RESUMEN
This paper presents a simulation method to study and improve the technology of designing magnets. With the finite element method, it analyzes the magnetic field distribution of the magnet model constructed by CAD software. Based on the distribution characteristics of magnetic field, the redundancy parts of the magnet configuration are removed accurately. The experiment results show that this method can significantly lighten the magnet.
Asunto(s)
Análisis de Elementos Finitos , Imagen por Resonancia Magnética/métodos , Magnetismo , Simulación por Computador , Programas InformáticosRESUMEN
Based on the theory of magnet circuits, the paper introduces the process of designing MRI (Magnetic Resonance Imaging) permanent magnet. The measurement of magnet properties is improved by simulation technology. In order to increase the magnetic field homogeneity. We have designed a shim-loop and a trapeziform shim-board to optimize the magnetic field distribution. The results of both simulation analysis and experiments show that the innovative design improves magnetic field properties significantly and the magnet structure accords with the technology requirements.
Asunto(s)
Algoritmos , Imagen por Resonancia Magnética/instrumentación , Magnetismo/instrumentación , Simulación por Computador , Campos Electromagnéticos , Diseño de Equipo , Humanos , Imagen por Resonancia Magnética/métodosRESUMEN
Imaging objects are spatially encoded by gradient magnetic fields in magnetic resonance imaging systems. The eddy current caused by rapid switches of gradient fields will result in artifacts in the images. A method of eddy current compensation based on pre-emphasis of gradient current is presented in this thesis. The compensation parameters are acquired rapidly utilizing Faraday's induction theorem and data fitting method. The experiments prove that the method is efficient for reduction of the debugging time and for the improvement of the image quality.