Micro-magnetic simulation study on the magnetic particle imaging performance of anisotropic mono-domain particles
Micro-magnetic simulation study on the magnetic particle imaging performance of anisotropic mono-domain particles
复制标题
各向异性单畴粒子磁粒子成像性能的微磁模拟研究
DOI：
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发表时间：
2012
影响因子：
3.5
通讯作者：
J. Borgert
中科院分区：
文献类型：
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作者：
J. Weizenecker;B. Gleich;J. Rahmer;J. Borgert
单畴磁性粒子的性能在磁粒子成像（MPI）中至关重要。到目前为止，单畴粒子的行为已经在朗之万理论的框架内建模。该理论预测了MPI信号对颗粒核尺寸的依赖性，但不能解释形状的影响，即颗粒核的各向异性。在这项研究中，我们提出了第一个微磁从头计算模拟光谱的各向异性粒子具有不同的核心直径在振荡磁场在25和100 kHz。我们发现，MPI信号强烈地依赖于磁芯的各向异性。因此，具有30 nm球体体积的长椭圆体的主轴之间的3 nm的差异可以导致MPI信号的完全丢失。然而，较小的各向异性可以增加颗粒的MPI性能。仿真结果表明，各向异性对MPI信号的影响取决于振荡磁场的频率。在100 kHz时，发现最佳信号的各向异性小于25 kHz时的各向异性。此外，模拟表明，Resovist®的实验光谱结果只能通过具有至少25 nm的磁芯尺寸的颗粒来定量解释。
The performance of magnetic mono-domain particles is of crucial importance in magnetic particle imaging (MPI). So far, the behavior of mono-domain particles has been modeled within the framework of Langevin theory. This theory predicts the dependence of the MPI signal on the particle core size, but cannot account for the influence of the shape, i.e. the anisotropy of the particle core. In this study we present the first micro-magnetic ab initio simulation of spectra of anisotropic particles with different core diameters in an oscillating magnetic field at 25 and 100 kHz. We find that the MPI signal strongly depends on the anisotropy of the magnetic core. Thus, a difference of 3 nm between the principal axes of a prolate ellipsoid with the volume of a 30 nm sphere can result in a complete loss of the MPI signal. Smaller anisotropies, however, can increase the MPI performance of the particle. The simulations show that the effect of the anisotropy on the MPI signal depends on the frequency of the oscillating magnetic field. At 100 kHz, the optimal signal is found at smaller anisotropies than at 25 kHz. Furthermore, the simulations show that experimental spectroscopic results for Resovist® can only be explained quantitatively by particles with a magnetic core size of at least 25 nm.
影响因子：
3.4
作者：
Schneider, H.;Vilanova, E.;Jakob, G.
通讯作者：
Jakob, G.