中文摘要：

目的：针对不同长度和不同体积的食管癌个性化选择放射治疗技术。方法：选择16例不同靶区大小的食管癌患者，分别用Xio计划系统制定一个三维适形（3DCRT）计划、Monaco计划系统制定一个静态调强（IMRT）计划和一个容积旋转调强（VMAT）计划。应用剂量体积直方图和最小显著差异法比较3种治疗计划中靶区、危及器官的剂量学差异并进行数据分析。结果：对于不同大小的靶区，VMAT能较好地控制靶区高剂量在112％处方剂量内，对肺高剂量区、脊髓最大值和心脏剂量的控制均优于其它两种放疗技术。对于头脚方向长度小于13cm且体积小于200CC的靶区，3种计划均满足计划要求，且3DCRT的靶区低剂量区面积小于VMAT。对于头脚方向长度大于13cm且体积大于200CC的靶区，3DCRT无法满足计划要求，IMRT和VMAT计划可较好地控制肺高剂量区，但低剂量区照射面积稍大。结论：对于头脚方向长度较短、体积较小的靶区，考虑肺低剂量面积，可优先选择3DcRT技术；对于头脚方向长度较长、体积较大的靶区，可选择IMRT技术或尽量控制肺低剂量区的VMAT技术，或比较这两种计划，权衡利弊后再选择放疗方式。

英文摘要：

Objective To determine personalized radiotherapy technique for esophageal cancer with different lengths and volumes. Methods Sixteen esophageal cancer patients with different target volumes were selected. Three radiotherapy techniques were respectively prepared for each patient. A three-dimensional conformal radiotherapy （3DCRT） was established by using Xio planning system. A static intensity-modulated radiotherapy （IMRT） and a volumetric modulated arc therapy （VMAT） were designed by using Monaco planning system. Dose-volume histogram and least significant difference method were used to compare and analyzed the dosimetric difference of target volumes and organs at risk. Results For different target volumes, VMAT preferably kept the high dose of target volume within 112% ofpreseription dose, and had a better control effect for the high dose area of lungs, the maximum dose of spinal cord and cardiac dose than the other two radiotherapy techniques. When the head-feet length was less than 13 era and the target volume was less than 200 co, all the three plans met the planning requirements, and the low-dose area of 3DCRT plan was less than that of VMAT. When the head-feet length was more than 13 cm and the target volume was more than 200 co, 3DCRT didn＇t met the planning requirements; comparatively, IMRT and VMAT preferably regulated the high dose area of lung, with but had a slightly larger radiation area of the low dose region. Conclusion Considering the low dose area of lungs, 3DCRT should be preferred for the target volume with shorter head-feet length and smaller volume. For the target volume with longer head-feet length and larger volume, IMRT or VMAT that could control the low dose area of lungs may be an option, or the radiotherapy technique should be determined after comparing and analyzing the advantages and disadvantagesof IMRT and VMAT.