目的 探究体层摄影(CT)与磁共 振成像(MRI)应用于非小细胞肺癌(NSCLC) 患者放疗前靶区勾画的临床价值。方法 回顾性分析146例NSCLC放疗患者临床资 料，根据靶区勾画借助影像学方法不同 分为CT组(n=74)与MRI组(n=72)。以分析 两组勾画体积[大体肿瘤体积(GTV)、临床 靶区体积(CTV)、计划靶区体积(PTV)]及 肺辐照剂量[剂量≥5Gy体积分数(V5)、 V20、平均肺受量(MLD)]差异。结果 CT组 GTV、CTV、PTV、V5、V20水平均明显高于 MRI组(P＜0.05)，而两组MLD水平比较则 无统计学意义(P＞0.05)。结论 NSCLC患 者放疗前应用MRI相对于CT勾画出靶区体 积更小，指导辐照方案更为精准，可降低 正常肺组织辐射损伤风险，对提高其放疗 效率与安全性有利。

Objective To study the clinical value of computed tomography (CT) and magnetic resonance imaging (MRI) in the delineation of target area of patients with nonsmall cell lung cancer (NSCLC) before radiotherapy. Methods The clinical data of 146 patients with NSCLC radiotherapy were retrospectively analyzed. They were divided into CT group (n=74) and MRI group (n=72) according to different imaging methods for target area delineation. The delineation volume [gross tumor volume (GTV), clinical target volume (CTV), planned target volume (PTV)] and lung irradiation dose [dose≥5 Gy volume fraction (V5), V20, mean lung DOSE (MLD)] were analyzed in the two groups. Results The levels of GTV, CTV, PTV, V5 and V20 in CT group were significantly higher than those in MRI group (P<0.05), but there was no significant difference in the MLD level between the two groups (P>0.05). Conclusion In patients with NSCLCbefore radiotherapy, MRI has smaller delineated target area than CT, and has more accurate guiding irradiation regimen, and it can reduce the risk of radiation damage in normal lung tissues, and it is beneficial to improve the efficacy and safety of radiotherapy.