Magnetic particle imaging (MPI) is a fast and sensitive technique for imaging of magnetic nanoparticle (MNP) concentrations. MPI directly measures and maps the particle concentration over a measured spatial position. Functional MPI (fMPI) is a specific application of MPI that aims to detect the change of cerebral blood volume (CBV) through imaging. Assuming that the concentration of MNPs in the CBV is uniform, the resultant concentration of MNPs can indicate the CBV changes. Magnetic particle spectroscopy (MPS) is basically a zero-dimensional MPI scanner which can be used to conduct spectroscopic studies and fMPI. In this letter, we suggest an MPS for fMPI with a bore size of 50 mm compatible with rat head dimensions. The system utilizes 0.015 T magnetic field at a frequency of 29.5 kHz and uses an integrated method to measure the small iron component of magnetic particles. Based on the integrated output signal, the MPS consisting of an excitation coil and a gradiometer coil with three parts—a receive coil, a cancellation coil, and a calibration coil—can detect down to 25 ng of Fe. The suggested MPS has demonstrated the achievement of sensitivity that is feasible for fMPI.

中文翻译：

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用于功能性磁粒子成像的大鼠尺度磁粒子光谱学的发展

磁性粒子成像 (MPI) 是一种快速、灵敏的磁性纳米粒子 (MNP) 浓度成像技术。MPI 直接测量并映射测量空间位置上的粒子浓度。功能性 MPI (fMPI) 是 MPI 的一个特定应用，旨在通过成像检测脑血容量 (CBV) 的变化。假设 CBV 中 MNPs 的浓度是均匀的，MNPs 的合成浓度可以表明 CBV 的变化。磁粒子光谱 (MPS) 基本上是一种零维 MPI 扫描仪，可用于进行光谱研究和 fMPI。在这封信中，我们建议为 fMPI 使用 MPS，其孔径为 50 毫米，与鼠头尺寸兼容。该系统使用频率为 29 的 0.015 T 磁场。5 kHz 并使用集成方法测量磁性颗粒的小铁成分。基于集成的输出信号，由激励线圈和梯度计线圈组成的 MPS 由三部分组成——接收线圈、抵消线圈和校准线圈——可以检测低至 25 ng 的 Fe。建议的 MPS 已经证明了实现 fMPI 可行的灵敏度。