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[目的]用DVH评价胸中段食管癌放疗的常规、二维(2D)和三维(3D)方案 ,为合理选择治疗计划提供参考。[方法]在7例患者中模拟常规、2D和3D方案 ,用DVH评价不同计划中GTV、PTV、肺脏和脊髓剂量与体积的关系。[结果]2D和3D方案原发灶100 %体积均达64.6Gy,常规方案受照体积较低 ;2D和3D方案中淋巴结均达60Gy,常规方案肿大淋巴结受照不足 ;2D和3D方案PTV190 %体积达64.6Gy,常规方案有4例低于75 % ;3种方案肺脏受照30Gy体积均未超过1/3 ;例6和例7的2D和3D方案脊髓受照体积较高。[结论]病灶偏右或居中、长度<10cm、横径≤4cm、无淋巴结转移时可使用常规方案 ;2D方案的剂量分布有较好的代表性 ;3D方案给予肿瘤足够照射的同时减少正常组织受量
[Objective] To evaluate the routine, two-dimensional (2D) and three-dimensional (3D) schemes of esophageal cancer radiotherapy in the middle and upper thoracic esophagus with DVH, providing a reference for the rational selection of treatment plans. [Methods] The routine, 2D and 3D regimens were simulated in 7 patients. The relationship between dose and volume of GTV, PTV, lung and spinal cord in different plans was evaluated by DVH. [Results] 100% of the volume in the 2D and 3D protocols reached 64.6Gy, and the volume of the conventional protocol was lower. The volume of lymph nodes in both 2D and 3D protocols reached 60Gy, and the conventional regimen enlarged lymph nodes were under-illuminated. The 2D and 3D protocols PTV190 % Of volume reached 64.6Gy, 4 of the conventional regimens were less than 75%; none of the 3 regimens received 30% of the lung volume of the irradiated 30Gy; and the 2D and 3D regimens of Examples 6 and 7 had a higher volume of irradiated spinal cord. [Conclusion] The conventional approach was used when the lesion was right or middle, the length was less than 10cm and the diameter was less than or equal to 4cm. The dose distribution of 2D regimen was well represented. The 3D regimen gave enough radiation to the tumor and reduced the normal tissue By the amount