• Title/Summary/Keyword: Dual Energy

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A Study of the Metal Artifact Reduction using Dual Energy CT : Clinical Applications of Dual Energy and MAR Algorithm (Dual Energy CT를 이용한 금속물질 인공물 감소방법 : Dual Energy와 MAR알고리즘의 임상적 응용)

  • Park, Ki Seok;Choi, Woo Jeon;Kim, Dong Hyun
    • Journal of the Korean Society of Radiology
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    • v.15 no.3
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    • pp.273-279
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    • 2021
  • Metal material inserted into the body have a large difference in density from human tissues or bones around the Metal during CT scans.. Therefore, the Metal material inserted into the body produces Artifact. Metal Artifact, which occurs around Metals, can degrade the quality of CT images, causing confusion when medical team diagnose lesions. Through this experiment, we confirm that the occurrence of Artifacts decrease by using Dual energy CT and MAR algorithm in Single source Dual energy CT. We also want to present basic data on clinical application methods by comparing and analyzing the characteristics of images obtained by each method. Using GE 750HD CT, artificial implants were scanned using general method and Dual energy. Then we apply the MAR algorithm to each image obtained. And all previously acquired images were compared and analyzed the characteristics of the examination, such as image quality evaluation and dose evaluation. Images with MAR algorithm and Dual Energy confirmed a decrease in Metal Artifact. Images with MAR algorithm have reduced Metal Artifact, but have the disadvantage of distorting the details of artificial joint implants. On the other hand images teseted with Dual Energy have the advantage of being able to implement details than those applied with MAR algorithms, it takes longer to reconstruct the image and the exposure dose was about four times higher than those applied with MAR algorithm. In order to locate Metals, such as the post-operative follow-up period, it is useful to apply MAR algorithm to obtain images. And it is more useful to examine with Dual Energy when micro lesion identification, such as cardiac examination, and surgical planning or when tests are performed in diagnostic way.

Dual Phase Conductive CO2 Membranes: Mechanism, Microstructure, and Electrical Conductivity (Dual Phase 전도성 CO2 분리막: 메커니즘, 미세구조 및 전기전도도)

  • Lee, Shi-Woo;Yu, Ji-Haeng;Woo, Sang-Kuk
    • Journal of the Korean Ceramic Society
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    • v.44 no.8
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    • pp.424-429
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    • 2007
  • Novel conductive $CO_2$ membranes composed of dual phases, molten carbonates and electronic conducting ceramics, were investigated. As the microstructure control of electronic conducting ceramic supports is extremely important to keep the molten carbonates stable in the membranes by a capillary force applied by the pore structure of the supports, we have scrutinized the microstructure of the electronic conducting supports utilizing microscopic images and gas permeability measurement. From the evaluation of the electrical conductivities of the molten carbonates and the electronic conducting ceramic supports, we found that the ionic conductivity of the molten carbonates could determine $CO_2$ flux through the dual phase membranes if the surface exchange rate were relatively high enough.

Performance Analysis of Heat Pump System with Air Source Evaporator and Single Unit Dual Sink Condenser (공기열원 2중히트싱크 열펌프의 성능해석)

  • Woo, J.S.;Lee, S.K.;Lee, J.H.;Park, H.S.
    • Solar Energy
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    • v.18 no.4
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    • pp.11-22
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    • 1998
  • Floor panel heating system using hot water is the primary heating system of domestic residential building. This paper presents the results of performance analysis of the heat pump system with air source evaporator and single unit dual sink(SUDSk) condenser. The heat exchanger combines two separated condensers into a single condenser and the object of the SUDSk condenser is to release energy to dual sinks, i.e. air for air heating system and water for panel heating system in one single unit. Simulation program is developed for single unit dual source(SUDS) SUDSk heat pump system and some experimental data are obtained and compared with simulation results. Differences of heating capacity and COP in dual source operating mode are 7% and 8% respectively. Simulation results are in good agreement with test results. Therefore, developed program is effectively used for design and performance prediction of dual source dual sink heat pump system with SUDS evaporator and SUDSk condenser.

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Energy and exergy analysis of CI engine dual fuelled with linseed biodiesel and biogas

  • S. Lalhriatpuia;Amit Pal
    • Advances in Energy Research
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    • v.8 no.4
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    • pp.213-222
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    • 2022
  • Our overdependence on the limited supply of fossil fuel with the burden of emission as a consequence of its utilization has been a major concern. Biodiesel is emerging as a potential diesel substitution for its similar performance, with the additional benefits of emitting lesser emissions. Due to the easy availability of feedstock for Biogas production, Biogas is studied for its use in CI engines. In this study, we considered Linseed Biodiesel and Biogas to run on dual fuel mode in a CI engine. An energy and exergy analysis was conducted to study the rate of fuel energy and exergy transformation to various other processes. Exergy relocation to exhaust gases was observed to be an average of 5% more for dual fuel mode than the diesel mode, whereas exergy relocation to the diesel mode was observed to be more than the dual fuel modes. Also, exergy loss to exhaust gas is observed to be more than the exergy transferred to cooling water or shaft. The exergy efficiency observed for biodiesel-biogas mode is only lesser by 3% compared to diesel-biogas mode, suggesting Biodiesel can be a substitute fuel for diesel.

APPLICATION OF A DUAL-ENERGY MONOCHROMATIC XRAY CT ALGORITHM TO POLYCHROMATIC X-RAY CT: A FEASIBILITY STUDY

  • Chang, S.;Lee, H.K.;Cho, G.
    • Nuclear Engineering and Technology
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    • v.44 no.1
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    • pp.61-70
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    • 2012
  • In this study, a simple post-reconstruction dual-energy computed tomography (CT) method is proposed. A dual-energy CT algorithm for monochromatic x-rays was adopted and applied to the dual-energy CT of polychromatic x-rays by assigning a representative mono-energy. The accuracy of algorithm implementation was tested with mathematical phantoms. To test the sensitivity of this algorithm to the inaccuracy of representative energy value in energy values, a simulation study was performed with mathematical phantom. To represent a polychromatic x-ray energy spectrum with a single-energy, mean energy and equivalent energy were used, and the results were compared. The feasibility of the proposed method was experimentally tested with two different micro-CTs and a test phantom made of polymethyl methacrylate (PMMA), water, and graphite. The dual-energy calculations were carried out with CT images of all possible energy pairs among 40, 50, 60, 70, and 80 kVp. The effective atomic number and the electron density values obtained from the proposed method were compared with theoretical values. The results showed that, except the errors in the effective atomic number of graphite, most of the errors were less than 10 % for both CT scanners, and for the combination of 60 kVp and 70 kVp, errors less than 6.0 % could be achieved with a Polaris 90 CT. The proposed method shows simplicity of calibration, demonstrating its practicality and feasibility for use with a general polychromatic CT.

Development of Dual Energy Radiation Detector (이중 에너지 방사선 검출기 개발)

  • Yeo, Hwa-Yeon
    • Journal of the Korean Society of Radiology
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    • v.4 no.3
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    • pp.5-11
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    • 2010
  • In this paper, we are suggested development of dual-mode detector for dual-energy digital radiography. Design of dual-energy radiography module for commercial BIS (Baggage Inspection System) is used in the spectrum of the X-ray generator and detector for dual-mode features and radiological characteristics were analyzed. BIS suggestl on the image detector module being used to target X-ray tube to simulate X-ray spectrum and simulated spectrum to offer through the new radiographic characteristics of the detector modules were investigated. Using X-ray experiments with an increase in the thickness of the copper filter low energy detector (LED) and high-energy detector (HED) as the difference between the output signal increases. HED, especially in the size of the output signal decreases with increasing thickness of the copper filter was found.

Image System Using Dual Energy Detector (이중 에너지 검출기를 이용한 영상 시스템)

  • Yeo, Hwa-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.9
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    • pp.3517-3523
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    • 2010
  • Single exposure dual X-ray imaging can be used to separate soft and dense-material images for medical and industrial applications. This study keep focusing baggage inspection system(BIS) specifically. New detector modules for single exposure dual X-ray imaging are consisted of low energy detector (LED) and high energy detector (HED). First, the optimized thickness of copper filter coupled HED to separate low energy and high energy was simulated by the given X-ray energy (140 kVp, 1 mA) using Monte Carlo simulation codes, MCNPX. So as a result of simulation, the copper filter thickness is 0.7 mm. For the design of PIN photodiode, ATLAS device simulation tool was used. 16 channels PIN photodiode of 1.5 mm ${\times}$ 3.2 mm for Dual X-ray imaging detector was fabricated in the process of ETRI. And its dark current and quantum efficiency, terminal capacitance were measured. It was proven that the Lanex Fast B coupled HED were a sufficient candidate to replace the CsI(Tl) commerced in dual X-ray system, since these give a strong signal, overcoming system noise. Finally dual X-ray image was acquired through correction of the LED X-ray Image and the HED X-ray Image.

Energy Spectrum Analysis between Single and Dual Energy Source X-ray Imaging for PCB Non-destructive Test (PCB 비파괴 검사에 있어서 단일 에너지 소스와 이중 에너지 소스의 영상비교를 위한 엑스선 스펙트럼 분석)

  • Kim, Myungsoo;Kim, Giyoon;Lee, Minju;Kang, Dong-uk;Lee, Daehee;Park, Kyeongjin;Kim, Yewon;Kim, Chankyu;Kim, Hyoungtaek;Cho, Gyuseong
    • Journal of Radiation Industry
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    • v.9 no.3
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    • pp.153-159
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    • 2015
  • Reliability of printed circuit board (PCB), which is based on high integrated circuit technology, is having been important because of development of electric and self-driving car. In order to answer these demand, automated X-ray inspection (AXI) is best solution for PCB non-destructive test. PCB is consist of plastic, copper, and, lead, which have low to high Z-number materials. By using dual energy X-ray imaging, these materials can be inspected accurately and efficiently. Dual energy X-ray imaging, that have the advantage of separating materials, however, need some solution such as energy separation method and enhancing efficiency because PCB has materials that has wide range of Z-number. In this work, we found out several things by analysis of X-ray energy spectrum. Separating between lead and combination of plastic and copper is only possible with energy range not dose. On the other hand, separating between plastic and copper is only with dose not energy range. Moreover the copper filter of high energy part of dual X-ray imaging and 50 kVp of low energy part of dual X-ray imaging is best for efficiency.

EFFECTS OF HEAT TREATMENTS ON MICROSTRUCTURES AND MECHANICAL PROPERTIES OF DUAL PHASE ODS STEELS FOR HIGH TEMPERATURE STRENGTH

  • Noh, Sanghoon;Choi, Byoung-Kwon;Han, Chang-Hee;Kang, Suk Hoon;Jang, Jinsung;Jeong, Yong-Hwan;Kim, Tae Kyu
    • Nuclear Engineering and Technology
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    • v.45 no.6
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    • pp.821-826
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    • 2013
  • In the present study, the effects of various heat treatments on the microstructure and mechanical properties of dual phase ODS steels were investigated to enhance the high strength at elevated temperature. Dual phase ODS steels have been designed by the control of ferrite and austenite formers, i.e., Cr, W and Ni, C in Fe-based alloys. The ODS steels were fabricated by mechanical alloying and a hot isostatic pressing process. Heat treatments, including hot rolling-tempering and normalizing-tempering with air- and furnace-cooling, were carefully carried out. It was revealed that the grain size and oxide distributions of the ODS steels can be changed by heat treatment, which significantly affected the strengths at elevated temperature. Therefore, the high temperature strength of dual phase ODS steel can be enhanced by a proper heat treatment process with a good combination of ferrite grains, nano-oxide particles, and grain boundary sliding.

Effect of Improving Accuracy for Effective Atomic number (EAN) and Relative Electron Density (RED) extracted with Polynomial-based Calibration in Dual-energy CT

  • Daehong Kim;Il-Hoon Cho;Mi-jo Lee
    • Journal of the Korean Society of Radiology
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    • v.17 no.7
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    • pp.1017-1023
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    • 2023
  • The purpose of this study was to improve the accuracy of effective atomic number (EAN) and relative electron density (RED) using a polynomial-based calibration method using dual-energy CT images. A phantom composed of 11 tissue-equivalent materials was acquired with dual-energy CT to obtain low- and high-energy images. Using the acquired dual-energy images, the ratio of attenuation of low- and high-energy images for EAN was calibrated based on Stoichiometric, Quadratic, Cubic, Quartic polynomials. EAN and RED were extracted using each calibration method. As a result of the experiment, the average error of EAN using Cubic polynomial-based calibration was minimum. Even in the RED image extracted using EAN, the error of the Cubic polynomial-based RED was minimum. Cubic polynomial-based calibration contributes to improving the accuracy of EAN and RED, and would like to contribute to accurate diagnosis of lesions in CT examinations or quantification of various materials in the human body.