Optical radionuclide imaging strategies for preclinical studies

Preclinical imaging is a key step in a variety of scientific endeavors, including basic understanding of biological processes and pharmaceutical research and development. Two common classes of preclinical molecular imaging methods are (1) optical techniques, including fluorescence and bioluminescence, and (2) nuclear techniques, including PET, SPECT, as well as new optical imaging techniques discussed in this note. In many cases, the goal of preclinical molecular imaging is to look at the uptake, distribution, or interaction of a specific targeted molecule in vivo. These agents are typically referred to as probes or tracers in optical and nuclear imaging, respectively.
These agents are typically labeled or tagged with a distinguishing moiety in order to actively track them. However, fluorescent tags can be large relative to the target molecule of interest. On the other hand, radiolabeling typically has very little or no effect on the molecular shape, size, or function of a tagged molecule and many radionuclides can be directly incorporated into the native structure of the molecule of interest.

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