We propose to provide new non-invasive optical imaging technology for guiding clinical decisions in the diagnosis and management of oral cancer. This new technology is called optical coherence tomography (OCT) and is analogous to ultrasound imaging except light is used as the imaging signal instead of sound. OCT can provide 3-dimensional images of tissue with resolution approaching histology. Currently, there is no OCT instrument specialized for imaging oral lesions. We propose to build such an instrument that will provide clinicians unprecedented detailed bedside views of oral tissue. Annually, oral cancer is diagnosed in 4100 Canadians and results in 1150 deaths. On the diagnostic front, determining the correct course of treatment for a patient with a suspicious oral lesion requires biopsy and diagnosis by a pathologist. However, the choice of biopsy location is not always obvious, and for larger lesions clinicians often need to take multiple biopsies to try to ensure sampling of the most severe pathology. This incomplete sampling means that the most severe pathology may be overlooked, leading to misdiagnosis. It is hoped that our OCT instrument will enable clinicians to find the most severe pathological site directly, necessitating only a single biopsy while ensuring accurate diagnosis. From the oral cancer management perspective, once oral cancer has been identified, surgical removal is usually the best curative treatment option. The challenge, however, is to determine where are the boundaries of the cancer to ensure precise surgical removal of the entire tumour. We hope that our OCT instrument will provide an additional tool for surgeons to accurately identify the boundary of the tumour so that it can be completely excised to prevent cancer recurrence. If successful, these oral cancer OCT applications will improve patient care and healthcare efficiency by reducing biopsies and ensuring accurate diagnosis, and by preventing cancer recurrence.