基于目标场法的磁共振成像小尺寸射频线圈设计

发布时间：2018-02-27 16:21

本文关键词： 磁共振成像射频线圈目标场法 Tikhonov正则化流函数 Fourier级数　出处：《高电压技术》2014年12期 　论文类型：期刊论文

【摘要】：为得到分辨率较高的实蝇磁共振图像(MRI),将目标场法引入小尺寸射频(RF)线圈设计,设计了一种磁场均匀性较好、适合实蝇磁共振成像的小尺寸圆柱体射频线圈。首先采用目标场法求出线圈表面的电流密度分布,利用流函数将电流密度离散为Fourier级数;然后基于Tikhonov正则化的方法,引入最小曲率惩罚函数和最小化电流密度的散度惩罚函数,解决了积分方程的高度病态问题,获得了线圈的绕线形状和感兴趣区域(ROI)内的磁场强度。结果表明,2种惩罚函数对应的惩罚因子λ1和λ2均会对线圈的绕线形状和磁场分布均匀性造成影响;对于不同尺寸的线圈,其合适的λ1和λ2的取值不同。因此,选取λ1和λ2时应综合考虑线圈绕线结构和磁场分布均匀性的要求。
[Abstract]:To fly high resolution magnetic resonance image (MRI), the target field method into small size radio frequency (RF) coil design, design a magnetic field uniformity is good, suitable for small size cylindrical RF coil fly magnetic resonance imaging. The target field method to calculate the current density distribution of the coil surface. The flow function of current density for discrete Fourier series; then the Tikhonov regularization method based on divergence is introduced minimum curvature penalty function and minimize the current density of the penalty function to solve the ill posed problem of highly integral equation, the winding coil shape and area of interest (ROI) in magnetic field strength. The results showed that the penalty factor lambda 2 and lambda 1 penalty function corresponding to the 2 all have effect on the shape of the coil winding and the magnetic field distribution uniformity; the coils of different sizes, the appropriate values of 2 lambda 1 and lambda so different. When selecting lambda 1 and lambda 2, the requirements of the coil structure and the uniformity of the magnetic field distribution should be taken into consideration.

【作者单位】：中国计量学院信息工程学院;丽水市人民医院;浙江大学医学院附属二院临床工程部;
【基金】：国家自然科学基金(81101031) 国家质检总局公益性项目(201210079) 浙江省科技厅项目(2011C33027;2013C24019)~~
【分类号】：TM55

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