Physics·Technique·Biology
Evaluation the combined effect of three dose reconstruction systems on VMAT dosimetry verification of lung cancer
Ma Yangguang, Mai Rizhen, Pei Yuntong, Hu Jinyan, Kong Fanyang, Wang Xuemin, Guo Yuexin
Published 2021-01-15
Cite as Chin J Radiat Oncol, 2021, 30(1): 76-80. DOI: 10.3760/cma.j.cn113030-20191213-00519
Abstract
ObjectiveTo evaluate the combined effect of an trajectory log field based(LBF)and two commercial dose reconstruction systems on volume-modulated arc therapy(VMAT)dose verification of lung cancer.
MethodsAn in-house program was developed to introduce errors in trajectory log of TrueBeam to the origin plan and recalculate the dose of the error plan in treatment planning system(TPS). A total of 18 lung cancer cases treated by two-arc VMAT were selected to perform on LINAC and measured by ArcCheck simultaneously. Then, the reconstructed doses were obtained by 3DVH. The mode of reconstruction was calculated by LFB and Compass. Five of the 18 cases were performed on LINAC two times in four hours and measured by ArcCheck to evaluate the stability of the TrueBeam performance. The 18 plans were recalculated and performed on LINAC with a solid water phantom with 5 cm build-up, 4 cm back scattering thickness and a FC65-G detector in the center. The measured dose by detector was compared with the reconstructed dose by three systems.
ResultsTheTruebeam performance was stable. For all of the 18 cases, the point dose measured by FC65-G and reconstructed by three systems had a deviation of less than 2% to the TPS calculated. For all of the organs reconstructed by LBF and most organs reconstructed by 3DVH and Compass, the γ pass rate between them and TPS all exceeded 90% under all criteria, as well as the ArcCheck measured results. For all the organ dose difference between reconstructed and TPS, LBF system had the smallest difference, followed by the Compass system except the lung, and the 3DVH had the highest difference.
ConclusionsLBF, 3DVH and Compass can reflect the VMAT dose verification results of lung cancer from different perspectives. The combined application of three systems can demonstrate the verification results in an intuitive manner, which is beneficial for subsequent analysis.
Key words:
Three-dimensional dose reconstruction; Trajectory-log reconstruction; Three-dimensional gamma analysis; Dose volume histogram; Dosimetry verification
Contributor Information
Ma Yangguang
Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
Mai Rizhen
Department of Medical Equipment, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
Pei Yuntong
Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
Hu Jinyan
Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
Kong Fanyang
Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
Wang Xuemin
Department of Radiotherapy Hospital Unit Radiation Therapy, Shaanxi Provincial Tumor Hospital, Xi′an 710061, China
Guo Yuexin
Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
