乳腺癌保乳术后全乳及锁骨上下区三种调强剂量学分析

目的 比较乳腺癌保乳术后全乳及锁骨上下区同时照射的固定野静态IMRT、固定野动态IMRT (DMLC)与VMAT的剂量学差异。 方法 选择2012—2015年本院女性乳腺癌患者 14例,照射范围包括胸壁及锁骨上下区。每例患者分别设计3种计划并使用相同优化条件,以DVH为依据比较PTV及OAR剂量。采用单因素方差分析或非参数Wilcoxon符号秩检验。 结果 IMRT、DMLC、VMAT三者的 V₉₅、V₉₈、CI、HI值组间比较结果均为VMAT最优(P<0.009)。患侧肺 V₅、V₂₀及 D_mean值,健侧肺 V₅及 D_mean值VMAT计划值均最优(P<0.022)。脊髓平均剂量VMAT最低(P=0.004)。 结论 对于全乳及锁骨上下区的乳腺癌患者治疗方式首选VMAT,在能保证靶区剂量的同时有效控制正常组织受量,减轻放疗并发症的风险。

Dosimetric comparison between three radiotherapy regimens involving supraclavicular and infraclavicular regions in breast cancer patients after breast-conserving surgery

Objective To evaluate the dosimetric difference between fixed-field static intensity-modulated radiotherapy (IMRT), fixed-field dynamic multileaf collimator (DMLC), and volumetric modulated arc therapy (VMAT), all of which involve supraclavicular and infraclavicular regions, in breast cancer patients after breast-conserving surgery.Methods This study included 14 female patients with breast cancer who received radiotherapy after breast-conserving surgery in our hospital from October 2012 to April 2016.The radiation field included the chest wall and supraclavicular and infraclavicular regions.IMRT, DMLC, and VMAT plans were generated for each patient while using identical optimization conditions.The doses to planning target volume (PTV) and organs at risk (OARs) were compared based on dose-volume histogram (DVH);one-way analysis of variance or nonparametric Wilcoxon rank test was used for comparison.Results For the dose distribution of PTV, VMAT achieved the best V95, V98, CI, and HI (P<0.009).Concerning the doses to OARs, VMAT achieved the best V5, V20, and Dmean of the ipsilateral lung and the best V5 and Dmean of the contralateral lung (P<0.022).Dmean of the spinal cord was significantly lower in VMAT than in IMRT and DMLC (P=0.004).Conclusions VMAT is preferred for the patients with breast cancer to be treated with radiotherapy involving supraclavicular and infraclavicular regions after breast-conserving surgery.It can improve the dose distribution of target and reduce the doses to organs at risk and radiotherapy toxicities.