目的 研究三维适形调强放疗与常规电子线放疗在左侧乳腺癌改良根治术后患者靶区剂量学分布中的对比.方法 选取行左侧乳腺癌改良根治术后患者60例,均采用CT进行定位,分别采用常规电子线放疗和三维适形调强放疗两种方式,比较两种放射方式剂量学差异并进行分析.结果 患者三维适形调强放疗均匀性指数(HI)、适形指数(CI)、接受≥95％处方剂量时计划靶区的体积数值(PTVVD95％)均明显高于电子线放疗,PTVVD110％、PTVVD105％均明显低于电子线放疗,差异均有统计学意义(P﹤0.01);患者三维适形调强放疗心脏计划靶区体积(PTV)平均剂量(Dmean)、全肺Dmean和患肺V5值均明显高于电子线放疗,全肺V20、心脏V30、心脏V40和患侧肺V20值均低于电子线放疗,差异均有统计学意义(P﹤0.05).结论 三维适形调强放疗不仅能够提升剂量均匀性和靶区适形性,还能够减少对心脏与肺部的照射剂量和体积,优于常规电子线放疗.%Objective To compare the dosimetric distribution between three-dimensional conformal intensity radio-therapy (3DCRT) and conventional electron beam radiotherapy in patients with left breast cancer after modified radical mastectomy. Method 60 cases with left breast cancer after modified radical mastectomy were administered with conven-tional electron beam radiotherapy or 3DCRT with CT positioning, to compare the difference of dosimetric distribution be-tween the two radiation modalities. Result 3DCRT showed higher homogeneity index (HI), conformity index (CI), and planned target volume value with prescribed dose exposure≥95％(PTVVD 95％), while with significantly lower PTVVD110％, PTVVD105％than electron beam radiotherapy, the differences were statistically significant (P<0.01);in patients treated with 3DCRT, the mean dose (Dmean) for planned target volume (PTV) of heart, Dmean of whole lung, and lung V5 were significant-ly higher than in those with electron beam radiotherapy, while V20 values of whole lung, V30, V40 of heart, and V20 of affect-ed lung were lower, with statistically significant differences observed (P<0.05). Conclusion 3DCRT can improve the ho-mogeneity of dose and the conformity of target area, and can reduce the dose and volume of radiation to heart and lung, showing a better effect than conventional electron beam radiotherapy.
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