摘要
目的 探讨基于双层多叶准直器(MLC)计算的医用直线加速器射野复杂度指标与剂量的相关性.方法 回顾性分析 2022 年 3 月至 2023 年 10 月于医院行胸部固定野调强放射治疗的 70 例患者临床资料,分析患者胸部固定野调强放射治疗计划中远源端与近源端MLC的射野复杂度差别,并通过Spearman检验分析射野复杂度指标[调制复杂度分数(MCS)、射野小孔经分数(SAS)、射野面积(BA)、射野不规则(BI)及射野周长面积比(C/A)]与剂量的相关性.结果 胸部固定野调强放射治疗患者的 1%/1 mm和 2%/2 mm γ通过率分别为(93.00±2.72)%和(95.96±2.37)%.远源端MLC的MCS小于近源端MLC,远源端MLC的BI、SAS、C/A均大于近源端MLC,差异有统计学意义(P<0.05),远源端和近源端MLC的BA比较,差异无统计学意义(P>0.05).在 1%/1 mm标准下,远源端MLC的MCS与γ通过率呈弱相关,远源端MLC的BA、SAS2 mm、SAS5 mm、SAS10 mm、SAS15 mm与γ通过率呈中度相关,远源端MLC的C/A与γ通过率呈强相关(P<0.05),远源端MLC的BI与γ通过率无相关(P>0.05);在 2%/2 mm标准下,远源端MLC的MCS与γ通过率呈弱相关,远源端MLC的BA、SAS2 mm、SAS5 mm、SAS10 mm、SAS15 mm、C/A与γ通过率呈中度相关(P<0.05),远源端MLC的BI与γ通过率无相关(P>0.05).在 1%/1 mm标准下,近源端MLC的MCS与γ通过率呈弱相关,近源端MLC的BA、BI、SAS2 mm、SAS5 mm、SAS10 mm与γ通过率呈中度相关,近源端MLC的SAS15 mm、C/A与γ通过率呈强相关(P<0.05).在 2%/2 mm标准下,近源端MLC的MCS与γ通过率呈弱相关,近源端MLC的BA、BI、SAS2 mm、SAS5 mm、SAS10 mm、SAS15 mm、C/A与γ通过率呈中度相关(P<0.05).远源端和近源端MLC射野复杂度指标与剂量间存在显著相关性,其中C/A和SAS对剂量分布的影响较大.结论 双层MLC医用直线加速器中,射野复杂度指标与剂量之间存在相关性,C/A和SAS对剂量分布的影响较大.
Abstract
Objective To investigate the correlation between field complexity index of medical linear accelerators and dose based on double-layer multi-leaf collimator(MLC)calculation.Methods With the retrospective analysis of the clinical data of 70 patients with chest fixed field intensity-modulated radiation therapy in hospitals from March 2022 to October 2023,the differences of field complexity between the distal and proximal MLC in the patient's chest fixed field intensity-modulated radiation therapy plan were analyzed,and the correlation between field complexity index[modulation complexity score(MCS),small aperture score(SAS),beam area(BA),field beam irregularity(BI),ratio of the circumference and area(C/A)]and dose was analyzed by Spearman test.Results The 1%/1 mm and 2%/2 mm γ pass rates for patients with chest fixed field intensity-modulated radiation therapy were(93.00±2.72)%and(95.96±2.37)%,respectively.The MCS of the distal MLC was lower than that of the proximal MLC.The BI,the SAS,and the C/A of the distal MLC were all greater than those of the proximal MLC,and the differences were statistically significant(P<0.05).There was no statistically significant difference in the BA between the distal and proximal MLC(P>0.05).With the 1%/1mm standard,the MCS of the distal MLC was weakly correlated with the γ pass rate,the BA,SAS2 mm,SAS5 mm,SAS10 mm,SAS15 mm of the distal MLC were moderately correlated with the γ pass rate,and the C/A of the distal MLC was strongly correlated with the γ pass rate(P<0.05).There was no correlation between BI and γ passing rate of distal MLC(P>0.05).With the 2%/2 mm standard,the MCS of the distal MLC was weakly correlated with the γ pass rate,and the BA,SAS2 mm,SAS5 mm,SAS10 mm,SAS15 mm,and C/A of the distal MLC were moderately correlated with the γ pass rate(P<0.05).There was no correlation between BI and γ passing rate of distal MLC(P>0.05).With the 1%/1 mm standard,MCS of proximal MLC were weakly correlated with γ pass rate,BA,BI,SAS2 mm,SAS5 mm and SAS10 mm of proximal MLC were moderately correlated with γ pass rate,and SAS15 mm,C/A of proximal MLC were strongly correlated with γ pass rate(P<0.05).With the 2%/2 mm standard,MCS of proximal MLC were weakly correlated with γ passing rate,and BA,BI,SAS2 mm,SAS5 mm,SAS10 mm,SAS15 mm,C/A of proximal MLC were moderately correlated with γ passing rate(P<0.05).There was significant correlation between the distal and proximal MLC field complexity index and the dose.Among them,C/A and SAS have a significant impact on dose distribution.Conclusion There is a correlation between the field complexity index and dose in a double-layer MLC medical linear accelerator.In addition,C/A and SAS have a significant impact on dose distribution.
维普
万方数据