Bronchial carcinoma in-situ will progress to invasive cancer in over 40% of individuals, and although the progression occurs over a long period of time, the majority of carcinomas are detected in the later stages of disease development, offering patients only a very slim chance of cure. Although, significant effort in the development of screening paradigms for the detection of lung cancer in the central airway has been made, to date there is still no widely accepted and validated approach. Optical Frequency Domain Imaging (OFDI) is a recent derivative of optical coherence tomography (OCT). As in OCT, OFDI is an interferometric ranging technique that can roughly be considered to be an optical analogue of ultrasound imaging and can provide tomographic images of tissue at resolutions comparable with architectural histology. The long term goal of this study is to use OFDI to screen the airways with the hope of detecting Squamous Cell Carcinoma at an earlier more curable stage.