不同浓度影像增强剂对鼻咽癌调强放疗剂量计算的影响

Effects of different concentrations of image intensifiers on dose calculation for NPC

目的:探讨使用不同浓度影像增强剂的定位CT增强图像替代平扫图像用于靶区勾画和剂量计算的临床可行性。方法:收集40例鼻咽癌病例,随机分为2组,每组20例,2组使用不同浓度的影像增强剂。所有病例均在平扫图像上勾画靶区和危及器官轮廓,再把靶区和危及器官轮廓复制到增强图像上。在Eclipse计划系统中分别以增强图像和平扫图像设计2组放疗计划,比较2组靶区和危及器官的剂量分布和治疗总跳数。结果:2组图像的计划靶区和危及器官剂量分布、治疗总跳数均无统计学差异(P>0.05)。结论:影像增强剂对鼻咽癌放疗计划剂量计算影响极小,鼻咽癌放疗中可以使用定位CT增强图像替代平扫图像用于靶区勾画和放疗计划剂量计算。

Objective To evaluate the clinical feasibility of localization CT enhanced image replacing plain CT scan image for target delineation and dose calculation. Methods Forty cases of NPC were collected and divided into two groups with different concentrations of contrast agents. The contours of planning target volume(PTV) and organs at risk(OARs) of each case were delineated in the plain scan image, and the contours of PTV and OARs were copied to the enhanced image. Two plans based on the plain scan image and the enhanced image were designed in the planning system of Eclipse. The dose distribution and OARs and MU were compared between the groups. Results No statistical differences were found in the dosimetry of PTV, OARs and MU(P >0.05). Conclusion The image intensifier has little effect on the dose calculation of Eclipse for NPC. In the radiotherapy for NPC, the localization CT enhanced image can be used to replace the plain CT scan image for target delineation and dose calculation.