• 대한디지털의료영상학회논문지
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• 제3권1호
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• pp.110-118
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• 1997

Recently, to make a diagnosis of the patient different X-Ray examinations are used. To name a few, Computed Tomography(CT). Magnetic Resonance Image(MRI) Single Photon Emission Computed Tomography(SPET) and Positron Emission Tomography(PET). But diagnosticians face difficulties sometimes when they make a diagnosis with images from those examinations. One of the problem is whether the Lesions of the patient is captured in the image correctly. Another one is whether the images are taken with same angle. in this paper, a study 9 on the method to obtain the hybrid image from the different images to different examinations. The procedure done in this paper is described as future study. Although small errors in position between images would occurred, this method more useful as it does not make patients in convenient. To reconstruct a image, some images are scanned by scanner and stored to personal computer for further image processing with Aldus photostyler program. The method to generate a sharpened image are also described.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.38-41
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• 2002

Mammography is considered the single most important diagnostic tool in the early detection of breast cancer. Today's dedicated mammographic equipment, specially designed x-ray screen/film combinations, coupled with controlled film processing, produces excellent image quality and can detect very low contrast small lesions. In mammography, it is most important to produce consistent high-contrast, high-resolution images at the lowest radiation dose consistent with high image quality. Some of the major technical development milestones that have let to today's high quality in mammographic imaging are reviewed. Both the American College of Radiology Mammography Accreditation Program and the Mammography Quality Standards Act have significant impact on the improvement of the technical quality of mammographic images in the United States and worldwide. A most recent development in digital mammography has opened up avenues for improving diagnosis.

• 대한디지털의료영상학회논문지
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• 제10권1호
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• pp.51-58
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• 2008

Obesity which causing many physical and psychological problems is difficult to treatment. The purpose study was investigate relationships between weight, height, body mass index (BMI) and BMD of according to the low, normal, over, obesity, high group. According to obesity index, each group was divided into five proup. Study subjects were man(n=135) and woman(n=145). We checked the BMD of femoral neck and lumbar spine by using dual energy X-ray bone densitometry. Weight was positively correlation with height (p<0.05) by Pearson's correlation matrix. There was a significant difference in BMD of femoral neck and lumbar spine between four(low, normal, over, obesity) groups except for high obesity groul.

• 대한디지털의료영상학회논문지
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• 제2권1호
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• pp.92-95
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• 1996

Computed Radiography(CR) is a relatively new technology that relies on an image plate(IP) as an alternate x-ray sensor to screen/film. Standard CR cassettes do not have lead foil behind the IP to control scatter radiation. The result of this study indicate that such control is needed. In most screen/film cassettes, that lines the rear of the cassette eliminates back scatter radiation. This study was performed to Investigate on the effects of back scatter in CR images by size of exposure field, distance between the CR cassette and the wall of radiography room. 1. It showed artifacts from hinges and clips located on the back of CR cassette by back scatter radiation. 2. The greater effects of back scatter radiation in CR images was attributed to the greater size of exposure field and the longer distance between the CR cassette and the wall of radiography room.

• 대한전자공학회논문지
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• 제17권3호
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• pp.26-35
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• 1980

모든 디지탈 영상계에서 검출기는 일정한 크기를 가지며, 이에 의해 영상은 흐려지고 공간분해능은 저하된다. 이제까지는 검출기 크기를 줄임으로써, 즉 검출기 수효를 증가시킴으로써 이 문제를 해결해 왔다. 본논문에서는 광학에서 사용한 방법에 의한 공간분해능 향상을 공간 및 주파수 대역에서 시도하였다. 또한 이 방법을 CT(전산화 단층 영상 처리기)에 응용하였으며 검출기 수효를 증가하지 않고서도 공간분해능이 매우 향상됨을 알 수 있었다. 이 방법에 대한 전본이론 및 simulation결과를 정리하였다.

• 대한기계학회논문집B
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• 제33권1호
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• pp.1-8
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• 2009

Recently microscale biofluid flows have been receiving large attention in various research areas. However, most conventional imaging techniques are unsatisfactory due to difficulties encountered in the visualization of microscale biological flows. Recent advances in optics and digital image processing techniques have made it possible to develop several advanced micro-PIV/PTV techniques. They can be used to get quantitative velocity field information of various biofluid flows from visualized images of tracer particles. In this paper, as new advanced micro-PIV techniques suitable for biofluid flow analysis, the basic principle and typical applications of the time-resolved micro-PIV and X-ray micro-PIV methods are explained. As a 3D velocity field measurement technique for measuring microscale flows, holographic micro-PTV method is introduced. These advanced PIV/PTV techniques can be used to reveal the basic physics of various microscale biological flows and will play an important role in visualizing veiled biofluid flow phenomena, for which conventional methods have many difficulties to analyze.

• 한국방사선학회논문지
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• 제5권5호
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• pp.283-287
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• 2011

본 연구는 고해상도 디지털 X선 영상 검출기 적용을 위해 미세 $Gd_2O_2S$:Tb 형광체 분말을 저온 액상법을 이용하여 합성하였다. 제조된 형광체 분말을 이용하여 입자침전법을 이용하여 형광체 필름을 제작하여 발광특성을 조사하였다. 측정결과, Tb 첨가농도에 따른 상대적인 발광량 측정결과 5 wt%의 첨가농도에서 가장 높은 발광효율을 보였으며, 첨가농도가 증가할수록 소광현상에 의한 발광강도가 급격히 감소하는 경향을 보였다. 또한 270 ${\mu}m$ 두께의 $Gd_2O_2S$:Tb에서 2945 pC/$cm^2$/mR의 발광 강도를 가졌으며, 발광 강도가 거의 포화되는 것을 관찰할 수 있었다. 끝으로 제조된 형광체의 영상획득 성능을 평가하기 위해 상용화된 CMOS 센서를 이용하여 X선 영상을 획득하여 MTF, NPS를 측정하여 DQE 평가를 수행하였다. 측정결과, DQE(0)의 값은 37%로 다소 낮은 값을 보였다. 향후 필름 제조 공정상의 문제점을 해결한다면, DQE를 개선할 수 있을 것으며, 고해상도 의료 방사선 영상 시스템 적용에 유용하게 적용 가능할 것으로 판단된다.

• Imaging Science in Dentistry
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• 제31권1호
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• pp.17-22
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• 2001

Purpose: To compare the film density of Insight dental X-ray film (Eastman Kodak Co., Rochester, NY, USA) with that of Ektaspeed Plus film (Eastman Kodak) under manual and automatic processing conditions. Materials and Methods : Insight and Ektaspeed Plus films were exposed at three different exposure conditions with an aluminum step wedge on the films under the three different exposure times. The exposed films were processed by both manual and automatic ways. The Base plus fog density and the optical density made by exposing step wedge were calculated using a digital densitometer (model 07-443, Victoreen Inc, Cleveland, Ohio, USA). The optical densities of the Insight and Ektaspeed film versus thickness of alumimun wedge at the same exposure time were plotted on the graphs. Statistical analyses were applied for comparing the optical densities of the two films. Results: The film density of both Insight films and Ektaspeed Plus films under automatic processing condition was significantly higher over the manual processing. The film density of Insight films was significantly higher than that of Ektaspeed Plus films on both automatic and manual processing conditions. Conclusion: The radiation exposure time can be reduced when using Insight over Ektaspeed Plus film. To take the full advantage of reducing exposure time, Insight film should be processed automatically.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.420-423
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• 2002

In recent years, there has been keen interest in developing f1at panel detectors for all modalities of radiology, including gerneral radiology, fluoroscopy(angiography and cardiology), electronic portal imaging, and mammography. In this paper, we report the new hybrid x-ray detector consisted of CsI(Tl) photoemission layer and a-Se photoconductor layer to resolve conventional x-ray detector such as the direct detector using a-Se and the indirect detector using CsI(Tl)/a-Si. To design the structure of CsI(Tl)/a-Se detector, the penetrated energy spectrum and absorption fraction was estimated using MCNP 4C code. Experimental results showed that the absorption fraction of $500{\mu}m-Se$ film and $150{\mu}m-CsI\left(Tl \right)/a-Se\left( 30{\mu}m \right)$ film is 70% at 70 kVp. The absorption energy is 90% at $350{\mu}m-CsI(Tl)$.

• 한국콘텐츠학회논문지
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• 제16권12호
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• pp.70-77
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• 2016

본 연구에서는 거머리의 미세한 해부구조를 3차원적으로 분석 가능한 방사광의 경 엑스선 이미징을 통하여 객관적 분석법 및 생체모사기술 구축을 위한 기초자료를 구축하고자 하였다. 우리는 방사광을 이용하여 거머리의 미세 구조영상을 얻을 수 있었고, 3차원적인 해부학적 분석이 가능함을 확인하였다. 또한 방사광을 통해 얻은 데이터는 내부구조의 미세조직까지 관찰 가능하기 때문에 성분 분석 및 생리적, 기능적 측면으로도 연구의 토대가 될 것으로 사료된다. 더 나아가 추후 거머리로부터 생체모사기술 연구 분야 등에 기여할 수 있을 것이라 기대된다.