THE DEVELOPMENT OF IN-VIVO IMAGING-SYSTEMS TO STUDY GENE-EXPRESSION

Imaging techniques are currently being developed to map the topography and level of gene expression following gene therapy. To date, two dif ferent imaging strategies have been investigated - using marker genes encoding either intracellular enzymes or cell-surface receptors. The f irst approach employs the ability of certain enzymes to modify imaging prodrugs, so that tissue accumulation of such drugs reflects the expr ession. The second approach utilises cell-surface expression of a liga nd-binding receptor that can be detected using imaging tracers. In thi s review, we discuss nuclear-and magnetic-resonance-imaging techniques that have been developed to detect gene expression.