• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.412-414
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• 2003

This paper is about research of scintillator layer, which is used for Hybrid method to increase electric signals in a-Se, the material of Direct method. In case of the thermal evaporation, CsI has column structure which is an disadvantage as scintillator. But it decreases scattering of incident X-ray, has better Light output intensity than other scintillation materials. CsI was made by Thermal evaporation. The Doping material, Na, 0.1, 0.3, 0.5, 0.7g were added in each sample. Analysis of absorbed wavelength, PL(Photoluminescence), Light output intensity, SEM, and XRD analysis were performed to analyze optical characteristics. Doping rate of CsI:Na to use as scintillation layer in a-Se based detector could be optimized.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1113-1116
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• 2004

This paper presents the method for analyzing surface temperature of Electric incoming Apparatus. For the experiment, the surface temperature of electric power apparatus was measured and analyzed by using a infrared thermal imaging system. Surface Discharges(SD) have very complex characteristics of discharge patterns, therefore it requires the development of precise analysis methods. recently, studies on infrared thermal imaging system are carried out to analyze temperature distribution of power equipments through condition diagnosis and to diagnose the degradation of power equipments. The changes in suface temperature was measured by using the infrared thermal imaging system under hot line condition. The system was set up based on the diagnostic method of the electric incoming apparatus.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.938-940
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• 2014

This paper discusses a coherence-gated three-dimensional imaging system based on photorefractive holography, which was applied to imaging through turbid media with a view to developing biomedical instrumentation. A rapid response photorefractive device doped with 2,4,7-trinitro-9-fluorenylidene malononitrile was used to generate the hologram grating. The estimated depth resolution was $20{\mu}m$, which corresponds to the coherence length of the light source. In this coherence imaging system, tomographic imaging of a 3-dimensional object composed of a $50{\mu}m$ thick cylindrical layer was achieved. The proposed coherence imaging system using an organic photorefractive material can be used as an optical tomography system for biological applications.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.380-383
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• 2003

The purpose of this study is to develope prototype EPID system and improve image quality of radiation therapy field imaging system using CCD camera. For this research we used Linac(Clinac 4/100), Copper metal plate, $Gd_2O_2S_2$ phosphor and CCD camera(Photronic). In this study we find best thickness of buil-up metal plate and acquired projection image of humanoid head phantom. Also we enhanced raw image data using superposition and histogram stretching method. Through the thickness optimized of metal plate and image processing, we confirmed of an improved image quality of an EPID system using CCD camera. As result, highest quality image was acquired at 1mm thickness of Copper metal plate and improved image quality by image processing methods.

• 대한디지털의료영상학회논문지
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• 제10권2호
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• pp.39-49
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• 2008

Extravasation of contrast material is a not infrequent complication of enhanced imaging studies and large volume extravasation may result in severe damage. Subcutaneous extravasation of the radiographic contrast medium is one of the complications of the contrast medium-enhanced procedures. Automated power injectors enable the contrast material to be delivered at a uniform high-flow-rate and as a nonfragmented bolus, and this is essential for many contrast material enhanced CT(computed tomography) applications. The major risk associated with the use of automated power injectors is the well known complication of contrast material extravasation at the injection site. Automated injection of CT contrast material can produce the compartment syndrome. Selection of the nonionic contrast material after careful evaluation of the intravenous administration site and monitoring of the patient during the use of a mechanical power injector may help minimize or prevent extravasation injuries. Early identification is important and conservative management is effective in most cases. Prevention of these injuries with the education of radiological technologist remains the ultimate aim.

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1259-1265
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• 2021

In the present study, a large-area hybrid gamma imaging system was designed by adopting coded aperture imaging on the basis of a large-area Compton camera to achieve high imaging performance throughout a broad energy range (100-2000 keV). The system consisting of a tungsten coded aperture mask and monolithic NaI(Tl) scintillation detectors was designed through a series of Geant4 Monte Carlo radiation transport simulations, in consideration of both imaging sensitivity and imaging resolution. Then, the performance of the system was predicted by Geant4 Monte Carlo simulations for point sources under various conditions. Our simulation results show that the system provides very high imaging sensitivity (i.e., low values for minimum detectable activity, MDA), thus allowing for imaging of low-activity sources at distances impossible with coded aperture imaging or Compton imaging alone. In addition, the imaging resolution of the system was found to be high (i.e., around 6°) over the broad energy range of 59.5-1330 keV.

• Journal of electromagnetic engineering and science
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• 제12권1호
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• pp.128-134
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• 2012

In this manuscript, we consider electromagnetic imaging of perfectly conducting cracks completely hidden in a homogeneous material via boundary measurements. For this purpose, we carefully derive a topological derivative formula based on the asymptotic expansion formula for the existence of a perfectly conducting inclusion with a small radius. With this, we introduce a topological derivative based imaging algorithm and discuss its properties. Various numerical examples with noisy data show the effectiveness and limitations of the imaging algorithm.

• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2011년도 추계 학술발표회 및 심포지엄
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• pp.116-117
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• 2011

• Applied Microscopy
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• 제38권3호
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• pp.185-193
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• 2008

전자 빔 조사 민감 물질인 gibbsite(${\gamma}-Al(OH)_3$)의 전자 빔 조사 상전이 연구에서 전자회절 자료의 기록에 대한 imaging plate와 필름의 기록 특성을 실험적으로 비교하였다. Imaging plate는 극단적으로 낮은 전자 강도와 높은 전자 강도를 동시 기록하기에 충분한 선형 dynamic range를 갖기 때문에, 매우 낮은 전자 조사 조건(${\leq}0.1\;e^-/{\mu}m^2$)에서 전자 회절 자료를 기록할 때 필름에 비해 회절 자료의 spatial frequency 범위가 두 배 이상 확장되었다. 심지어 이미 기록 포화된 투과 빔 주위의 신호 정보 레벨을 세분화하는 데에도 훨씬 우수한 분해 성능을 나타내었다. 따라서 본 연구 결과는 imaging plate가 극단적으로 낮은 전자 강도 기록이 필요한 전자 빔 조사 민감 물질이나 cryo-biological 시편들의 구조 연구 관점에서 가장 적절한 기록 매체임을 나타낸다.

• Korean Journal of Radiology
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• 제22권1호
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• pp.86-96
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• 2021

CT is a diagnostic tool with many clinical applications. The CT voxel intensity is related to the magnitude of X-ray attenuation, which is not unique to a given material. Substances with different chemical compositions can be represented by similar voxel intensities, making the classification of different tissue types challenging. Compared to the conventional single-energy CT, spectral CT is an emerging technology offering superior material differentiation, which is achieved using the energy dependence of X-ray attenuation in any material. A specific form of spectral CT is dual-energy imaging, in which an additional X-ray attenuation measurement is obtained at a second X-ray energy. Dual-energy CT has been implemented in clinical settings with great success. This paper reviews the theoretical basis and practical implementation of spectral/dual-energy CT.