• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
• /
• pp.334-343
• /
• 1996

Quality evaluation for food and agricultural products have always been one of the most elusive problems associated with the handling , processing and marketing in a food plant production. In order to detect physical foreign materials in food and agricultural products, non-destructive techniques have been developed for many years. Application of X-ray system to detect physical foreign materials in food and agricultural products could be considered to be a high potential method. Especially , it is impossible to detect internal physical foreign materials by visual inspections. In this study, it was tried to be applied for two different X-ray devices. Soft X-ray system with CdTe sensor and X-ray CT scanner were evaluated for advantage of the detection of non-meltallic foreign materials in food and agricultural products . Though the soft X-ray is not a high energy radiation, it is possible to detect small different density in a material. The CdTe sensor has a high resolution for t e soft X-ray energy region. The density characteristics of foods and foreign material were expressed region. The density characteristics of foods and foreign materials were expressed as a soft X-ray energy spectrum. The energy spectrum was analyzed by a personal computer with a multi-channel analyzer. X-ray CT scanner can provide visual image and analyze by three dimensional information inside food and agricultural products. The X-ray CT scanner using as a medical equipment was used to detect a foreign material. The density characteristics of food and foreign materials in food were tried to be detected by the threshold value on the basis of the CT numbers. The soft X-ray absorption characteristics for acrylin plates and distilled water were obtained and could be found the possibility of detecting a small physical foreign materials such as a plastic wrapping film , a stone and grasshopper in food and agricultural products.

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

• 한국방사선학회논문지
• /
• 제13권4호
• /
• pp.517-522
• /
• 2019

이 연구의 목적은 AAPM CT 성능 팬텀 안에 있는 CT 수 교정 삽입부의 CT 슬라이스 영상들을 사용하여 CT X-선 빔들의 유효에너지를 결정하는데 있다. AAPM CT 성능 팬텀의 CT 수 교정 삽입부는 80, 100, 120 kVp X-선 빔에 대하여 CT 스캐너로 5번 스캔되었다. 각 핀의 CT 수는 각각의 CT 슬라이스 영상에 대하여 측정되었다. 상관계수들은 각 핀에서 측정된 CT 수의 평균값과 미국표준기술연구소의 자료로부터 계산된 다른 광자에너지 하에 선감약계수를 선형정합하여 얻었다. 얻어진 상관계수의 최대값에 대응하는 광자에너지는 유효에너지로 결정하였다. 결과로서, 유효에너지는 80, 100, 120 kVp X-선 빔들에 대하여 각각 56, 62, 66~67 keV이다.

• Journal of Acupuncture Research
• /
• 제19권6호
• /
• pp.125-133
• /
• 2002

Objective : This study was designed to analyze the of correlation between narrowing disc space of lumbar X-ray and HIVD of L-spine CT in lumbosacral strain patients. Methods : 63 cases of lumbosacral strain patients who visited Bul-kyooh Oriental Hospital from June 13, 2000 to August 9, 2001 were selected. We performed the radiography by lumbar X-ray and L-spine CT for all cases. Results : 28 of 63 cases revealed narrowing disc space in Lumbar X-ray and these 28 cases were diagnosed as HIVD in L-spine CT at all. 35 of 63 cases revealed normal in Lumbar X-ray and 13 of these 35 cases were diagnosed as HIVD in L-spine CT. Conclusions : We found that narrowing disc space in lumbar X-ray has significant relevance to HIVD in L-spine CT(P-value = 0.001). For accurate diagnosis and treatment of lumbosacral strain patients. combination of clinical symptoms, physical examination and radiography of X-ray and HIVD is needed.

• 대한의용생체공학회:의공학회지
• /
• 제29권5호
• /
• pp.364-370
• /
• 2008

Recent development in large area flat-panel x-ray detector technology enables clinical application of digital tomosyntesis. Unlike conventional motion tomography using x-ray films, flat-panel x-ray detectors provide projection images in digital formats so that tomographic images can be synthesized in a more flexible way. For the digital tomosynthesis, precise movements of the x-ray source and the x-ray detector with respect to a fulcrum point are necessary. In this study, we apply the digital tomosynthesis technique to the flat-panel detector based micro-CT in which the flat-panel detector and the x-ray source rotate together on a circular arc. The experimental results suggest that flat-panel detector based 3D CTs can be used for digital tomosynthesis in the clinical environment.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2012년도 춘계학술대회 논문집
• /
• pp.879-880
• /
• 2012

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2010년도 추계 학술발표회
• /
• pp.392-403
• /
• 2010

In this study, a new methodology by using the X-ray CT scan is proposed for estimating void ratio of very fine clayey soil. Since the particle size of the clay is too fine to calculate the volume of void inside the clays, CT scanning tests with a number of clay specimens that were artificially set to have various designated void ratios have been carried out. From the tests, a relationship between the CT values and void ratios is given to be used for estimating the invisible void ratio of very fine clay from a representative CT value scanned. The linear relationship was able to be acquired finally. It is expected that micro X-ray CT scanning can be capable of capturing the void ratio of very fine soils without any errors inherent in the conventional specific gravity tests.

• 전기전자학회논문지
• /
• 제23권3호
• /
• pp.768-776
• /
• 2019

4차 산업 혁명 시대를 맞이하여, 최근 기계, 전자 부품의 설계, 제조, 검사에 첨단 IT 기술을 융합하는 사례가 늘고 있다. 본 연구에서는 최근에 구축된 산업용 X-ray CT(computed tomography)를 사용한 산업용 부품의 검사에 대한 최신기술에 대해서 다룬다. 먼저 구축된 첨단의 최신 산업용 CT의 구조와 원리에 대해서 설명하며, 이러한 장비의 역할과 성능에 대해서 설명하고, 본 장비의 분석기법을 보완하기 위한 새로운 연구기반의 구축에 대해서 다룬다. 특히 장비의 출력데이터를 Matlab과 같은 범용 연구 툴로 전송하여 연구를 진행할 수 있는 기반을 구축하며, 이를 토대로 기존의 운용 소프트웨어가 제공하지 못했던 보조적인 3D user interface와 3차원 영상처리를 위한 플랫폼을 구축하는 연구를 진행 하였다. 산업용 3차원 X-ray는 아직 소개 된지 얼마 되지 않은 첨단의 고가의 장비로서 이를 활용할 연구의 종류와 내용이 매우 풍부한 주제로, 이러한 기초적인 연구기반은 추후의 보다 발전적인 연구를 위한 아주 유용한 토대가 될 것으로 판단된다.

• 한국의학물리학회:학술대회논문집
• /
• 한국의학물리학회 2002년도 Proceedings
• /
• pp.464-467
• /
• 2002

We propose the use of visible scintillation light for monitoring the X-ray CT in the gantry of a diagnostic CT for its performance test and maintenance works. We placed a disk of bare plastic scintillator disk in the gantry opening area of a helical X-ray CT. When we operated the CT, we could observe the emission of blue scintillation light from the scintillator in a dark room. Visible light was identified under all scanning conditions of diagnostic uses. As a result, we observed the direction and the spread of the incident X-ray in the scintillator. We also observed the change of the part of the scintillator where visible light was generated, and the move that took place associating with the rotation of the X-ray tube during one CT scan. On the basis of the observation, we examined the usefulness of the visible scintillation light as a convenient performance-evaluating tool as well as a maintenance tool of the CT.

• 대한의용생체공학회:의공학회지
• /
• 제28권1호
• /
• pp.95-101
• /
• 2007

Recently, small-animal imaging technology has been rapidly developed for longitudinal screening of laboratory animals such as mice and rats. One of newly developed imaging modalities for small animals is an x-ray micro-CT (computed tomography). We have developed two types of x-ray micro-CT systems for small animal imaging. Both systems use flat-panel x-ray detectors and micro-focus x-ray sources to obtain high spatial resolution of $10{\mu}m$. In spite of the relatively large field-of-view (FOV) of flat-panel detectors, the spatial resolution in the whole-body imaging of rats should be sacrificed down to the order of $100{\mu}m$ due to the limited number of x-ray detector pixels. Though the spatial resolution of cone-beam CTs can be improved by moving an object toward an x-ray source, the FOV should be reduced and the object size is also limited. To overcome the limitation of the object size and resolution, we introduce zoom-in micro-tomography for high-resolution imaging of a local region-of-interest (ROI) inside a large object. For zoom-in imaging, we use two kinds of projection data in combination, one from a full FOV scan of the whole object and the other from a limited FOV scan of the ROI. Both of our micro-CT systems have zoom-in micro-tomography capability. One of both is a micro-CT system with a fixed gantry mounted with an x-ray source and a detector. An imaged object is laid on a rotating table between a source and a detector. The other micro-CT system has a rotating gantry with a fixed object table, which makes whole scans without rotating an object. In this paper, we report the results of in vivo small animal study using the developed micro-CTs.