Multi-modal and multi-wavelength imaging in xenografts bearing human tumor cells

摘要

Dynamic multi-wavelength fluorescence imaging was accomplished using a liquid crystal tunable filter (LCTF). Since several different emission wavelengths can be selected by tuning the LCTF, two wavelength dynamic fluorescence imaging was conducted in mice bearing human melanoma M21 and M21L after injection of a mixture of (ⅰ) RGD peptide conjugated with a near-infrared (NIR) dye that targeted integrin αvβ3 and (ⅱ) non-specific dye, Cy5.5. Dynamic multi-wavelength imaging with LCTF can differentiate the uptake of the two different fluorescent contrast agents between tumor and normal tissue ROIs in the M21 and M21L xenograft models. Although the LCTF attenuated fluorescence signals by a factor of two when compared to holographic and bandpass filter sets used previously, Tumor to background ratio (TBR) from NIR fluorescence images with a bandpass and holographic filter were not statistically different from those acquired with the LCTF. Therefore, the benefit of spectral information as well as dynamic multi-wavelength may outweigh the impact of the lower transmission efficiencies, and could enable in vivo small animal imaging.