静脉注射造影剂对妇科肿瘤全盆腔放疗剂量分布的影响

Effect of intravenous contrast agent on dose distribution in treatment planning for postoperative whole pelvic radiotherapy of gynecologic cancer

目的探讨静脉注射造影剂对妇科肿瘤术后全盆腔放疗剂量分布的影响。方法选择10例接受术后全盆腔放疗的子宫内膜癌和子宫颈癌患者。对每例患者静脉注射造影剂前后相同体位下行CT模拟定位扫描,在平扫图像和增强图像上为每例患者设计相同的三维适形全盆腔放疗计划。比较两组计划靶区、危及器官和正常组织剂量分布。结果增强计划的靶区、危及器官和正常组织平均剂量均低于平扫计划,但两组计划间差异均<1.0Gy,危及器官和正常组织最大剂量差异均<2.0 Gy,差异均无统计学意义。结论静脉注射造影剂对妇科肿瘤术后全盆腔适形放疗剂量分布影响很小,临床上可以忽略。

Objective To evaluate the effect of intravenous contrast agent on dose distribution in postoperative whole pelvic radiotherapy（WPRT） plans for gynecologic cancers.Methods Ten endometrial and cervical cancer patients undergoing postoperative WPRT were enrolled.Two sets of computerized tomography（CT） images were acquired in the same position before and after intravenous contrast agent injections.Three dimensional WPRT plans were created for each patient on the non-enhanced CT and enhanced CT.The dose distribution calculated from the two sets of CTs was compared with regard to planning target volumes（PTV）,OARs and normal tissue.Results The doses calculated from the enhanced CTs were lower than those from the non-enhanced CTs,but the differences of mean dose to PTV,OARs and normal tissue were less than 1.0 Gy,the differences of the maximum dose to OARs and normal tissue were less than 2.0 Gy.The differences were not statistically significant between the non-enhanced and enhanced CTs.Conclusion Planning from CT scans with intravenous contrast agent results in tolerably small errors clinically for postoperative three-dimensional conformal WPRT.