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研究生:周家政
研究生(外文):Jiazheng Zhou
論文名稱:3T人腦磁共振多通道勻場線圈之優化
論文名稱(外文):Optimization of multi-coil shim for human brain magnetic resonance imaging at 3T
指導教授:林發暄
口試日期:2017-07-14
學位類別:碩士
校院名稱:國立臺灣大學
系所名稱:醫學工程學研究所
學門:工程學門
學類:綜合工程學類
論文種類:學術論文
論文出版年:2017
畢業學年度:105
語文別:英文
論文頁數:27
中文關鍵詞:陣列主磁場均勻正交
外文關鍵詞:arraymagnetic fieldhomogeneityorthogonal
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一個均勻的主磁場是高品質磁共振影像或是頻譜的重要保障。然而,主磁場的靜態或者動態的擾動,使得磁共振信號減弱,並產生相應的偽影。
使用多通道勻場線圈能夠幫助克服主磁場局部不均勻多問題。在此基礎之上,發展出了整合射頻信號接收的均場線圈(iPRES)。然而, 將勻場線圈整合到多通道射頻線圈中,往往會導致射頻線圈的信噪比下降。在這篇文章中,我們發現,將勻場線圈與射頻線圈垂直放置,不僅僅能夠減少勻場線圈對於射頻線圈的干擾,還能夠保持勻場線圈的勻場效果。我們設計、製作了一個7通道的正交均場線圈,用來展示我們的想法
High-quality magnetic resonance imaging and spectroscopic measurements require a highly homogeneous magnetic field. However, both static and dynamic variations in the main magnetic field (B0) cause various artifacts. These artifacts can be corrected by providing a compensating magnetic field generated by shim coils. Different from correcting global magnetic field inhomogeneity by large volume shim coils, localized off-resonance can be corrected by using multiple shim coils. Previously, arrays of circular shim coils and integrated radio-frequency (RF)-shimming coils have been implemented. However, these designs cause non-negligible interference to RF coils and consequent image quality degradation.

Here we propose a new design of multi-coil shimming, where shim coils and nearby RF coils are arranged on two orthogonal planes. This orthogonal positioning minimizes the interference between RF coils and shim coils, while multiple shim coils provide similar shimming performance like previous multi-coil shim array designs. We use both simulatiosn and phantom experiments to demonstrate the feasibility of this design.
誌謝 i
中文摘要 ii
ABSTRACT iii
CONTENTS iv
Chapter 1 Introduction 1
Chapter 2 Methods 5
2.1 Simulations 5
2.2 Hardware 8
2.3 Experiments 9
Chapter 3 Results 11
Chapter 4 Discussions 19
Chapter 5 Conclusions 22
Chapter 6 Supporting information 23
REFERENCE 25
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[10]Truong TK, Darnell D, Song AW. Integrated RF/shim coil array for parallel reception and localized B0 shimming in the human brain. NeuroImage 2014;103:235-240
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