Magnetorelaxometry for localization and quantification of magnetic nanoparticles for thermal ablation studies
Magnetorelaxometry for localization and quantification of magnetic nanoparticles for thermal ablation studies
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DOI：
10.1088/0031-9155/55/3/005
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发表时间：
2010-02-01
影响因子：
3.5
通讯作者：
Trahms, L.
中科院分区：
文献类型：
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作者：
Richter, H.;Kettering, M.;Trahms, L.
在磁加热治疗中，肿瘤内注射的超顺磁性氧化铁纳米颗粒（MNP）暴露在外部施加的交变磁场中，会产生热量，特别是在肿瘤区域。这可以使癌细胞失活，对正常组织的副作用最小。因此，需要彻底控制MNP的数量，以控制足够的产热。在这里，我们展示了磁松弛法（MRX）在小动物模型中对MNP积累的非侵入性量化和定位的能力。本文介绍了采用多通道矢量磁强计系统和304个超导量子干涉装置（squid）对携带不同癌症模型（9L/lacZ和MD-AMB-435）的3只小鼠进行MRX测量的结果。利用Levenberg-Marquadt算法，通过磁偶极子模型拟合，从测量的空间磁场分布中重建磁矩的位置和大小。从而确定小鼠体内MNP的重心和积累总量。此外，对于第四只小鼠，通过单通道SQUID测量分析了MNP在单个器官和肿瘤上的分布，获得了敏感的空间量化。这项研究表明磁松弛法非常适合在癌症治疗前监测MNP的积累，磁加热是治疗成功的重要前提。
In magnetic heating treatments, intratumorally injected superparamagnetic iron oxide nanoparticles (MNP) exposed to an externally applied alternating magnetic field generate heat, specifically at the tumor region. This inactivates cancer cells with minimal side effects to the normal tissue. Therefore, the quantity of MNP needs to be thoroughly controlled to govern adequate heat production. Here, we demonstrate the capability of magnetorelaxometry (MRX) for the non-invasive quantification and localization of MNP accumulation in small animal models. The results of our MRX measurements using a multichannel vector magnetometer system with 304 SQUIDs (superconductive quantum interference device) on three mice hosting different carcinoma models (9L/lacZ and MD-AMB-435) are presented. The position and magnitude of the magnetic moment are reconstructed from measured spatial magnetic field distributions by a magnetic dipole model fit applying a Levenberg-Marquadt algorithm. Therewith, the center of gravity and the total amount of MNP accumulation in the mice are determined. Additionally, for a fourth mouse the distribution of MNP over individual organs and the tumor is analyzed by single-channel SQUID measurements, obtaining a sensitive spatial quantification. This study shows that magnetorelaxometry is well suited to monitor MNP accumulation before cancer therapy, with magnetic heating being an important precondition for treatment success.