宫颈癌术后放射治疗容积旋转调强与静态调强和三维适形计划的剂量学研究  

Dosimetric Comparison among Volumetric-modulated Arc Therapy, Intensitymodulated Radiotherapy and Three-dimensional Conformal Radiotherapy as Adjuvant Radiotherapy for Cervical Cancer

作　　者：沈亚丽[1] 李霞[2] 赵娅琴[1] 柏森[2] 许峰[1] 

机构地区：[1]四川大学华西医院腹部肿瘤科,成都610041 [2]四川大学华西医院放射物理技术中心,成都610041

出　　处：《华西医学》2015年第6期1096-1100,共5页West China Medical Journal

基　　金：国家高技术研究发展计划(863计划)(2014AA020509)~~

摘　　要：目的探讨旋转容积调强技术(VMAT)与静态调强放射治疗(放疗)技术(IMRT)和三维适形放疗技术(3D-CRT)在宫颈癌术后放疗中的剂量学差异及其保护危及器官的价值。方法采用随机抽样法选择2013年3月1日-9月30日接受宫颈癌术后辅助放疗的15例患者。在pinnacle 9.2计划系统上分别对同一CT扫描图像进行3种技术的设计:二弧VMAT计划、7野IMRT计划和4野3D-CRT计划,处方剂量为50 Gy/2.0 Gy/25次。比较3种放疗技术的靶区适形指数、均匀性指数、D98%、D2%、D50%,危及器官关注体积的受照剂量,并对机器跳数及治疗时间进行分析。结果 3种计划均能达到对靶区的有效覆盖。IMRT和VMAT的适形度明显优于3D-CRT。在危及器官保护方面,IMRT、VMAT计划与3D-CRT计划相比,明显降低了骨盆V20、直肠和膀胱V50,小肠V40、V50的受照体积(P<0.05),尤其显著降低了小肠高剂量(50 Gy)和骨盆低剂量(20 Gy)的受照体积。IMRT和VMAT计划在对危及器官的保护上无明显差异。VMAT计划的机器跳数较7野IMRT计划减少(P>0.05),VMAT的治疗时间较IMRT治疗时间减少200 s(P<0.01)。结论宫颈癌术后放疗VMAT计划具有与7野IMRT计划相当甚至略好的剂量分布,明显优于3D-CRT计划。在加速器跳数和治疗时间上,VMAT占优势。Objective To compare the dosimetric differences among the double-arc volumetric-modulated arc therapy （VMAT）, 7 field intensity-modulated radiotherapy （IMRT） and 3-dimensional conformal radiotherapy （3D-CRT） techniques in treatment planning for cervical cancer as adjuvant radiotherapy. Methods Fifteen patients who underwent adjuvant chemotherapy for cervical cancer between March 1st and September 30th, 2013 were chosen to be our study subjects through random sampling. Under Pinnacle 9.2 planning system, the same CT image was designed through three different techniques： VMAT, IMRT and 3D-CRT. We then compared target zone fitness index, evenness index, D98%, D2%, D50% among those different techniques. Monitor unit （MU） and treatment time were also analyzed. Results Three techniques showed similar target dose coverage. The IMRT and VMAT plans achieved better target dose conformity, which reduced the V20 of the pelvic, the V50 of the rectum and bladder, as well as the V40/50 of the small intestine （P 〈 0.05）. The VMAT technique showed few dosimetric advantages over the IMRT technique. VMAT technique had the advantages of less MU （P 〉 0.05） and shorter overall treatment time （P 〈 0.01） compared with IMRT technique. Conclusions The IMRT and VMAT plans achieve similar dose distribution to the target, and are superior to the 3D-CRT plans, in adjuvant radiotherapy for cervical cancer. VMAT technique has the advantages of less MU and shorter overall treatment time.

关 键 词：宫颈癌 旋转容积调强治疗 静态调强放射治疗 三维适形放射治疗 剂量学比较 

分 类 号：R737.33[医药卫生—肿瘤] R730.55[医药卫生—临床医学]