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A comparison between traditional shift-and-add (SAA) and point-by-point back projection (BP) -- relevance to morphology of microcalcifications for isocentric motion in Digital Breast tomosynthesis (DBT)

A comparison between traditional shift-and-add (SAA) and poi...

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IEEE Symposium on Bioinformatics and Bioengineering (BIBE)

作者： Ying Chen Joseph Y. Lo James T. Dobbins Department of Electrical and Computer Engineering Southem Illinois University Carbondale Carbondale IL USA Duke Adavanced Imaging Laboratories Duke University Medical Center Duke University Durham NC USA Department of Biomedical Engineering Duke University and Duke University Medical Center Durham North Carolina 27710 Duke Advanced Imaging Laboratories Duke University and Duke University Medical Center Durham North Carolina 27710 Medical Physics Graduate Program Duke University and Duke University Medical Center Durham North Carolina 27710

Digital breast tomosynthesis (DBT) is a three-dimensional imaging technique providing an arbitrary set of reconstruction planes in the breast with limited series of projection images. This paper describes a comparison between traditional shift-and-add (SAA) and point-by-point back projection (BP) algorithms by impulse response and modulation transfer function (MTF) analysis. Due to the partial isocentric motion of the x-ray tube in DBT, structures such as microcalcifications appear slightly blurred in traditional shift-and-add (SAA) images in the direction perpendicular to the direction of tube's motion. Point-by-point BP improved rendition of microcalcifications. The sharpness and morphology of calcifications were improved in a human subject images. A filtered back projection (FBP) deblurring approach was used to demonstrate deblurred point-by-point BP tomosynthesis images. The point-by-point BP rather than traditional SAA should be considered as the foundation of further deblurring algorithms for DBT reconstruction.

关键词： Morphology Image reconstruction X-ray imaging Back Image edge detection Breast cancer Detectors Biomedical engineering Transfer functions Humans

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Novel multifunctional PHDCA/PEI nano-drug carriers for simultaneous magnetically-targeted cancer therapy and diagnosis using magnetic resonance imaging

Novel multifunctional PHDCA/PEI nano-drug carriers for simul...

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2007 Pacific Rim Conference on Lasers and Electro-Optics (CLEO/PACIFIC RIM 2007), vol.2

作者： Sungbaek Seo Jaemoon Yang Woochan Hyung Eun-Jin Cho Yong Jin Song Ho-Geun Yoon Jin-Suck Suh Yong-Min Huh Seungjoo Haam Graduate Program for Nanomedical Science Yonsei University Seoul 120-749 South Korea Department of Chemical Engineering College of Engineering Yonsei University Seoul 120-749 South Korea Department of Radiology College of Medicine Yonsei University Seoul 120-752 South Korea Department of Physics College of Natural Science Ajou University Suwon 433-749 South Korea Department of Biochemistry and Molecular Biology Center for Chronic Metabolic Disease Research College of Medicine Yonsei University Seoul 120-752 South Korea

ISBN: (纸本)1424411742

Novel multifunctional magnetic polycation drug carriers (MPDCs) were synthesized to provide simultaneous magnetically targeted cancer therapy and diagnosis using magnetic resonance imaging (MRI). The MPDCs demonstrated ultra-sensitivity via MRI and sufficient magnetic mobility under an external magnetic field. Drug loading efficiency and release kinetics were also investigated to assess the therapeutic potential of the MPDCs.

关键词： In vivo imaging Magnetic fields Magnetic resonance imaging Microscopy Nanocrystals Nanoparticles

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Decision Fusion of Circulating Markers for Breast Cancer Detection in Premenopausal Women

Decision Fusion of Circulating Markers for Breast Cancer Det...

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IEEE Symposium on Bioinformatics and Bioengineering (BIBE)

作者： Jonathan L. Jesneck Sayan Mukherjee Loren W. Nolte Anna E. Lokshin Jeffrey R. Marks Joseph Lo Duke Advanced Imaging Labs Institute for Genome Sciences and Policy Department of Computer Science Duke University USA Department of Electrical and Computer Engineering Division of Hematology/Oncology University of Pittsburgh School of Medicine Pittsburgh PA USA Division of Hematology/Oncology University of Pittsburgh Cancer Institute Pittsburgh PA USA Division of Hematology/Oncology University of Pittsburgh Cancer Institute Pittsburgh PA Institute for Genome Sciences and Policy Department of Experimental Surgery Medical Center Duke University USA Department of Experimental Surgery Duke University Medical Center Medical Physics Graduate Program Duke University Durham NC USA

Current mammographic screening for breast cancer is less effective for younger women. To complement mammography for premenopausal women, we investigated the feasibility screening test using 98 blood serum proteins. Because the data set was very noisy and contained only weak features, we used a classifier designed for noisy data: decision fusion. Decision fusion outperformed both a support vector machine (SVM) and linear regression with forward stepwise feature selection on all three two-class classification tasks: normal tissue vs. cancer, normal tissue vs. benign lesions, and benign lesions vs. cancer. Decision fusion detected cancer moderately well (AUC=0.84 on normal vs. cancer), demonstrating promise as a screening tool. Decision fusion also detected benign lesions similarly well (AUC=0.83 on normal vs. benign lesions) and was the only classifier to achieve any success in separating benign from malignant lesions (AUC=0.64 on benign vs. cancer). The classification results suggest that the assayed proteins are more indicative of a secondary effect, such as immune response, rather than specific for breast cancer. In conclusion, the decision fusion classifier demonstrated some promise in detecting breast lesions and outperformed other classifiers, especially for the very noisy classification problem of distinguishing benign from malignant lesions.

关键词： Breast cancer Cancer detection Lesions Proteins Support vector machines Support vector machine classification Mammography Testing Blood Linear regression

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An inverted-pendulum thrust stand for high-power electric thrusters

An inverted-pendulum thrust stand for high-power electric th...

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AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference

作者： Kodys, A.D. Murray, R. Cassady, L. Choueiri, E.Y. Electric Propulsion and Plasma Dynamics Laboratory Mechanical and Aerospace Engineering Department Princeton University Princeton NJ 08511 United States NASA Graduate Student Research Program Princeton Plasma Science and Technology Program United States EPPDyL United States Applied Physics Group United States AIAA United States

ISBN: (纸本)1563478188

The inverted-pendulum method of thrust measurement for high-power electric thrusters is described analytically and experimentally. Two sources of uncertainty in the thrust measurements are investigated: those due to changes in the sensitivity of the inverted pendulum and those due to tare forces resulting from thermal stresses and electromagnetic forces acting on the flexural elements. An idealized analytical model shows that changes in sensitivity occur due to changes in the mass loading of the inverted pendulum and the temperature of the flexure elements. The sensitivity can be increased only at the expense of more stringent requirements on mass loading and thermal control. The results of the model are validated with measurements made using a carefully calibrated inverted pendulum thrust stand having several advantageous design features including gallium pots for current conduction, an optical two-axis displacement sensor, and careful consideration of flexure shape and cooling requirements. The sensitivity is shown to be constant over a wide range of operating conditions. Measurements show that thermal drifts of the stand are linear on the time scale of the thrust measurements and are less than 0.6% of the expected thrust. The thrust stand operation was demonstrated during experiments with a 30-kW lithium-fed applied-field magnetoplasmadynamic thruster. Under nominal conditions (400 A, 0.1 T, 17.5 mg/s) the thermal and electromagnetic tare forces were measured at less than 9% of the thrust and the total thrust uncertainty at ≤ 10% of the thrust.

关键词： Electric propulsion

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Ottenimento di silice amorfa a partire da pula di riso madiante estrazione

C e Ca

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C e Ca 2006年第2期36卷 141-145页

作者： Junkes, J.A. Della, V.P. Acchar, W. Oliveira, A.P.N. Hotza, D. Materials Science and Engineering Graduate Program Federal University of Santa Catarina Florianopolis Brazil Department of Physics Federal University of Rio Grande do Norte Natal Brazil Department of Chemical Engineering Federal University of Santa Catarina Florianopolis Brazil

Rice husk can be an interesting source of raw material for obtaining silica, due to its composition, availability and cost. The extraction process of silica from rice husk can be divided in two parts. First some components of rice husk are removed by acid leaching, using HCl, H2SO4, or a mixture of them, followed by calcination for burning out carbon compounds. The residue obtained after calcination is composed of about 95% amorphous silica. In this work, silica was produced from rice husk following the steps previously described, using leaching solutions of 10% HCl, 10% H 2SO4 and a mixture of 10% HCl and 10% H2SO 4. Calcination of leached materials was carried out at 600 or 700°C for 3 h. The silica powder obtained presented a mean particle size of 18 μm, around 98% amorphous SiO2 with a specific surface area of about 300 m2/g.

关键词： Hulls (seed coverings)

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SiO2-coated porous anodic alumina membrane for electroosmotic pumping

SiO2-coated porous anodic alumina membrane for electroosmoti...

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2006 ASME International Mechanical engineering Congress and Exposition, IMECE2006

作者： Vajandar, Saumitra K. Xu, Dongyan Li, Deyu Markov, Dmitry Wikswo, John Hofmeister, William Interdisciplinary Graduate Program in Materials Science Vanderbilt University Nashville TN 37235 United States Department of Mechanical Engineering Vanderbilt University Nashville TN 37235 United States Department of Physics and Astronomy Vanderbilt University Nashville TN 37235 United States Center for Laser Applications University of Tennessee Space Institute Tullahoma TN 37388 United States

ISBN: (纸本)0791837904

Electroosmotic pumping has been extensively used in biomedical lab-on-a-chip devices and micropumps for critical applications such as microelectronic cooling. In many applications, a high flow rate is a key requirement in desired performance so constant efforts have been made to increase the pumping flow rate through unit area to achieve the compact design. We report here an attempt of using SiO2-coated anodic porous alumina membrane as the material to achieve high electroosmotic pumping flow rate. High quality porous alumina membranes of controllable pore diameter in the range of 20-300 nm and pore length of 60-100 μm have been fabricated with electrochemical anodization. The pores are uniform and hexagonally packed with a high porosity of up to 50% and a tortuosity of a bare minimum of unity. In addition, the inner surface of the pores could be conformally coated with a thin layer (∼ 5 nm) of SiO2 with sol-gel chemistry to achieve a high zeta potential. Scanning electron microscopy of the cross section of the membrane verified these facts. Electroosmotic pumping performance of these membranes has been investigated using standard relevant aqueous electrolyte buffer solutions and results showed that SiO2-coated porous alumina could achieve a higher flow rate compared with other microporous materials such as glass frit and porous silicon reported in the literature. Copyright © 2006 by ASME.

关键词： Membranes

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Pinhole Trajectories for SPECT Imaging of the Breast, Axilla, and Upper Chest

Pinhole Trajectories for SPECT Imaging of the Breast, Axilla...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： James E. Bowsher Justin R. Roper Joerg Peter Ronald J. Jaszczak Departments of Radiation Oncology and Radiology Duke University Medical Center Durham NC USA Medical Physics Graduate Program University Medical Center Durham NC USA German Cancer Research Center Heidelberg Germany Department of Biomedical Engineering Duke University Durham NC USA

Several methods have been proposed for dedicated SPECT imaging of the breast. Two key characteristics achieved by these methods are shortened distance and lessened attenuation between the SPECT collimator and the breast. However, many of these methods are unable to image the important regions of the axilla and upper chest. Partial-Circle pinhole trajectories can image into the axilla, but only over a narrow axial range. Here we propose X and X-Line trajectories that can effectively image a broad axial range of the breast, axilla, and upper chest. The X and X-Line trajectories provide a third dimension of pinhole displacement, which is key to expanding the range of sufficient sampling. In order to investigate spatial variations in the imaging characteristics of different pinhole trajectories, phantoms were constructed with hot lesions and Defrise slabs distributed throughout the breast and torso. Projection data were computer simulated, and images were reconstructed by OSEM. These studies indicate that all three trajectories can sample activity well into the axilla. However, the axial range of good sampling is narrow with the Partial-Circle trajectory. The X and X-Line trajectories provide good sampling well into the axilla and over a broad axial range. The convex hulls of the X and X-Line trajectories encompass the breast and much of the axilla and upper chest, thereby satisfying Tuy's condition for sufficient sampling of those regions, truncation issues aside. The spatial extent of the convex hull is tunable. At the same time, the X and X-Line trajectories achieve two other key characteristics of dedicated SPECT breast imaging: Shortened average distance and lessened average attenuation between the collimator, i.e. the pinhole, and the breast and other nearby tissue of interest.

关键词： Breast Axilla Image sampling Attenuation Collimators Imaging phantoms Lesions Slabs Torso Computational modeling

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Approach to an interdisciplinary bionanotechnology education program: International network perspective

Approach to an interdisciplinary bionanotechnology education...

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2006 MRS Spring Meeting

作者： Vaseashta, A. Irudayaraj, J. Vaseashta, S. Stamatin, I. Erdem, A. Graduate Program in Physical Sciences Nanomaterials Processing and Characterization Laboratories Marshall University Huntington WV 25755-2570 United States Agricultural and Biological Engineering Purdue University 225 S. University Street West Lafayette IN 47907-2093 United States Nanomaterials Processing and Characterization Laboratories Marshall University One John Marshall Drive Huntington WV 25755 United States Faculty of Physics University of Bucharest 3 Nano and Alternative Energy Sources Research Center Bucharest-Magurele Romania Analytical Chemistry Department Ege University 35100 Bornova Izmir Turkey

ISBN: (纸本)1558998888

Materials in reduced dimensions demonstrate size dependence and may exhibit properties different from the bulk. Nanomaterials are a fundamentally and entirely new class of materials with remarkable electrical, optical, and mechanical properties, thus offering unique applications. With a 9.7% increase in FY 2004-05 private sector investments and an expected worldwide labor force shortage, education and training has become a key component of the National Nanotechnology Initiative (NNI). The slow response by the academic community to develop nanotechnology curriculum is evidenced by the small number of universities offering fundamental undergraduate level courses in nanoscience and nanotechnology. There is a strong need to develop cohesive undergraduate curriculum to equip the future engineers, scientists, and researchers charged with commercializing nanotechnology applications. We are in the process of developing and implementing some core courses and laboratory modules, which can easily adapt to either a major or minor in nanotechnology, nano-biotechnology, or nanoscience programs. The course modules are being developed by a multi-disciplinary team consisting of faculty in physics, Agricultural and Biological engineering, Materials engineering, and Molecular Biology at universities in the U.S., Europe, and the Consortium of South East European Network on Nanoscience and Technology (COSENT). The joint effort specifically addresses an undergraduate curriculum in nanotechnology with courses emphasizing applications in biological systems and agriculture, through hands-on modules and experimental kits. Selected course and laboratory modules are being developed to be affordable, flexible, accessible, and appealing to a diverse student population crossing basic sciences, life sciences, agriculture, and engineering departments. Internet ready, multimedia intensive curriculum and assessment modules will include self-directed individualized learning modules as well as team-bas

关键词： Nanotechnology

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Real-time organ motion tracking and fast image registration system for MRI-guided surgery

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Systems and Computers in Japan 2006年第1期37卷 83-92页

作者： Tokuda, Junichi Hirano, Masaya Tsukamoto, Tetsuji Dohi, Takeyoshi Hata, Nobuhiko Graduate School of Information Science and Technology University of Tokyo Tokyo 113-8656 Japan GE Yokogawa Medical Systems Ltd. Hino 191-8503 Japan International Society for Computer-Aided Surgery Japan Society for Computer-Aided Surgery Japan Society for Magnetic Resonance in Medicine GE Yokogawa Medical Systems Ltd. Imaging Application Tech. Center MR Group R and D Laboratory Technology Center GE Yokogawa Medical Systems Ltd. Society for Magnetic Resonance in Medicine Graduate School of Information Science and Technology Society for Life Support Technology Japan Society for Organ Preservation Biology and Medicine Society for Precision Engineering Society for Medical Image Computing and Computer Assisted Intervention International Union for Physics and Engineering Sciences in Medicine JSMEBE Japan Society for Life Assistance Technology Brigham and Women's Hospital Harvard Medical School MR Therapy Program

The advantage of magnetic resonance imaging (MRI)-guided surgery, in which MR images taken during surgery are used to guide the surgery, has been recognized recently. However, there is a problem, due to long imaging time of MRI, that it is difficult to capture the respiratory organ motion. It is often a constraint that the patient must hold his or her breath, especially in the treatment of the abdominal region. Consequently, this paper proposes a method of eliminating this constraint in MRI-guided surgery by real-time monitoring of the movement of the organ involved in the surgery by means of the signal derived from MRI. Specifically, the navigator echo is extracted in imaging during surgery. The movement of the organ involved in surgery is detected on the basis of the change in the calculated projection profile, and the results are presented to the surgeon. In this study, the procedure is built into a 1.5-T clinical MRI system. The feasibility of the proposed system was examined under clinical conditions by evaluating its accuracy and delay in a phantom experiment, and also in an in vivo experiment on the liver of a volunteer. The results are reported in this paper. © 2005 Wiley Periodicals, Inc.

关键词： Motion estimation

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Erratum: "Contrast-detail analysis of three flat panel detectors for digital radiography" [Med. Phys., - (2006)]

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Medical physics 2006年第9期33卷 3580页

作者： Giovanni Borasi Ehsan Samei Marco Bertolini Andrea Nitrosi Davide Tassoni Servizio di Fisica Sanitaria Azienda Ospedaliera Santa Maria Nuova V.le Risorgimento 80 42100 Reggio Emilia (RE) Italy. Duke Advanced Imaging Laboratories Departments of Radiology Physics and Biomedical Engineering and Medical Physics Graduate Program Duke University DUMC 3302 Durham North Carolina 27710.

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