大体积宫颈癌单程与二程VMAT计划的物理、生物等效剂量变化研究  

Study of physical and biological equivalent dose changes in single-pass and re-course VMAT plans for large volume cervical cancer

作　　者：吴伟伟 尹慧 赖小云 罗红樱 李政欢 WU Wei-wei;YIN Hui;LAI Xiao-yun;LUO Hong-ying;LI Zheng-huan(Center of Radiation Oncology,Ganzhou Tumor Hospital,Ganzhou 341000,Jiangxi Province,China;Department of Radiation Oncology,the Third Affiliated Hospital of Sun Yat-Sen University,Guangzhou 510630,China)

机构地区：[1]赣州市肿瘤医院放疗中心,江西赣州341000 [2]中山大学第三附属医院放射治疗科,广州510630

出　　处：《医疗卫生装备》2021年第12期42-47,97,共7页Chinese Medical Equipment Journal

基　　金：江西省卫生健康委科技计划项目(202140807)。

摘　　要：目的:研究大体积宫颈癌患者在容积旋转调强放疗(volumetric modulated arc therapy,VMAT)过程中因肿瘤退缩和器官体积变化所致的剂量学改变,分析单程与二程VMAT计划的物理剂量与生物等效剂量变化。方法:选取某院25例宫颈原发肿物体积>80 cm^(3)的宫颈癌患者,每位患者均进行VMAT,并每周采用锥形束CT(cone beam CT,CBCT)分析患者的靶区和危及器官体积变化。将初始VMAT计划定义为Plan1,在放疗15次后再次进行CT扫描,将Plan1移植到新的CT图像上形成移植计划Plan2,并在新CT图像上再次设计新的二程VMAT计划(Plan3),分析宫颈癌患者Plan1、Plan2和Plan33组计划的物理剂量和生物等效剂量变化。采用SPSS 19.0软件进行统计学分析。结果:肿瘤靶区(gross tumor volume,GTV)5周共退缩65.41%,平均每周退缩13.08%;GTVnd 5周共退缩42.78%,平均每周退缩8.56%。对比Plan1,Plan2中PGTV的平均剂量D_(mean)、平均生物等效剂量eD_(mean)和PCTV的D_(mean)、eD_(mean)、适形性指数(conformity index,CI)和eCI的均值均略有增大,相比Plan2,Plan3中PGTV的D_(mean)、eD_(mean)和PCTV的D_(mean)、eD_(mean)及CI和eCI的均值均有所降低,差异均具有统计学意义(P<0.05)。对比Plan1,Plan2中PGTVnd的95%体积所受剂量(D_(95))和生物等效剂量(eD_(95))的均值均有所降低,对比Plan2,Plan3中PGTVnd的D_(95)和eD_(95)的均值均有所增大,差异均具有统计学意义(P<0.05)。对比Plan1,Plan2中肠道的近似最大剂量(D_(2))、近似最大生物等效剂量(eD_(2)),膀胱的D_(mean)、eD_(mean)和直肠的D_(2)、D_(mean)、eD_(2)和eD_(mean)均显著增加,对比Plan2,Plan3中肠道的D_(2)、eD_(2),膀胱的D_(2)、eD_(2)、D_(mean)、eD_(mean)和直肠的D_(2)、D_(mean)、eD_(2)和eD_(mean)均显著降低,差异均具有统计学意义(P<0.05)。结论:大体积宫颈癌VMAT期间,宫颈原发肿瘤和转移淋巴结均有较大幅度的退缩,二程放疗较单程放疗在物理剂量和生物等效剂量方面均具有�Objective To investigate the dosimetric changes due to tumor regression and organ volume changes during volumetric modulated arc therapy(VMAT)in patients with large volume cervical cancer,and to analyze the physical dose and equivalent dose in 2 Gy/f(EQD2)changes between single-pass and re-course VMAT plans.Methods Twenty-five patients with radical radiotherapy for cervical masses>80 cm^(3) in some hospital were selected,and each patient was treated with VMAT radiotherapy(Plan1)and weekly cone beam CT(CBCT)to analyze the target area and organ volume changes of the patients,and re-CT scan again after 15 radiotherapy sessions,and Plan1 was transplanted to the new CT to form transplant plan(Plan2).A new second course VMAT plan(Plan3)was designed again to explore the physical dose and equivalent dosimetric changes of the 3 groups of plans:initial plan(Plan1),transplant plan(Plan2)and modified plan(Plan3).SPSS 19.0 software was used for statistical analysis.Results The gross tumor volume(GTV)regressed by a total of 65.41%at 5 weeks,with an average weekly regression of 13.08%;the GTVnd regressed by a total of 42.78%at 5 weeks,with an average weekly regression of 8.56%.Plan 2 had the values of the mean dose(D_(mean))and mean bioequivalent dose(eD_(mean))of PGTV and the D_(mean),eD_(mean),conformity index(CI)and eCI of PCTV all higher significantly than those of Plan1,and Plan3 had the values of D_(mean) and eD_(mean) of PGTV and the D_(mean),eD_(mean),CI and eCI of PCTV all lower than those of Plan 2(P<0.05).Plan 2 had the values of the mean D_(95) and eD_(95) of PGTVnd significantly lower than those of Plan 1,and Plan3 had the values of the mean D_(95) and eD_(95) of PGTVnd significantly higher than those of Plan 2(P<0.05).Plan 2 had the values of the approximate maximum dose(D_(2))and the approximate maximum bioequivalent dose(eD_(2))of the bowel,the D_(mean) and eD_(mean) of the bladder and the D_(2),D_(mean),eD_(2) and eD_(mean) of the rectum significantly higher than those of Plan 1,and Plan3 had the values of D_(2

关 键 词：宫颈癌 容积旋转调强放疗 物理剂量 生物等效剂量 肿瘤退缩 单程放疗 二程放疗 

分 类 号：R318[医药卫生—生物医学工程] R815[医药卫生—基础医学]