Fig. 2. Shell-scan around the surface of interest.

a–c Overlay of full scan XY sections of the tissue (gray) with the estimated shell (green) at 3 different planes. Imaginal cells are well encapsulated by the shell, while cells of the overlying peripodial membrane (red arrows) are properly discarded. d Maximum intensity projection of the normalized signal (equation (1)) acquired with the shell scan on a wing imaginal disc. e–h Comparing image acquisition with shell scan and full scan. A hybrid scanning strategy is performed to simultaneously image half of the tissue in full scan and half in shell-scan (e). f, g Maximum intensity projection. While the two adjacent zones are initially indistinguishable (f), bleaching is more prominent in the full scan zone after 60 min of continuous imaging (g). h Quantification of the bleaching process showing the temporal evolution of the maximum intensity projection averaged over the full scan or shell-scan regions