Abstract: This research investigates the feasibility of monitoring tissue damage in real time by Visible-Near Infrared(V-NIR) spectroscopy during laser thermal lesions. Thermal lesions are produced in fresh pork livers by laser whose wavelength is 808nm and power output is 5W. The V-NIR spectra are acquired respectively during heating at distances of 4, 8 and 12 mm from the center of the damage, and intensities of the diffused light at 720 nm（Rd720）are chosen as the evaluation factors. The results show that Rd720 increases quickly with tissue’s temperature going up at the beginning, and reaches a stable state after an effective damage is attained when the laser is switched on. After switching off, Rd720 decreases slightly and remains almost a constant which is far higher than its value at the beginning, in the meantime, temperature return to normal degree. The smaller distance between the measurement point and the laser damage center is set, the faster Rd720 rises. In conclusion, the intensity of diffused V-NIR light intensity can be used as a parameter to monitor thermal damage of biological tissue.

Key words: real-time monitoring