Posters, Symposia, etc., School of Biomedical Engineering and Sciences

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    Fast CT Reconstruction - Practical Performance via Parallelization
    Wang, Ge (2008-06-12)
    Parallel computing has been used to solve large-scale problems in many fields. While CT is being developed towards high-resolution, volumetric, dynamic and spectral imaging, datasets become increasingly large, and reconstruction speeds are often too slow. To meet this challenge, in 2004 Drs. Wang and Ni co-found a High performance Computing Lab, and have been working in this area ever since. In 2006, we designed and implemented the first parallel Katsevich algorithm. We have also parallelized EM, OS-EM, SART and OS-SART algorithms, respectively.
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    Fluorescence Tomography - Monitor Malignancy in Mice
    Cui, Zheng; Wang, Ge (2008-06-12)
    Dr. Cui's group at Wake Forest has been investigating a newly discovered innate anticancer immunity in a colony of cancer resistant mice, and already demonstrated that the anticancer activity in the mice stems from the innate immune system, specifically from the granulocytes and macrophages. In 2007, they confirmed in vitro that the human granulocytes are capable of killing cancers effectively, suggesting a novel approach for cancer treatment. The FDA has approved this granulocyte infusion therapy (GIFT) for a phase II clinical trial. In collaboration with Dr. Cui's group, our main hypothesis is that optical molecular imaging of the granulocyte infiltration and cancer-killing activities in a mouse-based test-bed would identify potential donors and optimize outcomes in the clinical trial. The overall goal of this project is to develop a unique fluorescence tomography system that quantifies the leukocyte infiltration and cancer-killing abilities on prostate cancer sites in the murine model to evaluate the cancer-killing mechanisms and guide the GIFT trial.
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    Bioluminescence Tomography - Inner-light, Insight from Infrared
    Wang, Ge (2008-06-12)
    Bioluminescence tomography (BLT) is a molecular imaging modality, which derives a bioluminescent source distribution inside a small animal from external bioluminescent signals. We published the first paper on BLT in 2004 using the modality fusion approach. The introduction of BLT can be compared to the development of x-ray CT based on radiography. Without BLT, bioluminescent imaging is basically qualitative. With BLT, quantitative and 3D analyses become feasible inside a living mouse, which reveal important molecular and cellular information for numerous preclinical applications. *Complimentary film demonstrates 3D analysis of a living mouse with bioluminescent source
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    Spiral Cone-beam CT - Successes with Spiral Scans
    Wang, Ge (2008-06-12)
    X-ray computed tomography (CT) is instrumental in medicine, industry and homeland security, which depicts internal structures of an object from its shadows projected in a fan-beam or cone-beam from an x-ray source along a appropriate trajectory. We published the first paper on spiral conebeam CT in 1991 to solve the long object problem. Now, spiral conebeam scanning has been widely used in modern CT scanners, in which conebeam rotation and table translation are simultaneously performed, and spiral cone-beam CT remains a major area in CT research and development.
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    Interior Tomography - Depict with Direct Data
    Wang, Ge (2008-06-14)
    While the conventional wisdom states that the interior problem - to reconstruct a region of interest (ROI) only from projection data through the ROI - does not have a unique solution, in June 2007 we published the first paper on interior tomography to solve the interior problem exactly and stably, aided by the prior knowledge on a subregion in the ROI. We underline that interior tomography is potentially a powerful, even indispensable tool to handle large objects, reduce radiation dose, suppress scattering artifacts, refine image quality, decrease engineering cost, increase system functionalities, and boost scanner throughput in many biomedical and other applications. Interior tomography can be extended to other similar tomography modalities including MRI, ultrasound tomography, SPECT and PET.
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    Bolus-chasing CT Angiography - Catch the Contrast via Control
    Wang, Ge (2008-06-16)
    Intravenous injection of contrast media is required to enhance conspicuity of the vasculature, organs and tumors in CT angiography (CTA) for diagnosis of cardiovascular structures, peripheral vessels and solid organs. The overall goal of this project is to develop boluschasing CTA for a wide class of diagnostic applications. This will be achieved by instantaneously reconstructing CT images, dynamically predicting bolus propagation, and adaptively varying scanning pitch from the aortic arch to the feet to allow real-time correction of any significant deviation from the prediction. *Complimentary film demonstrates the solution to resonating the bolus peak and imaging aperture of the CTA angiography function, that is, via real-time peak bolus identification and prediction as well as adaptively moving the patient table.
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    Axiomatic Imaging Theory - Formulate with Fairness & Fun
    Wang, Ge (2008-06-17)
    There are many imaging systems. Their performance characterization is important for all applications. Various definitions are introduced for quantification of image resolution, which is the ability of an imaging system to separate two localized signals. In the nonnegative space, we postulated a set of axioms that a good image resolution measure should satisfy, obtained such an image resolution measure, applied our finding in comparing medical CT scanners, and won a 2004 Herbert M. Stauffer Award. We believe that imaging theory can be unified using the axiomatic approach.
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    X-ray Grating-based Imaging - Waves Work Wonderfully
    Wang, Ge (2008-06-17)
    Current x-ray imaging is of critical for clinical and pre-clinical applications but it is fundamentally restricted by the attenuation mechanism. X-ray grating-based imaging represents outstanding opportunities and major challenges, especially for tomography utilizing the wave nature of x-rays for superior tissue contrast at minimal radiation dose. Our general hypothesis is that 2D grating-based imaging can be developed to produce better projective/ and tomographic images of biomedical interest than 1D grating-based techniques. The overall goal is to develop the first of its kind 2D-grating-based imaging system for mouse and breast imaging.
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    Phase Approximation Model - Approximation Amazingly Accurate
    Wang, Ge (2008-06-20)
    The radiative transfer equation (RTE) well describes the photon propagation but its high computational cost is prohibitive for tomographic imaging. The diffusion approximation (DA) to RTE is the most popular but it only works well in weakly absorbing and highly scattering media, and breaks down near sources and across boundaries. In 2007, we derived the phase approximation (PA) model from RTE based on the generalized Delta-Eddington phase function. The generalized phase function is a linear combination of isotropic scattering and strongly peaked forward scattering with anisotropy weight as a free coefficient. PA is highly accurate over a broad range of coefficients with a computational complexity comparable to that of DA.
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    Image Warping - Unravel Unevenness into Uniformity
    Wang, Ge (2008-06-21)
    Demonstrations of anatomical systems computationally extracted from spiral CT images and then unraveled onto a plane in vivo to ultimately conceive 3D individualized models.
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    Results in the Past
    Wang, Ge (2010-02-04)
    Past research results include the following: • Modern CT scanners that use spiral-beam scanning and perform >100-million scans annually in the USA • Construction of the only 500nm resolution micro-CT system on the East Coast and the only 50nm nano-CT system with the interior tomography capability in the world from inside the walls of SAM-CT x-ray imaging facility • With further promise to handle large objects, reduce radiation dose, and improve temporal resolution, Interior tomography has already been extended to SPECT, MRI and other imaging modalities • A 3D analysis of the underlying molecular/cellular activities is taken from a mouse subject with an embedded bioluminescent source after an imaging model is built, linking the bioluminescent measurement and the source distribution.
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    Work at the Present
    Wang, Ge (2010-02-04)
    Cardiovascular diseases are pervasive at tremendous social and healthcare costs. There are urgent needs for higher fidelity cardiac CT with lower radiation dose. Based on the academic-industrial partnership between Virginia Tech and the GE Global Research Center (GEGR), we are defining a next generation cardiac CT architecture and the associated algorithms, which will achieve 16cm coverage, 50ms temporal resolution, 20lp/cm spatial resolution, 10HU noise level, and 5mSv effective dose simultaneously for the entire examination, with detailed specifications and performance evaluation. This project will set the stage for prototyping the next-generation cardiac CT system in a Phase-II project.
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    Development and Applications of Interior Tomography - Multi-source Interior Tomography for Ultrafast Performance
    Wang, Ge; Ritman, Erik; Ye, Yangbo; Katsevich, Alexander; Yu, Hengyong; Cao, Guohua; Zhou, Otto (2010-04-05)
    Conventional tomography allows excellent reconstruction of an object from non-truncated projections. The long-standing interior problem is to reconstruct an interior ROI accurately only from local projection segments. Interior tomography solves the interior problem with practical knowledge such as a known sub-region or a sparsity model using compressive sensing. Advantages of interior tomography include radiation dose reduction (no x-rays go outside an ROI), scattering artifact suppression (no cross-talk from radiation outside the ROI), image quality improvement (with the novel reconstruction approach), large object handling (measurement can be truncated in any direction), and ultrafast imaging performance (with multiple source detector chains tightly integrated targeting the ROI).
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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.
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    How to Define the Next Generation Cardiac CT Architecture? - a Contemporary Challenge for Interdisciplinary Collaboration
    Yu, Hengyong; DeMan, Bruno; Carr, Jeff; Frontera, Mark; Zeng, Kai; Bennett, James; Fitzgerald, Paul; Iatrou, Maria; Shen, Haiou; Santago, Peter; Wang, Ge (2010-05-21)
    Cardiovascular diseases are pervasive with high mortality and morbidity at tremendous social and healthcare costs. There are urgent needs for significantly higher fidelity cardiac CT with substantially lower radiation dose, which is currently not possible because of technical limitations. Although cardiac CT technology has improved significantly from 16 to 320 detector rows and from single to dual source, there remain technical challenges in terms of temporal resolution, spatial resolution, radiation dose, and so on. Based on an ideal academic-industrial partnership between Virginia Tech and the GE Global Research Center (GEGR), we are motivated to advance the state-of-the-art in cardiac CT. The overall goal of this project is to develop novel cardiac CT architectures and the associated reconstruction algorithms, and define the next-generation cardiac CT system. The specific aims are to (1) design, analyze and compare novel cardiac CT architectures with novel sources and scanning trajectories; (2) develop analytic and iterative cardiac CT reconstruction algorithms for ROI-oriented scanning and dynamic imaging for the proposed cardiac CT architectures; and (3) evaluate and validate the proposed architectures and algorithms in theoretical studies, numerical simulations, phantom experiments and observer studies. On completion of this project, we will have singled out the most promising cardiac CT architectures and algorithms to achieve 16cm coverage, 50ms temporal resolution, 20lp/cm spatial resolution, 10HU noise level, and 1mSv effective dose simultaneously for the entire examination, with detailed specifications and performance evaluation, setting the stage for prototyping a next-generation cardiac CT system in a Phase-II project. This project will enable significantly better diagnostic performance and bring major therapeutic benefits that affect over 60 million Americans.
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    Gel'fand-Graev's Reconstruction Formula in the 3D Real Space - a Framework towards a General Interior Tomography Theory
    Ye, Yangbo; Yu, Hengyong; Wang, Ge (2010-05-31)
    In [1-4], I. M. Gel'fand and M. I. Graev proposed inversion formulas for x-ray transforms in different spaces. In particular, Gel’fand-Graev’s inversion formula [1] is a fundamental relationship linking projection data to the Hilbert transform of an image to be reconstructed. This finding was re-discovered in the CT field; see [5-9]. It has wide applications, including local reconstruction [10-11], backprojection filtration (BPF) [12], interior tomography [13-17], and limited-angle tomography [18]. For a survey, see [19, 20]. Despite its high information density, Gel’fand-Graev’s inversion formula [1] was cast in high dimensions and specialized terms, and difficult to follow for a well-trained engineer. In this poster, we represent this formula and its proof for the 1D x-ray transform in a 3D real space for easy access and further extension.
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    Spiral CT of the Temporal Bone
    Wang, Ge; Skinner, Margaret W.; Vannier, Michael W. (2010-11-01)
    Maximum image resolution with commercial spiral CT scanners is inadequate to define clearly the anatomical features and electrode positions within this intricate, 3D space. The objective of this research was to develop theory, algorithms and equipment to increase spiral CT image resolution for temporal bone imaging, especially in cochlear implantation. Summary: Spiral CT with overlapping reconstruction allows better 3D resolution than conventional CT, and is important for temporal bone imaging • Spiral CT image deblurring achieves a 40% resolution gain without significant noise and ringing artifacts • Implant unwrapping measures the array insertion length with 0.3 mm mean accuracy, and facilitates electrode localization • Sub-mm scanning improves high-contrast resolution and suppresses stair-step artifacts. However, 0.5 mm collimation introduced more than doubled image noise
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    12th Annual Graduate Student Research Symposium: School of Biomedical Engineering and Sciences
    (Virginia Tech, 2013-05-16)
    The SBES Graduate Student Research Symposium was developed to provide students and faculty the opportunity to interact and exchange research ideas with colleagues and industry personnel. This program book features a schedule of events and abstracts from the 12th annual symposium held on May 16, 2013, at The Inn at Virginia Tech.
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    2015 Student Symposium: Department of Biomedical Engineering and Mechanics
    (Virginia Tech, 2015)
    This program book includes a schedule of events and abstracts from the 14th annual School of Biomedical Engineering & Sciences Graduate Student Research Symposium.
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    TIM-OS: A General Monte Carlo Optical Simulator for Biomedical Optics
    Shen, Haiou; Wang, Ge (2015-11-15)
    A high-performance public-domain Monte Carlo optical simulator is highly desirable to solve complex heterogeneous optical problems in biomedical engineering. Recently, we developed a Tetrahedron-based Inhomogeneous Monte- Carlo Optical Simulator (TIM-OS) pubware, which addresses this challenge efficiently and accurately based on the tetrahedral mesh.