AAA和AcurosXB算法对局部晚期食管鳞状细胞癌SIB-VMAT计划剂量学差异的研究

AAA and AcurosXB Algorithms for Dosimetric Differences in SIB-VMAT Schemes for Locally Advanced Esophageal Squamous Cell Carcinoma

目的:探讨各向异性分析算法(AAA)与光子剂量算法(AcurosXB或AXB)对局部晚期食管鳞状细胞癌SIB-VMAT计划剂量学的差异。方法:选取24例行SIB-VMAT放射治疗的局部晚期食管鳞状细胞癌患者的影像学资料,分别采用AAA和AXB两种算法设计具有相同射束、MLC以及优化约束函数的SIB-VMAT计划,比较两组计划剂量学参数结果的差异。结果:在靶区D_(max)、D_(mean)、D_(98%)、D_(50%)方面,AXB组计划结果明显高于AAA组,有统计学意义(P<0.05)。AXB组计划的靶区适形性指数(CI)和均匀性指数(HI)对PGTV好于AAA组,有统计学意义(P<0.05),而对PTV两者差异无统计学意义(P>0.05)。在肺组织受量方面,AXB组可有效降低D_(min)、D_(mean)、D_(50%)及V_(5)受量,但V_(20)和D_(max)受量略高于AAA,有统计学意义(P<0.05);在心脏受量方面,除V_(30)低于AAA(1.29%),D_(max)略高于AAA(0.82%),有统计学意义(P<0.05)外,其他参数差异不显著。在脊髓保护区受量方面,AXB组的D_(max)略高于AAA(0.59%),差异有统计学意义(P<0.05)。AXB组的机器调数(MU)略高于AAA(1.53%),有统计学意义(P<0.05)。结论:AXB算法与AAA算法对局部晚期食管癌SIB-VMAT计划模型的剂量结果有一定的差异,但都满足临床剂量学要求,均可用于局部晚期食管癌SIB-VMAT的临床治疗。

Objective:To investigate the difference of dosimetry between anisotropic analytical algorithm(AAA)and acuros external Beam algorithm(AXB)to the SIB-VMAT for locally advanced esophageal squamous cell carcinoma.Methods:Twenty four patients with locally advanced esophageal squamous cell carcinoma who received SIB-VMAT radiotherapy were randomly selected.Two algorithms modes of AAA and AXB were used to design SIB-VMAT plans with the same beam,MLC and optimized constraint function,to compare the differences of dosimetry parameters between the two groups.Results:In terms of D_(max),D_(mean),D_(98%),and D_(50%)of the target area,the AXB group were significantly higher than those in the AAA group,which was statistically significant(P<0.05).The conformity index(CI)and homogeneity index(HI)of the AXB group were better than those of the AAA group for PGTV,with statistical significance(P<0.05),but there was no significant difference in the PTV(P>0.05).About the dose of lung,AXB group could effectively reduce the dose of D min,D_(mean),D_(50%)and V_(5),but V_(20) and D_(max)were slightly higher than AAA,which was statistically significant(P<0.05).About the dose of cardiac,except V_(30) was lower than AAA(1.29%),and D_(max)was slightly higher than AAA(0.82%),which was statistically significant(P<0.05).About the dose of spinal cord protection area,the D_(max)of AXB group was slightly higher than AAA(0.59%),which was statistically significant(P<0.05).The monitor unit(MU)of the AXB group was slightly higher than AAA(1.53%),which was statistically significant(P<0.05).Conclusion:The SIB-VMAT plan optimized by the AAA and AXB algorithms can meet the clinical requirements.Although the AXB algorithm and the AAA algorithm have certain differences in the dose results of the SIB-VMAT planning model,they both meet the clinical dosimetry requirements and can be used for the clinical treatment of locally advanced esophageal squamous cell carcinoma by the SIB-VMAT.