Dosimetric comparison between gamma knife SBRT and linear accelerator-based SBRT for lung tumors
10.3760/cma.j.cn112271-20230806-00033
- VernacularTitle:伽马刀SBRT与直线加速器SBRT治疗肺部肿瘤的剂量学对比研究
- Author:
Wenyue DUAN
1
;
Huajian WU
;
Genghao ZHAO
;
Chuanhao ZHANG
;
Zhijun FAN
;
Zhe WANG
;
Ruoyu WANG
Author Information
1. 大连大学附属中山医院肿瘤中心 辽宁省乳腺及消化肿瘤分子标志物高通量筛选及靶向药物转化重点实验室 辽宁省放射性粒子及热精准治疗重点实验室，大连 116001
- Keywords:
Stereotactic body radiation therapy;
Gamma knife;
Lung tumors;
Dose distribution
- From:
Chinese Journal of Radiological Medicine and Protection
2024;44(6):482-488
- CountryChina
- Language:Chinese
-
Abstract:
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.
