Radiotherapy
Dosimetric comparison between gamma knife SBRT and linear accelerator-based SBRT for lung tumors
Duan Wenyue, Wu Huajian, Zhao Genghao, Zhang Chuanhao, Fan Zhijun, Wang Zhe, Wang Ruoyu
Published 2024-06-25
Cite as Chin J Radiol Med Prot, 2024, 44(6): 482-488. DOI: 10.3760/cma.j.cn112271-20230806-00033
Abstract
ObjectiveTo 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.
MethodsSeven 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.
ResultsCompared 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).
ConclusionsGamma 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.
Key words:
Stereotactic body radiation therapy; Gamma knife; Lung tumors; Dose distribution
Contributor Information
Duan Wenyue
Department of Medical Oncology, Affiliated Zhongshan Hospital of Dalian University, The Key Laboratory of Biomarker High Throughput Screening and Target Translation of Breast and Gastrointestinal Tumor, The Key Laboratory of Radioactive Particles and Thermal Precision Therapy, Dalian University, Dalian 116001, China
Wu Huajian
Department of Medical Oncology, Affiliated Zhongshan Hospital of Dalian University, The Key Laboratory of Biomarker High Throughput Screening and Target Translation of Breast and Gastrointestinal Tumor, The Key Laboratory of Radioactive Particles and Thermal Precision Therapy, Dalian University, Dalian 116001, China
Zhao Genghao
Department of Medical Oncology, Affiliated Zhongshan Hospital of Dalian University, The Key Laboratory of Biomarker High Throughput Screening and Target Translation of Breast and Gastrointestinal Tumor, The Key Laboratory of Radioactive Particles and Thermal Precision Therapy, Dalian University, Dalian 116001, China
Zhang Chuanhao
Department of Medical Oncology, Affiliated Zhongshan Hospital of Dalian University, The Key Laboratory of Biomarker High Throughput Screening and Target Translation of Breast and Gastrointestinal Tumor, The Key Laboratory of Radioactive Particles and Thermal Precision Therapy, Dalian University, Dalian 116001, China
Graduate School of Dalian Medical University, Dalian 116044, China
Fan Zhijun
Department of Medical Oncology, Affiliated Zhongshan Hospital of Dalian University, The Key Laboratory of Biomarker High Throughput Screening and Target Translation of Breast and Gastrointestinal Tumor, The Key Laboratory of Radioactive Particles and Thermal Precision Therapy, Dalian University, Dalian 116001, China
Wang Zhe
Department of Medical Oncology, Affiliated Zhongshan Hospital of Dalian University, The Key Laboratory of Biomarker High Throughput Screening and Target Translation of Breast and Gastrointestinal Tumor, The Key Laboratory of Radioactive Particles and Thermal Precision Therapy, Dalian University, Dalian 116001, China
Wang Ruoyu
Department of Medical Oncology, Affiliated Zhongshan Hospital of Dalian University, The Key Laboratory of Biomarker High Throughput Screening and Target Translation of Breast and Gastrointestinal Tumor, The Key Laboratory of Radioactive Particles and Thermal Precision Therapy, Dalian University, Dalian 116001, China
