Visualizing Method of Colon Cancer Marking-clip using Near-infrared Light During Laparoscopic Surgery

This paper presents a near-infrared light detection method of colon cancer lesion using a marking-clip, which is applied to laparoscopic surgery. In this method, the near-infrared light backscattering from colon tissue and marking-clip is captured on the abdomen side by an endoscope. In this study, irradiating 700 nm near-infrared light, the visualizing experimentation was demonstrated using a colon phantom. The marking-clip can be imaged as decreasing and increasing intensity regions, i.e. cold spot and hot spot. Monte Carlo simulation was carried out to compare with the experimental results and evaluate the system parameters, e.g. irradiating wavelength. Cold and hot spots could be simulated as an image of marking-clip and their contrasts were related to reflectance of marking-clip and irradiating wavelength. Consequently, cold spot was considered to be visualized due to the non-transparent volume of marking-clip, according to the shield of light scattered by medium and reflecting light on marking-clip. The dynamic range of proposed detection can be enhanced in an irradiating condition of 1 000 nm.