Figure 2.

Dynamic SE-FRET spectral correction in vivo using IVIS. (A) three-cube (background-corrected) image data of mice injected with NIR-Tf, 30 min post injection (p.i.). Top row: donor-only mouse, middle row: acceptor-only mouse, bottom row: donor + acceptor mouse (acceptor/donor ratio = 2:1). Each row is composed of a $F_{D_{ex}}^{D_{em}}$ (DD Channel), a $F_{A_{ex}}^{A_{em}}$ (AA Channel), and a $F_{D_{ex}}^{A_{em}}$ (DA Channel) image, as indicated on the top of each image column. The intensity is color-coded as indicated by the color bar shown in the top right of each column. (B) Spectral correction coefficient maps for t = 30 min p.i. for the liver and bladder ROIs as indicated in the top-right corner of each map. The $l_D$ and $d_D$ maps are computed from the images shown in the top row (donor-only mouse), whereas the $l_A$ and $d_A$ maps are computed from the images shown in the middle row (acceptor-only mouse), color-coded according to the color bar shown on the right of each map. (C) Temporal evolution of the spectral correction coefficients in both ROIs. The plots show the average and standard deviation of each coefficient in the liver (red curve and red shaded area) and the bladder (blue curve and blue shaded area), corresponding to the respective maps shown in (B). The 30-min p.i. time point illustrated in (A) and (B) is indicated by a dashed vertical line in all plots.