單邊核磁共振磁鐵設計、製作與特性分析

Abstract

核磁共振技術至今已經相當成熟，在化學方面，有核磁共振分子光譜法等技術行之有年。結合醫療用的電腦斷層掃描、腦電圖等，以不侵入人體的方式進行造影，已經在醫學方面有巨大貢獻。核磁共振技術應用廣泛，其中，磁振造影裝置更是檢查癌症、腫瘤組織的主力工具。但是，因為主磁場使用的超導線圈，裝置始終有體積龐大、難以移動的特點，導致限制待測物位置、及物理設計上限制了待測物的尺寸等狀況。單邊核磁共振裝置則解決了以上的問題。單邊核磁共振裝置的設計有許多方式，包括了經典的U型設計、Halbach磁鐵陣列、單邊Halbach陣列等，而本篇論文參考了《The Novel Design of a Single-Sided MRI Probe for Assessing Burn Depth》的磁鐵設計。期望藉由參數的調整，產生待測平面大小達15*15 mm^2的平面、且在此範圍內具有磁場大小變化小於0.001 T的均勻度。並進一步，比較對磁共振訊號具有代表性意義的參數B^2/G_Z ，找出最有機會實現單面核磁共振的測量區。並實際架設裝置，量測目標區域磁場的實際狀況。分別量測各分量，可發現各分量與模擬中的數值具有一定的相似度。然而在進行分量相加後，總磁場的均勻度，與模擬的均勻度具有一定落差。經由觀察數據，推測可能是由於各分量間，量測點有錯位的情形導致。為進一步減少數據誤差，使用自動擷取以利增加測量點的密度，並擴大量測範圍。確認大範圍磁場分布與模擬一致後，再進一步作小範圍精細量測，並確認在Z≥ 15 mm 區域中，可用磁場範圍足夠論文所需要求。Nuclear magnetic resonance technology has been quite mature so far. In chemistry, nuclear magnetic resonance molecular spectroscopy and other technologies have been available for many years. Combined with medical computer tomography,electroencephalogram, etc., to perform imaging in a way that does not invade the human body, it has made a great contribution to medicine. Nuclear magnetic resonance technology is widely used, among which the magnetic resonance imaging device is the main tool for detecting cancer and tumor tissue. However, because of the superconducting coil used in the main magnetic field, the device always has the characteristics of being bulky and difficult to move, which leads to restrictions on the position of the object to be measured and physical design limits the size of the object to be measured.The unilateral nuclear magnetic resonance device solves the above problems. There are many ways to design a single-sided MRI device, including classic U-shaped design, Halbach magnet array, single-sided Halbach array, etc., and this paper refers to the magnet design of “The Novel Design of a Single-Sided MRI Probe for Assessing Burn Depth. ” It is expected that we can design a plane with the size of 15*15〖 mm〗^2, and within this range, the difference of the magnetic field will be less than 0.001 T. And further, compare the parameters B^2/G_Z which is proportional to the magnetic resonance signal, and find the measurement area that has the best chance of realizing single-sided nuclear magnetic resonance. Setting up the device to measure the actual size of the target area.By separately measuring each component, it was observed that the values of each component showed some resemblance to the simulation results. However, when the components were combined to calculate the total magnetic field uniformity, there were some discrepancies compared to the simulated uniformity. Upon examining the data, it is speculated that this mismatch may be due to misalignment of measurement points between the individual components.To further reduce data errors, automatic data acquisition will be employed to increase the density of measurement points and expand the measurement range. After confirming that the wide-range magnetic field distribution aligns with the simulation results, further precise measurements will be conducted in a smaller area. Additionally, it will be verified that within the Z ≥ 15 mm region, the available magnetic field range is sufficient to meet the requirements of the research paper.