简化调强技术应用于直肠癌术后放疗的剂量学比较  

Comparison of dose distribution with simplified IMRT to different postoperative radiotherapy plansof rectal cancer

作　　者：邓垒[1] 李晔雄[1] 金晶[1] 金大伟[1] 戴建荣[1] 

机构地区：[1]中国医学科学院北京协和医学院肿瘤医院肿瘤研究所放疗科,北京100021

出　　处：《中华放射肿瘤学杂志》2008年第6期450-453,共4页Chinese Journal of Radiation Oncology

基　　金：863项目（2006AA02Z345）;吴阶平医学基金会重大项目（WKJ2005-3-006）

摘　　要：目的评价直肠癌根治术后不同照射技术的靶区和正常组织剂最分布特点，为临床治疗方法的优选提供依据。方法对10例男性、Ⅱ～Ⅲ期直肠癌经腹前切除（Dixon手术）术后患者分别进行三维适形放疔（3DCRT）、简化调强放疗（sIMRT）和调强放疗（IMRT）的计划设计，利用剂量体积直方图评价小同照射技术对靶区和正常组织照射剂量、适形指数和不均匀指数。处方剂是为50Gy。结果靶Ⅸ适形指数IMRT〉sIMRT〉3DCRT，靶区剂量不均匀指数3DCRT〉sIMRT〉IMRT。对危及器官保护sIMRT和IMRT优于3DCRT计划。sIMRT的子野跳数与3DCRT技术相当，但显著低于IMRT计划。3个野3DCRT、5个野3DCRT、5个野sIMRT、5个野IMRT和7个野IMRT的子野跳数平均值分别为482±13、504±11、4554±42、841±36和884±46。结论与3DCRT、IMRT计划相比sIMRT计划具最优的时效比。此处方剂量水平下3种技术均能较好保护残端直肠和肛管。Objective To evaluate the dose distribution of target volume and normal tissues with different treatment planning such as three dimensional conformal radiotherapy （3DCRT） , simplified intensity modulated radiotherapy（ sIMRT）, and intensity modulated radiotherapy（IMRT） for patients with radically resected rectal cancer. Methods Ten male patients with stage Ⅱ and Ⅲ rectal cancer after radical resection （Dixon surgery） were enrolled in this study. 3-field or 5-field 3DCRT,sIMRT and 5-field or 7-field IMRT plans were performed for each patient. The dose distributions of target volume and normal tissues, conformal index（CI） and heterogeneous index（HI） were analyzed using the dose-volume histogram（DVH）. The prescription dose was 50 Gy in 25 fractions. Results The CI for PTV of IMRT and sIMRT was superior to 3DCRT. Conversely,the HI for PTV of 3DCRT was superior to sIMRT and IMRT. sIMRT and IMRT can protect the organs at risk better than 3DCRT. The mean of total MU for 3DCRT3r,3DCRT5f, sIMRT,IMRT5f and IMRTTf was 482 ± 13,504 ±11,455 ±42,841 ± 36 and 884 ±46,respectively. Conclusions Comparing with 3DCRT plans and IMRT plans, sIMRT plan was the optimal plan for clinical practice. All of the three radiotherapy techniques can protect the rectal stump and anal canal well with the prescription dose of 50 Gy.

关 键 词：直肠肿瘤/放射疗法 三维适形 调强适形 简化调强 剂量学 

分 类 号：R686[医药卫生—骨科学]