乳腺癌根治术后VMAT技术对心脏受照剂量风险评估  

Risk Assessments of the Heart Dose from VMAT Radiotherapy for Post-Mastectomy Breast Cancer

作　　者：叶威[1] 龚敏勇 熊超[1] 

机构地区：[1]江西省九江市第一人民医院,332000

出　　处：《实用癌症杂志》2016年第2期286-289,共4页The Practical Journal of Cancer

摘　　要：目的分析乳腺癌根治术后VMAT技术对心脏的物理剂量学和生物学的指标，评估心脏的受照风险。方法随机选取10例左侧乳腺癌根治术后患者，设计4种常用计划：①改良野中野调强计划FIF（8-10个子野）；②四野调强计划4F—IMRT；③五野（增加正对心脏射野）计划5F—IMRT；④包含心脏正对弧双弧VMAT计划。统计每个患者靶区、心脏和冠状动脉左前降支区LAD剂量体积参数，用NTCP—RSM模型计算放射性心脏病死亡率。统计分析VMAT技术的结果与其余技术之间的差异。结果患者心脏Dmean和V25在4种计划下平均值分别是：7．7Gy，6．9Gy，9．7cGy，6．4Gy；9．1％，7．9％，9．7％，4．9％；LAD的平均剂量分别是29．0Gy，27．6Gy，32．8Gy，26．1Gy；NTCP的平均值分别为2．7％，1．1％，1．3％，0．86％。靶区CI四套计划平均值为：0．44、0．56、0．61、0．71，HI为0．82、0．78、0．70、0．53，VMAT技术的cI和HI结果与另外3种的结果有统计学差异（P〈0．05）。结论与常规调强技术相比，包含心脏正对弧的VMAT计划不会显著影响心脏的并发症概率（NTCP），同时VMAT计划靶区的CI、HI要优于静态IMRT计划，VMAT技术可以在提高靶区剂量的同时不明显增加心脏的受照风险。Objective To analyze the heart dose parameters of breast cancer radiotherapy andrisk of heart exposure from breast cancer volumetric modulated arc therapy（ VMAT） technique. Methods 10 cases of left breast cancer patients after radical mastectomy were randomly selected. 4 kinds of commonly used plans were designed for each patient： 1） Improved field in field IMRT plan（ FIF）; 2） 4-field IMRT plan（ 4F-IMRT）; 3） 5-field IMRT plan（ 5F-IMRT）（ including a directly exposing to the heart beam）; 4） Double-arc VMAT plan. The conformal index（ CI） and dose homogeneity index（ HI） of PTV,the dose volume parameters of heart and the left anterior descending（ LAD） coronary artery of the patients were calculated from DVH. NTCP-RSM model was used to calculate the heart complication possibility. There had statistical differences between the results of the VMAT technique and the results of the others. Results The average values of Dmean and V25 in 4 plans were 7. 7 Gy,6. 9 Gy,9. 7 c Gy,6. 4 Gy and 9. 1%,7. 9%,9. 7%,4. 9%,respectively. The mean dose of LAD were 29. 0 Gy,27. 6 Gy,32. 8 Gy,26. 1 Gy. The mean NTCP were 1. 1%,1. 3%,0. 86%,2. 7%,respectively. The mean CI and HI of the target were： 0. 56,0. 44,0. 61,0. 77 and0. 82,0. 78,0. 70,0. 53. The results of CI and HI of VMAT were significantly different from the other 3 technique（ P〈 0. 05）.Conclusion Compared with conventional intensity modulation radiotherapy,the VMAT technique can increase the coverage of the target without obviously increasing the heart dose.

关 键 词：乳腺癌根治术 放射治疗 容积旋转调强 心脏剂量学 

分 类 号：R737.9[医药卫生—肿瘤]