摘要目的:探讨逆向IMRT (IP-IMRT)技术下内乳淋巴结放疗(IMNI)能否把正常组织体积剂量控制在合理范围内。方法:回顾性入组2015-2016年间上海瑞金医院收治的以IP-IMRT技术行乳房切除术后放疗、处方剂量为50 Gy分25次的乳腺癌患者并按比例抽样。在定位CT上对抽样患者全心、患侧肺进行勾画，并在ADAC Pinnacle系统上收集心肺"剂量-体积"参数。结果:对67例左侧乳腺癌IMNI患者全心D mean 　2016年低于2015年，分别为(976.65±411.16) cGy和(687.47±134.65) cGy ( P＝0.008)。样本中2015年心脏D mean在12、10、8 Gy以上的各占33.3%、33.3%、66.7%，而2016年则各分别占0%、3.8%、11.5%。对65例右侧乳腺癌患者，2016年IMNI组心脏D mean、V 2Gy、V 10Gy、V 15Gy、V 20Gy均较无IMNI组显著增高(均 P<0.05)。对于患侧肺，IMNI组D mean、V 10Gy、V 20Gy、V 30Gy均较无IMNI组有所增高(均 P<0.05)。 结论:IMNI客观上带来一定程度的心肺体积剂量增加，但随着调强放疗实践经验的增加及对心脏剂量限制意义的强化，将心脏剂量增加限制在一定范围内是可行的。

abstractsObjective:To explore whether internal mammary node irradiation (IMNI) can control the normal tissue volume dose within a reasonable range under inverse-planned intensity-modulated radiation therapy (IP-IMRT).Methods:The patients with breast cancer received postmastectomy combined with radiotherapy from January 2015 to July 2016 in Department of Radiation Oncology in Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine were retrospectively screened and sampled. The prescription dose was 50 Gy/25 times. The whole heart and ipsilateral lung were outlined on CT scan, and the dose-volume histogram parameters were quantified in the RT planning system (ADAC Pinnacle).Results:For the left breast cancer patients ( n=67) who received IMNI, the total heart dose-volume histogram parameters in 2016 were significantly decreased compared with those in 2015. The D mean in 2015 was (976.65±411.16) cGy, significantly larger than (687.47±134.65) cGy in 2016( P=0.008). Among the same sampled population, the percentage of whole heart D mean at the doses of 12 Gy, 10 Gy, 8 Gy was 33.3%, 33.3%, and 66.7% in 2015, and 0%, 3.8%, and 11.5% in 2016, respectively. For the right breast cancer patients ( n=65) , D mean, V 2Gy, V 10Gy, V 15Gy and V 20Gy of the heart in the IMNI group were significantly higher than those in the non-IMNI group in 2016(all P<0.05). For the ipsilateral lung, D mean, V 10Gy, V 20Gy, and V 30Gy in the IMNI group were remarkably higher than those in the non-IMNI group (all P<0.05). Conclusions:IMNⅡs found to be associated with increased cardiopulmonary dose volume with IP-IMRT technique. Nevertheless, with the practical experience of IMRT and the increasing awareness of cardiac dose limitation, it is feasible to control the cardiac dose increment within a limited range.