RESUMEN
Objective To develop a fast shimming method for permanent magnet MRI system. Methods Peak location method (PLM) was improved by calculating the eddy current effect, and the time deviation was replaced by their phase to increase the precision. Results Experiment showed that the new method took less than 45 s, which was 3 times faster than conventional method while providing the same homogeneity. The result of PLM satisfied the requirement of homogeneity. Conclusion This new method can significantly improve the homogeneity in a short time and satisfy further fast pulse sequence development on 0.5T permanent magnet MRI system, which can be generalized for any permanent magnet first order shimming.
RESUMEN
MRI system,as an imaging diagnosis equipment,plays a very important role in diagnosis and treatment.For the steady avail of MRI system,MRI eliminable faults in CBMDisc(1995~2006) were analyzed.The types and occurrence frequency of MRI eliminable faults were elaborated so as to provide reliable data for reference.
RESUMEN
The main composition of MRI system is introduced including magnet,gradient-RF system,cooling system,reconstruction system and operation system.According to the principle and functions of every component,the common troubles and the corresponding reasons of MRI system in using are analyzed,and the solutions are presented.[Chinese Medical Equipment Journal,2008,29(2):90,93]