Browsing by Author "Wang, Steve"

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    Piecewise-Constant-Model-Based Interior Tomography Applied to Dentin Tubules
    He, Peng; Wei, Biao; Wang, Steve; Stock, Stuart R.; Yu, Hengyong; Wang, Ge (Hindawi Publishing Corporation, 2013)
    Dentin is a hierarchically structured biomineralized composite material, and dentin's tubules are difficult to study in situ. Nano-CT provides the requisite resolution, but the field of view typically contains only a few tubules. Using a plate-like specimen allows reconstruction of a volume containing specific tubules from a number of truncated projections typically collected over an angular range of about 140 degrees, which is practically accessible. Classical computed tomography (CT) theory cannot exactly reconstruct an object only from truncated projections, needless to say a limited angular range. Recently, interior tomography was developed to reconstruct a region-of-interest (ROI) from truncated data in a theoretically exact fashion via the total variation (TV) minimization under the condition that the ROI is piecewise constant. In this paper, we employ a TV minimization interior tomography algorithm to reconstruct interior microstructures in dentin from truncated projections over a limited angular range. Compared to the filtered backprojection (FBP) reconstruction, our reconstruction method reduces noise and suppresses artifacts. Volume rendering confirms the merits of our method in terms of preserving the interior microstructure of the dentin specimen.
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    SBES Advanced Multi-scale CT Facility at Virginia Tech - From Multi-scale to Multi-energy and Multi-Parameter Imaging Capabilities
    Wang, Ge; Wyatt, Christopher Lee; Yu, Hengyong; Sharma, Kriti S.; Prater, Mary R.; Xiao, Shuhai; Markert, Chad; Saul, Justin; Fox, Edward A.; Lee, Seung W.; Feser, Michael; Lau, S. H.; Yun, Wenbing; Wang, Steve (2010-04-05)
    While clinical CT scanners are available at our medical school, for preclinical imaging we have a Scanco micro-CT scanner, an Xradia micro-CT scanner and an Xradia nano-CT scanner. With all these scanners, we can cover image resolution and sample size over six orders of magnitude. The Scanco scanner has resolution 16 µm and FOV 20-38 mm. The Xradia micro-CT scanner, purchased using an NIH SIG grant in 2008, is the highest resolution micro-CT system on the market. It produces 0.5 µm resolution and handle samples of up to 100 mm diameter. The Xradia nano-CT scanner, purchased using an NSF-MRI grant in 2009, has 50 nm resolution and represents the state-of-the-art. It allows tomographic imaging in either the attenuation or Zernike phase contrast mode. For the high-resolution performance of the micro-/nano-CT systems, special housing is vital to ensuring technical development and biomedical applications. We have a dedicated space for these systems in the Institute for Critical Technologies and Applied Sciences (ICTAS; http://www.ictas.vt.edu) Building A, adjacent to the Nanoscale Characterization and Fabrication Lab (NCFL; http://www.ictas.vt.edu/NCFL) at Virginia Tech, which hosts most other cutting-edge imaging systems under one roof.