The Study On Technologies Of Magnetic Resonance Imaging Spectrometer

Magnetic Resonance Imaging(MRI)scanners with better performance are required to meet the development of MRI applications.The spectrometer is a key component of the MRI system.A pulse programmer and a frequency source for the MRI spectrometer have been studied in this paper.The pulse programmer is critical for the MRI spectrometer.It is used to generate multi-channel trigger signals to synchronize other functional units in the spectrometer.In this way,all parts of the MRI system are synchronized with each other.The relative delays among hardware components,which are due to the different response delays to trigger signals,will worsen image quality.So it is essential to correct the relative delay.A pulse programmer with the capability of independently delay control was proposed in this paper.The relative delays among the components will be corrected by using this pulse programmer with asynchronous triggering.As the high field MRI system has been applied,high resolution images can be acquired very quickly.However,the RF frequency increases with the magnetic field strength.When the wave length is close to the size of human body,the uniformity of the RF field will be broken due to standing waves.In this study,a dual-channel frequency source was designed to solve this problem.The main contents of this paper include:(1)The development of MRI technology and the structure of MRI system.(2)The hardware design,firmware design and verification of the proposed pulse programmer.(3)The hardware design,firmware design and verification of the proposed dual-channel frequency source.(4)Summary and outlook of the study.