多叶准直器叶片宽度对宫颈癌调强放疗计划的影响  

Effect of different leaf widths of multileaf collimators on treatment of cervical cancer by intensity modulated radiation therapy

作　　者：陈济杭 柏朋刚[2] 陈文娟[2] 林发生[2] 李奇欣[2] CHEN Ji-hang;BAI Peng-gang;CHEN Wen-juan;LIN Fa-sheng;LI QI-xin(Department of Pediatric Surgery, Fuzhou Children's Hospital, Fuzhou 350014, China;Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Fuzhou 350014, China)

机构地区：[1]福州儿童医院小儿外科,福州350014 [2]福建省肿瘤医院放疗科,福州350014

出　　处：《医疗卫生装备》2019年第10期49-52,共4页Chinese Medical Equipment Journal

基　　金：福建省卫生健康科技项目(2017-ZQN-15,2018-ZQN-19,2017-CX-8)

摘　　要：目的:探讨2种不同宽度的多叶准直器(multi-leaf collimator,MLC)对宫颈癌调强放疗(intensity modulated radiation therapy,IMRT)计划的影响,比较2组计划在靶区剂量均匀性、适形性以及危及器官受照剂量等方面的差异。方法:选取宫颈癌患者20例,在Pinnacle3计划系统上分别选择配置10 mm MLC的Elekta Synergy直线加速器和5 mm MLC的Elekta Axesse直线加速器,以相同的剂量限制条件来设计IMRT计划,依据剂量-体积直方图(dosevolume histogram,DVH)比较2组计划的靶区适形性指数(conformity index,CI)、均匀性指数(homogeneity index,HI)、平均剂量、最大剂量、危及器官受照剂量和机器跳数(machine unit,MU)等的差异。利用SPSS 19.0软件对2组数据进行配对t检验分析。结果:2种不同MLC配置的IMRT计划均能满足临床需求。配置5 mm MLC的IMRT计划的靶区CI为0.87±0.01、HI为0.092±0.012,优于配置10 mm MLC的计划的CI(0.86±0.02)和HI(0.102±0.010),差异均具有统计学意义(P<0.05)。配置5 mm MLC的IMRT计划的危及器官包括膀胱、直肠、小肠、股骨头和骨髓的平均受量均略有降低,膀胱受照剂量超过45 Gy的体积百分比(V45)减少了2.3%,直肠V45减少了4.0%(P<0.05)。配置5 mm MLC的计划MU为720.0±49.7,明显高于配置10 mm MLC的计划(652.1±55.3)(P<0.05)。结论:对于宫颈癌的IMRT计划,配置5 mm MLC的计划无论在靶区适形性、均匀性还是在危及器官受量上都有一定的优势,但MU明显上升。在IMRT临床应用中要充分考虑多方面相关因素如靶区大小、机器设备维修保养、操作方便等来选择参数配置。Objective To investigate the dosimetric effect of multi-leaf collimator (MLC) with different leaf widths on the intensity modulated radiation therapy (IMRT) for cervical cancer from the aspects of target dose uniformity, conformity and exposure dose for the organs at risk (OARs). Methods Totally 20 patients with cervical cancer were selected to undergo IMRT. With the same dose constraints in Pinnacle3 TPS, IMRT plans were made on the basis of Elekta Synergy (10 mm MLC) and Elekta Axesse (5 mm MLC). Target coverage, conformity index (CI), homogeneity index (HI) and OARs dose were calculated and compared based on dose-volume histogram (DVH). SPSS 19.0 software paired t-test analysis was carried out on the two sets of data. Results Both of the two IMRT plans with different leaf widths of MLC were able to meet the clinical requirements. The HI and CI of plans made by 5 mm MLC (0.87±0.01 and 0.092±0.012) were slightly better those of 10 mm MLC (0.86±0.02 and 0.102±0.010, P<0.05). For OARs, the mean dose of bladder, rectum, intestine, femoral and marrow were slightly decreased in the plans made by 5 mm MLC, while V45 for bladder and rectum were decreased by 2.3% and 4.0%(P<0.05), respectively. In contrast, mean MU of plans made by 5 mm MLC and 10 mm MLC were 720.0±49.7 and 652.1±55.3 (P<0.05), respectively. Conclusion For cervical cancer, IMRT plans obtained with 5 mm MLC has a better HI and CI as well as OARs dose, and the mean MU of IMRT plans with 5 mm MLC is significantly increased. In IMRT clinical practice, various factors such as target volume and maintenance should be taken into considerations.

关 键 词：宫颈癌 调强放射治疗 多叶准直器 剂量-体积直方图 剂量学指标 

分 类 号：R318[医药卫生—生物医学工程] R815[医药卫生—基础医学]