直肠癌术前不同照射技术剂量学比较  

Dosimetric comparison of different preoperative radiotherapy techniques for rectal cancer

作　　者：姚文良[1] 许波[1] 戚金凤[1] 张佳卉[1] 王雷[1] 

机构地区：[1]淄博市中心医院,放疗科,山东淄博255000

出　　处：《中国医学物理学杂志》2016年第3期317-321,共5页Chinese Journal of Medical Physics

摘　　要：目的:通过比较常规放疗(Con-RT)、三维适形放疗(3DCRT)和调强放疗(IMRT)3种放疗计划模式的剂量分布,探讨直肠癌术前放疗的理想计划模式。方法:选取10例直肠癌术前患者,采用三维治疗计划系统对每例患者分别行3野Con-RT、3野三维适形(3DCRT3)、5野三维适形(3DCRT5)、5野调强放疗(IMRT5)和7野调强放疗(IMRT7)计划设计,利用剂量体积直方图(DVH)评价5种照射技术下靶区和危及器官的体积剂量分布,处方剂量为50 Gy。结果:Con-RT计划中肿瘤靶区(GTV)的最小剂量为(4991.5±69.1)c Gy,靶区内有冷点。计划靶区(PTV)的适形指数(CI):IMRT7>IMRT5>3DCRT>Con-RT;PTV的剂量不均匀指数(HI):Con-RT>3DCRT3>3DCRT5>IMRT5>IMRT7。相比3DCRT计划,IMRT计划减少了小肠、膀胱、股骨头的V40、V50体积(P<0.05)。结论:直肠癌术前放疗中Con-RT计划的靶区剂量分布不均,适形度差;相比于3DCRT计划,IMRT计划剂量分布均匀,适形度优,危及器官高剂量照射体积明显减少;在剂量分布和适形度方面,IMRT7计划优于IMRT5计划。Objective To discuss on the best preoperative radiotherapy plan for rectal cancer by evaluating the dose distribution of conventional radiotherapy （Con-RT）, three-dimensional conformal radiotherapy （3DCRT） and intensity- modulated radiotherapy （IMRT）. Methods Ten preoperative patients with rectal cancer were selected. Five plans were respectively designed for each patient by using 3D treatment planning system, including 3-field Con-RT plan, 3-field 3DCRT （3DCRT3） plan, 5-field 3DCRT （3DCRT5） plan, 5-field IMRT （IMRT5） plan and 7-field IMRT （IMRTT） plan. The volume-dose distribution of target volumes and organs at risk in the five plans were evaluated by using dose-volume histogram. The prescription dose was 50 Gy. Results The minimum dose of gross tumor volume in the Con-RT plan was （4991,5±69,1） cGy, and some cold spots were found in the target volume, The comparative result of conformity index （CI） of planning target volume （PTV） was IMRTT〉IMRT5〉3DCRT〉Con-RT; the comparative result of homogeneity index of PTV was Con-RT〉3DCRT3〉3DCRT5〉IMRT5〉IMRTT. Compared with 3DCRT plan, IMRT plan reduced the V40, V50 of small intestine, bladder and femoral head （P 〈 0.05）. Conclusion The dose distribution of target volume in preoperative Con-RT plan for rectal cancer has unsatisfactory dose distribution and conformity. Compared with 3DCRT plan, IMRT plan has a satisfactory dose distribution and a good conformity, obviously reducing the high dose radiation volume of organs at risk. And IMRT7plan is suoerior to IMRT5 plan in dose distribution and conformity.

关 键 词：直肠癌 常规放疗 三维适形放疗 调强适形放疗 剂量体积直方图 

分 类 号：R735.37[医药卫生—肿瘤]