• 대한디지털의료영상학회논문지
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• 제9권2호
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• pp.17-21
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• 2007

The purpose to recognize change of average pixel value of acquisition image by control panel's density and right set up method of speed (sensitivity) and exposure dose(mAs) change that dose in purpose digital flatpanel-detector. X -ray generator DHF-158H2(Hitachi, Japan). Detector CXDI 4OG(Canon, Japan), 12 : 1 grid and exposure ray 135 kVp, 250 mA, 10 ms. focus-detector distance 180 cm and used AEC mode. DICOM reflex analysis program used image J that is digital reflex analysis program that offer in United States America National Health Center(National Institutes of Health : NlH) phantom used chest phantom(Anthromorphic : Flukebrome.medicaI USA). An experiment chest phantom that consist by formation equivalence material use because density value( -3${\sim}$+3) in X-ray control panel and seep that is speed step(slow, medium, fast) each control experimentalize. image analysis reflex neted through an experiment using image j each image compare. These was change in dose according to slow, medium, fast and density's change in an experiment result. According to detector sensitivity and density condition set, dose was relationship dissimilarity 500% from 200%. The dose came highest when is density +3 to slow. and dose more increases gray scale's extent could know that rise. Could know whether how equipment set is important through this experiment. cause of disease which change by digital radiography system forward is thought to increase more, it is considered that suitable education by this and continuous interest about equipment need absolutely.

• 대한방사선치료학회지
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• 제18권2호
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• pp.67-73
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• 2006

목 적: 암 환자의 증가와 함께 방사선 치료기술도 날로 발전하고 있으며 이로인해 치료를 위해 사용되는 영상 및 데이터의 양들도 대폭 증가하는 결과를 가져오게 되어 이들을 저장, 보관, 관리하는데 많은 어려움이 있었다. 이러한 문제점 해결을 위해 과에서 발생되는 모든 영상 및 data의 PACS (picture archiving and communication system)화를 목적으로 의료정보팀의 협조 하에 본 System을 개발, 적용하게 되었다. 대상 및 방법: 본과 방사선치료 관리 시스템(RO-radiation oncology)에서 PACS에 접근할 수 있는 code를 부여한 후 영상은 R&V (Record and Verify: Varis vision, Varian, USA) 시스템 및 planning system에서 export 한다. 이때 DICOM (digital image and communication system) head에 있는 많은 정보들 중에서 필요한 정보를 이용하여 프로그램화 하였다. 결 과: 방사선종양학과에서 발생되는 모든 영상 및 자료 즉, 모의치료, CT, L-gram 영상, structure (normal organ & target volume), DRR (Digital Reconstruction Radiography), 선량 분포도, DVH (dose volume histogram) 등을 PACS에 구현 하였으며 과내 어느 컴퓨터에서도 선명히 영상을 볼 수 있고 출력할 수 있도록 하였다. 결 론: 본 시스템의 개발로 film less화가 가능하게 되어 현상 처리에 관련한 암실 공간과 유지비용이 소멸되었고 film 저장공간 및 film을 찾는데 소요되는 인력과 시간을 포함한 유, 무형의 경제적 비용뿐만 아니라 영상 저장을 위한 별도의 저장장치의 구입도 불필요하게 되었다. 아울러 방사선 치료를 위해 복잡하게 행해졌던 일련의 과정들이 본 시스템을 통해서 현재는 전산 상에서 쉽게 처리할 수 있게 되어 업무에 많은 도움이 될 것으로 사료된다.

• 한국산학기술학회논문지
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• 제11권9호
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• pp.3517-3523
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• 2010

본 논문은 이중 에너지 DR(Digital Radiography) 방식 중, 단일 조사 X-선(single shot X-ray exposure) 장치와 이중 모드 검출기 모듈 (Low Energy Detector & High Energy Detector)을 이용한 이중 X-선 이미징이 가능한 검출기 모듈에 관한 연구이다. 상용 BIS(baggage inspection system)에서 사용되고 있는 X-선 발생장치의 스펙트럼과 이중 모드 검출기에 대한 특징 및 방사선적 특성을 분석하여 새롭게 제안 할 검출기 모듈의 최적 설계 방향을 기술하고 상용화된 용화된 LED 및 HED 검출기와 새롭게 제안 한 검출기 모듈에 대해 전기적, 광학적, 방사선적 특성 실험을 실시하여, 새롭게 제안된 검출기 모듈이 BIS 용도로 사용 가능함을 증명하였다. 새롭게 제안 된 검출기 모듈이 적용된 BIS에 대해, 기본 특성 실험에 대한 X-선 영상을 획득하여 실험 및 분석을 실시하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.146-146
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• 2009

최근에 광도전체와 형광체를 기반으로 평판형 디지털 방사선 검출기의 상업적 발전가능성에 많은 관심을 가지고 있다. 본 연구는 기존의 직접변환방식에 널리 사용되었던 비정질 셀레늄 (amorphous selenium) 기반의 디지털 방사선 검출기보다 높은 전기적신호 및 동작특성을 가지는 물질층을 제작하기 위해 High Purity (99.99%)의 상용화된 $PbI_2$를 특수용매에 담가두었다가 약 1시간동안 Biology 초음파 처리한 후 농축기를 사용하여 건조된 $PbI_2$를 3Roll-milling을 사용하여 미세크기의 Powder를 얻어내었다. 합성된 $PbI_2$ Powder를 PIB(Particle-in-Binder)법을 이용하여 전도성을 가진 ITO(Indium-tin-oxide)코팅된 유리판에 제작된 필름의 상부에 Magnetron sputtering system 을 사용하여 전극을 $1cm{\times}1cm$의 크기로 증착하였다. I-V 테스트를 통하여 X선 조사시 $PbI_2$필름의 Sensitivity, Dark current, SNR(signal-to-noise ratio)을 측정하여 필름의 전기적 검출 특성을 정량적으로 평가하였고 SEM(scanning electron microscope)을 통하여 입자의 크기를 관찰하였다.

• 대한정형도수물리치료학회지
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• 제23권1호
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• pp.73-78
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• 2017

Background: The purpose of this study was to identify the effects of morphological Change of cervical spine to apply to neck retraction and extension regarding the straight deformity of cervical spine. Methods: A 40-year male subject with straight deformity of cervical spine participated in this study. The study subject underwent a cervical lateral radiography on the static position, neck retraction and neck extension on standing. Measurement method were using computer-based digital radiogram on a picture achieving computer system forthe centroid method, Cobb's angle and Jackson's angle. Results: Neck retraction was increased kyphosis on the C2-4 with lordosis on the C5-7. Neck extension was increased lordosis on the C2-7. Conclusions: These findings suggest that neck retraction was increased kyphosis and neck extension was increased lordosis based on the straight deformity of cervical spine. Therefore, we should be consider that neck extension exercise when increased lordosis for the patients of straight deformity of cervical spine.

• The Journal of Advanced Prosthodontics
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• 제7권5호
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• pp.380-385
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• 2015

PURPOSE. The aim of this study was to determine the frequency of significant panoramic radiographic findings and eventual treatment requirements before conventional or implant supported prosthetic treatment in asymptomatic edentulous patients. MATERIALS AND METHODS. A total of 743 asymptomatic edentulous patients were retrospectively evaluated using a digital panoramic system. We analyzed the radiographic findings, including impacted teeth, retained root fragments, foreign bodies, severe atrophy of the posterior maxillary alveolar bone, mucous retention cysts, soft tissue calcifications and radiopaque-radiolucent conditions. RESULTS. Four-hundred-eighty-seven (65.6%) patients had no radiographic finding. A total of 331 radiographic findings were detected in 256 (34%) patients. In 52.9% (n=175) of these conditions, surgical treatment was required before application of implant-supported fixed prosthesis. However, before application of conventional removable prosthesis surgical treatment was required for 6% (n=20) of these conditions. CONCLUSION. The edentulous patients who will have implant placement for implant-supported fixed prosthesis can frequently require additional surgical procedures to eliminate pathological conditions.

• 대한의용생체공학회:의공학회지
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• 제30권6호
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• pp.476-481
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• 2009

The most troublesome artifacts in micro computed tomography (micro-CT) are ring artifacts. The ring artifacts are caused by non-uniform sensitivity and defective pixels of the x-ray detector. These ring artifacts seriously degrade the quality of CT images. In flat-panel detector based micro-CT systems, the ring artifacts are hardly removed by conventional correction methods of digital radiography, because very small difference of detector pixel signals may make severe ring artifacts. This paper presents a novel method to remove ring artifacts in flat-panel detector based micro-CT systems. First, the bad lines of a sinogram which are caused by defective pixels of the detector are identified, and then, they are corrected using a cubic spline interpolation technique. Finally, a ring artifacts free image is reconstructed from the corrected projections. We applied the method to various kinds of objects and found that the image qualities were much improved.

• Imaging Science in Dentistry
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• 제45권2호
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• pp.81-87
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• 2015

Purpose: Contrast, sharpness, enhancement, and density can be changed in digital systems. The important question is to what extent the changes in these variables affect the accuracy of caries detection. Materials and Methods: Forty eight extracted human posterior teeth with healthy or proximal caries surfaces were imaged using a photostimulable phosphor (PSP) sensor. All original images were processed using a six-step method: (1) applying "Sharpening 2" and "Noise Reduction" processing options to the original images; (2) applying the "Magnification 1:3" option to the image obtained in the first step; (3) enhancing the original images by using the "Diagonal/"option; (4) reviewing the changes brought about by the third step of image processing and then, applying "Magnification 1:3"; (5) applying "Sharpening UM" to the original images; and (6) analyzing the changes brought about by the fifth step of image processing, and finally, applying "Magnification 1:3." Three observers evaluated the images. The tooth sections were evaluated histologically as the gold standard. The diagnostic accuracy of the observers was compared using a chi-squared test. Results: The accuracy levels irrespective of the image processing method ranged from weak (18.8%) to intermediate (54.2%), but the highest accuracy was achieved at the sixth image processing step. The overall diagnostic accuracy level showed a statistically significant difference (p=0.0001). Conclusion: This study shows that the application of "Sharpening UM" along with the "Magnification 1:3" processing option improved the diagnostic accuracy and the observer agreement more effectively than the other processing procedures.

• 대한방사선기술학회지:방사선기술과학
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• 제34권1호
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• pp.9-15
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• 2011

본 논문은 현재 임상에서 사용되고 있는 비정질 셀레늄을 이용한 평판형 X선 영상 검출기를 통해 획득된 영상의 변조전달함수(MTF)에 대한 정량적인 값을 도출하였다. 영상 질(quality)의 주요변수인 MTF의 측정은 먼저 test pattern 영상을 획득한 다음, contrast method를 이용하여 공간주파수(spatial frequency)에서의 line profile을 디지털 값으로 획득하여 MTF를 계산하였다. 측정 결과, test pattern 영상에서 3.0 lp/mm에서 36.1%의 MTF 값을 나타냈으며, 종래의 필름 영상보다 약 2배 높은 해상력을 가짐을 알 수 있었다. 측정된 값은 비정질 셀레늄을 이용한 직접방식의 디지털 방사선 검출기의 임상적 사용가치가 충분함을 뒷받침 할 수 있는 기초 자료로서 제공될 수 있을 것으로 판단된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.436-439
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• 2002

Recently, It has performed that the basic research of the photoconductive material and the development and application of the digital radiograph detector which is divided into the direct and indirect method. The objective of this study investigate the effect of the electric characteristic about changing the composition of Arsenic in hybrid detector system for compensating a defect of conventional. We fabricated samples using the amorphous Selenium and Arsenic alloy with various concentrations of the Arsenic{seven step 0.1%, 0.3%, 0.5%, 1%, 1.5%, 3%, 5%). And using EFIRON optical adhesives the formed multi-layer$(Gd_{2}O_{2}S(Eu^{2+}))$ composed phosphor layer. X-ray and light sensitivity was measured to study x-ray response characteritics. As results, highest value was measured as output net charge and SNR were $315.7pC/cm^2/mR$ and 99.4 at 0.3%As doping ratio.