Single Photon Emission Computed Tomography Magnetic Resonance Imaging Research Articles

99mTc-Labeled Iron Oxide Nanoparticles as Dual-Modality Contrast Agent: A Preliminary Study from Synthesis to Magnetic Resonance and Gamma-Camera Imaging in Mice Models.

The combination of two imaging modalities in a single agent has received increasing attention during the last few years, since its synergistic action guarantees both accurate and timely diagnosis. For this reason, dual-modality contrast agents (DMCAs), such as radiolabeled iron oxide (namely Fe3O4) nanoparticles, constitute a powerful tool in diagnostic applications. In this respect, here we focus on the synthesis of a potential single photon emission computed tomography/magnetic resonance imaging (SPECT/MRI) DMCA, which consists of Fe3O4 nanoparticles, surface functionalized with 2,3-dicarboxypropane-1,1-diphosphonic acid (DPD) and radiolabeled with 99mTc, [99mTc]Tc-DPD-Fe3O4. The in vitro stability results showed that this DMCA is highly stable after 24 h of incubation in phosphate buffer saline (~92.3% intact), while it is adequately stable after 24 h of incubation with human serum (~67.3% intact). Subsequently, [99mTc]Tc-DPD-Fe3O4 DMCA was evaluated in vivo in mice models through standard biodistribution studies, MR imaging and gamma-camera imaging. All techniques provided consistent results, clearly evidencing noticeable liver uptake. Our work documents that [99mTc]Tc-DPD-Fe3O4 has all the necessary characteristics to be a potential DMCA.

Triple Therapy of HER2+ Cancer Using Radiolabeled Multifunctional Iron Oxide Nanoparticles and Alternating Magnetic Field.

By using radio-labeled multifunctional superparamagnetic iron oxide nanoparticles (SPIONs) and an alternating magnetic field (AMF), we carried out targeted hyperthermia, drug delivery, radio-immunotherapy (RIT), and controlled chemotherapy of cancer tumors. We synthesized and characterized Indium-111-labeled, Trastuzumab and Doxorubicin (DOX)-conjugated APTES-PEG-coated SPIONs in our previous work. Then, we evaluated their capability in SPECT/MRI (single photon emission computed tomography/magnetic resonance imaging) dual modal molecular imaging, targeting, and controlled release. In this research, AMF was introduced to evaluate therapeutic effects of magnetic hyperthermia on radionuclide-chemo therapy of HER2+ cells and tumor (HER2+)-bearing mice. In vitro and in vivo experiments using synthesized complex were repeated under an AMF (f: 100 KHz, H: 280 Gs). Instead of an intra-tumor injection in most hyperthermia experiments, SPIONs were injected to the tail vein, based on our delivery strategies. For magnetic delivery, we held a permanent Nd-B-Fe magnet near the tumor region. The results showed that simultaneous magnetic hyperthermia enhanced SKBR3 cancer cells, killing by 24%, 28%, 33%, and 80% at 48 hours post-treatment for treated cells with (1) bare SPIONs; (2) antibody-conjugated, DOX-free, surface-modified SPIONs; (3) 111In-labeled, antibody-conjugated surface-modified SPIONs; and (4) 111In-labeled, antibody- and DOX-conjugated surface-modified SPIONs, respectively. Moreover, tumor volume inhibitory rate was 85% after a 28 day period of treatment. By using this method, multimodal imaging-guided, targeted hyperthermia, RIT, and controlled chemotherapy could be achievable in the near future.

99mTc-conjugated manganese-based mesoporous silica nanoparticles for SPECT, pH-responsive MRI and anti-cancer drug delivery.

In recent decades, hybrid imaging techniques that exploit the advantages of multiple imaging technologies have aroused extensive attention due to the deficiencies of single imaging modes. Along with the development of single photon emission computed tomography-magnetic resonance imaging (SPECT-MRI), it is currently necessary to develop a series of dual probes that can combine the outstanding sensitivity of SPECT with the high spatial resolution of MRI. Herein, the commonly used technetium-99 (99mTc) was labelled on the surface of manganese oxide-based mesoporous silica nanoparticles (MnOx-MSNs) for use in SPECT-MRI dual-modal imaging. The radiolabelling yield was as high as 99.1 ± 0.6%, and the r1 value of the nanoprobes was able to reach 6.60 mM-1 s-1 due to the pH-responsive properties of the MnOx-MSNs. The high-performance SPECT-MRI dual-modal imaging was confirmed in vivo in tumour-bearing mice, which could also provide semi-quantitative information for tumour detection. Importantly, these nanoprobes can deliver anti-cancer drugs in cancer therapy due to their unique mesoporous structures. Thus, nanotheranostics combining dual-modal imaging with anti-cancer therapeutic properties were achieved.

Engineering of radiolabeled iron oxide nanoparticles for dual-modality imaging.

Over the last decade, radiolabeled iron oxide nanoparticles have been developed as promising contrast agents for dual-modality positron emission tomography/magnetic resonance imaging (PET/MRI) or single-photon emission computed tomography/magnetic resonance imaging (SPECT/MRI). The combination of PET (or SPECT) with MRI can offer synergistic advantages for noninvasive, sensitive, high-resolution, and quantitative imaging, which is suitable for early detection of various diseases such as cancer. Here, we summarize the recent advances on radiolabeled iron oxide nanoparticles for dual-modality imaging, through the use of a variety of PET (and SPECT) isotopes by using both chelator-based and chelator-free radiolabeling techniques. WIREs Nanomed Nanobiotechnol 2016, 8:619-630. doi: 10.1002/wnan.1386.