非小细胞肺癌自适应放疗肿瘤和肺体积比值变化对肺受照剂量的影响

Effect of tumor and lung volume ratio changes on the irradiated dose of lung cancer in patients with nonsmall cell lung cancer

目的探讨非小细胞肺癌自适应放疗中肿瘤和肺体积变化对肺受照剂量的影响。方法回顾性分析南京市胸科医院2016年1月到12月实施调强放疗的非小细胞肺癌患者120例,处方剂量66Gy/33f。参照ICRU63标准设计计划Plan0(66Gy/33f),记录肿瘤体积、肺体积以及相关危及器官受照剂量如肺受照剂量MLD、V20、V5等相关指标。实际执行计划40Gy/20f,记为plan1,再次进行CT模拟定位设计放疗计划Plan2(26Gy/13f)。将实际执行计划plan1和plan2融合叠加成plan1+2,比较plan0和plan1+2各危及器官受照剂量。结果随着肿瘤退缩,肿瘤和肺组织体积比值发生变化,在合适的时机进行自适应放疗,相比全程靶区和治疗计划无更改,心脏和脊髓受照剂量变化不明显,肺组织受量有显著差异,能够有效降低肺平均受照剂量(MLD)、接受20Gy剂量的肺体积(V20)等指标。结论非小细胞肺癌放疗到三分之二疗程进行自适应放疗,对于降低肺组织的受量,降低放射性肺炎的发生概率有积极意义。

Objective To investigate the effect of tumor and lung volume changes on the dose of lung irradiation in patients with non-small cell lung cancer undergoing adaptive radiotherapy. Methods A retrospective analysis of 120 patients with non-small cell lung cancer who underwent IMRT from January to December 2016 in Nanjing Chest Hospital was performed. The prescription dose was 66 Gy/33 f. According to ICRU63 standard Plan0（ 66 Gy/33 f）,their tumor volume,lung volume and the related endangering organs dose such as lung dose MLD,V20,V5 and other related indicators were recorded. The actual implementation was the plan 40 Gy/20 f as plan1,then CT simulation positioning design radiotherapy plan was taken as Plan2（ 26 Gy/13 f）. The actual implementation plan（ plan1 and plan2） fusion into a superposition was as plan1 ＋ 2. The organ dose of Plan0 and Plan1 ＋ 2 was compared. Results As the tumor shrank,the volume ratio of tumor and lung tissue changed. At the right time for adaptive radiotherapy,compared with the whole program without change,the dose of the heart and spinal cord did not change significantly,but the amount of lung tissue,MLD and V20（ 20 Gy dose） was significantly different. Conclusion Radiotherapy can reduce the amount of lung tissue and the incidence of radiation pneumonitis for non-small cell lung cancer to two thirds of the course of treatment.