Zeitschrift für molekulare Bildgebung und Dynamik
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Abstrakt

Targeted therapy and molecular imaging using nanotechnology

Steinacker Nils

Because molecules are too tiny to be photographed directly with noninvasive techniques, epitopes of interest are often depicted using precise and sensitive site-targeted contrast agents. A site-targeted agent, unlike typical blood pool contrast agents, is designed to increase a specific biomarker that would otherwise be difficult to identify from surrounding normal tissue. With the use of targeted radionuclides, molecular imaging has been a clinical reality for some time. Somatostatin-receptor imaging for neuroendocrine tumour identification, as well as fluorodeoxyglucose (FDG) imaging by PET for characterization of various disease states, is just two clinical examples. The use of technetium-labeled annexin for targeted detection of cellular apoptosis is now in clinical trials based on binding to membrane phosphatidyl serine epitopes that are exposed during apoptosis. Other nuclear constructions appear to be beneficial for imaging proteins that are produced after reporter gene transcription to monitor transfection events. Herpes virus thymidine kinase genes, for example, can be utilised as a reporter construct in conjunction with a therapeutic gene by phosphorylating exogenously provided radiolabeled probes (or substrates), which are subsequently trapped inside cells and photographed.