Abstract：Objective To compare the dosimetric differences of intensity-modulated radiotherapy (IMRT) for mid-thoracic esophageal
cancer with different field numbers and incidence directions. Methods Ten patients with middle thoracic esophageal cancer were
selected for retrospective study on the Pinnacle 9.10 treatment planning system. Three kinds of IMRT plans were designed for each
patient, which were based on the 5 fields of butterfly shaped (PA, 180°, 140°, 20°, 340° and 220° of the field direction), 7 fields (Pb,
180°, 150°, 120°, 20°, 340°, 240° and 210° of the field direction) and 7 fields equally divided (PC, 180°, 128°, 76°, 24°, 332°,
280° and 228° of the field direction) . The prescription of planning target volume (PTV) dose was 50.4Gy/28F, and the PTV dose
of 95% volume was not less than 50.4Gy. The dose volume histograms (DVH) were used to compare the dose differences between
PTV and organs at risk for each plan. All data were analyzed by using SPSS 19.0 software. Results Comparison of PTV dosimetry
of 3 radiotherapy plans, D95%, mean dose (Dmean), the difference was not statistically significant (P>0.05). The conformity index of
PC was the highest, PA was the lowest (P<0.05)| PA had the lowest Dmean, and the PC wsa the highest (P<0.05), but compared with
V20 and V30 of the double lungs, the PC was lower than the PA (P<0.05)| PC was superior to PA in dosimetry comparison of heart
and spinal cord dosimetry| NT dosimetry comparison was similar to that of double lungs| PA had the highest monitor unit and PC
the lowest. All indicators of PB plans were between PA and PC. Conclusion For the vast majority of patients with postoperative
radiotherapy of mid-thoracic esophageal cancer, the PB plan can be preferentially selected| for patients with poor lung function or
higher requirements for lung protection, the PA can be preferred| for patients with strict heart protection, the PC can be considered.
刘小龙，庞皓文，杨波. 胸中段食管癌术后不同布野方案对调强放疗剂量分布的影响[J]. 中国医疗设备, 2021, 36(2): 46-49.
LIU Xiaolong, PANG Haowen, YANG Bo. Effects of Different Field Arrangements on Dose Distribution of Postoperative Intensity-
Modulated Radiotherapy for Mid-Thoracic Esophageal Cancer. China Medical Devices, 2021, 36(2): 46-49.
