Doyle Owen, Bryan Jacob, Kim Melissa, Saayujya Chinmoy, Nazarian Sophie, Mokkarala-Lopez Javier, Kuo Renesmee, Yousuf Mariam, Chandrasekharan Prashant, Fellows Benjamin, Conolly Steven
Department of Bioengineering, UC Berkeley, Berkeley CA, USA.
Magnetic Insight, Alameda CA, USA.
Int J Magn Part Imaging. 2023;9(1 Suppl1). doi: 10.18416/IJMPI.2023.2303056. Epub 2023 Mar 19.
Magnetic Particle Imaging (MPI) is a tracer-based imaging modality with immense promise as a radiation-free alternative to nuclear medicine imaging techniques. Nuclear medicine requires "hot chemistry" wherein radioactive tracers must be synthesized on-site, requiring expensive infrastructure and labor costs. MPI's magnetic nanoparticles, superparamagnetic iron oxide nanoparticles (SPIOs), have no significant signal decay over time which removes cost barriers associated with nuclear medicine studies such as FDG-PET. While SPIOs are the current industry standard MPI tracer, recent developments in synthesizing superferromagnetic iron oxide nanoparticles (SFMIOs) and high resolution SPIOs (HR-SPIOs), a new class of nanoparticle with almost zero coercivity, have yielded a 30-fold improvement in resolution (0.4 mT) and SNR. To better understand the long-term performance of these new nanoparticles, this investigation reports changes in SPIO (VivoTrax Plus), HR-SPIO, and SFMIO resolution, along with SFMIO coercivity, at low temperatures (-2, 2 °C) and room temperature (18-22 °C) over 12 weeks. We find that changes in HR-SPIO resolution are more sensitive to storage temperature than SFMIOs. Additionally, we observe no appreciable difference in SFMIO coercivity between the two temperatures over time. These results can inform research on optimizing tracer synthesis while lending practical information to future hospitals about the highly accessible conditions for the transit and storage of tracers.
磁粒子成像（MPI）是一种基于示踪剂的成像方式，作为核医学成像技术的无辐射替代方案，具有巨大的前景。核医学需要“热化学”，其中放射性示踪剂必须在现场合成，这需要昂贵的基础设施和劳动力成本。MPI的磁性纳米颗粒，即超顺磁性氧化铁纳米颗粒（SPIO），不会随时间产生明显的信号衰减，这消除了与核医学研究（如FDG-PET）相关的成本障碍。虽然SPIO是当前行业标准的MPI示踪剂，但在合成超铁磁性氧化铁纳米颗粒（SFMIO）和高分辨率SPIO（HR-SPIO，一种矫顽力几乎为零的新型纳米颗粒）方面的最新进展，使分辨率（0.
4 mT）和信噪比提高了30倍。为了更好地了解这些新型纳米颗粒的长期性能，本研究报告了SPIO（VivoTrax Plus）、HR-SPIO和SFMIO在低温（-2、2°C）和室温（18 - 22°C）下12周内分辨率的变化，以及SFMIO的矫顽力。我们发现，HR-SPIO分辨率的变化对储存温度比SFMIO更敏感。此外，我们观察到随着时间推移，两种温度下SFMIO的矫顽力没有明显差异。这些结果可以为优化示踪剂合成的研究提供信息，同时为未来医院提供有关示踪剂运输和储存的高度可达条件的实用信息。
