提高食管癌放疗局部控制率的关键在于靶区的精准定位及勾画。食管癌易发生黏膜下浸润，在CT定位图像上勾画纵向GTV主观差异大，很难实现精准定位、勾画及实时追踪验证。通过食管EUS植入基准标记物，可以精准确定食管癌纵向边界，但目前用于该方法的标记物尚有诸多缺陷。能否构建新型标记物联合EUS精准定位纵向GTV，以实现靶区精确勾画及实时验证，成为提高放疗疗效的关键。本课题组对小鼠皮下植入不同混合物的实验研究显示NBCA联合碘化油有可能成为理想标记物。因此，我们拟在前期工作基础上，通过体内外实验验证新型基准标记物的安全性、稳定性和可视性；利用食管EUS在动物和食管癌患者中植入标记物，通过随访EUS、分析CT图像和术后病理标本为新型基准标记物指导食管癌精准放疗提供理论基础；并进一步评估新型基准标记物在GTV勾画、SIB-IMRT和IGRT中的应用价值，从而为实现食管癌精准放疗提供新型技术手段。

The key to improve the local control rate of radiotherapy for esophageal cancer lies in the accurate location and delineation of the target volume. Esophageal cancer is prone to submucosal infiltration. There are great subjective differences in the delineation of longitudinal GTV on CT localization images, so it is difficult to achieve accurate localization, delineation and real-time follow-up verification of GTV. The longitudinal length of esophageal cancer can be determined by implanting standard markers of esophageal EUS, which provides a new method for accurate radiotherapy, but most of the markers used in this method can not be popularized in clinic because of their own defects. Whether the construction of new benchmark markers combined with EUS accurate localization of longitudinal GTV is the key to improve the efficacy of radiotherapy. Our experimental study on subcutaneous implantation of different mixtures in mice shows that NBCA combined with lipiodol has better safety, stability and visibility, and may become an ideal new marker. Therefore, on the basis of previous work, it is proposed to continue to verify the safety, stability and visibility of the new markers in vitro and in vivo, on the basis of which esophageal EUS is used to implant markers in pigs and patients with esophageal cancer. The follow-up of EUS, CT and analysis of postoperative pathological specimens provided a theoretical basis for the guidance of new benchmark markers for precise radiotherapy of esophageal cancer, and further compared with the traditional benchmark markers to evaluate the value of new benchmark markers in GTV mapping, SIB-IMRT and IGRT, and to provide a new localization method for precise radiotherapy of esophageal cancer.