Molecular immunolabeling allows us to recognize location of molecules within complex biomolecular assemblies, cells, and organs. This technology helps us to facilitate correlations of the data available from biochemistry, molecular biology, pathology, and molecular imaging laboratories concerned with the gene expression as well as location and functions of its products. in this sense, molecular imaging serves as an integrative factor for life sciences endeavors (Albrecht et al. 1992, Bazett-Jones et al. 1996, Hainfeld and Powell 2000, Malecki et al. 1998, Robinson et al. 2000, Malecki 2000). Nevertheless, the essential requirement for pursuit of those projects is availability of molecular markers, which are detectable with various imaging instruments (Malecki 1996). Correlations between positron emission tomography (PET) providing metabolic information, magnetic resonance imaging (MRI) delineating precise anatomical location, and energy filtering transmission electron microscopy (EFTEM) expanding insights into the molecular level are particularly powerful. We have designed three main strategies for pursuit of this project: (a) expression of fusion proteins containing amplified metal binding sites (Malecki et al. 1998), (b) expression of recombinant single chain variable fragment (scFv) antibodies containing elemental recipient (Malecki et al. 2000), and (c) covalent coupling of IgG and Fab with organometallic clusters (Malecki 1996). Herewith, we report the results obtained through imaging of organometallic clusters inserted into the recombinant single chain variable fragment (scFv) antibodies.