摘要
目的:探究在局部进展期直肠癌术前新辅助短程放射治疗中最小子野宽度(MSW)设置对容积旋转调强放射治疗(VMAT)计划的剂量学和质量参数的影响。方法:采用随机数表法选取在医院完成直肠癌术前新辅助短程放射治疗的29例患者,采用Monaco治疗计划系统(TPS),依据调强放射治疗逆向计划优化中最小子野宽度参数设置,为每例患者设计MSW0.5、MSW1.0、MSW1.5和MSW2.0的4种VMAT计划,MSW分别设置为0.5 cm、1.0 cm、1.5 cm和2.0 cm,在相同优化函数限制条件下进行计算,并采用三维剂量验证系统进行计划验证,分析比较4种计划的靶区和危及器官(OAR)的剂量学2%、50%和98%靶区体积的受照剂量(D_(2)、D_(50)、D_(98))、最大剂量(D_(max))、最小剂量(D_(min))、平均剂量(D_(mean))、107%处方剂量覆盖的体积(V_(107%))、均匀性指数(HI)和适形度指数(CI)差异;通过机器跳数和γ通过率结果分析MSW对计划执行质量的影响。结果:计划靶区中4种计划之间D_(98)、D_(2)、D_(min)及V_(107%)具有统计学差异,而D_(50)、D_(max)和D_(mean)则无统计学差异;4种计划的靶区剂量HI、CI和机器跳数比较,差异有统计学意义(x^(2)=25.561,x^(2)=32.298,x^(2)=85.841;P<0.05)。在OAR中,MSW0.5和MSW1.0对股骨头、膀胱和小肠的保护能力优于MSW1.5和MSW2.0,4种VMAT计划之间机器跳数随MSW设置增加而依次减小,MSW2.0的机器跳数显著小于其余3种计划,其差异有统计学意义(x^(2)=85.841,P<0.05);γ通过率方面,在2mm/2%和1mm/1%标准下,MSW0.5的γ通过率低于其余3种计划;在3mm/3%标准下,MSW0.5与MSW1.0相当,且均低于其余2种计划,其差异有统计学意义(x_(3mm/3%)^(2)=64.959;P<0.05)。结论:在直肠癌术前新辅助短程VMAT计划中,MSW设置为0.5 cm和1.0 cm时,能够获得略好的靶区处方剂量覆盖和OAR保护,MSW设置为2.0 cm时能够满足临床要求的同时具有更小的机器跳数和更好的计划验证通过率。
Objective:To explore the effect of the setting of the minimum segment width(MSW)on the parameters of the dosimetry and quality of the volume-modulated arc therapy(VMAT)radiotherapy in the short-term radiotherapy with preoperative neoadjuvant therapy of locally advanced rectal cancer.Methods:A total of 29 patients who completed short-term radiotherapy with preoperative neoadjuvant therapy of locally advanced rectal cancer in hospital were enrolled in our study as random number table.The Monaco treatment plan system(TPS)was adopted,and 4 groups of VMAT plans(group MSW 0.5,group MSW 1.0,group MSW 1.5 and group MSW 2.0)were designed for each patient according to the MSW parameter setting in the optimization of the reverse planning of intensity modulated radiotherapy(IMRT).The MSWs were respectively set as 0.5 cm,1.0 cm,1.5 cm and 2.0 cm.The calculation was conducted under the restrictive condition of same optimization function,and the three dimensional(3D)dose verification system was adopted to perform plan verification.The differences of exposure doses(D_(2),D_(50) and D_(98))of target volume to 2%,50% and 98%,the maximum dose(D_(max)),the minimum dose(D_(min)),the mean dose(D_(mean)),the covered volume of 107% prescription dose(V_(107%)),homogeneity index(HI)and conformity index(CI)of dosimetry among 4 groups of target region and organ at risk(OAR)were analyzed and compared.The effect of MSW on the quality of plan execution was analyzed through machine units andγpass rate.Results:There were significant differences in D_(98),D_(2),D_(min) and V_(107%)among 4 groups in the planning target volume,while there were no significant differences in D_(50),D_(max) and D_(mean) among them.The differences of HI,CI and machine units of target region doses among 4 groups were significant(x^(2)=25.561,x^(2)=32.298,x^(2)=85.841,P<0.05).In OAR,the protective capacities of group MSW 0.5 and group MSW 1.0 were respectively better than those of group MSW 1.5 and group MSW 2.0 for femoral head,bladder and small intestine,and the machi
作者
周鹏
刘岩海
陈川
耿明英
罗佳
ZHOU Peng;LIU Yan-hai;CHEN Chuan(Department of Oncology,Daping Hospital,Army Medical University,Chongqing 400042,China;不详)
出处
《中国医学装备》
2023年第8期12-18,共7页
China Medical Equipment
基金
国家重点研发计划(2018YFC0114402)“国产放射治疗设备在肿瘤精准治疗中的应用”
重庆市科卫联合重点课题(2022ZDXM027)“局部晚期直肠癌的精准放射治疗智能化模式研究”。
