Passive Shimming for a Permanent MRI Magnet
A new method for allowing a permanent magnet for MR imaging to meet its stringent field homogeneity requirements has been developed. The method is called passive shimming and uses the permanent magnetic pieces instead of the ferromagnetic material in the magnet bore at locations of the hardware. Software and hardware have facilitated this shimming procedure with high efficiency and stabilization. The method can be considered as a function approximation. In this paper, the function of a magnetic dipole is presented as a basis function. From the functional space that consists of simple functions of a series of magnetic dipoles, the specific function that approximates the negative quantity of the error function in the homogeneous magnetic field with the desired accuracy can be found. The series of magnetic dipoles are realized by the permanent magnetic pieces located in the hardware. The result shows that this method is fixable and normative over the traditional method.
magnetic resonance imaging (MRI) passive shimming function approzimation permanent magnetic piece
ZHAO Wei TANG Xiao-ying HU Guo-jun LIU Yong
School of Life Science and Technology, Beijing Institute of Technology, Beijing 100081, China Beijing Taijie Magneto-electric Institute, Beijing 100088, China
国际会议
北京
英文
415-418
2006-08-29（万方平台首次上网日期，不代表论文的发表时间）