静态多子野MLC调强和容积调强方式在脑转移癌全脑联合同期局部加量放疗中的剂量学研究

Dosimetric Comparison Study Between Multiple-Sataic-Field Multileaf Collimator Intensity Modulate Radiotherapy and Volume Modulated Arc Therapy for Whole Brain Radiotherapy with Simultaneous Integrated Boost in Patients with Brain Metastases

目的:研究静态多叶准直器(MLC)调强和容积调强方式在脑转移癌全脑联合同期局部加量放疗的剂量学特点。方法:选择35例脑转移癌患者分别设计静态多子野(MSF)-MLC调强放疗(IMRT)和容积旋转调强放疗(VMAT)2种放疗计划,均采用全脑放疗联合同期局部加量放疗的放疗方案,处方剂量为全脑临床靶区(CTV)30Gy/10F、肿瘤靶区(GTV)40Gy/10F,比较两者在靶区剂量分布、危及器官照射剂量和机器跳数上的差异。结果:两种技术均能满足临床放疗的基本要求。VMAT在左右眼球、左右视神经和垂体的最大剂量(Dmax)以及在右晶体、左右眼球、左右视神经和脑干的平均剂量上均较MSF有降低,机器跳数也较MSF明显下降。结论:VMAT可以作为脑转移癌全脑联合同期局部加量放疗中一个优化选择。

Objective:To explore the dosimetric characteristics of multiple-sataic-field multileaf collimator intensity modulate radiotherapy and volume modulated arc therapy for whole brain radiotherapy with simultaneous integrated boost in patients with brain metastases.Methods:Thirty-five patients with brain metastatic carcinoma were designed to treat with whole brain radiotherapy with simultaneous integrated boost by using the 5 fields multiple-sataic-field multileaf collimator intensity modulated radiotherapy plan or the dual-arc volume modulated arc therapy plan.The prescribed dose for the whole brain was 30 Gy/10 F,and the dose for brain metastases was 40 Gy/10 F.The target area dose distribution,the dose of organs at risk,and monitor unit were evaluated.Results:Both two radiotherapy plans both reached the clinical treatment needs.Between 5 fields multiple-sataic-field multileaf collimator intensity modulated radiotherapy plan and the dualarc volume modulated arc therapy plan,the statistically significant differences were found in Dmaxof bilateral eyeballs,bilateral optic nerves and pituitary,and also found in Dmeanof rignt lens,bilateral eyeballs,bilateral optic nerves and brainstem.The monitor units of the dual-arc volume modulated arc therapy plan were significantly less than that of 5 fields multiple-sataic-field multileaf collimator intensity modulated radiotherapy plan.Conclusion:The usage of volume modulated arc therapy would became an better choice for whole brain radiotherapy with simultaneous integrated boost in patients with brain metastase.