Fig. 1.

Diagram illustrating steps required for bioluminescence imaging (BLI). A: therapeutic cells are transduced with a luciferase (Luc) reporter construct and injected into an animal. B: alternatively, luciferase-expressing cells can be isolated from a luciferase transgenic animal and injected to the experimental subject. C: after systemic substrate injection, a charge-coupled device camera can be used to localize the luciferase photon signals in vivo. Pseudo-colored images that represent signal intensity are overlaid with grayscale reference images of the animal to facilitate localization of the signal. Cell survival, expansion, and homing, as well as the expression of therapeutic genes, can be monitored using this strategy.