Hybrid system calibration for multidimensional magnetic particle imaging
Hybrid system calibration for multidimensional magnetic particle imaging
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DOI：
10.1088/1361-6560/aa5340
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发表时间：
2017-05-07
影响因子：
3.5
通讯作者：
Buzug, T. M.
中科院分区：
文献类型：
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作者：
von Gladiss, A.;Graeser, M.;Buzug, T. M.
磁性粒子成像可视化超顺磁性纳米粒子的空间分布。由于其具有良好的灵敏度、高的时间和空间分辨率以及示踪材料的生物相容性等关键特征，它可以用于多种医学成像应用。Lissajous型轨迹的常见重建技术使用必须在耗时的校准扫描中预先采集的系统矩阵，导致扫描设备的长停机时间。在这项工作中，系统矩阵是由一个混合的方法。利用混合系统矩阵进行重构，可以忽略扫描设备的校准停机时间。此外，混合系统基质的信噪比高得多，因为所需纳米颗粒样品的尺寸可以独立于期望的体素尺寸来选择。由于信噪比影响重建过程，因此所得图像具有更好的分辨率并且受伪影影响较小。此外，提出了一种新的方法来解决图像重建中的背景信号。减去背景信号的常见技术被用代表背景的条目扩展系统矩阵所取代。结果表明，这种方法减少了重建图像中的伪影。
Magnetic particle imaging visualizes the spatial distribution of superparamagnetic nanoparticles. Because of its key features of excellent sensitivity, high temporal and spatial resolution and biocompatibility of the tracer material it can be used in multiple medical imaging applications. The common reconstruction technique for Lissajous-type trajectories uses a system matrix that has to be previously acquired in a time-consuming calibration scan, leading to long downtimes of the scanning device. In this work, the system matrix is determined by a hybrid approach. Using the hybrid system matrix for reconstruction, the calibration downtime of the scanning device can be neglected. Furthermore, the signal to noise ratio of the hybrid system matrix is much higher, since the size of the required nanoparticle sample can be chosen independently of the desired voxel size. As the signal to noise ratio influences the reconstruction process, the resulting images have better resolution and are less affected by artefacts. Additionally, a new approach is introduced to address the background signal in image reconstruction. The common technique of subtraction of the background signal is replaced by extending the system matrix with an entry that represents the background. It is shown that this approach reduces artefacts in the reconstructed images.