CAJ | 학술논문

磁共振成像(MRI)系统是一种重要的医学诊断设备.作者提出了一种针对使用铁磁材料匀场的开放式超导MRI主磁场匀场的优化方法.在这种方法中,为了使这种包含非线性铁磁轭结构的MRI磁体产生高均匀度的磁场,集成了改进的多输入多输出负反馈控制理论和有限元方法,来计算匀场区非线性铁磁材料的形状.特别要指出的是,这种方法对初始值的要求不高,一定可以收敛,如果配置得当,可以快速收敛.另外,由于收敛速度快,这种方法也可以应用于大型的非轴对称三维模型优化分析.在文中,作者在一个二维轴对称磁体模型上测试了该方法,表现良好.
자공진성상(MRI)계통시일충중요적의학진단설비.작자제출료일충침대사용철자재료균장적개방식초도MRI주자장균장적우화방법.재저충방법중,위료사저충포함비선성철자액결구적MRI자체산생고균균도적자장,집성료개진적다수입다수출부반궤공제이론화유한원방법,래계산균장구비선성철자재료적형상.특별요지출적시,저충방법대초시치적요구불고,일정가이수렴,여과배치득당,가이쾌속수렴.령외,유우수렴속도쾌,저충방법야가이응용우대형적비축대칭삼유모형우화분석.재문중,작자재일개이유축대칭자체모형상측시료해방법,표현량호.
Magnetic resonance imaging (MRI) system is an important medical diagnostic equipment.We present a practical method for optimizing the shapes of ferromagnetic materials to generate a target static magnetic field for open superconducting MRI magnet.The method integrates improved Multi - Input - Multi - Output (MIMO) negative feedback control theory with the finite element method (FEM) to calculate nonlinear ferromagnetic material configurations,subjecting to high magnetic field homogeneity constraints for MRI systems containing nonlinear ferromagnetic yoke structures.It should be noted that the initial condition of the material shape isnt critical for convergence.In particular,the method is well suited for magnet design problems necessitating large three - dimensional FEM models which can be realized easily and quickly.We demonstrate this method works well with a test 2D axisymmtric yoked bi-planar magnet.