优化角度分组对宫颈癌容积旋转调强计划剂量分布的影响  

Effect of Increment on Planned Dose Distribution of Volumetric Modulate Arc Therapy Plans of Cervical Cancer

作　　者：王成 陈维军 李玉成 贾勇士[2] 詹文明[2] 李强[2] 杨帆 赵桂芝[1] WANG Cheng;CHEN Wei-jun;LI Yu-cheng;JIA Yong-shi;ZHAN Wen-ming;LI Qiang;YANG Fan;ZHAO Gui-zhi(School of Nuclear Science and Technology, University of South China, Hengyang 421001, China;Zhejiang Provincial People's Hospital/Affiliated Hospital of Hangzhou Medical College, Hangzhou 310014, China)

机构地区：[1]南华大学核科学技术学院,衡阳421001 [2]浙江省人民医院放疗科/杭州医学院附属人民医院,杭州310014

出　　处：《科学技术与工程》2021年第15期6236-6241,共6页Science Technology and Engineering

基　　金：国家自然科学基金(11975120);浙江省基础公益研究计划(GF21H180053)。

摘　　要：为了明确Monaco计划系统中优化角度分组(increment,Inc)的选择对宫颈癌患者的单弧容积旋转调强放射治疗(volumetric-modulated arc therapy,VMAT)剂量分布的影响,指导临床选择合适的Inc参数用于宫颈癌患者的VMAT计划设计。首先选取了15例宫颈癌患者,在Inc=30°下设计全弧VMAT计划,再将治疗计划结果分别在Inc=10°、20°、40°下进行计算,比较4种不同Inc下计划靶区(planning target volume,PTV)的D2、D50、均匀性指数(homogeneity index,HI)、适形度指数(conformity index,CI)和危及器官中的左右股骨头、盆骨、直肠、小肠、膀胱、乙状结肠、脊髓等器官的相关剂量学参数的差异(Dx表示x%的体积包含的剂量)。其结果表明,与对照组Inc=30°相比较,Inc=10°中PTV的CI、骨盆V10、V20、Dmean明显减小(Vx表示x Gy剂量所占的体积百分比),直肠膀胱的D2及PTV的D50明显增加,差异均具有统计学意义(P<0.05),Inc=40°中PTV的D2、左股骨头及盆骨的Dmean均显著增加(P<0.05),其余靶区及危及器官的差异不明显(P>0.05),Inc=20°的靶区和危及器官与Inc=30°时相比,差异全部不明显,所有计划的平均跳数和平均计划时间均随着Inc的增大而增加。因此对于宫颈癌病例,选择用Inc=30°能满足大多数患者,在保证靶区剂量充足和分布均匀的条件下,可以更好地减少跳数和计划时间,当计划优化结果较差时,将Inc设置为20°,其精度更高,可以得到更好的结果。In order to clarify the effects of increment(Inc)parameter selection in the Monaco planning system on the dose distribution of cervical cancer patients treated with the single-arc volumetric-modulated arc therapy(VMAT),and to guide clinical selection of appropriate Inc parameters for VMAT planning design of cervical cancer patients.Firstly,fifteen patients with cervical cancer were selected,a full arc VMAT plan was designed under the condition of Inc of 30°,the results of treatment plan were calculated at 10°,20°,and 40°,respectively.The differences of D2,D50,homogeneity index(HI),conformity index(CI)and the relevant dosimetric parameters of left and right femur head,pelvis,rectum,small intestine,bladder,sigmoid colon,spinal cord and other organs-at-risk in the target area of planning target volume(PTV)under four different Inc were compared(Dx is the dose to x%of the volume).The results indicated that compared with the control group Inc=30°,The CI,V10,V20 and Dmean of PTV in Inc of 10°were decreased significantly(Vx represents the volume percentage of the dose of x Gy),while the D2 of rectum and bladder and the D50 of PTV increased obviously(P<0.05),and all with statistically significant differences(P<0.05).The Dmean of D2,left femur head and pelvis of PTV in 40°increased significantly,but there was no statistical difference in other target areas and organs-at-risk(P>0.05).Compared with Inc=30°,there was no marked differences in target areas and organs-at-risk between 20°and 30°,and the average MU and the average planning time of all plans increased with the increase of Inc.Therefore,for patients with cervical cancer,the choice of Inc of 30°would satisfy most patients.Under the condition of sufficient dose and uniform distribution of the target dose,the MU and planning time can be better reduced.When the plan optimization results are terrible,set Inc to 20°,The accuracy is higher,and better results can be obtained.

关 键 词：宫颈癌 优化角度分组 剂量差异 容积旋转调强 

分 类 号：R737.33[医药卫生—肿瘤]