计算网格大小对Eclipse治疗计划系统剂量计算的影响  

Effects of different calculation grids on dose calculation in treatment plan system of Eclipse

作　　者：刘翔宇[1] 柳先锋[1] 何亚男[1] 靳富[1] 王辉东[2] 

机构地区：[1]重庆市肿瘤研究所放疗科,重庆400030 [2]吉林大学物理学院原子核科学与技术研究中心,吉林长春130012

出　　处：《吉林大学学报（医学版）》2011年第5期843-847,共5页Journal of Jilin University：Medicine Edition

基　　金：重庆市卫生局医学科学技术研究项目资助课题(2008-2-283)

摘　　要：目的：探讨治疗计划系统（TPS）中不同大小计算网格对靶区剂量以及危及器官（OAR）受量的影响,为临床应用提供依据。方法：10例接受固定野调强放射治疗的鼻咽癌患者,采用3A（AAA）算法,对每例患者分别制作计算网格为2.50 mm的对照组和计算网格分别为5.00、4.00、3.00、2.00和1.25 mm的实验组共6种治疗计划;采用笔形束（PBC）算法,对每例患者分别制作计算网格为2.50 mm的对照组和计算网格分别为10.00、5.00和1.25 mm的实验组共4种治疗计划。利用剂量体积直方图,分析不同计算网格大小对靶区剂量最大值、最小值、均值和适形度指数、均匀度指数,以及脑干受量最大值、左晶体受量最大值、左视神经受量最大值、视交叉受量最大值和脊髓受量最大值的影响。结果：与对照组比较,采用3A算法,计算网格变大,靶区剂量最大值、均值和适形度指数变大,均匀度指数变小,OAR左晶体受量最大值变小（P〈0.05）。采用PBC算法,计算网格变大,靶区剂量最大值、最小值、均值和适形度指数变大,均匀度指数变小,OAR左晶体受量最大值和脊髓受量最大值变小,视交叉受量最大值变大（P〈0.05）。结论：靶区的剂量分布以及OAR的受量随计算网格的变化而改变,选择合适的计算网格大小,可精确评估靶区及OAR受量。在临床使用中,计算网格一般应选择2.50~5.00 mm,推荐使用2.50 mm。Objective To explore the effect of different calculation grids in the treatment planning system（TPS） on the dose distribution for the target and recepted doses of organs at risk（OAR） and to provide basis for clinical treatment.Methods Ten nasopharyngeal carcinoma patients recepted fixed-field IMRT rediation therapy were treated with Anisotropic Analytical Algorithm（3A） method.Calculation grid of 2.50 mm was selected as control group and calculation grids of 5.00,4.00,3.00,2.00,1.00 and 1.25 mm were selected as experiment groups to perform 6 treatment plans.Pencil Beam Convolution（PBC） Algorithm were used for calculation,calculation grid of 2.50 mm was selected as control group and calculation grids of 10.00,5.00 and 1.25 mm were selected as experiment groups to perfrom 4 treatment plans respectively for 10 patients.The effects of different calculation grids on the maximum dose,the minimum dose,the mean dose,conformal index and homogeneity index of the target,and the maximum dose of brain stem,left lens,left optic nerve,optic chiasm and spinal cord were analyzed by dose volume histogram.Results Compared with control group,with 3A method,the size calculation grid was increased,the maximum dose,the mean dose and conformal index of the target were increased;but the homogeneity index,the maximum dose of the target,and the maximum dose of left len were decreased（P0.05）.With PBC Algorithm,the size calculation grid,the the maximum dose,the minimum dose,the mean dose and conformal index of the target were increased;but the homogeneity index of the target,and the maximum doses of left len and spinal cord were decreased,and the maximum dose of optic chiasm was increased（P0.05）.Conclusion The target dose distribution and the dose of OAR change with the changes of calculation grids.Using the right size calculation grid can evaluate accurately the doses of the target and OAR.In clinical use,the calculation grid should generally choose 2.5-5.0 mm,and the recommended grid is 2.5 mm.

关 键 词：计算网格 治疗计划系统 剂量 

分 类 号：R73-36[医药卫生—肿瘤]