Characterization of imaging distortion of high-field magnetic resonance imaging-guided linear accelerator (MR-Linac) and its influencing factors
10.3760/cma.j.cn113030-20200628-00324
- VernacularTitle:高场强MR加速器的图像畸变及其影响因素分析
- Author:
Bin WANG
;
Hongdong LIU
;
Biaoshui LIU
;
Yongbao LI
;
Shouliang DING
;
Xiaoyan HUANG
- From:
Chinese Journal of Radiation Oncology
2021;30(2):146-150
- CountryChina
- Language:Chinese
-
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 400 mm, few test points surpassed 1 mm imaging distortion in 3D directions. However, imaging distortion surpassed 2 mm in part of region within DSV 400-500 mm, with the largest distortion over 7 mm. 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 400-500 mm.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.
