Hyperpolarized silicon particles have been shown to exhibit long spin-lattice relaxation times at room temperature, making them interesting as novel MRI probes. Demonstrations of hyperpolarized silicon particle imaging have focused on large micron size particles (average particle size (APS) = 2.2 μm) as they have, to date, demonstrated much larger polarizations than nanoparticles. We show that also much smaller silicon-29 particles (APS = 55 ± 12 nm) can be hyperpolarized with superior properties. A maximum polarization of 12.6% in the solid state is reported with a spin-lattice relaxation time of 42 min at room temperature thereby opening a new window for MRI applications.

中文翻译：

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用于超极化MRI的纳米级硅颗粒。

超极化硅粒子已显示出在室温下具有长的自旋晶格弛豫时间，这使其成为新型MRI探针的有趣之处。超极化硅粒子成像的演示集中在大微米尺寸的粒子（平均粒子尺寸（APS）= 2.2μm）上，因为迄今为止它们已显示出比纳米粒子更大的极化。我们表明，更小的硅29粒子（APS = 55±12 nm）也可以超极化，具有优异的性能。据报道，在固态下最大极化率为12.6％，在室温下自旋晶格弛豫时间为42分钟，从而为MRI应用打开了新的窗口。