Differential diagnosis of gallstones by using hypericin as a fluorescent optical imaging agent

Figure 4 Macroscopy and fluorescence observations of hypericin-treated human gallstones under white and UV (365 nm) lights. A yellow cholesterol stone (A1) showed homogeneous and red fluorescence on the surface (A2). A mixed stone with yellowish and brown patches (B1) revealed red fluorescence solely on the yellow cholesterol region (B2). A pigment stone appeared dark brown (C1) with almost no fluorescence (C2).