Cellular CT Scans with Soft X-ray Tomography

Carolyn A. Larabell
Department of Anatomy, University of California San Francisco
National Center for X-ray Tomography, Lawrence Berkeley National Laboratory

Much like medical CT scans reveal anatomical structures in the body, soft x-ray tomography (SXT) visualizes and quantifies the organization of sub-cellular structures within a cell. In SXT, the specimen is illuminated with x-ray photons from within a region of the spectrum known as the 'water window' (284 - 543eV). 'Water window' x-ray photons are absorbed an order of magnitude more strongly by carbon- and nitrogen-containing organic material than by water. Consequently, variation in biomolecule composition and concentration gives rise to quantitative, high-contrast images of intact, fully hydrated cells. Attenuation of soft x- rays as they pass through the specimen adheres to the Beer-Lambert Law. Attenuation is, therefore, a function of chemical composition and concentration of organic material, yielding unique quantitative Linear Absorption Coefficient (LAC) measurements for cellular components. To localize molecules without perturbing cell structures, we use correlated cryogenic fluorescence tomography (CFT). This multi-modal approach - imaging the same cell using both CFT and SXT - allows localization of labeled molecules directly in the context of a high-resolution 3-D tomographic reconstruction of the cell in the near-native state.

Friday, September, 21, 2018
McCormick Tribune Campus Center, 3201 S. State St.
1 p.m. Lecture- Auditorium
2 p.m. Reception- Ballroom

Please RSVP to kersh@iit.edu