ObjectiveTo compare the dosimetric differences among flattening filter free intensity modulated radiotherapy (3FIMRT), flattening filter free volumetric modulated arc therapy (3FVMAT), filter free intensity modulated radiotherapy (IMRT), and filter free volumetric modulated arc therapy (VMAT) for hyperthyroidism exophthalmus patients.MethodsComputed tomography (CT) scans of 29 patients, who were diagnosed with hyperthyroidism exophthalmus and treated with radiation therapy between September 2016 and September 2017, were selected for study. Four treatment plans with the same dose prescription and objective constrains were designed for each patient based on their images, consisting of IMRT, VMAT, 3FIMRT, and 3FVMAT. The target dosimetric distribution, normal tissue radiation dose, monitor units, and treatment time of each plan were evaluated.ResultsFour types of plans were all able to satisfy the clinical treatment requirements, and there were no significant differences in maximum dose, mean dose (Dmean), homogeneity index of the targets (P>0.05). For the parameters minimum dose, V50%, conformity index (CI), gradient index of the targets, statistically significant differences were observed among the four kinds of technologies (F=10.920, 35.860, 11.320, 17.790; P<0.05). The CI of IMRT and 3FIMRT were superior to those of VMAT and 3FVMAT, but there was no significant difference between IMRT and 3FIMRT. In terms of Lens Dmean and Brain Dmean, statistically significant differences were observed among the four kinds of technologies (F=5.054, 83.780; P<0.05). For Lens Dmean and Brain Dmean, 3FVMAT achieved better sparing effects when compared with the other three plans. The total monitor units and treatment time did not significantly differ between 3FVMAT and VMAT. The mean monitor units of 3FVMAT were 65.07% and 70.22% less than that of IMRT and 3FIMRT respectively. The mean treatment time of 3FVMAT were 48.1% and 35.24% less than that of IMRT and 3FIMRT respectively.Conclusion3FVMAT can bring more dosimetric advantages for hyperthyroidism exophthalmus radiation therapy when compared with IMRT, 3FIMRT, and VMAT.
Objective To analyze the efficacy of and recurrence mode after adjuvant radiotherapy for lower thoracic esophageal squamous cell carcinoma (TESCC) patients after radical operation with anastomosis above aortic arch. Methods Sixty-three patients with lower TESCC who received adjuvant radiotherapy after R0 radical operation with anastomosis above aortic arch between February 2011 and February 2019 were retrospectively enrolled. The clinical tumor volume (CTV) included anastomotic stoma, and lymph node drainage area in mediastinum and upper abdomen. The survival status, recurrence and metastasis of tumors, and the influencing factors were analyzed. Results The 1-, 2-, and 3-year overall survival rates were 98.3%, 83.3%, and 63.7%, respectively. The median disease-free survival (DFS) was 33 months [95% confidence interval (23.2, 42.8) months], and the 1-, 2-, and 3-year DFS rates were 76.3%, 58.5%, and 41.7%, respectively. Patients with N0-1 had longer DFS than those with N2-3 (median: not reached vs. 15 months, P=0.045). The recurrence rate of anastomotic site was 7.9%. The recurrence rates of lymph nodes in supraclavicular region, upper middle mediastinum, and upper abdomen were 4.8%, 15.9%, and 1.6%, respectively. The distant metastasis rate was 17.5%. The incidence of grade 2-3 radiation pneumonitis, grade 3 anastomotic stenosis, and grade 3 tracheal fistula were 4.8%, 3.2%, and 1.6%, respectively. Conclusions N2-3 is a poor prognostic factor for such patients. Regional lymph node recurrence is mainly revealed in the middle and upper mediastinum. Whether the CTV should include anastomotic stoma and lymph node drainage area in lower mediastinum and upper abdomen is questionable.