Abstract
Reporter systems can analyze the biochemical and molecular processes in viable cells and organs and help imaging of cancer. That includes gene transcription activity, protein–protein interactions, sub-cellular localization and proteases activities. This helps studying the aspects of neoplastic trans¬formation, drug development, monitoring specific cancer-related events and tracing complex patho¬logical events (angiogenesis, apoptosis, proto-oncogene activity, oncongenes, tumor suppressor genes and tumor promoting signals). Resolution and sensitivity govern the choice of reporters. Nanoparticles have diverse uses (magnetic, catalytic, optical, thermodynamic, and electrochemical). Nanoparti¬cles include aptamers, quantum dots, core-shell silica particles, gold nanoparticles, carbon nanotubes, liposomes, dendrimers, oligonucleotides and magnetic nanoparticles. Superparamagnetic iron oxide nanoparticles (SPIONs) have the advantages of easy visualization using Magnetic resonance imaging (MRI), easy cellular targeting, possibility of generating hyperthermia, and easy biodegradation into metabolizable iron particles. Magnetic nanoparticles can be used in chemotherapy, magnetic hyper¬thermia, photodynamic therapy and photothermal therapy. MRI is the most valuable noninvasive imaging techniques to overcome magnetic nanoparticles colloidal instability. In conclusion, SPIONs are among the best nanoparticles to date owing to their easy visualization using MRI, easy cellular targeting, possibility of generating hyperthermia, and easy biodegradation into metabolizable iron particles. Research regarding reporter systems and nanoparticles is quite interesting and challenging. More research efforts are needed to optimize in vivo cancer imaging and therapeutics monitoring.

Key words: Reporter systems, Nanoparticles, Cancer imaging, SPIONs, Aptamers, Quantum dots