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高场强MR加速器的图像畸变及其影响因素分析
王彬, 刘红冬, 刘镖水, 李永宝, 丁寿亮, 黄晓延
中山大学肿瘤防治中心放疗科 华南肿瘤学国家重点实验室 肿瘤医学协同创新中心,广州 510060
Characterization of imaging distortion of high-field magnetic resonance imaging-guided linear accelerator (MR-Linac) and its influencing factors
Wang Bin, Liu Hongdong, Liu Biaoshui, Li Yongbao, Ding Shouliang, Huang Xiaoyan
State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine,Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou 510060,China
Abstract：Objective To characterize the imaging distortion of the 1.5T magnetic resonance imaging-guided linear accelerator (MR-Linac) and to analyze the influence of MR-Linac and peripheral devices on the geometric distortion. Methods Specialized MRI imaging distortion phantom and analysis software were applied. The baseline of imaging distortion within diameter spherical volume (DSV) around the center of the magnet was established. The influence of the beam generation system, mechanical system and peripheral devices on the imaging distortion was analyzed. The long-term stability of imaging distortion was tested on the MR-Linac. Results Imaging distortion of the MR-Linac was increased with the increasing distance to the center of the magnet. Within DSV 400mm, few test points surpassed 1mm imaging distortion in 3D directions. However, imaging distortion surpassed 2mm in part of region within DSV 400-500mm, with the largest distortion over 7mm. Imaging distortion of the MR-Linac remained unchanged within 7 months after installation. And the influence of the MR-Linac and peripheral devices on the imaging distortion was only observed in the overall largest distortion within DSV 400-500mm. Conclusions Cautions should be taken during the application of high-field MR-Linac in patients whose tumor location is over 20 cm from the ISO center. Imaging distortion of the MR-Linac remains stable within 7 months after installation. The influence of the MR-Linac and peripheral devices on the imaging distortion is trivial, which can be neglected in clinical practice.
Wang Bin,Liu Hongdong,Liu Biaoshui et al. Characterization of imaging distortion of high-field magnetic resonance imaging-guided linear accelerator (MR-Linac) and its influencing factors[J]. Chinese Journal of Radiation Oncology, 2021, 30(2): 146-150.
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2021, Vol. 30 
