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Zhou O, Lu J, Calderon-Colon X, Qian X, Yang G, Cao G, Gidcumb E, Tucker A, Shan J, Spronk D, Sprenger F. TU-E-110-02: Multibeam X-Ray Source Array Based on Carbon Nanotube Field Emission. Med Phys 2011. [DOI: 10.1118/1.3613204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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27
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Zhang J, Hadsell M, Cao G, Laganis P, Sprenger F, Schreiber E, Tracton G, Chang S, Lu J, Zhou O. MO-G-BRB-04: Feasibility Study of a Nanotechnology-Enabled Desktop Image-Guided Microbeam Radiation Therapy System. Med Phys 2011. [DOI: 10.1118/1.3613055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Qian X, Yang G, Sultana S, Gidcumb E, Tucker A, Spronk D, Sprenger F, Lu J, Zhou O. SU-C-301-03: A Spatially Distributed X-Ray Source Array for High Resolution Digital Breast Tomosynthesis. Med Phys 2011. [DOI: 10.1118/1.3611503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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29
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Hadsell M, Zhang J, Cao G, Schreiber E, Lu J, Chang S, Zhou O. TH-C-220-01: Pilot Study for the Development of Clinical Microbeam Radiation Therapy Using a Carbon Nanotube Field Emission Micro-CT Scanner. Med Phys 2011. [DOI: 10.1118/1.3613544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Sprenger F, Calderon X, Gidcumb E, Lu J, Qian X, Spronk D, Tucker A, Yang G, Zhou O. Stationary digital breast tomosynthesis with distributed field emission X-ray tube. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2011; 7961. [PMID: 21617760 DOI: 10.1117/12.878280] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Tomosynthesis requires projection images from different viewing angles. Using a distributed x-ray source this can be achieved without mechanical motion of the source with the potential for faster image acquisition speed. A distributed x-ray tube has been designed and manufactured specifically for breast tomosynthesis. The x-ray tube consists of 31 field emission x-ray sources with an angular range of 30°. The total dose is up to 100mAs with an energy range between 27 and 45 kVp. We discuss the source geometry and results from the characterization of the first prototype. The x-ray tube uses field emission cathodes based on carbon nanotubes (CNT) as electron source. Prior to the manufacturing of the sealed x-ray tube extensive testing on the field emission cathodes has been performed to verify the requirements for commercial tomosynthesis systems in terms of emission current, focal spot size and tube lifetime.
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Cui H, Palmer D, Zhou O, Stoner BR. Aligned Carbon Nanotubes Via Microwave Plasma Enhanced Chemical Vapor Deposition. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-593-39] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTAligned multi-wall carbon nanotubes have been grown on silicon substrates by microwave plasma enhanced chemical vapor deposition using methane/ammonia mixtures. The concentration ratio of methane/ammonia in addition to substrate temperature was varied. The morphology, structure and alignment of carbon nanotubes were studied by scanning electron microscopy and transmission electron microscopy. Both concentric hollow and bamboo-type multi-wall carbon nanotubes were observed. Growth rate, size distribution, alignment, morphology, and structure of carbon nanotubes changed with methane/ammonia ratio and growth temperature. Preliminary results on field emission properties are also presented.
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Tang XP, Kleinhammes A, Shimoda H, Fleming L, Bennoune KY, Bower C, Zhou O, Wu Y. Electronic Structures of Single-Walled Carbon Nanotubes Studied by NMR. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-593-143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTAn individual single-walled carbon nanotube (SWNT) has been shown [1-4] to exhibit remarkable electronic properties which depend on its diameter and chirality. In this work, the 13C nuclear magnetic resonance technique is used to measure quantitatively the electronic density-of-state (DOS) at the Fermi level in a bulk SWNT sample. Two types of 13C nuclear spins are observed with drastically different nuclear spin-lattice relaxation time (Tl). About onethird of the 13C nuclear spins with shorter Tl, are identified to reside at the metallic SWNTs and two-thirds can be associated with the semiconducting SWNTs. For the metallic SWNTs, the DOS at the Feimi level is measured quantitatively, which is about 0.022 states/(eV·atom·spin). The measured electronic DOS at the Fermi level agrees with the theoretical prediction for metallic tubes. This study also found that the semiconducting SWNTs in bundles, in fact, possess weak metallic characters. This indicates that tube-tube interactions within SWNT bundles could change the electronic properties.
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Bower C, Zhou O, Zhu W, Ramirez AG, Kochanski GP, Jin S. Fabrication and Field Emission Properties of Carbon Nanotube Cathodes. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-593-215] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTA variety of carbon nanotube films have been fabricated and tested as cold cathodes. A spray deposition technique was developed for processing as-grown bulk nanotubes, both single-walled and multi-walled, into films of randomly oriented nanotubes. Films of randomly oriented multi-walled nanotubes were grown using thermal chemical vapor deposition, and arrays of well-aligned multi-walled nanotubes have been fabricated using a microwave plasma enhanced chemical vapor deposition technique. The emission current-voltage (I-V) characteristics of these nanotube cathodes have been measured. Both multi-walled (random and aligned) and single-walled carbon nanotubes exhibit low turn-on fields (∼ 2 V/μm to generate 1 nA) and threshold fields (< 5 V/μm to generate 10 mA/cm2). Significantly, these cathodes were capable of operation at very large current densities (> 1A/cm2), making them candidates for application in a variety of vacuum microelectronic devices.
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Zhang J, Peng R, Chang S, Lu J, Zhou O. WE-E-201C-05: Performance of Multiplexing X-Ray Imaging Based on Multi-Beam X-Ray Source Technology. Med Phys 2010. [DOI: 10.1118/1.3469442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Wang S, Peng R, Zhang J, Schreiber E, Zhou O, Chang S. SU-GG-J-130: Recent Development of a Carbon Nanotube Field Emission Based X-Ray Micro-Radiotherapy System for Small Animal Radiotherapy. Med Phys 2010. [DOI: 10.1118/1.3468354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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36
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Sprenger F, Calderon-Colon X, Cheng Y, Englestad K, Lu J, Maltz J, Paidi A, Qian X, Spronk D, Sultana S, Yang G, Zhou O. Distributed source x-ray tube technology for tomosynthesis imaging. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2010; 7622:76225M. [PMID: 21785671 DOI: 10.1117/12.844586] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Tomosynthesis imaging requires projection images from different viewing angles. Conventional systems use a moving xray source to acquire the individual projections. Using a stationary distributed x-ray source with a number of sources that equals the number of required projections, this can be achieved without any mechanical motion. Advantages are a potentially faster image acquisition speed, higher spatial and temporal resolution and simple system design. We present distributed x-ray sources based on carbon nanotube (CNT) field emission cathodes. The field emission cathodes deliver the electrons required for x-ray production. CNT emitters feature a stable emission at high current density, a cold emission, excellent temporal control of the emitted electrons and good configurability. We discuss the use of stationary sources for two applications: (i) a linear tube for stationary digital breast tomosynthesis (sDBT), and (ii) a square tube for on-board tomosynthesis image-guided radiation therapy (IGRT). Results from high energy distributed sources up to 160kVp are also presented.
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Peng R, Zhang J, Calderon-Colon X, Quan E, Wang S, Sultana S, Chang S, Lalush D, Lu J, Zhou O. SU-FF-J-156: High Throughput Micro-CT Scanner Using a Distributed Multi-Beam Field Emission X-Ray Source. Med Phys 2009. [DOI: 10.1118/1.3181449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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38
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Zhang J, Bordelon D, Snider J, Schreiber E, Cox A, Zhou O, Chang S. WE-D-303A-01: Feasibility Study of Microbeam Radiation Therapy Using a Carbon Nanotube Field Emission Based Electron Microbeam Irradiator. Med Phys 2009. [DOI: 10.1118/1.3182528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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39
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Wang S, Schreiber E, Calderon-Colon X, Peng R, Sultana S, Zhang J, Zhou O, Chang S. TH-C-BRC-03: An Image-Guided Micro-Radiotherapy System Based On Carbon Nanotube Field Emission Technology for Small Animal Irradiation for Cancer Research. Med Phys 2009. [DOI: 10.1118/1.3182617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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40
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Qian X, Rajaram R, Yang G, Calderon-Colon X, Phan T, Sultana S, Lalush D, Lu J, Zhou O. WE-D-304A-09: Characterization of Multi-Beam Field Emission X-Ray Source for Stationary Digital Breast Tomosynthesis. Med Phys 2009. [DOI: 10.1118/1.3182545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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41
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Chang S, Zhou O. TU-C-BRD-05: Carbon Nanotube Field Emission Based Imaging and Irradiation Technology Development for Basic Cancer Research. Med Phys 2009. [DOI: 10.1118/1.3182323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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42
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Cao G, Lee YZ, Peng R, Liu Z, Rajaram R, Calderon-Colon X, An L, Wang P, Phan T, Sultana S, Lalush DS, Lu JP, Zhou O. A dynamic micro-CT scanner based on a carbon nanotube field emission x-ray source. Phys Med Biol 2009; 54:2323-40. [PMID: 19321922 DOI: 10.1088/0031-9155/54/8/005] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Current commercial micro-CT scanners have the capability of imaging objects ex vivo with high spatial resolution, but performing in vivo micro-CT on free-breathing small animals is still challenging because their physiological motions are non-periodic and much faster than those of humans. In this paper, we present a prototype physiologically gated micro-computed tomography (micro-CT) scanner based on a carbon nanotube field emission micro-focus x-ray source. The novel x-ray source allows x-ray pulses and imaging sequences to be readily synchronized and gated to non-periodic physiological signals from small animals. The system performance is evaluated using phantoms and sacrificed and anesthetized mice. Prospective respiratory-gated micro-CT images of anesthetized free-breathing mice were collected using this scanner at 50 ms temporal resolution and 6.2 lp mm(-1) at 10% system MTF. The high spatial and temporal resolutions of the micro-CT scanner make it well suited for high-resolution imaging of free-breathing small animals.
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Zhang J, Peng R, Yang G, Chang S, Lu J, Zhou O. SU-GG-J-92: Feasibility Study of Hadamard Multiplexing Radiography Based On Carbon Nanotube Field Emission Multi-Pixel X-Ray Technology. Med Phys 2008. [DOI: 10.1118/1.2961642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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44
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Bordelon D, Zhang J, Graboski S, Cox A, Schreiber E, Zhou O, Chang S. TU-D-352-09: Development of a Carbon-Nanotube Field Emission Based Multi-Pixel Microbeam Cellular Irradiation System. Med Phys 2008. [DOI: 10.1118/1.2962567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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45
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Cao G, Peng R, Lee Y, Rajaram R, Calderon-Colon X, An L, Phan T, Lalush D, Lu J, Zhou O. SU-GG-J-16: A Physiologically Gated Micro-CT Scanner for Dynamic Small Animal Imaging Based On a Carbon Nanotube X-Ray Source. Med Phys 2008. [DOI: 10.1118/1.2961573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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46
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Rajaram R, Yang G, Lee YZ, Lalush D, Lu J, Zhou O. TH-C-332-08: Calibration of the Geometry in a Stationary Digital Breast Tomosynthesis System. Med Phys 2008. [DOI: 10.1118/1.2962874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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47
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Wang S, Liu Z, Schreiber E, Sultana S, Zhou O, Chang S. SU-GG-J-71: Development of Carbon Nanotube Field Emission Micro-Radiotherapy System for Cancer Research. Med Phys 2008. [DOI: 10.1118/1.2961621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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48
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Chang S, Zhou O. SU-GG-J-44: Carbon Nanotube Field Emission Technology Enables Novel Imaging and Irradiation System Development for Cancer Research and Clinical Application. Med Phys 2008. [DOI: 10.1118/1.2961602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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49
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Yang G, Rajaram R, Zhang J, Sultana S, Cao G, Lalush D, Lu J, Zhou O. SU-FF-I-40: A Novel Gantry-Free DBT System Using a Stationary Multi-Beam Field Emission X-Ray Source Array Based On Carbon Nanotubes (CNTs). Med Phys 2007. [DOI: 10.1118/1.2760417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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50
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Zhang J, Yang G, Lee Y, Chang S, Lu J, Zhou O. MO-E-L100J-07: Multiplexing Radiography for Ultra-Fast Computed Tomography: A Feasibility Study. Med Phys 2007. [DOI: 10.1118/1.2761263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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