How to troubleshoot your in-vivo fluorescence imaging studies

C6 glioma cells label with self-illuminating quantum dots conjugated with cell penetrating peptides. Credit: Jianghong Rao, Stanford School of Medicine" />C6 glioma cells label with self-illuminating quantum dots conjugated with cell penetrating peptides. Credit: Jianghong Rao, Stanford School of Medicine User: Jianghong Rao, Assistant Professor in Radiology, Stanford University

GFP-labeled T cells and background autofluorescence is almost impossible to distinguish (left). Friedman pulls out the T cells by double labeling them with an orange vital dye (right). Credit: Rachel Friedman and Matthew Krummel, UC San Francisco" />GFP-labeled T cells and background autofluorescence is almost impossible to distinguish (left). Friedman pulls out the T cells by double labeling them with an orange

In vivo imaging of the coexpression of endothelial adhesion molecules E-selectin and P-selectin in the mouse skin. Red, E-selectin; green, P-selectin. Credit: Charles P. Lin, Harvard Medical School" />In vivo imaging of the coexpression of endothelial adhesion molecules E-selectin and P-selectin in the mouse skin. Red, E-selectin; green, P-selectin. Credit: Charles P. Lin, Harvard Medical School User:

NIR QDs injected into the tail vein of a mouse can detect tumor metastatic lesions in the lung (red) using the Kodak In Vivo FX Imaging system. The optical image was obtained 48 hrs after the tail vein injection of the QDs. Credit: Lily Yang, Emory University" />NIR QDs injected into the tail vein of a mouse can detect tumor metastatic lesions in the lung (red) using the Kodak In Vivo FX Imaging system.

The endogenous fluorophore PpIX labels cells in a rat brain tumor (left), but the fluorescence is absent after surgery to resect the tumor (right). Credit: Brian Wilson, University of Toronto" />The endogenous fluorophore PpIX labels cells in a rat brain tumor (left), but the fluorescence is absent after surgery to resect the tumor (right). Credit: Brian Wilson, University of Toronto

Choose your target carefully.Even before you optimize your imaging protocol, says Jeff Peterson, vice president for biology at ViSen Medical, make sure you choose the right target for a particular biological question. For example, to image a breast tumor in vivo, appropriate targets might include matrix metalloproteases at the tumor's leading edge, the proliferative-phase nuclear protein Ki-67, the estrogen-linked cathepsin D, or a variety of other molecular markers. Each