Lüdtke-Buzug Kerstin, Haegele Julian, Biederer Sven, Sattel Timo F, Erbe Marlitt, Duschka Robert L, Barkhausen Jörg, Vogt Florian M
Biomed Tech (Berl). 2013 Dec;58(6):527-33. doi: 10.1515/bmt-2012-0059.
Magnetic particle imaging (MPI) recently emerged as a new tomographic imaging method directly visualizing the amount and location of superparamagnetic iron oxide particles (SPIOs) with high spatial resolution. To fully exploit the imaging performance of MPI, specific requirements are demanded on the SPIOs. Most important, a sufficiently high number of detectable harmonics of the receive signal spectrum is required. In this study, an assessment of commercial iron oxide-based MRI contrast agents is carried out, and the result is compared with that of a new self-synthesized high-performance MPI tracer. The decay of the harmonics is measured with a magnetic particle spectrometer (MPS). For the self-synthesized carboxymethyldextran-coated SPIO, it can be demonstrated that despite a small iron core diameter, the particle performance is as good as in Resovist, the best-performing commercial SPIO today. However, the self-synthesized particles show the lowest iron concentration compared with Resovist, Sinerem, and Endorem. As the iron dose will be an important issue in human MPI, the synthesis technique and the separation chain for self-synthesis will be pursued for further improvements. In evaluations carried out with MPS, it can be shown in this work that the quality of the self-synthesized nanoparticles outperforms the three commercial tracer materials when the decay of harmonics is normalized by the iron concentration. The results of this work emphasize the importance of producing highly uniform and monodisperse superparamagnetic particles contributing to lower application of tracer concentration, better sensitivity, or a higher spatial resolution.
磁粒子成像（MPI）最近作为一种新的断层成像方法出现，它能够以高空间分辨率直接可视化超顺磁性氧化铁颗粒（SPIO）的数量和位置。为了充分发挥MPI的成像性能，对SPIO有特定要求。最重要的是，接收信号频谱需要有足够数量的可检测谐波。在本研究中，对基于氧化铁的商用磁共振成像（MRI）造影剂进行了评估，并将结果与一种新的自合成高性能MPI示踪剂的结果进行了比较。谐波的衰减通过磁粒子光谱仪（MPS）进行测量。对于自合成的羧甲基葡聚糖包被的SPIO，可以证明，尽管铁芯直径较小，但颗粒性能与Resovist（当今性能最佳的商用SPIO）相当。然而，与Resovist、Sinerem和Endorem相比，自合成颗粒的铁浓度最低。由于铁剂量在人体MPI中将是一个重要问题，因此将对自合成的合成技术和分离链进行进一步改进。在使用MPS进行的评估中，本研究表明，当谐波衰减通过铁浓度归一化时，自合成纳米颗粒的质量优于三种商用示踪剂材料。这项工作的结果强调了生产高度均匀和单分散的超顺磁性颗粒的重要性，这有助于降低示踪剂浓度的应用、提高灵敏度或提高空间分辨率。
