容积调强在左侧乳腺癌保乳术后放疗中的应用

Application of volumetric modulated radiation therapy in the radiotherapy of patients with left breast cancer after breast-conserving surgery

目的研究容积调强技术应用到左侧乳腺癌保乳术后放疗中的优势。方法随机选取10例左侧乳腺癌保乳术患者,利用Monaco治疗计划系统设计3类治疗计划,分别为3DCRT计划,IMRT计划和ARC+CRT计划,处方剂量为50 Gy/25f,比较靶区和危及器官受照剂量及计划执行效率,利用SPSS软件进行统计学分析。结果靶区剂量方面,V105%、V110%和Dmean均是ARC+CRT最小,IMRT次之,3DCRT最大(P<0.05)。靶区适形指数和均匀性指数方面,ARC+CRT计划最好,分别为(0.803±0.043)和(1.049±0.011)。危及器官剂量,三种方式左肺低剂量V5差异显著,3DCRT最低(P<0.05),V30、V20的差异不明显(P>0.05);ARC+CRT计划心脏的Dmax最小(P<0.05);IMRT和ARC+CRT两种方式在右肺、右侧乳腺的V5和脊髓的Dmax方面有所增加(P<0.05)。结论左侧乳腺癌保乳术后,ARC+CRT计划能改善靶区剂量分布,减少心脏受照剂量和体积,提高计划执行效率。

Objective To explore the advantage of the volumetric modulated radiation therapy in the treatment of patients with left breast cancer after breast-conserving surgery. Methods For each of 10 randomly chosen patients,3 kinds of plan（ 3DCRT plan,IMRT plan and ARC ＋ CRT plan） were designed by using the Monaco Treatment Planning System. The prescription dose was 50 Gy /25 f,and 95% of target volume received this dose（ i. e. D95% = 50Gy）. The dose distributions of the target and organs at risk exposure as well as the efficiency of plan execution were compared. The paired t-test with SPSS software was applied. Results With regard to the dose distribution of PTV,the ARC ＋ CRT plan was the best in V105%,V110% and Dmean（ P〈 0. 05）. The conformity index（ CI） of ARC ＋ CRT plan was（ 0. 803 ± 0. 043） and the homogeneity index（ HI） was（ 1. 049 ± 0.011）,which were the best as well（ P〈 0. 05）. Concerning the dose of organs at risk exposure,the V30 and V20 of left lung had no significant difference（ P〈 0. 05）,the 3DCRT was the lowest in V5 of left lung（ P〈 0. 05）. The ARC ＋ CRT plan was the least in the Dmax of the heart（ P〈 0. 05）.The IMRT and ARC ＋ CRT plans increased a little in V5 of right lung and right breast and Dmax of spinal cord（ P〈 0. 05）. Conclusion Implementation of ARC ＋ CRT plan for patients with left breast cancer after breast conserving surgery can improve the dose distribution of target,reduce the dose of heart and improve the efficiency of plan execution.