CAJ | 학술논문

目的：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、36～45 Gy。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%。
목적：탐토심장아결구（CS）적계화위급체적（PRV）재좌유암조강방료（IMRT）중고계CS조사제량적작용。방법：구화23례좌유선암보유후IMRT환자적CS，이CS적평균운동폭도위외방변계건립PRV。설계2개불동적IMRT계화병계산CS급PRV적체적、평균제량、최대제량（D2%）화표준차，병계산CS화기PRV적평균제량、D2%적차별。결과：여CS본신상비，심장화좌심실PRV체적증가50%～80%，관상동맥주간급주요분지PRV체적증가18.7～42.6배。재량개불동IMRT계화중，심장、심장전벽구역（AMT）、전강지급상응적PRV적평균제량분별위9.4～11.4 Gy、11.0～17.5 Gy、22.6～27.8 Gy，기D2%분별위24.5～36.2 Gy、28.2～38.8 Gy、36～45 Gy。관상동맥좌우주간、우연지화좌선지적평균제량위8.6～14.9 Gy，D2%위12.5～23.7 Gy。여CS적제량상비，상응적PRV적평균제량차별위-2.5%～12.5%，D2%증가료8.0%～43.1%。다수CS적PRV제량적표준차명현증대。결론：재좌유암보유후IMRT중CS화상응PRV적평균제량차별<12%。
Objective:To investigate the role of planning risk volume (PRV) in estimating the radiation dose for various cardiac substructures (CS). Methods:The CS of 23 patients 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 (D2%), 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 by 50%to 80%, whereas the PRV of the main coronary arteries and sub-branches increased by 18.7 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 to 17.5 Gy, and 22.6 Gy to 27.8 Gy, respectively. The D2%to CS and its PRV was 24.5 Gy to 36.2 Gy, 28.2 Gy to 38.8Gy, and 36 Gy to 45 Gy. The mean dose and D2%to the coronary arteries, including both left and right main coronary arteries, right marginal artery, and left circumflex artery, were 8.6 Gy to 14.9 Gy and 12.5 Gy to 23.7 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%.