Optic Nerve Imaging Using Synchrotron Radiation (P07.254)

Abstract

Objective: We performed experimental synchrotron radiation (SR) imaging techniques on the leporine optic nerve to see if high resolution, detailed images of optic nerve microstructure could reliably be obtained. Our long term objective is to pursue safe in vivo imaging for the development of animal models for the study of optic neuropathies. Background There are no previous SR imaging studies of the optic nerve in either humans or animals. SR imaging techniques including diffraction enhanced imaging (DEI), and CT planar imaging have been successfully used to image biological tissues including the porcine eye, murine internal organs, canine articular cartilage, and human breast cancer tissue. Design/Methods: Specimen preparation included previously frozen dissected rabbit globes, optic nerves and chiasm, and one whole rabbit head. These samples were preserved and imaged in 10% formalin. A double crystal monochromator was used to select a very small energy band from the polychromatic synchrotron beam. The monochromatic beam passed through samples, with an analyzer crystal similar to that in the monochromator placed after the sample. Results: The analyzer crystal was sensitive to the refractive effects within the samples. In addition, absorption and scattering effects were used to create images with differing contrast properties. By moving the analyzer crystal various images of the optic nerve and ocular structures that showed apparent absorption and refraction properties were obtained. Conclusions: By using an intense monochromatic radiation beam from a synchrotron, we were able to image microscopic structures of the leporine optic nerve and surrounding tissues using both diffraction enhanced and CT planar imaging techniques. As far as we know, we are the only synchrotron research group in the world attempting to image the optic nerve, and the work is highly experimental and preliminary. We will continue to refine our methods and techniques of image acquisition. Supported by: Saskatchewan Health Research Foundation. Disclosure: Dr. Atkins has nothing to disclose. Dr. de Jager has nothing to disclose. Dr. Wiebe has nothing to disclose. Dr. Grahn has nothing to disclose. Dr. Chapman has nothing to disclose.