Narrow Band Imaging (NBI)
The traditional endoscope consists of a soft, flexible tube with a light and lens on one end and an eyepiece on the other for the doctor — or, more likely, for the digital imaging device the doctor is using. The light used on the distal end of the endoscope, inside the patient, has typically been a full-spectrum source. By contrast, NBI endoscopes use only selected wavelengths of the white light spectrum, from 415 nanometers (blue) to 540 nanometers (green). By dropping out the red wavelengths, small blood vessels become more visible and, hence, so do smaller, newly emerging lesions, such as precancerous polyps of the colon."
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