Illuminating the optical properties of an LED-based spectral light source for hyperspectral endoscopy

In the United States, the gold standard for endoscopic screening is white light endoscopy (WLE) which uses a singular broad spectrum light source to illuminate the colorectum. However, WLE provides minimal contrast to small, flat or early growth lesions compared to the surrounding mucosa, in turn, increasing the miss rate of these lesions allowing for further growth of potentially fatal cancer (colorectal cancer is the 3rd highest risk cancer). The most notable addition to endoscopy is narrow-band imaging (NBI) illuminating with two specific bandwidths of blue and green light to enhance the vascular structures through absorption. NBI provides enhanced contrast but minimal improvements in detection accuracy. A logical extension of NBI would be to use more than 2 wavelength bands to generate contrast. We propose an LED-based spectral light source to provide hyperspectral imaging for the potential of enhancing endoscopic images. This would provide 8+ bandwidths of light plus the potential of fluorescence, doubling the possible information content of enhanced images. Here, we report on improved illumination throughput, initial resolution testing and color testing for a previously reported prototype LED-based spectral light source. Results show that, while optical transmission is low, spectral illumination is still possible when combined with high-power LED emitters. Resolution results are compared to the gold standard white light source and color testing results provide baseline validation for the spectral output of the system. These results provide benchmark data for evaluating the potential of hyperspectral imaging for enhanced endoscopic imagery.