| 李定杰,丁丹红,魏胜涛,陈文远,黎田,蔡璟,葛红.半野分段弧照射技术对乳腺癌放疗危及器官的保护作用[J].中华放射医学与防护杂志,2021,41(5):340-345 |
| 半野分段弧照射技术对乳腺癌放疗危及器官的保护作用 |
| A new approach to spare organs at risk for breast cancer radiotherapy-half field segmented VMAT delivery technique |
| 投稿时间：2020-09-21 |
| DOI：10.3760/cma.j.issn.0254-5098.2021.05.004 |
| 中文关键词: 乳腺肿瘤 容积调强放疗 半野 危及器官 |
| 英文关键词:Breast neoplasms Volumetric modulated arc therapy Half field delivery Organs at risk |
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| 中文摘要: |
| 目的 利用半野的剂量分布特性和容积调强（VMAT）技术的特点，探索一种可以更好保护肺和心脏的新技术。方法 采用三维水箱测量对称野及半野的射野边缘剂量分布，并比较分析各自特征。回顾性选取50例左侧乳腺癌术后放疗患者，保乳术和根治术各25例，处方剂量50 Gy/25次，基于RayStation计划系统，分别采用对称野连续弧VMAT技术和半野分段弧VMAT技术进行计划设计，比较和分析靶区的剂量适合度、治疗效率，以及心脏、肺等危及器官的各种剂量数据。结果 半野的辐射野大小在水模内不随深度增加而增加，对称野则因张角因素射野逐步变大，30 cm处增大到约2 cm，而且半野的射野外剂量低于对称野，差值愈近射野边缘愈明显。与对称野连续弧计划相比，半野段弧VMAT计划能显著改善肺和心脏的受照射剂量，差异有统计学意义（t=-4.11、-4.42，P=0.00），其中心脏整体结构的V5、V30、Dmean均值减少为52.5%、65.5%、47%，与靶区关系紧密的左侧冠状动脉前降支降幅超过20%，患侧肺V5、V10、V20、Dmean的均值分别减少21.6%、24.8%、25.0%、23.2%，其他正常器官剂量均值，半野段弧计划同样优于连续弧计划。结论 对于乳腺癌放疗，半野与VMAT结合可以充分发挥半野和VMAT的优势，显著改善心脏、患侧肺、健侧乳腺等危及器官的受照射剂量。 |
| 英文摘要: |
| Objective To explore a new technology that can protect the lungs and heart better by utilizing the dose distribution attributes of the half-field and the characteristics of the VMAT (volumetric modulated arc therapy) technology. Methods A three-dimensional water tank was used to measure the dose of symmetrical field and half field edge and analyze them comparatively. A total of 50 patients with left breast cancer receiving the postoperative radiotherapy were selected. Among them, 25 patients were performed conserving surgery and 25 patients were performed radical mastectomy. After the operation, all the patients received the prescription dose of 50 Gy in 25 fractions. Based on the Eclipse system, the symmetrical field continuous arc VMAT technology and the semi-field segmented arc VMAT technology were used to design the plan. Besides, the dose suitability data and the treatment efficiency of target areas and organs at risk were compared and analyzed. Results The radiation size of half-field did not increase with the increased depth in the water mode. The symmetric field gradually enlarged due to the angle of tensor factor, increased to about 2 cm at the depth of 30 cm, and the delivery dose in the half-field was lower than that in the symmetric field. The closer the field edge is, the more obvious it is. Compared with the symmetric field continuous arc plan, the half-field segmental arc VMAT plan significantly improved the delivery dose of the lungs and heart (t=-4.11,-4.42,P=0.00), in which the mean values of V5, V30, and Dmean for the whole structure of the heart were reduced by 52.5%, 65.5%, and 47%, respectively. The left anterior descending coronary artery, which was closely related to the target area, had a decrease of more than 20%. The mean values of V5, V10, V20, and Dmean of the affected lung were reduced by 21.6%, 24.8%,25.0%, and 23.2%, respectively. The mean values of the doses of other endangered healthy organs, and the execution time of half-field segment arc plan were also better than the continuous arc plan. Conclusions For breast cancer radiotherapy, the combination of half-field and VMAT can give full play to the advantages of half-field and VMAT, and significantly reduce the irradiated dose of the heart, affected lung, and healthy side of the breast. |
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