摘要
目的利用多叶准直器(MLC)遮挡技术减少左侧乳腺癌患者保乳术后混合调强放疗中心脏的受照剂量,降低放射性心脏损伤发生的风险。方法选取18例左乳癌保乳术后患者,在自由呼吸状态下获取3DCT和4DCT图像。利用4DCT在3DCT图像上确定出靶区并分别制定混合调强治疗计划(H_IMRT)和为降低心脏受量而引入MLC遮挡技术的治疗计划(HSH_IMRT),利用Compass系统对治疗计划进行剂量学验证。靶区处方剂量为50Gy,分25次完成。比较两种治疗计划结果与剂量验证结果中靶区及危及器官的剂量学参数。结果计划结果显示,与H_IMRT比较,HSH_IMRT靶区剂量均匀性更好,适形度差异无统计学意义(P>0.05);全心脏Dmean较前者降低23.67%(t=13.693,P<0.05),心脏其他亚结构的Dmax和Dmean均较前者下降。剂量验证结果显示,两种计划靶区剂量均匀性与适形度差异无统计学意义(P>0.05);HSH_IMRT与H_IMRT比较,全心脏的Dmean降低24.88%(t=13.782,P<0.05);除左心室、右心室外,其他心脏亚结构的Dmax以及所有心脏亚结构的Dmean均降低。患侧肺的V20和Dmean在计划结果与验证结果中均显示HSH_IMRT更低。结论在H_IMRT中合理引入MLC遮挡技术能够在保证其剂量学优势的前提下更多地减少心脏组织的受量,进一步降低心脏发生放射性损伤的风险。
Objective To reduce the risk of radiation-induced cardiac injury in patients with left breast cancer after breast-conserving surgery by multileaf collimator (MLC) shielding technique. Methods A total of 18 patients with left breast cancer after breast conserving surgery were selected to obtain 3DCT and 4DCT images at free breathing state. The target area was identified on the 3DCT image by registration with 4DCT images and to develop a hybrid intensity-modulated treatment plan (H_IMRT) and a heart sparing hybrid intensity-modulated treatment plan (HSH_IMRT) to introduce MLC shielding technology to reduce the cardiac exposure dose, and to perform dosimetry verification of the treatment plan by using the Compass verification system. The prescription dose was 50 Gy in 25 fractions. The dosimetry parameters of the target area and the organs at risk were compared between the two treatment plans and the dose verification result. Results The result of the treatment plan showed that compared with H_IMRT, the dose uniformity of the target area of HSH_IMRT was better, and the difference of conformability was not statistically significant(P>0.05). The mean dose of the whole heart decreased by 23.67%(t=13.693, P<0.05) compared with the former. Dmax and Dmean of other substructures of the heart were lower than the former. The result of dose verification showed that there was no statistically significant difference in uniformity and conformity between the two planned target doses(P>0.05). The mean dose of the whole heart of HSH_IMRT was 24.88%(t=13.782, P<0.05) lower than that of H_IMRT, and except for the left ventricle and right ventricle, the Dmax of other heart substructures and Dmean of all heart substructures decreased. Both the planned and the dose verification result showed that the V20 and the Dmean of the affected lung were lower in HSH_IMRT. Conclusions Reasonable introduction of MLC shielding technology in H_IMRT can reduce the exposure dose of cardiac and further reduce the risk of radiation damage in heart.
作者
赵培峰
周钢
孙彦泽
邹莉
田野
Zhao Peifeng;Zhou Gang;Sun Yanze;Zou Li;Tian Ye(Department of Radiotherapy and Oncology ,The Second Affiliated Hospital to Soochow University,Institute of Radiotherapy and Oncology,Soochow University,Suzhou 215004,China)
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
2019年第2期107-112,共6页
Chinese Journal of Radiological Medicine and Protection
关键词
乳腺癌
调强放射治疗
心脏不良反应
多叶准直器
心脏遮挡
Breast cancer
Intensity-modulated radiotherapy
Cardiac toxicity
Multileaf collimator
Cardiac shielding
