Magnetic nanoparticle imaging by means of minimum norm estimates from remanence measurements
Magnetic nanoparticle imaging by means of minimum norm estimates from remanence measurements
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DOI：
10.1007/s11517-008-0404-1
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发表时间：
2008-12-01
影响因子：
3.2
通讯作者：
Haueisen, Jens
中科院分区：
文献类型：
--
作者：
Baumgarten, Daniel;Liehr, Mario;Haueisen, Jens
在磁性纳米颗粒成像中，磁性纳米颗粒被包裹并功能化以结合特定的目标。在测量了它们的磁松弛或剩余物后，可以用逆方法确定它们的分布。本文提出的重建算法包括首先使用Levenberg-Marquardt优化器进行偶极子拟合以确定重建平面。其次，对该平面上的规则网格进行最小范数估计。涉及不同参数集和条件的计算机模拟表明，所使用的方法允许重建分布式源，尽管重建的形状受到模糊效果的扭曲。重建质量取决于测量的信噪比，并且随着传感器源距离和网格间距的增大而降低。在幻影测量中，用两种常见的测量系统来确定具有临床相关尺寸的纳米颗粒柱的剩磁。这些测量结果的重建表明，该方法适用于临床测量。我们的结果为最小规范方法在磁性纳米颗粒成像中的成功应用提供了参数集。
In magnetic nanoparticle imaging, magnetic nanoparticles are coated and functionalized to bind to specific targets. After measuring their magnetic relaxation or remanence, their distribution can be determined by means of inverse methods. The reconstruction algorithm presented in this paper includes first a dipole fit using a Levenberg-Marquardt optimizer to determine the reconstruction plane. Secondly, a minimum norm estimate is obtained on a regular grid placed in that plane. Computer simulations involving different parameter sets and conditions show that the used approach allows for the reconstruction of distributed sources, although the reconstructed shapes are distorted by blurring effects. The reconstruction quality depends on the signal-to-noise ratio of the measurements and decreases with larger sensor-source distances and higher grid spacings. In phantom measurements, the magnetic remanence of nanoparticle columns with clinical relevant sizes is determined with two common measurement systems. The reconstructions from these measurements indicate that the approach is applicable for clinical measurements. Our results provide parameter sets for successful application of minimum norm approaches to Magnetic Nanoparticle Imaging.