Dual-modality contrast agents (DMCA), such as radiolabeled magnetic nanoparticles, are promising candidates for a number of diagnostic applications, since they combine the advantages of two different imaging modalities, namely single photon emission computed tomography (SPECT) or positron emission tomography (PET) with magnetic resonance imaging (MRI). The benefit of such a combination relates to the interpretation of the obtained imaging information in a more efficient and accurate way so that underlying diseases are reliably diagnosed at early stages.
The objective of the project focuses on a novel DMCA and refers to synthesis, basic characterization (crystallographic, morphologic etc.), thorough evaluation of the physical properties (radioactivity, magnetization etc.) and eventually both in vitro and in vivo evaluation on donated human blood and animal models. The DMCA consists of magnetic nanoparticles, mainly iron oxides (i.e. magnetite Fe3O4 and/or maghemite Fe2O3), radiolabeled with gamma-emitting (i.e. Technetium-99m) and/or positron-emitting (i.e. Gallium-68) isotopes. The DMCA is evaluated extensively all the way up to (i) in vitro biocompatibility experiments conducted on donated human blood, (ii) in vivo biodistribution experiments on animal models and (iii) imaging applications in animal models by means of SPECT/MRI and PET/MRI standard modalities.
For the realization of the project, the following experimental techniques are used:
Wet chemistry methods: for the preparation of the DMCA
X-Ray Diffraction (XRD): to crystallographically characterize the starting materials and the DMCA
Superconducting Quantum Interference Device (SQUID): to study the magnetic properties of starting materials and the DMCA.
Atomic Force Microscopy (AFM): to study the morphology of the DMCA and to obtain reliable quantitative information on their geometric characteristics at the nanoscopic level.
Optical Microscopy (OM): to study the morphology of the DMCA and to obtain reliable quantitative information on their geometric characteristics at the microscopic level to check the possible existence of agglomerates.
Standard MRI unit employed in clinical practice.
Experimental small-animal SPECT camera.
Experimental small-animal PET camera.
All ex vivo biodistribution studies on animal models are conducted at the animal experimentation facilities of the Radiochemical Studies laboratory, I.P.R.E.T.E.A, NCSR “Demokritos”, in compliance with European and national legislation. These studies have been further approved by the Ethics Committee of the NCSR “Demokritos” and animal care and procedures followed are in accordance with institutional guidelines and licenses issued by the Department of Agriculture and Veterinary Policies of the Prefecture of Attiki.