaluated as described in the radiation therapy oncology group (RTOG) 0225 protocol to prevent violation of the tolerance limits.