Minimally invasive diagnostic imaging using high resolution Optical Coherence Tomography

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references.Advances in medical imaging have given researchers unprecedented capabilities to visualize, characterize and understand biological systems. Optical Coherence Tomography (OCT) is a high speed, high resolution imaging technique that utilizes low coherence interferometry to perform cross-sectional tomographic imaging of tissue in real time and in vivo. The design, development, and implementation of ultrahigh resolution OCT systems in both laboratory and clinical experiments has been pursued in this work. Biomedical imaging studies in the areas of arthroscopy, cardiology, and endoscopy have been investigated with ultrahigh resolution capability achieved through the use of broadband femtosecond oscillators such as Ti:Sapphire and Cr:Forsterite light sources. OCT image resolutions of 1-5um in tissue have been realized, an order of magnitude greater than conventional MRI or ultrasound resolutions. In addition, through the use of coherent heterodyne detection techniques, the capability to visualize pathological tissue architecture in vivo for both animal and human experimental trials has been demonstrated. Because OCT can perform such "optical biopsy" with resolutions approaching that of conventional excisional biopsy and histology, it has the potential to become a powerful diagnostic tool in the field of medical imaging. In combination with small fiber-optic catheters, endoscopes, and other imaging devices, minimally invasive OCT imaging was carried out with novel diagnostic devices also developed in this work. The development and implementation of advanced OCT systems for both research and clinical applications will be presented as well as future directions for the technology.by Paul R. Herz.Ph.D