胸段食管癌不同调强放疗技术的剂量学差异分析  

Dosimetric comparison of static/dynamic intensity-modulated radiotherapy and volumetric modulated arc therapy for thoracic esophageal cancer

作　　者：王锐濠[1] 张书旭[1] 田允鸿[1] 沈国辉[1] 廖博玉 李万祯 王琳婧[1] 李慧君[1] 

机构地区：[1]广州医科大学附属肿瘤医院放疗中心,广东广州510095

出　　处：《中国医学物理学杂志》2017年第8期766-769,775,共5页Chinese Journal of Medical Physics

基　　金：国家自然青年科学基金项目(81502342);广东省科技计划项目(2016A02021517);广州市卫生局医药卫生科技一般引导项目(20161A011083;20161A011084;20161A011085)

摘　　要：目的:比较不同调强放疗技术在胸段食管癌的剂量学差异,探讨适用于胸段食管癌的调强放射治疗手段。方法:选取2016~2017年间收治的10例病理确诊的局部晚期胸段食管癌,用Monaco 5.11 TPS进行计划设计,分别制定固定角度5野和7野静态调强(sIMRT)和动态调强(dIMRT),360°单弧VMAT共5种放疗计划,比较不同计划靶区的剂量分布以及危及器官(OAR)受量,并比较加速器的总机器跳数(MU)和治疗执行时间,以评估不同技术的执行效率。结果:5种调强计划的靶区剂量均能满足临床处方要求,固定角度7野IMRT技术在靶区覆盖率、适形度和剂量分布均匀性方面均优于5野IMRT,但差异无统计学意义(P>0.05)。5种调强计划在双肺的高量区V_(20)、V_(30)的差异不明显。与sIMRT相比,dIMRT降低了双肺低剂量区V_5、V_(10)的受照体积。而对于VMAT计划来说,双肺低剂量区V_5、V_(10)的受照体积均高于固定野的IMRT计划,但仅V_5的剂量差异有统计学意义(P<0.05)。5种调强计划中心脏、脊髓的受照剂量无明显差异(P>0.05)。固定角度IMRT计划,随着野数增加,MU数显著增加,计划治疗执行时间也随着增加;dIMRT的MU数比sIMRT明显增多(P<0.05),但计划治疗时间明显减少(P<0.05)。VMAT计划的MU数比静态调强计划和5野动态调强明显增多(P<0.05),但VMAT计划的治疗时间最短,执行效率最高。结论:对胸段食管癌治疗,5野dIMRT可以在满足靶区剂量学要求和保护正常组织的同时,显著缩短治疗时间,并提高治疗效率。而VMAT计划虽能显著减少治疗时间,但同时提高了双肺低剂量区受照体积,对于胸段食管癌来说,VMAT并无明显剂量优势。Objective To explore the dosimetric differences of static intensity-modulated radiotherapy（sIMRT）, dynamic intensitymodulated radiotherapy（dIMRT） and volumetric modulation arc therapy（VMAT） for thoracic esophageal cancer. Methods The Monaco 5.11 treatment planning system was used to design 5 radiotherapy plans（namely, fixed 5-field sIMRT, 7-field sIMRT,5-field dIMRT, 7-field dIMRT and single arc VMAT plan） for 10 patients with pathologically-confirmed esophageal cancer randomly selected from patients admitted in 2016-2017. The dose distribution in target areas, the dose of organs-at-risk, monitor unit（MU）, and delivery time were compared to evaluate the efficiency of different plans. Results The dose in target areas met the requirements of clinical prescription in all 5 plans. The fixed 7-fieldIMRT plans were superior to fixed 5-fieldIMRT plans in target coverage, dose conformity and heterogeneity, without statistical significances（P〉0.05）. The differences in the high-dose regions（V20and V30） of whole lung among 5 plans didn’t showed statistical significances（P〉0.05）. Compared with sIMRT plans,dIMRT plans significantly reduced the dose in low-dose regions（V5and V10） of whole lung. Compared with fixed-fieldIMRT plans, VMAT increased the low-dose regions（V5 and V10） of whole lung, but only the dose difference in V5 had statistical significance（P〈0.05）. The dose of heart and spinal cord in 5 plans showed no statistical significances. The MU and delivery time significantly increased with the increasing number of fields in fixed-fieldIMRT plans. Compared with sIMRT plans, the MU of dIMRT plans increased significantly（P〈0.05）, while the delivery time decreased significantly（P〈0.05）. Compared with sIMRT and 5-field dIMRT plans, the MU of VMAT plans increased significantly（P〈0.05）, but VMAT plans had the shortest delivery time and the highest efficiency. Conclusion For thoracic esophageal cancer, 5-field dIMRT can shorten the delivery time and improve

关 键 词：食管癌 静态调强放疗 动态调强放疗 容积旋转调强放疗 剂量学 

分 类 号：R735.1[医药卫生—肿瘤]