Autofluorescence Imaging: Patients will be evaluated using a prototype autofluorescence endoscope (Olympus, Tokyo, Japan; excitation 395-475 nm, fluorescence detection 490-625 nm, red reflectance 600-620 nm and green reflectance 540-560 nm). The AFI scope has two different CCD (charge coupled device to detect the light waves emitted/reflected from the biological tissue - similar to the chip used in a digital camera), one for conventional and another for AFI endoscopy. There is also a rotary filter that allows blue, red or green light to be generated selectively. The video processor constructs video images (AFI images or normal optical images) based on the signals provided by CCD at the distal end of the endoscope. In this system, normal squamous and non-dysplastic BE appears green while the dysplastic areas appear magenta/purplish. Targeted biopsies will be obtained from the areas with abnormal fluorescence. Both the NBI and AFI equipment will be supplied by Olympus America Inc.