宫颈癌根治性放疗旋转容积调强技术及固定野动态调强放疗技术的剂量学差异  

Dosimetric study of volumetric modulated radiotherapy in cervical cancer treated with definitive radiotherapy

作　　者：吴丽丽[1] 谢文佳[1] 张武哲[1] 林珠[1] 翟田田[1] 谢良喜[1] 

机构地区：[1]汕头大学医学院附属肿瘤医院放疗科,广东汕头515041

出　　处：《中国老年学杂志》2014年第10期2617-2620,共4页Chinese Journal of Gerontology

基　　金：国家自然科学基金面上项目(81171994)

摘　　要：目的探讨旋转容积调强技术(VMAT)和固定野动态调强放疗技术(DMLC-IMRT)在宫颈癌根治性放疗中的剂量学差异及其保护骨盆骨髓的价值。方法选取9例接受根治性放疗的宫颈癌患者,在Eclipse 10.0计划系统上分别对其进行二弧VMAT计划和九野DMLC-IMRT计划设计,比较两者靶区、骨盆骨髓和其他危及器官的剂量学差异、加速器跳数和照射时间。结果与DMLC-IMRT计划相比,VMAT计划靶区适形性指数CI略好;两种计划的靶区均匀性指数HI和骨盆骨髓(V10,V20,V40)无差异,均能很好地满足临床要求;在VMAT计划中,小肠V40,V45和膀胱V45均略低于DMLC-IMRT(P<0.05),在直肠V45的保护上DMLC-IMRT略优于VMAT(P<0.05),而直肠Dmean两者相似。VMAT计划的MU为848.4±58.8,较DMLC-IMRT计划的1 850.3±227.8明显减少(P=0.000),VMAT的治疗时间为(136.2±3.6)s,仅为DMLC-IMRT的1/3(P=0.000)。结论 VMAT计划可以达到或优于DMLC-IMRT DIMRT计划的靶区剂量分布,两者均能很好地降低骨盆骨髓受照剂量,保护其他盆腔脏器,同时明显减少加速器跳数和照射时间。Objective To compare volumetic modulated radiotherapy ( VMAT) techniques with dynamic multileaf collimator intensi-ty-modulated radiotherapy ( DMLC-IMRT) techniques in cervical cancer treated with definitive whole pelvic radiotherapy , and to explore its advantage to protect the pelvic bone marrow ( PMB) .Methods CT datasets of 9 staged ⅡA~ⅢB intact cervical cancer patients were in-cluded.VMAT plans and DMLC-IMRT plans were created based on each CT dataset by planning treatment system (Eclipse 10.0).Plans were evaluated on parameters of target , PMB and other pelvic organs , derived from dose volume histograms .The MU and delivery time were scored to measure expected treatment efficiency .Results Both VMAT and DMLC-IMRT resulted in equivalent target coverage and heteroge-neity index (HI), but VMAT had a slightly improved conformity index (CI =0.93±0.00 for VMAT and 0.92±0.02 for DMLC-IMRT). Compared with DMLC-IMRT, VMAT showed comparable volume of PBM at dose level of 10, 20 and 40 Gy, and mildly reduced the volume of bowel at 40 Gy and 45 Gy dose level(P<0.05).Similar trends were observed for the bladder .However, on retumn the volume received 45 Gy were increased (P<0.05),and the mean doses were the similar .The MU from VMAT was (848.4±58.8)s corresponding to an average beam on time of(136.2±3.6)s per fraction of 2 Gy.IMRT plans presented significantly higher values with an average of MU =(1 850.3± 227.8)s and of beam on time =(353.2±25.1)s.Conclusions VMAT is invesgated for intact cervix cancer showing comparable avoidance of PBM and other organ at risk with umcompromised target coverage in regard to DMLC-IMRT.In combination with the confirmed shorter de-livery time and fewer MUs , could lead to clinically significant advances in the management of this highly aggressive cancer type .

关 键 词：宫颈癌 骨髓保护 旋转容积调强 根治性放疗 

分 类 号：R737.33[医药卫生—肿瘤]