IMRT和SRT大分割治疗肺部肿瘤的剂量分布研究  

Comparison of dose distribution between hypofractionated IMRT and SRT plans in lung tumor

作　　者：吴凤[1] 肖建平[1] 张可[1] 姜雪松[1] 宋一昕[1] 张红志[1] 李晔雄[1] 

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

出　　处：《中华放射肿瘤学杂志》2009年第4期281-284,共4页Chinese Journal of Radiation Oncology

基　　金：国家科技部重大基础研究前期专项资助（2005CCA0300）;国家卫生部专项资助（2007-2010）

摘　　要：目的比较肺部肿瘤调强放疗（IMRT）和立体定向放疗（SRT）的大分割治疗计划的剂量分布特点，为临床治疗优选方案提供依据。方法对近1年内收治的16例采用大分割IMRT的肺部肿瘤（非小细胞肺癌6例和肺转移癌10例）患者设计处方剂量与治疗间隔相似的SRT计划，采用剂量体积直方图评价IMRT和SRT计划对靶区和正常组织照射剂量等以及适形指数（CI）和不均匀指数（H1）。结果患者采用大分割IMRT和SRT计划时PTV接受的平均剂量分别为6282．1cGy和6340．6cGy（t=-0．93，P〉0．05），均一化剂量分别为6366．7cGy和6246．8cGy（t=-1．18，P〉0．05），CI平均值分别为0．78和0．57（t=2．77，P〈0．05），HI平均值分别为1．12和1．32（t=-4．38，P〈0．01）。IMRT和SRT计划的平均全肺组织受照剂量分别为（492．4±368．5）cGy和（310．0±73．1）cGy（t=1．68，P〉0．05），全肺V20分别为6．9％±2．1％和4．2％±1．9％（t：3．30，P〈0．01）。IMRT和SRT计划的心脏和脊髓平均受照剂量无差别。结论FrrV最大径〈4．7cm、靶体积〈57cm^3、靶区呈圆形或类圆形时，SRT靶区剂量与大分割IMRT接近并可满足临床要求；SRT计划正常肺组织受照剂量低于大分割IMRT计划。Objective To compare the characteristics of dose distribution between hypofractionated intensity modulated radiotherapy （IMRT） and hypofractionated stereotaetic radiotherapy （SRT） plans in lung tumor and to select an optimal clinical approach. Methods SRT plans were designed for 16 patients with lung tumors who had received IMRT between April 2007 and April 2008. The dose distribution of target volume and normal tissues, conformal index （ CI ） and heterogenous index （ HI ） were analyzed using the dose-volume histogram （DVH） for the IMRT and SRT plans. Results The mean dose and equivalent uniform dose of planning target volume （ PTV ） in IMRT were similar to those in SRT. SRT had significantly better CI and HI than IMRT （t = 2.77, P 〈 0.05 and t = - 4.38, P 〈 0.01 ）. The mean lung dose of IMRT and SRT was （492.4 ± 368.5 ） cGy and （ 310.0 ± 73.1 ） cGy, respectively （ t = 1.68, P 〉 0.05 ）. The lung V20 of IMRT and SRT was 6.9% ± 2.1% and 4.2% ＋ 1.9% , respectively （ t = 3.30,P 〈 0.01 ）. No significant differences were found in the mean dose to the heart or the spinal cord between IMRT and SRT. Conclusions When PTV is less than 57 cm3 or the long diameter of tumor is less than 4.7 cm, hypofractionated SRT has similar dose distribution to hypofractionated IMRT, while the lung dose was lower in the former.

关 键 词：肺肿瘤/放射疗法 放射疗法 调强 放射疗法 立体定向 放射疗法 大分割 剂量学 

分 类 号：R686[医药卫生—骨科学]