Neuroimaging and Interventional Radiology

Biography

Biography: Saiedeh Saghafi

Abstract

Ultramicroscopy-UM is a noninvasive powerful tool for volumetric measurements and 3D visualization of even cm-sized specimens such as cancerous tissues, spinal cords or whole mouse brain. It utilizes thin laser light sheet for optical sectioning of the samples in fluorescence microscopy. It enables us to obtain high resolution 3D images through computer reconstruction of stack of images revealing fine details of the outer as well as inner structure such as neuronal network of the brain. Lasers operating in the fundamental mode emit a circular radial bell-shaped beam, the so-called “Gaussian beam”. In standard UM, a combination of slit aperture and a cylindrical lens of focal length f that focuses the beam in one direction and approximately provides no changes in the perpendicular direction is used to produce a thin sheet of light. However, hard edge aperture effects, major power loss, non-uniformity in the intensity distribution along the light sheet and rapid expansion of the light sheet width are some of the drawbacks of the standard design. Here, we present a novel UM that utilize aspheric- as well as Meso-optical elements in combination with particular soft aperture that converts Gaussian beam into an ultrathin laser light sheet. The optical properties of the light sheet show marked improvements. Furthermore, our latest research and optimization related to sample clearing process (for reducing light scattering inside the tissues) as well as compensating the refractive index mismatch that occurs while collecting the signals by microscope objectives are presented.