脑胶质瘤放疗靶区确定的方法学研究

Study of delineation of GTV-CTV for gliomas

探讨脑胶质瘤放疗靶区的确定方法。方法:9例脑胶质瘤患者用核磁共振(magneticreso-nance,MR)勾画靶区,然后通过软件分别与计算机断层扫描(computed tomography,CT)图像融合,把在MR所勾画的肿瘤区(gross tumor volume,GTV)及水肿区覆盖在CT图像上,通过CT图像的电子密度来计算吸收剂量并设照射野。结果:通过CT与MR在勾画靶区上的不同体积比较,MR上勾画靶区体积往往大于在CT上勾画靶区体积,GTV平均增大18.1%,水肿区平均增大29.0%,计划靶区(planning target volume,PTV)平均增大40.1%,并可更清晰地区分GTV与水肿区。结论:初步研究结果提示,在脑胶质瘤靶区确定方面,MR有着CT无可比拟的优势。对于脑胶质瘤Ⅲ及Ⅳ级,水肿区为亚临床病灶(clinical target volume,CTV),而对于脑胶质瘤Ⅱ级,水肿区为GTV。

OBJECTIVE： The objective of this study was to research the delineation of GTV-CTV for gliomas. METHODS：CT simulation and MR were obtained from 9 patients. By using CT and MR CT/MR was fused to contour GTV and the area edematous, and by the images of CT, the doses were caculated. RESULTS： Comparison of the tumor volumes and the area edematous in CT-based and MR-based, the volumes of MR-based were greater than those of CT-based, and GTV increased about 18.1%, the area edematous increased about 29%, and PTV increased about 40. 1%, and the images of MR-based were more precise for the delineation of GTV-CTV than those of CT-based, and the same for the area edematous. CONCLUSIONS： The images of MR have an advantage over those of CT for gliomas. For the gliomas Ⅲ or Ⅳ grade, the area edematous is CTV, but for the gliomas Ⅱ, the area edematous is GTV.