直肠癌术后快速旋转调强与固定野动态调强放疗的剂量学比较  

Dosimetric comparison between RapidArc and fixed gantry dynamic IMRT for postoperative rectal cancer radiotherapy

作　　者：郑亚琴[1] 任俊丽[1] 褚薛刚[1] 郑旭亮[1] 孟慧敏[1] 邢晓汾[1] 

机构地区：[1]山西省肿瘤医院放射治疗中心,太原030013

出　　处：《肿瘤研究与临床》2013年第9期605-608,共4页Cancer Research and Clinic

摘　　要：目的探讨快速旋转调强（RapidArc）技术在直肠癌术后放疗的可行性及潜在优势。方法选择8例直肠癌术后患者，处方剂量为50Gy，2Gy／次，5次／周。用治疗计划系统分别进行固定野动态调强放疗（IMRT）计划和RapidArc计划设计，比较两组计划的靶区适形度指数、均匀性指数、危及器官的受照剂量体积、两组计划实施时的治疗时rq]和机器跳数。结果RapidArc计划的适形指数（O．89±0．02）优于五野（5F）-IMRT计划的适形指数（0．87±0．02）（t=3．286，P〈0．05），RapidArc计划靶区的均匀性指数（1．060±0．005）及平均剂量[（52．55±0．76）Gv]略低于5F—IMRT计划的均匀性指数（1．064±0．007）及平均剂量[（52．90±0．82）Gy]（t值分别为-1．459、-1．000，P〉0．05），RapidArc计划膀胱、小肠在高剂量区受量及平均剂量较5F-IMRT计划低，骨髓的受量RapidArc计划低于5F—IMRT计划，差异有统计学意义（P〈0．05）。RapidArc计划和5F—IMRT的机器跳数分别为（631±68）MU、（1046±146）MU，差异有统计学意义（t=-5．830，P=0．001），治疗时间分别为（78±5）s、（348±29）S，差异有统计学意义（t=-26．358，P〈0．05）。结论RapidArc计划较5F—IMRT计划提高了靶区的适形度，减少了危及器官高剂量区的受照剂量，降低了机器跳数，缩短了治疗时间，提高了患者的舒适性和治疗的效率。Objective To investigate the feasibility and potential advantages of RapidArc applied to the radiotherapy of the postoperative rectal cancer. Methods 8 postoperative patients with rectal cancer were selected to be treated with a dose of 50Gy in fraction of 2Gy every time and 5 times a week . IMRT and RapidArc were used respectively to compare different target conformities, homogeneity index, dose-volume histogram data, treatment times and monitor units. Results The conformal index by RapidArc was 0.89±0.02 which was better than those by 5F-IMRT, 0.87±0.02 （t = 3.286,P 〈 0.05）, while the homogeneity index of target volume （1.060±0.005） and average dose [（52.55±0.76） Gy] by RapidAre were a little less than the homogeneity index of target volume （1.064±0.007） and average dose [（52.90±0.82） Gy] by 5F-IMRT （t = -1.459, -1.000, P 〉 0.05）. The exposure dose and mean dose of bladder and small bowel in high dose region by RapidArc were lower than those by 5F-IMRT, as well as bone marrow. The differences were statistical significant （P 〈 0.05）. The monitor units by RapidArc and by 5F-IMRT were （631±68） MU and （1046±146） MU, respectively （t = -5.830, P 〈 0,05）, while the mean treatment times were （78±5） s and （348±29） s, respectively （t = -26.358, P 〈 0.05）. Conclusion Compared with 5F-IMRT, RapidArc improves the target conformities and lowers the exposure dose for the organs at risk in high dose region while using fewer monitor units and less treatment time, which helps comforting patients and improving the efficiency.

关 键 词：直肠肿瘤 快速旋转调强放疗 放射疗法 调强适形 放射治疗剂量 

分 类 号：R735.3[医药卫生—肿瘤]