脑胶质瘤放疗计划设计的探索和评价  

Exploration and evaluation of the radiotherapy plan for glioma

作　　者：王沛沛 李金凯 李彩虹 曹远东 昌志刚 顾宵寰 狄晓珂 杨焱 WANG Peipei;LI Jinkai;LI Caihong;CAO Yuandong;CHANG Zhigang;GU Xiaohuan;DI Xiaoke;YANG Yan(Center of Radiation Oncology,the First Affiliated Hospital of Nanjing Medical University,Jiangsu Nanjing 210029,China)

机构地区：[1]南京医科大学第一附属医院放射治疗中心,江苏南京210029

出　　处：《现代肿瘤医学》2023年第18期3442-3446,共5页Journal of Modern Oncology

基　　金：国家自然科学基金(编号:82003228)。

摘　　要：目的:设计一种通过降低脑胶质瘤瘤床区(GTVtb)剂量均匀性来降低正常脑组织受量的放疗计划,并利用剂量学以及放射生物学指标评价。方法:选取20例脑胶质瘤术后患者放疗用CT图像。处方剂量为计划靶区(PTV)60 Gy/30 f(2 Gy/f),使用容积旋转调强(VMAT)技术分别设计两组计划,一组是常规计划(PTV均匀性控制在处方剂量的95%~107%之间),另一组适当降低GTVtb剂量均匀性(95%~110%之间),分别命名为Vhomo、Vinho。在95%体积的PTV满足处方剂量的前提下评价两组计划。利用剂量学指标评价两组计划中靶区和正常脑组织的剂量差异。基于等效均匀剂量(EUD)编写Matlab程序计算正常组织并发症概率(NTCP),评价正常脑组织的放射性损伤概率。利用机器跳数(MU)和计划系统计算的预计出束时间评价计划执行效率。结果:两组计划PTV剂量的D_(2%)、D_(98%)以及D_(mean)三项指标均具有显著的统计学差异(P<0.001)。Vinho组D_(2%)、D_(mean)高于Vhomo组,Vinho组的D_(98%)低于Vhomo组。两组计划PTV的CI均值为0.88±0.03,无统计学差异;HI均值分别为0.08±0.01、0.10±0.02,具有显著统计学差异(P=0)。Vinho组的正常脑组织受量评价指标V_(50)、V_(40)、V_(20)以及D_(mean)均较低,具有显著统计学差异(P<0.001),两组计划的NTCP(5.21±3.30 vs 4.79±2.77)具有统计学差异(P=0.048)。Vinho组计划MU多于Vhomo组,具有显著统计学差异(P=0.001),但并未延长治疗时间,二者的出束时间几乎相同,无统计学差异。结论:对于脑胶质瘤的放疗计划,通过降低靶区均匀性限制,可减少正常脑组织的受量,进而降低患者的放射性毒副反应,可为临床计划设计提供参考。Objective:To develop a radiotherapy plan to reduce the dose of normal brain by reducing the dose homogeneity of the tumor bed(GTVtb)for glioma,and evaluate the plans with dosimetric and radiobiological indicators.Methods:Twenty CT image-datasets of glioma patients treated by postoperative radiotherapy were selected.The prescribed dose of planning target volume(PTV)was 60 Gy/30 f(2 Gy/f),and two groups of plans were designed by volume-modulated arc therapy(VMAT),one group were conventional plan(the dose homogeneity of PTV was controlled between 95%and 107%of prescribed dose),the other group plans were reduced the homogeneity appropriately(the dose distribution homogeneity of GTVtb was controlled between 95%and 110%of prescribed dose),which were named Vhomo and Vinho respectively.The two groups of plans were evaluated under the condition that 95%of the volume of PTV met the prescribed dose.The dose differences of target and normal brain were evaluated by dosimetric parameters.The normal tissue complication probability(NTCP)were calculated by Matlab program based on equivalent uniform dose(EUD),which were used to evaluate the probability of radiation damage of normal brain.The efficiencies of the plan delivery were evaluated by the machine units(MUs)and the estimated delivery time calculated by the treatment planning system.Results:There were significant differences in D_(2%),D_(98%)and D_(mean) of PTV between the two groups(P<0.001).Compared to the Vhomo group,the D_(2%)and D_(mean) of Vinho were higher,and D_(98%)were lower.The mean conformity index(CI)of PTV were 0.88±0.03 in two groups with no significant differences.The mean values of HI were 0.08±0.01 and 0.10±0.02,respectively,with significant statistical differences(P=0).For the normal brain,the V_(50),V_(40),V_(20) and D_(mean) in Vinho group were all lower,showing statistically significant differences(P<0.001),the NTCP of the two groups were statistically significant(5.21±3.30 vs 4.79±2.77)(P=0.048).Compared to the Vhomo,there was a significantly incr

关 键 词：脑胶质瘤 容积旋转调强 剂量均匀性 正常组织并发症概率 

分 类 号：R730.55[医药卫生—肿瘤]