Developing Optical Imaging Technologies for Biomedical Engineering and Auditory Neuroscience

Dr. Nam Hyun Cho

Hardvard Medical School

 

Abstract

Over the past century, historical breakthroughs in biomedical engineering and biological sciences have been strongly associated with advances in optical imaging technology. One of these advances is micron-scale resolution label-free imaging, which uses reflection intensity from each structural layer. However, technical challenges of label-free optical imaging due to light propagation and scattering in opaque tissue remain. Over decades, several techniques have been developed to overcome the limitations of penetration depth, including optical tissue clearing (e.g., using chemicals) to measure the emission beam from labeled structures. Optical coherence tomography (OCT) is an established label-free method of imaging used clinically in ophthalmology. More recently, OCT is quickly being used in otolaryngology for basic science investigations using animal models and for developments of clinical applications. The classical theories of inner ear micromechanics are being challenged owing to technological advances in OCT. OCT allows in vivo imaging of the intact sensory structures at micrometer-level resolution and vibration measurements with sub-nanometer precision. This talk focuses on three components of my past and ongoing projects: (1) development of a high-speed portable OCT system and handheld probe using graphical processing units for new clinical applications, (2) development of an optical tissue clearing method and multi-modal optical imaging system to extend light propagation with applications in several branches of neuroscience research, and (3) monitoring morphological changes that occur in animals from living to after death of intact sensory structures with unprecedented high resolution. The latter project also includes a new research paradigm for characterization of acoustic-trauma induced damage of sensory structures via direct measurements of motion response. The talk will be concluded with a future plan of developing new OCT systems based on a novel technique to compensate for the current limitations of measuring nano-scale sensory hair bundle motion in live animal cochlea.

 

Speaker Biography

Dr. Cho received his PhD from the School of Electrical Engineering and Computer Science at Kyungpook National University, South Korea. Currently, he a research associate at Harvard Medical School. He has designed, led, and performed multiple projects using optical imaging systems. His expertise and experiences span many fields, including biomedical engineering, electrical and computer engineering, and neuroscience. At Harvard Medical School, he is working on an auditory biomechanics and neuroscience project, developing an image-registration algorithm and a method to enable sub-nanometer vibrometry using optical coherence tomography technology. His long-term goal is to develop real-time optic-based measurement systems to better understand the underlying micromechanics of the auditory sensory system with a wide frequency range of normal hearing and acoustic trauma. He plans to further apply these systems to characterizing the functional consequences of pathologic structural changes. This will be important for the future goal of developing the next generation of assistive hearing devices.