SELECTED REFERENCES Multispectral Imaging Systems & LCTF Components Applicable to NuanceTM Multispectral Imaging Systems & MaestroTM In-Vivo Imaging Systems

We have recently developed a new model of tumor-host interaction consisting of red fluorescent protein (RFP)-expressing tumors transplanted to green fluorescent protein (GFP) transgenic mice expressing GFP in all tissues. We have previously shown that this model allows the whole-body imaging of tumor growth and metastasis and the visualization of host cells and structures including blood vessels interacting with the tumor in fresh tissue by dual-color fluorescence microscopy. In the present study, the MDA-MB-435 human breast cancer expressing RFP was orthotopically transplanted to transgenic nude mice expressing GFP in all tissues. Excitation at 470 nm and appropriate >500 nm emission filters visualized the RFP tumor growing in the GFP mice by whole-body imaging. Using the CRI spectral imaging system, we were able to visualize by whole-body imaging the GFP-expressing host vessels vascularizing the RFP-expressing tumor. Initial results indicate that the host vessels in the tumor may have a unique fluorescence spectrum with emission >600 nm, possibly related to interaction of GFP fluorescence with absorbance properties of the blood vessels. The powerful spectral imaging system measures all the spectra present in each pixel and can separate (unmix) any spectrum from the others. This spectral unmixing enabled the whole-body imaging of vessels in the tumor. This new dual-colored tumor-host model and spectral imaging can noninvasively visualize in real-time the onset and progression of angiogenesis in a tumor. Other host tissues in the tumor may also be visualized by spectral imaging.