Performance Evaluation System For The Main Magnetic Field Of Magnetic Resonance Imager

With the development and progress of magnetic resonance imaging technology, more and more hospitals to diagnose disease using magnetic resonance imager. Magnetic resonance imager is not only one of the most frequently used but also one of the highest prices of medical diagnostic device in hospital. It plays a very important role in the early detection and treatment of disease. Diagnostic device’s test results provide strong support for the diagnosis. However, if the detection result is not accurate, low accuracy or severe distortion, the accuracy of medical diagnosis cannot be ensured so that the patient cannot be effectively treated. Relevant departments issued a number of technical specifications, but the quality of supervision and control of magnetic resonance devices remains problematic so far, different instrumentation varies on the same device evaluation criteria so the evaluation results cannot achieve mutual recognition. This paper attempts to find a way through the analysis the main field magnetic of magnetic resonance imager to establish the performance evaluation system for the main magnetic field of magnetic resonance imager, so as to achieve the purpose of quality supervision and quality control of magnetic resonance imager.This paper analyzes the performance of the main magnetic field of a magnetic resonance imager and the features of various magnetic field measurement methods. Finally NMR Method is decided to use to measure the performance of the main magnetic field of magnetic resonance imager by comparison. A method to design evaluation system is selected from the many NMR methods. Oscillator is improved to make it suitable for the main magnetic field magnetic resonance imager performance test. The type of the sample probe and paramagnetic ions is determined. Because of the long probe rod will hinder the transmission of high frequency signals. Therefore, a network is designed to improve the long probe rod transmission line effects. High-frequency signal transmission problem is solved. Magnetic field modulation circuit and modulation coil is designed to increase the width of the measured field. The purpose of the automatic search and lock is reached. Frequency measurement circuit is designed to measure the frequency of nuclear magnetic resonance to achieve the purpose of the portable. The device of recording and processing data is also built into the chassis at the same time to automate measurements. After verification, the magnitude of relative uncertainty of the frequency meter is up to 3×10-7 in the measurement which is satisfies the requirements of magnetic field measurement. A permanent magnet is measured using the unit and the ultimately measurement result is: 50B0.739031(1 1.23 10)T?? ? ?;k=2.