Fig. 3

Representative two-photon images of esophageal cancer tissues from patients diagnosed with HGD for the second diagnosis (as the follow-up 6 months after the first diagnosis shown in Fig. 2). (a)-(e) show five image sets. Merge indicates the overlaying of SHG and TPF images. Dashed lines represent layer boundaries, while stars indicate the artifacts presumably due to photodamage from dye accumulation. Image size: 1.6 × 1.6 mm2.