保乳术后腋窝淋巴结标准切线野与多野放疗剂量比较

Comparison of standard tangential field and multiple fileld radiotherapy in axillary lymph node after conserving surgery

目的：探讨保乳术后标准切线野覆盖腋窝淋巴结状况以及对腋窝淋巴结实施调强计划（IMRT）后正常组织剂量，为临床诊治提供参考。方法选择20例左侧乳腺癌患者，所有患者接受保乳手术治疗，术后辅助放疗。所有患者放疗以标准切线野为基础，并实施逆向调强优化放疗。腋窝Ⅰ、Ⅱ站淋巴结使用原始计划计算覆盖程度，计算靶区剂量均匀度 HI、剂量适形度 CI、剂量学等参数。结果标准切线野照射下，I 站平均剂量为（33．95±8．24）Gy，明显高于Ⅱ站（22．13±6．67）Gy，且 V50、V45、V40分别为（22．45±6．32）％、（39．83±7．54）％、（49．65±8．31）％均高于Ⅱ站，Ⅰ站照射明显更多，对比差异均有统计学意义（t ＝5．632，P ＝0．009；t ＝7．214，P ＝0．000；t ＝8．954，P ＝0．000；t ＝6．121，P ＝0．002），Ⅱ站覆盖差；全乳腋窝多野调强照射计划中，19例患者（95．00％）均达到了95％体积 APTV≥50 Gy，覆盖情况较好；但 HI、CI 分别为（1．11±0．03）、（1．36±0．07），明显差于标准切线野，对比差异均有统计学意义（t ＝6．584，P ＝0．001；t ＝9．144，P ＝0．000）；全乳腋窝多野调强照射下同侧肺、心脏所受平均剂量分别为（1694．58±102．31）cGy、（645．54±74．44）cGy，明显多于标准切线野照射，对比差异有统计学意义（t ＝7．654，P ＝0．000；t ＝6．654，P ＝0．001）。结论标准切线野照射腋窝淋巴结Ⅱ站覆盖差，全乳腋窝多野调强照射覆盖较好，但正常组织所受剂量明显增加。

Objective To investigate the difference of standard tangential field and multiple fileld radiotherapy in axillary lymph node after conserving surgery,to provide a reference for clinical treatment.Methods 20 cases of left breast cancer patients were selected,all patients underwent breast -conserving surgery,postoperative radiotherapy.All patients used standard radiotherapy wild tangent based and reverse -intensity modulated radiation therapy optimization.Armpit I,Ⅱ lymph nodes were used to calculate the extent of coverage of the original plan,target dose uniformity HI,dose conformal CI,dosimetric parameters were calculated.Results Under standard tangential field irradiation,I stand mean dose was （33.95 ±8.24）Gy,which was significantly higher than Ⅱ station （22.13 ± 6.67）Gy,and V50,V45,V40 were （22.45 ±6.32）%,（39.83 ±7.54）%,（49.65 ±8.31）%,which were higher than Ⅱ stand,I stand irradiation was significantly more,the differences were statistically significant （t =5.632,P =0.009;t =7.214,P =0.000;t =8.954,P =0.000;t =6.121,P =0.002）.The whole breast irradiation armpit IMRT plan,19 patients （95.00%）reached 95% by volume APTV≥50Gy,coverage was better;but HI,CI were （1.11 ± 0.03）,（1.36 ±0.07）respectively,which were significantly worse than the standard wild tangent,the differences were statistically significant （t =6.584,P =0.001;t =9.144,P =0.000）.Under Hatano IMRT irradiation ipsilateral lung,heart suffered an average dose of （1 694.58 ±102.31）cGy,（645.54 ±74.44）cGy,which were significantly more than the standard tangential field irradiation,the differences were statistically significant （t =7.654,P =0.000;t =6.654,P =0.001）.Conclusion Standard tangential field irradiation has poor coverage in Ⅱ axillary lymph node station,irradiation intensity modulated radiation has better coverage,but significantly increased the dose to normal tissues.