磁共振成像谱仪关键技术的研究

发布时间：2018-01-27 11:41

本文关键词： 磁共振成像脉冲序列发生器独立延时功能双通道频率源　出处：《华东师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：为了适应磁共振成像方法的发展,需要不断提升磁共振成像系统的性能。磁共振成像谱仪是成像系统的重要组成部件,本文主要对谱仪中的脉冲序列发生器与频率源两个单元进行研究。脉冲序列发生器是谱仪的核心单元之一,用于实时控制谱仪中各单元与成像系统的其他部件之间的协同工作。由于成像系统的各硬件部件对触发信号的响应时间不同,因此在磁共振成像扫描过程中各部件之间存在相对延时。这种相对延时会导致磁共振图像质量下降,影响医学诊断,因此需要加以校正。本文提出了一种具有独立延时功能的脉冲序列发生器的设计方案,通过调整脉冲序列发生器发送到谱仪中其他单元的控制信号间的相对延时,达到校正成像系统中各部件间相对延时的目的。高场磁共振成像系统可以加快磁共振成像的速度,并且可以获得具有更高信噪比和分辨率的图像。但高场磁共振成像系统中采用的射频信号频率较高,信号波长接近人体尺寸,会在人体内部形成驻波,导致B1场的分布不均匀。本文提出了一种双通道磁共振频率源的设计方案,用于改善高场磁共振成像系统B1场的分布,提高磁共振图像的质量。本论文主要包括以下内容:(1)介绍磁共振成像技术的原理与发展以及仪器结构。(2)介绍本文所设计的脉冲序列发生器的硬件结构、内部控制逻辑以及测试结果。(3)介绍本文所设计的双通道频率源的硬件结构、内部控制逻辑以及测试结果。(4)对研究内容的总结与展望。
[Abstract]:In order to adapt to the development of magnetic resonance imaging (MRI), it is necessary to improve the performance of magnetic resonance imaging system, which is an important component of the imaging system. In this paper, the pulse sequence generator and the frequency source in the spectrometer are studied. The pulse sequence generator is one of the core units of the spectrometer. It is used to control the cooperative work between each unit in the spectrometer and other parts of the imaging system. The response time of each hardware part of the imaging system to the trigger signal is different. Therefore, there is a relative delay between the components in the process of MRI scanning, which will lead to the deterioration of the quality of MRI image and affect the medical diagnosis. Therefore, it needs to be corrected. In this paper, a design scheme of pulse sequence generator with independent delay function is proposed. The relative delay between the control signals transmitted by the pulse sequence generator to other units in the spectrometer is adjusted. In order to correct the relative delay between the components in the imaging system, the high field magnetic resonance imaging system can accelerate the speed of magnetic resonance imaging. Images with higher signal-to-noise ratio and resolution can be obtained, but the RF signal frequency used in high-field magnetic resonance imaging system is higher, the signal wavelength is close to the human body size, and the standing wave will be formed in the human body. In this paper, a design scheme of dual-channel magnetic resonance frequency source is proposed to improve the distribution of B1 field in high-field magnetic resonance imaging system. Improving the quality of Magnetic Resonance Imaging. This paper mainly includes the following contents: 1) introduce the principle and development of magnetic resonance imaging technology and instrument structure. The hardware structure of the pulse sequence generator designed in this paper is introduced. This paper introduces the hardware structure of the dual-channel frequency source, the internal control logic and the test result.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH834;TN782

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