使用DWI勾画食管癌靶区对于放射性肺损伤的影响

目的 探讨DWI扫描与CT扫描勾画食管癌靶区后放疗所致放射性肺损伤(RILI)的差异.方法 选取胸段食管癌患者40例,按照随机数字表法将患者随机分为DWI组及CT组,每组各20例,DWI组患者使用DWI与CT融合图像与单纯CT图像分别进行靶区勾画,并利用Pinnacle38.0计划系统分别计算出双肺V5、V20及MLD;CT组患者使用CT图像进行靶区勾画,并计算出双肺V5、V20及MLD.所有患者在出现明显RILI症状时行胸部CT扫描,在放疗后3、6个月行胸部CT扫描,并计算出RILI的体积.结果 DWI组患者中,利用DWI融合图像勾画的GTV、CTV、PTV体积均小于利用CT图像勾画的相应体积(P=0.000、0.000、0.000),且利用DWI融合图像勾画的双肺V5、V20、MLD体积剂量较利用CT图像勾画的相应体积剂量小(P=0.004、0.012、0.044).CT组和DWI组利用CT图像勾画的GTV、CTV、PTV体积及双肺V5、V20、MLD的平均值比较,差异均无统计学意义(P﹥0.05).CT组RILI的发生率高于DWI组(40%vs 10%,P=0.028).结论 使用DWI参与勾画的食管癌靶区优于单纯使用CT,并且可以降低RILI的发生率.

Influence of target volume delineated using DWI on the radiation-induced lung injury in esophageal carcinoma

Objective To investigate the variance between the tumor target volume delineated by CT scan or DWI in radiation-induced lung injury (RILI) of esophageal carcinoma. Method 40 thoracic esophageal cancer patients were in-cluded in our study and randomized as DWI group or CT group, and each had 20 cases. The target volume of DWI group were delineated by DWI-CT fusion imaging and additional simple CT imaging, and the dose-volumes of V5, V20 and MLD of both lungs were calculated by Pinnacle 38.0 treatment planning system;while the same schedule was performed for CT group using CT imaging;A chest CT scan was administered for any patient who experienced obvious symptoms of RILI, and was performed in 3 months and 6 months after radiotherapy to calculate the volume of RILI. Result The GTV, CTV, and PTV volume delineated by DWI fusion imaging in DWI group were less than those delineated by simple CT imaging (P=0.000, 0.000, 0.000), and so did for V5, V20 and MLD of both lungs (P=0.004, 0.012, 0.044, respective-ly). The GTV, CTV, PTV volume and mean V5, V20 and MLD of both lungs delineated by CT imaging in the two groups were similar (P>0.05). While a higher incidence of RILI was observed in CT group than DWI group (40%vs 10%, P=0.028). Conclusion Application of DWI is superior to simple CT in delineating the target volume, and it can reduce the incidence of radiation-induced lung injury in patients with esophageal carcinoma.