Articles by Fredrik Georgsson in JoVE
Near Infrared Optical Projection Tomography for Assessments of β-cell Mass Distribution in Diabetes Research Anna U. Eriksson*1, Christoffer Svensson*1, Andreas Hörnblad1, Abbas Cheddad1, Elena Kostromina1, Maria Eriksson1, Nils Norlin1, Antonello Pileggi2, James Sharpe3, Fredrik Georgsson4, Tomas Alanentalo1, Ulf Ahlgren1 1Umeå Centre for Molecular Medicine, Umeå University, 2Cell Transplant Center, Diabetes Research Institute, University of Miami,, 3EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Catalan Institute of Research and Advanced Studies, 4Dept. of Computing Science, Umeå University We describe the adaptation of optical projection tomography (OPT)1 to imaging in the near infrared spectrum, and the implementation of a number of computational tools. These protocols enable assessments of pancreatic β-cell mass (BCM) in larger specimens, increase the multichannel capacity of the technique and increase the quality of OPT data.
Other articles by Fredrik Georgsson on PubMed
Assessing the Macroporous Structure of Monolithic Columns by Transmission Electron Microscopy Analytical Chemistry. Jan, 2007 | Pubmed ID: 17194158 A set of monolithic stationary phases representing a broad span of monomers and porogens have been characterized directly in their capillary chromatographic format by computational assessment of their pore structure from transmission electron micrographs obtained after in situ embedment of the monoliths in contrast resin, followed by dissolution of the fused-silica tubing, further encasement of the resin-embedded monolith, and microtomy. This technique has been compared to mercury intrusion, a more conventional technique for macroporosity estimation. Supplementing the embedding resin by lead methacrylate gave a negative staining, and the resulting micrographs showed a good contrast between the polymeric monoliths and the embedding resin that allowed studies on the pore formation and polymer development. The technique was also applied to a commercial monolithic silica column.
Image Processing Assisted Algorithms for Optical Projection Tomography IEEE Transactions on Medical Imaging. Jan, 2012 | Pubmed ID: 21768046 Since it was first presented in 2002, optical projection tomography (OPT) has emerged as a powerful tool for the study of biomedical specimen on the mm to cm scale. In this paper, we present computational tools to further improve OPT image acquisition and tomographic reconstruction. More specifically, these methods provide: semi-automatic and precise positioning of a sample at the axis of rotation and a fast and robust algorithm for determination of postalignment values throughout the specimen as compared to existing methods. These tools are easily integrated for use with current commercial OPT scanners and should also be possible to implement in "home made" or experimental setups for OPT imaging. They generally contribute to increase acquisition speed and quality of OPT data and thereby significantly simplify and improve a number of three-dimensional and quantitative OPT based assessments.