Dosimetric comparison between gamma knife SBRT and linear accelerator-based SBRT for lung tumors
Objective To analyze the dosimetric differences between gamma knife stereotactic body radiation therapy(SBRT)and linear accelerator-based SBRT for lung tumors by comparison to provide a theoretical basis for the selection of treatment strategies.Methods Seven patients who underwent SBRT for lung tumors in the Cancer Center of Affiliated Zhongshan Hospital of Dalian University from January 2022 to May 2023 were enrolled.Plans of gamma knife SBRT(γ_SBRT)or linear accelerator-based SBRT plans(X_SBRT)were designed for the 13 lesions in the patients,with adjacent lesions in the same patient sharing one plan.As a result,10 γ_SBRT plans and 10 X_SBRT plans were obtained.All lesions received 30-50 Gy of radiation in 5-10 fractions.Then,dosimetric parameters were analyzed and compared between γ_SBRT and X_SBRT plans,including the target coverage,gradient index(GI),conformity index(CI),maximum dose(Dmax);mean dose(Dmean),and minimum dose(Dmin)of planning target volumes(PTVs);lung volumes receiving 20 Gy or more(V20),10 Gy or more(V10),5 Gy or more(V5),100％of the prescription dose(V100％),and 50％of the prescription dose(V50％);Dmean and the percentages of lung volume receiving doses of 20 Gy or more(Lung_V20)and 5 Gy or more(Lung_V5)of ipsilateral lung;Dmean and Lung_V5 of contralateral lung;and Dmax values of the esophagus,spinal cord,and heart.Results Compared to X_SBRT plans,γ_SBRT plans exhibited superior GI,V20,V10,V5,V50％,the Dmean,Lung_V20,and Lung_V5 of ipsilateral lung,the Dmean and Lung_V5 of the contralateral lung,and the Dmax of esophageal and heart(z=-2.81 to-1.99,P＜0.05),higher Dmax and Dmean of PTVs(z=-2.80,-2.80,P＜0.05),and longer delivery time(z=-2.70,P＜0.05).Meanwhile,there was no significant difference in target coverage,CI,and Dmax of the spinal cord(P＞0.05).Conclusions Gamma knife SBRT plans can achieve sharper dose falloff outside target volumes than linear accelerator-based SBRT plans.Gamma knife radiosurgery is expected to reduce the radiation dose to low-dose areas around PTVs and normal lung tissue in SBRT for lung tumors.However,it significantly prolongs the delivery time.
Stereotactic body radiation therapyGamma knifeLung tumorsDose distribution
万方数据
维普
