Fig. 5
Representative examples of intraoperatively detected tumor-involved surgical margin and a tumor negative surgical margin. Columns represent from left to right intraoperative imaging, fresh specimen imaging, fresh tissue slice imaging, FFPE block imaging, and imaging of 10-µm-thick sections. The two upper rows represent a patient with a tumor-positive surgical margin, a clear fluorescence signal was detected in the surgical cavity. Subsequently, the corresponding resection plane of the excised specimen was marked with an extra suture (a, b). Fluorescence imaging of the fresh surgical specimen showed high fluorescence signals at the area of the suture mark (c, d, asterisk). Corresponding fluorescence images of fresh tissue slices, FFPE blocks and 10-µm-thick sections showed high fluorescence signals at the margin (e–j, arrows). Histopathology confirmed the presence of tumor deposits in this area (i). The lower rows represent a patient with a tumor-free surgical margin Fig. 5 k–t. Deeper sectioning of the FFPE block (q, r) was performed to investigate the probable cause of the high fluorescent area within the green dashed line (t). u, v Arrow depicts the surgical positive margin. Dashed white/black circle indicates the area with the highest fluorescence signal intensities. The asterisk represents the position of the extra suture mark. The gray box represents the origin of the FFPE block in the fresh tissue slice. The dashed white/black line delineates tumor tissue. The dashed green line delineates collagen tissue with normal parenchyma. Scale bars represent 1 cm
