HyperArc performance in radiotherapy and its correlations with number and volume of multiple brain metastases  

作　　者：Hongtao Chen Zihuang Li Guixiang Liao Lijun Wang Xiaonian Deng Heli Zhong 

机构地区：[1]Department of Radiation Oncology,Shenzhen People's Hospital,The Second Clinical Medical College,Jinan University,The First Affiliated Hospital,Southern University of Science and Technology,Shenzhen,518020,China

出　　处：《Radiation Medicine and Protection》2024年第2期139-144,共6页放射医学与防护（英文）

摘　　要：Objective:To assess the performance and advantages of HyperArc for radiotherapy of multiple brain metastases with dosimetric parameters with respect to coplanar volumetric modulated arc radiotherapy(c-VMAT),and characterize implicit correlations between tumor features and dosimetric parameters.Methods:This retrospective study involved 40 patients with multiple brain metastases(4–16 tumors,12.8–240.8 cm3)who received simultaneous radiotherapy at the Department of Radiation Oncology,Shenzhen People's Hospital from January 2019 to December 2022.Both HyperArc and c-VMAT plans were designed by the same and qualified physicist using the Eclipse system with Truebeam.A single isocenter and a 6 MV flattening filter-free(6FFF)photon beam were used for radiotherapy of multiple brain metastases in each plan.Dosimetric parameters of tumors and organs at risk(OARs)were compared between HyperArc and c-VMAT plans.Corre-lations between tumor features(number and volume)and dosimetric parameters were revealed and analyzed.Furthermore,monitor units(MUs)of both plan types were recorded to assess rays utilization and delivery efficiency.Results:Compared to c-VMAT plans,HyperArc plans achieved higher maximum dose(D_(max))(5.23%,t=7.87,P<0.01),but lower minimum dose(Dmin)(3.94%,t=-2.12,P=0.04)and mean dose(D_(mean))(1.05%,t=-3.29,P<0.01)for planning gross tumor volumes(PGTVs).The conformity index(CI),homogeneity index(HI),gradient index(GI)and R50%of PGTVs with HyperArc were better than those with c-VMAT,with the improve-ments of 20.78%,1.68%,19.83%and 36.20%,respectively(P<0.01).The dosimetric parameters of OARs were significantly improved in HyperArc plans compared to c-VMAT plans.Specifically,the D_(max)and the D_(mean)to the brainstem decreased by 16.14%and 11.37%,respectively.The D_(max)for eye_L decreased by 16.88%,for eye_R decreased by 11.67%,for optical nerve_L decreased by 12.56%,and for chiasm decreased by 18.12%.Few correlations were observed between the differences of CI/HI/GI/R50%and the number of PGTVs between the two

关 键 词：HyperArc RADIOTHERAPY Multiple brain metastases CONFORMITY 

分 类 号：R739.41[医药卫生—肿瘤] R730.55[医药卫生—临床医学]