直肠癌术后三种不同放疗计划的剂量学比较  

Dosimetric evaluation of three techniques in postoperative radiotherapy for rectal cancer

作　　者：蓝玉玲[1] 冯林春[1] 王运来[1] 蔡博宁[1] 葛瑞刚[1] 戴相昆[1] 解传滨[1] 巩汉顺[1] 

机构地区：[1]解放军总医院放疗科,北京100853

出　　处：《中华放射医学与防护杂志》2012年第6期616-620,共5页Chinese Journal of Radiological Medicine and Protection

摘　　要：目的探讨直肠癌术后螺旋断层放疗（HT）、静态调强放疗（IMRT）及三维适形放疗（3D-CRT）的剂量学特点，为临床选择直肠癌术后放疗方法提供依据。方法回顾性选取10例Ⅱ、Ⅲ期中低位直肠癌切除术（Dixon手术）后患者，在其CT定位图像上勾画靶区及危及器官，并进行HT、IMRT及3D—CRT计划设计。要求至少95％的PTV达到处方剂量为50Gy。结果3种治疗计划均能满足处方剂量要求；除3D-CRT计划外，HT计划与IMRT计划均能较好地满足各危及器官剂量限制要求。HT、IMRT、3D-CRT计划的适形度指数c1分别为0．86、0．82和0．62（F=206．81，P〈0．001），剂量均匀性指数（HI）分别为0．001、0．157和0．205（X2=15．8，P〈0．001）。3D-CRT计划骨盆V50、膀胱V40、小肠V50、股骨头D5明显高于IMRT与HT计划（P〈0．05），而后两者差别无统计学意义。HT计划小肠U，大于IMRT计划与3D-CRT计划（71．1％VS．63．3％、67．7％），差异无统计学意义。结论HT、IMRT及3D—CRT3种治疗计划均可满足直肠癌靶区处方剂量要求。HT计划适形度和均匀性最好，其次为IMRT计划，3D．CRT计划最差。HT计划满足所有危及器官的剂量限制，对正常组织的保护略优于IMRT计划。3D-CRT计划简便、实用性强，但对危及器官的保护较差。Objective To evaluate the dosimetric characteristics of helical tomotherapy （HT）, intensity-modulated radiation therapy （IMRT） and three-dimensional conformal radiation therapy （3D- CRT） for postoperative radiotherapy of rectal cancer. Methods Ten male patients with stage 11 or m middle or low position rectal cancer were selected retrospectively. All of the 10 patients underwent Dixon surgery and CT simulation orientation. The target volumes and normal organs were drawn in the CT images and the plans for HT, IMRT and 3D-CRT were designed. The prescribed dose was given 50 Gy in 25 fractions, covering at least 95% of the planning target volume. Results All plans met the needs of the prescribed doses. The HT and IMRT plans met the needs of dose limit to organs at risk, however, the 3D- CRT plans failed to do that. The conformity indexes of HT, IMRT and 3D-CRT plans were 0.86, 0. 82 and 0. 62, respectively（ F = 206.81, P 〈 O. 001 ）, and the homogeneity indexes were 0. 001, O. 157, and 0. 205, respectively （X2 = 15.8,P 〈0. 001 ）. The 3D-CRT plans had larger volumes than the HT plans and IMRT plans in the high-dose regions such as pelvic Vs0, bladder V40, bowel Vso and femoral head D5 （P 〈 0. 05 ） , but the differences between the HT plans and IMRT plans were not statistically significant （ P 〉0.05）. The V15 value of bowel of HT plans were higher than those of the IMRT and 3D-CRT plans （71.1% vs. 63.3% and 67.7%, respectively）. However, there was no significantly difference. Conclusions All of the HT, IMRT and 3D-CRT plans are able to meet the prescription dose requirement of the target regions of rectal cancer. The HT plans show the best dose homogeneity and target conformity, followed by the IMRT plans, and then the 3D-CRT plans. The HT plans meet the needs of all OARs slightly better than the IMRT plans. 3D-CRT plans are simple and practical with poor protective ability toward the OARs.

关 键 词：螺旋断层放射治疗 调强放射治疗 三维适形放射治疗 直肠肿瘤 放射疗 法 剂量学 

分 类 号：R730.55[医药卫生—肿瘤]