Figure 6.

5-Aminolevulinic acid (ALA) penetration into tumors detected by fluorescence spectrometry. (a) Schematic showing detection method. Half of a freshly excised tumor with surface skin attached was placed in a holder and scanned for protoporphyrin IX fluorescence using an optical fiber moving along the vertical axis. Fluorescence was recorded at 1-mm intervals; (b–g) Fluorescence intensity at various depths of the tumor in control mice or detected at 1–5 h after application of ALA hydrogel to the skin. Depth of skin is set at 0 mm. Fluorescence intensity was calculated as described in the methods.