Fig. 1.

(a) Diagram shows the principle of fluorescence imaging in tumour localisation: radiation from the light source is filtered by a high-pass filter to remove the fluorescent wavelengths; the blood and ICG suspension under a tissue absorbs the excitation wavelengths and emits a fluorescent band; and the emitted light is received by the sensor through a low-pass filter to remove the excitation light reflected from the source.(35) Charts show the distribution of (b) pathological types in ICG-positive lesions; (c) fluorescence patterns in hepatocellular carcinomas; and (d) fluorescence patterns in colorectal liver metastases. CLRM: colorectal liver metastases; HCC: hepatocellular carcinoma; ICG: indocyanine green