Molecular imaging holds great promise in the noninvasive monitoring of several diseases with nanoparticles (NPs) being considered an efficient imaging tool for cancer, central nervous system, and heart- or bone-related diseases and for disorders of the mononuclear phagocytic system (MPS). In the present study, we used an iron-based nanoformulation, already established as an MRI/SPECT probe, as well as to load different biomolecules, to investigate its potential for nuclear planar and tomographic imaging of several target tissues following its distribution via different administration routes. Iron-doped hydroxyapatite NPs (FeHA) were radiolabeled with the single photon γ-emitting imaging agent [99mTc]TcMDP. Administration of the radioactive NPs was performed via the following four delivery methods: (1) standard intravenous (iv) tail vein, (2) iv retro-orbital injection, (3) intratracheal (it) instillation, and (4) intrarectal installation (pr). Real-time, live, fast dynamic screening studies were performed on a dedicated bench top, mouse-sized, planar SPECT system from t = 0 to 1 hour postinjection (p.i.), and consequently, tomographic SPECT/CT imaging was performed, for up to 24 hours p.i. The administration routes that have been studied provide a wide range of possible target tissues, for various diseases. Studies can be optimized following this workflow, as it is possible to quickly assess more parameters in a small number of animals (injection route, dosage, and fasting conditions). Thus, such an imaging protocol combines the strengths of both dynamic planar and tomographic imaging, and by using iron-based NPs of high biocompatibility along with the appropriate administration route, a potential diagnostic or therapeutic effect could be attained.

中文翻译：

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通过结合平面动态和断层成像优化体内研究：超顺磁性纳米粒子系统的工作流程评估。

分子成像在多种疾病的无创监测方面具有广阔的前景，纳米颗粒 (NP) 被认为是癌症、中枢神经系统、心脏或骨骼相关疾病以及单核吞噬系统 (MPS) 疾病的有效成像工具。在本研究中，我们使用了一种铁基纳米制剂（已作为 MRI/SPECT 探针），并负载不同的生物分子，以研究其通过不同给药方式分布后对几种靶组织进行核平面和断层成像的潜力路线。用单光子 γ 发射显像剂 [99mTc]TcMDP 对铁掺杂羟基磷灰石纳米粒子 (FeHA) 进行放射性标记。放射性纳米粒子的施用通过以下四种递送方法进行：（1）标准静脉内（iv）尾静脉，（2）静脉内眼眶后注射，（3）气管内（it）滴注，以及（4）直肠内安装（公关）。在注射后 t = 0 至 1 小时 (pi) 的专用台式、小鼠大小的平面 SPECT 系统上进行了实时、实时、快速的动态筛选研究，因此进行了断层扫描 SPECT/CT 成像，持续时间长达注射后 24 小时 已研究的给药途径为各种疾病提供了广泛的可能靶组织。可以按照此工作流程优化研究，因为可以快速评估少量动物的更多参数（注射途径、剂量和禁食条件）。因此，这种成像方案结合了动态平面成像和断层成像的优点，通过使用具有高生物相容性的铁基纳米颗粒以及适当的给药途径，可以获得潜在的诊断或治疗效果。