宫颈癌术后调强放疗中射野方向和数量对计划优化影响的初步探讨  

Preliminary exploration of the influence of beam orientation and beam number on the optimizationof IMRT plan with cervical cancer

作　　者：王冰[1] 刘士新[1] 杨金磊[1] 卜明伟 

机构地区：[1]吉林省肿瘤医院放疗一科,长春130012

出　　处：《中华放射医学与防护杂志》2013年第5期508-511,共4页Chinese Journal of Radiological Medicine and Protection

摘　　要：目的 探索射野方向及数量对宫颈癌计划优化的影响.方法 选取9例进行调强放疗的宫颈癌患者,分别设计射野方向均分、起始角度分别为0°、180°的15主野30子野和7主野55子野计划,比较4组计划的治疗时间、机器跳数及靶区、危及器官和靶区外正常组织的剂量分布.结果 7野计划起始角度为180°时小肠V30比另外3组计划高约4％（F=6.164,P＜0.05）.相同数量射野不同入射方向的计划间比较,靶区及危及器官各项剂量学结果差异无统计学意义;不同射野数量相同起始角度计划的直肠、膀胱的V40、V30和小肠的V40相似;15野计划危及器官的V20、Dmean明显减小（F=3.665～10.503,P＜0.05）,靶区的均匀性稍逊于7野计划（F=12.933,P＜0.05）.15野计划治疗时间略有增加（F=0.312,P＜0.05）,但是计划跳数明显减少（F=4.650,P＜0.05）.结论 增加入射野数量可以基本抵消子野减少带来的负面影响,获得相近的剂量学结果.Objective To explore the influence of the number and orientation of the beams on the optimization of IMRT plan.Methods Four IMRT plans were designed for 9 patients with cervical cancer,and 7 and 15 fields were applied.The 15-field plans had 30 segments and the 7-field plans had 55 segments.The initial beam angle degrees were 0° and 180°,respectively.Dose delivery time,MUs of plans,the dose distributions of the targets,organs at risk and normal tissues were analyzed and compared in the plans.Results Compared the plans with different beam directions under the same amount,no difference of the irradiation dosimetry in the target and organs at risk was found,except for irradiation dosimetry received by the 7-field 180° small intestine was about 4% higher than the other three plans（F=6.164,P〈0.05）.The terms of the volume of organs at risk got high dose irradiation（V40 and V30 of the rectum and bladder,V40 of the small intestine）,which was similar in the 7-and 15-field plans.V20 and Dmean of organs at risk were significantly smaller（F=3.665-10.503,P〈0.05）in the 15-field plans.The 15-field plans needed a little longer treatment time（F=0.312,P〈0.05）and HI was slightly worse （F=12.933,P〈0.05）,but the number of MUs was significantly reduced（F=4.650,P〈0.05）.Conclusions Increasing the beam number will offset the negative impact of sub field reduction and get the similar dose distribution result.

关 键 词：宫颈癌 调强放疗 射束方向 射野数量 

分 类 号：R737.33[医药卫生—肿瘤]