【摘要】 目的:对多叶准直器动态调强和静态调强方式进行对比性分析。方法:利用Varian 23EX直线加速器和Eclipse—Helios计划系统对5名鼻咽癌患者进行调强根治放疗。比较和分析SW和SS(并将SS按照强度分级为SS5,SS10,SS20)在总机器跳数、总治疗时间、靶区和危及器官的剂量体积参数上的差别。结果:观察剂量体积直方图(DVH)发现,在靶区剂量分布方面,SW最佳而SS5较差。在危及器官的保护上SS优于SW。利用SS治疗的总机器跳数比SW少了9%～23%,总治疗时间却是SW的2倍。结论:当强度分级在10级以上时,SS与SW的比较结果无明显差别。在质量保证方面,SS只需考虑叶片到位精度,而SW还需考虑叶片运动速度对剂量的影响,故建议用SS10方式进行调强放疗。更多还原

【Abstract】 Objective To compare and analyze DMLC(Sliding Window,SW)and SMLC(Step and Shoot,SS)for delivering IMRT.Methods 5 patients with nasopharyngeal carcinoma were treated with radical intensity modulated radiation therapy using Varian 23EX and Helios tool on a Varian Eclipse system.Different modalities to deliver IMRT were considered for Sliding Window(SW) and Step and Shoot(SS) techniques using a different number of intensity levels(e.g.5,10 and 20).The total beam-on-time,total delivery time and a number of dose-volume parameters regarding PTV and OARs were considered.Results Comparing with the DVH,it was found that SW was the best of the four modalities in the dose distribution of PTV,but SS was better when considering the protection of OARs.The total beam-on-time(MUs) requirement for SS was 9～23% less than SW,but the total delivery time(in minutes)was about twice as long.Conclusion With the number of intensity level of 10 or more,no differences between SS and SW can be appreciated in the dose distribution of PTV and OARs sparing.Referring to the quality assurance,only leaf position needed to be checked in SS,whereas both leaf position and leaf speed need to be checked in SW,so it is proposed to use SS10 for delivering IMRT.更多还原