危及器官边界在估计心脏亚结构照射剂量中的作用  

Estimated radiation dose to cardiac substructures and their corresponding planning risk volumes

作　　者：黎艳萍[1] 王晓红[1] 李莹[1] 李俊玉[1] 谭文勇[1] 胡德胜[1] 

机构地区：[1]湖北省肿瘤医院放疗科武汉市430079

出　　处：《中国肿瘤临床》2014年第3期194-199,共6页Chinese Journal of Clinical Oncology

基　　金：湖北省自然科学基金项目(编号:2012FFB01702)资助~~

摘　　要：探讨心脏亚结构（CS）的计划危及体积（PRV ）在左乳癌调强放疗（IMRT）中估计CS照射剂量的作用。方法：勾画23例左乳腺癌保乳后IMRT 患者的CS，以CS的平均运动幅度为外放边界建立PRV 。设计2 个不同的IMRT 计划并计算CS及PRV 的体积、平均剂量、最大剂量（D2%）和标准差，并计算CS和其PRV 的平均剂量、D2% 的差别。结果：与CS本身相比，心脏和左心室PRV 体积增加50% ～80% ，冠状动脉主干及主要分支PRV 体积增加18.7～42.6 倍。在两个不同IMRT 计划中，心脏、心脏前壁区域（AMT）、前降支及相应的PRV 的平均剂量分别为9.4～11.4 Gy、11.0～17.5 Gy、22.6～27.8 Gy，其D2%分别为 24.5～36.2 Gy、28.2～38.8 Gy、36～45Gy。冠状动脉左右主干、右缘支和左旋支的平均剂量为8.6～14.9 Gy，D2% 为12.5～23.7 Gy。与CS的剂量相比，相应的PRV 的平均剂量差别为-2.5% ～12.5% ，D2% 增加了8.0% ～43.1% 。多数CS的PRV 剂量的标准差明显增大。结论：在左乳癌保乳后IMRT 中CS和相应PRV 的平均剂量差别〈12%。Objective：To investigate the role of planning risk volume （PRV） in estimating the radiation dose for various cardiac substructures （CS）. Methods：The CS of23patients with left-sided breast cancer who underwent postoperative intensity-modulated ra-diotherapy （IMRT） was delineated. PRV was expanded from CS with an additional margin determined by the mean amplitude of cardi-ac motion. Two IMRT plans were designed. The volume, mean dose, maximal dose （D 2%）, and standard deviation of CS and its PRV were calculated. Results： In comparison to the volume of CS, the PRV of the heart, specifically the left ventricle, increased by50% to 80%, whereas the PRV of the main coronary arteries and sub-branches increased by18.7 times to 42.6 times. In the two IMRT plans, the mean dose to the heart, anterior myocardial territory, anterior descending artery, and their corresponding PRVs ranged from 9.4 Gy to 11 .4 Gy,11 .0 Gy to17.5 Gy, and22.6 Gy to27.8 Gy, respectively. The D2% to CS and its PRV was24.5 Gy to36.2 Gy,28.2 Gy to 38.8Gy, and36Gy to45Gy. The mean dose and D 2% to the coronary arteries, including both left and right main coronary arteries, right marginal artery, and left circumflex artery, were 8.6 Gy to14.9 Gy and12.5 Gy to23.7 Gy, respectively. The difference of the mean dose and D2% to CS and its corresponding PRVs was 2.5% to 12.5% and 8.0% to 43.1%, respectively. Compared with the stan-dard deviation of the radiation dose to CS, majority of the standard deviation to PRVs increased significantly. Conclusion：The radia -tion dose difference between CS and its corresponding PRVs is 〈12%.

关 键 词：乳腺癌 放射疗法 调强放疗 器官运动 心脏病 

分 类 号：R142[医药卫生—公共卫生与预防医学]