In vivo hyperspectral fluorescence images after injection of QD into CSF. Ventral view of head and neck 20 min (a), 40 min (b), 1 h (c), 2 h (d) and 6 h (e) following injection of QD into CSF of cisterna magna. QD signal (red) is seen in the submandibular region of the right and left side of the neck. Skin/fur autofluoresence (green), autofluorescence from food (blue). (f) Spectral emission profile (grey dotted line) of the region indicated by the arrow in (e) shows that the signal matches the profile for QD (red line) and is distinct from that for skin/fur autofluorescence (green line) and that of autofluorescence from food (blue line). Scale = 1 cm.