An 512MSDRAM Based Pulse Sequence Generator For Magnetic Resonance Imaging

With the rapid development of NMR, nowadays MRI has become a significant tool in many research fields, especially in the Medical Science. Since MRI is the medical imaging modality which will cause no harm or invasion, and has high space and temporal resolution, it has become a well-known focus. Along with the development of the MRI, the high-standard Imaging Equipment is truly in need. MRI spectrometer is an important part of the MR scanner. How to improve the performance and increase the functionality has become the development direction in the design of the MRI spectrometer. Pulse sequence generator is a key functional component of the MRI spectrometer. It provides all the sequence timing to. the whole spectrometer during the operation. The design and implementation of the pulse sequence generator is developed in the thesis.The main content of the thesis includes:Firstly, the basic principles of NMR and MRI are introduced. There are the principle of the layer selection, the concept of frequency coding and Phase Encoding, and K space. In the end, two widely-used sequence are introduces. They are spin echo sequence and gradient echo sequence.Secondly, the structure of MRI system is introduced. The structure of MRI spectrometer which is composed of DDS, digital receiver and pulse sequence generator etc, is described.Thirdly, the design of the pulse sequence generator is introduced. Since the MRI technology is continuously developed and there are more and more new sequence being developed, the primary pulse sequence generator can not fulfill the demand of some MRI any more. Therefore, we proposed a new pulse sequence generator which is based on the 512M SDRAM.