中晚期宫颈癌术后容积旋转调强放疗计划剂量学研究  

Dosimetric Study of Volumetric Modulation Arc Therapy for Postoperative Cervical Cancer

作　　者：张怀文[1] 钟晓鸣[1] ZHANG Huaiwen;ZHONG Xiaoming(Jiangxi Cancer Hospital,Nanchang,330029)

机构地区：[1]江西省肿瘤医院

出　　处：《实用癌症杂志》2019年第9期1451-1454,共4页The Practical Journal of Cancer

基　　金：江西省卫生厅科技计划项目(编号:20185368)

摘　　要：目的比较中晚期宫颈癌术后常用调强放疗技术的靶区及其周围正常组织受照剂量的差异,为宫颈癌术后放疗方法的临床选择提供理论依据。方法随机选取10例宫颈癌术后患者,经增强CT扫描后在pinnacle 39.6治疗计划系统中进行靶区勾画。每例患者分别设计固定5野计划Ⅰ,固定7野计划Ⅱ,VMAT双弧计划Ⅲ三种不同调强计划。三种设野方法的机架角度分别为计划Ⅰ:0°,72°,144°,216°,288°;计划Ⅱ:0°,52°,104°,156°,208°,260°,312°;计划Ⅲ:179°~181°,181°~179°。在满足PTV临床靶区达到95%处方剂量的前提下,利用剂量体积直方图(DVH)评价三种调强照射技术的靶区和周围正常组织照射剂量和靶区适形指数(CI)及剂量不均匀性指数(HI)。结果①三种计划的靶区平均剂量以及靶区均匀性指数HI之间的差异没有统计学意义,而靶区的适形度指数计划Ⅲ最优,计划Ⅱ次之,而计划Ⅰ最差;②对小肠的保护,计划Ⅱ的小肠所受照射的平均剂量略高于计划Ⅰ和Ⅲ,计划Ⅰ的小肠在中高剂量处V 30、V 40接受的受照体积稍高于计划Ⅱ和Ⅲ;③对膀胱的保护,膀胱受照平均剂量计划II略小于计划Ⅰ,在V 40接受的照射剂量体积计划Ⅲ最优;④对左股骨头的保护,三者间除V 30处计划I稍小外,其余差异无统计学意义;⑤对右股骨头的保护,三者间差异无统计学意义。结论三种调强设野方法的靶区照射剂量差异不大,但是VMAT方法的计划适形度最好,且在对小肠和膀胱等重要危及器官的保护上优于常规固定野调强Ⅰ,Ⅱ方法。Objective To compare the dose difference of intensity-modulated radiotherapy(IMRT)in target volume and surrounding normal tissues for postoperative cervical cancer,so as to optimize the protocol for clinical practice.Methods 10 postoperative patients with postoperative cervical cancer were chosen randomly.They were marked by enhanced CT scan and the PTV and OAR were contoured on the pinnacle3 9.6 treatment planning system.3 common IMRT plansⅠ(IMRT five-field plan),Ⅱ(IMRT seven-field plan),andⅢ[two arcs volumetric modulation arc therapy plan]were designed for each patient according to the target region of the cancer.The gantry angles of three plans wereⅠ:0°,72°,144°,216°,288°;Ⅱ:0°,52°,104°,156°,208°,260°,312°;Ⅲ:arc 179°~181°,arc 181°~179°.Based on 95%of the planning target volume received the prescribed dose,the dose distributions of plan target volume and normal tissues,conformal index(CI)and heterogeneous index(HI)were analyzed using the dose volume histogram(DVH).Results There was no significant difference between the average PTV and HI among them.The conformal index in planⅢof target volume was the best,planⅡwas the second,and planⅠis the worst.As regarded as the protection on organs at risk,for small intestine,The average dose of plannedⅡwas slightly higher than plannedⅠandⅢ,and the volume of plannedⅠwas slightly higher than plannedⅡandⅢin the medium and high dose region at V 30 and V 40;for bladder,the average dose of planⅡis slightly smaller than planⅠ,Ⅲshowed difference with other 2 plans at theV 40;for femoral head,there was no significant difference among three plans,except at V 30 of planⅠwas slightly smaller in left femoral head.Conclusion There is no significant difference in target dose among the 3 plans,but the VMAT plan had the best conformal index planned conformity,and was superior to the conventional fixed field intensity modulation plans I and II in protecting organs at risk such as small intestine and bladder.

关 键 词：宫颈癌术后 调强放射治疗 VMAT 

分 类 号：R737.33[医药卫生—肿瘤]