RayArc在胸部旋转调强放射治疗计划设计中的应用  

Application of RayArc in volumetric modulated arc therapy planning of chest cancer

作　　者：邵凯南[1] 杜锋磊[1] 李剑龙[1] 

机构地区：[1]浙江省肿瘤医院放射物理室/浙江省肿瘤放射治疗重点实验室,浙江杭州310022

出　　处：《中国医学物理学杂志》2017年第2期131-138,共8页Chinese Journal of Medical Physics

基　　金：浙江省医药卫生科技计划项目(2017PY014)

摘　　要：目的:利用RayStation计划系统提供的RayArc模块,在Varian公司的Trilogy加速器上进行胸部容积旋转调强(VMAT)计划设计,并对胸部VMAT和静态调强放射治疗(sIMRT)两种治疗计划的结果进行评价。方法:利用RayStation计划系统进行VMAT计划设计,需要对加速器参数和计划参数进行正确设置。计划设计使用直接子野优化算法,目标函数的选择遵循与sIMRT类似的标准。随机挑选10例胸部肿瘤(食管癌5例,肺癌5例)患者分别使用RayArc模块,制定VMAT计划,并与相应的sIMRT计划比较剂量分布、靶区适形度,以及危及器官剂量方面的差异情况。VMAT计划采用182°到178°的两个360°对偶治疗弧,sIMRT计划采用角度分别为182°、220°、310°、345°、15°、50°、150°的前后7个照射野,子野数为50,两者使用相同的逆向优化目标函数。结果:VMAT治疗计划经过多次优化,基本上可以在30min内完成,并达到放疗医师制定的临床目标。与前后7野sIMRT计划相比,356°双弧VMAT计划具有更好的靶区适形度,但是肺部的低剂量区(V_5)略高。另外,加速器运行VMAT计划治疗效率较高,可将治疗时间由sIMRT的6~8min缩短为2~3min。结论:使用RayStation计划系统的RayArc模块可以快速高效制定VMAT计划。RayArc制定出的胸部对偶双弧VMAT计划与常见的胸部7野sIMRT计划都可以满足放疗医师的临床目标要求,但是VMAT计划具有更好的靶区适形度和更高的治疗效率。Objective To design a volumetric modulated arc therapy（VMAT） plan of chest cancer on Varian Trilogy linear accelerator with the use of Ray Arc module of Ray Station treatment planning system, and evaluate the results of VMAT and static intensity-modulated radiotherapy（s IMRT） of chest cancer. Methods Before designing VMAT plan in Ray Station system,the parameters of accelerator model and plan were configured correctly. The direct machine parameter optimization（DMPO）algorithm used in IMRT plan was also used in VMAT plan, with the objective functions according to the similar standards of s IMRT plan. Ray Arc module was used to design VMAT plans. VMAT plans and s IMRT plans were designed for 10 randomly selected patients with chest cancer（including 5 patients with esophageal cancer and 5 with lung cancer）, respectively. The dose distribution, conformal index, and the dose of organs- at- risk（OARs） were compared between VMAT plan and s IMRT plan.The VMAT plan used two full arcs with a range from 182° to 178°, while s IMRT plan used 7 beams with 50 segments and different degrees（182°, 220°, 310°, 345°, 15°, 50°, 150°）. The same objective functions were chosen for two plans. Results After several times of optimization, VMAT plan was completed in 30 minutes, and reached the clinical goals made by radiation therapists. Compared with 7- beam s IMRT plan, the two- arc VMAT planswith 356° had better conformity index, and larger lower dose areas of lung（V_5）. The treatment of VMAT plan on linear accelerator was more efficient than s IMRT plan, and the treatment time of VMAT plan was 2-3 minutes, as compared with 6-8 minutes in sIMRT plan. Conclusion Using the Ray Arcmodule of Ray Station system can design VMAT plans rapidly and efficiently. Both the VMAT plan with two full arcs made by RayArc module and the 7-beam sIMRT plan for chest cancer can meet the clinical goals of radiation therapists, but VMAT plan show better conformity index of target areas and higher treatment efficiency.

关 键 词：RayArc 食管癌 肺癌 容积旋转调强 静态调强放射治疗 

分 类 号：R730.55[医药卫生—肿瘤]