In vivo and ex vivo red fluorescence optical imaging obtained with the In-Vivo FX Pro small-animal imaging system. A) Representative red fluorescence in vivo images of subcutaneous melanoma bearing mice in different treatment groups. Red fluorescence protein (RFP)-expressing melanoma cells in density of 2 × 106 were delivered either alone or concurrently with 7.5 × 105 of genetically modified ADSCs (GM-ADSCs). Mice were anesthetized with isoflurane and images were captured using a multi-wavelength source with a 2 min exposure time. B) Upper image showing a lung with RFP-melanoma lung metastases at day 28. Lower image, red fluorescence optical imaging of the same lung, indicating that some of RFP-melanoma metastases are not superficially visible. C) Representative red fluorescence ex vivo images of dissected lungs in different treatment groups. On day 0, 7.5 × 105 of RFP-melanoma cells were injected into the lateral tail vein of mice. Ten days later, mice were given PBS or 7.5 × 105 of GM-ADSCs by tail vein injection. Mice were sacrified at day 28 for ex vivo optical imaging of lung samples, performed using a multi-wavelength source with a 2 min exposure time. D) Quantification of fluorescent signal intensities was performed using the Bruker Molecular Imaging Software. Fluorescence intensity was expressed as arbitrary units (AU) and was reported as a mean ± SD in the bar graphs. (Left) Quantification of in vivo images (photons/s of subcutaneous tumor region). Bar graphs indicate significant subcutaneous tumor regression in mice that were treated with IFNγ-expressing ADSCs, whereas tumors grew rapidly in the other groups. (Right) Quantification of ex vivo images (photons/s of lung region). Bar graphs demonstrating reduced red fluorescence intensity in lung samples from mice injected with IFNγ-expressing ADSCs, while red fluorescence intensity significantly increased in other groups. Each group consisted of six mice. ***P < .001 (ANOVA).