乳腺癌保乳术后不同放疗方式的剂量学比较
Different Intensity-Modulated Radiotherapy Plans for Breast Cancer: A Dosimetric Comparison

目的：设计三组不同的治疗计划用于乳腺癌保乳术后的放疗，通过比较三组治疗计划的剂量学差异，确定它们在乳腺癌放射治疗中的应用价值。资料与方法：随机选择20例早期乳腺癌保乳手术后进行全乳放疗的患者，左右侧各10例，在Xio三维治疗计划系统为每个患者设计做三维适形治疗计划(3D-CRT)、调强治疗计划(IMRT)及适形调强混合治疗计划(Hybrid-IMRT)。分别对三组计划的等剂量分布、靶区和正常组织器官剂量体积直方图(DVH)，评估靶区剂量适形度和均匀性。结果：通过比较三组治疗计划发现，适形调强混合计划和三维适形计划可以很好的保护心脏和肺等危及器官，适形调强混合计划和调强计划有比较好的靶区剂量均匀指数和适形指数。结论：适形调强混合治疗计划相比另两种计划既保证了靶区的均匀性、适形度又能明显的改善心脏、肺等危及器官的照射剂量。但是乳腺癌保乳术后的治疗计划设计必须结合临床，因此对于体位重复性较好的患者，在摆位精度的前提下，适形调强混合治疗计划是最好的选择。对于心肺功能略差的患者，则要考虑适形计划优先。
Objective: Design three different treatment plans for breast cancer after breast conserving surgery radiotherapy, by comparing three groups of treatment plan dosimetry differences, determine their value in breast cancer radiotherapy. Methods: A total of 20 patients with early breast cancer who underwent whole breast radiotherapy after breast conserving surgery were randomly selected, with 10 patients in each side. Three dimensional conformal treatment plan (3D-CRT), intensity modulated treatment plan (IMRT) and hybrid intensity-modulated radiotherapy (Hybrid- IMRT) were designed for each patient in the Xio three-dimensional treatment planning system. The planned isodose distribution, target and normal tissue and organ dose volume histogram (DVH) and target dose uniformity of the three groups were evaluated respectively. Results: By comparing the treatment plans of the three groups, it is found that hybrid IMRT and 3D-CRT can well protect dangerous organs such as heart and lung, and hybrid IMRT and IMRT have better target dose Homogeneity Index and conformal index. Conclusion Compared with the other two plans, can not only ensure the HI and CI, but also significantly improve the radiation dose of dangerous organs such as heart and lung. However, the design of breast cancer after breast conserving surgery must be combined with clinical practice. Therefore, for patients with good posture repeatability, on the premise of positioning accuracy, Hybrid-IMRT is the best choice. For patients with slightly poor cardiopulmonary function, 3D-CRT should be given priority.