• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.969-974
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• 2022

In order to maximize dynamic range and to minimize image lag in digital X-ray imaging, diminishing residual parasitic capacitance in photodiode in pixels is critically necessary. These requirements are more specifically requested in dynamic X-ray imaging with high frame rate and low image lag for industrial 2D/3D automated X-ray inspection and medical CT imaging. This study proposes duoPIX^TM X-ray imaging sensor for the first time that is composed of reset thin film transistor, readout thin film transistor and photodiode in a pixel. To verify duoPIX^TM X-ray imaging sensor, designing duoPIX^TM pixel and imaging sensor was executed first then X-ray imaging sensor with 105 ㎛ pixel pitch, 347 mm × 430 mm imaging area and 3300 × 4096 pixels (13.5M pixels) was fabricated and evaluated by using module tester and image viewer specifically for duoPIX^TM imaging sensor.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.179-186
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• 2017

Purpose of this study is present the normal range of cardiac size and cardiothoracic ratio according to patient position(chest PA and AP) and age of Korean adult male on digital chest X - ray, And to propose a mutually compatible conversion rate. 1,024 males were eligible for this study, among 1,300 normal chest patients who underwent chest PA and low-dose CT examinations on the same day at the 'S' Hospital Health Examination Center in Seoul From January to December 2014. CS and CTR were measured by Danzer (1919). The mean difference between CS and CTR was statistically significant (p<0.01) in Chest PA (CS 135.48 mm, CTR 43.99%) and Chest AP image (CS 155.96 mm, CTR 51.75%). There was no statistically significant difference between left and right heart in chest PA and AP images (p>0.05). CS showed statistically significant difference between Chest PA (p>0. 05) and Chest AP (p<0.05). The thorax size and CTR were statistically significant (p<0.01) in both age and chest PA and AP. Result of this study, On Chest AP image CS was magnified 15%, CTR was magnified 17% compare with Chest PA image. CS and CTR were about 10% difference by changing posture at all ages.

• Journal of the Korean Society of Radiology
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• v.11 no.1
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• pp.55-61
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• 2017

There are no recommended test conditions for digital photography in Chest PA examinations. However, each company recommends shooting examinations of the high voltage applied to the previous analog examination. The condition that satisfies the value of 200 ~ 800 which is the recommended Exposure Index value recommended by Philips was selected, and the dose was evaluated by Monte Carlo simulation, and the SNR and CNR were compared. As a result, it was possible to reduce the effective dose up to 77% by controlling the tube voltage, tube current, and additional filter, not the conventional high voltage imaging method. Although there were some differences according to the test conditions, the image evaluation results were similar to the images. We will compare the exposure dose according to changes in tube voltage, tube current, and additional filter at the digital chest radiograph and evaluate the image quality of the image to propose optimal conditions.

• Journal of Periodontal and Implant Science
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• v.31 no.4
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• pp.777-785
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• 2001

치주질환이 진행되는 동안이나 치주처치후 치유되는 과정에서 치조골의 변화가 야기되는데 방사선 사진은 치조골 변화를 감지하는 유일한 비외과적인 방법이다. 미묘한 치조골 변화의 진단은 치료시나 유지관리기 환자의 평가시 중요한 바, 최근에는 규격화시킨 디지털 영상을 이용하여 정량적인 골변화 측정이 가능하게 되었다. 본 연구의 목적은 중등도의 치주질환을 지닌 환자에서 국소마취하에 초기 치주처치를 시행한후 참조체와 함께 구내 방사선 사진을 촬영하고 디지털화 한 다음 참조체 당량치를 이용하여 치조골의 밀도변화를 평가하기 위한 것이다. 이 연구를 위하여 치주질환에 이환된 환자 5명(남자 3명, 여자 2명 : 평균 47.4세)에서 탐침깊이가 5㎜ 이상이고 골내낭이 있는 제 $1{\cdot}2$ 소구치, 제 $1{\cdot}2$ 대구치 40개(상악 24개, 하악 16개)를 대상으로 구강위생교육과 치석제거술, 치근면활택술을 시행하였다. 임상지수는 술전과 술후 8주째에 측정하였고, 방사선 사진은 술전, 술후 2주, 4주, 6주, 8주째에 촬영하였고, 구리 스텝웨지를 사용하여 규격화 하였다. 촬영된 영상은 NIH image program(U.S.A)에 의해 분석되어졌고 이들 자료를 통해 다음과 같은 결과를 얻었다. 1. 치조골의 밀도는 초기치료후 2주째 까지는 감소된 양상을 보이다가 4주 이후로는 점차적으로 증가하는 양상을 보였다. 2. 치조골의 밀도는 초기치료전과 비교시 초기치료수 6주째와 8주째에서 유의한 차이를 보였다.(p<0.01) 3. 상하악 간의 치조골 밀도는 유의한 차이를 보이지 않았다(p>0.05). 이상과 같은 결과를 통하여 볼때 초기 치주처치만으로도 치조골의 밀도가 증가됨을 확인할 수 있었다.

• Journal of Conservation Science
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• v.37 no.3
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• pp.220-231
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• 2021

The use of digital copies of film-based analog images and the introduction of digital radiographic imaging systems using image plates gradually replace the non-destructive radiationirradiation method of Cultural Heritage. The quality of images obtained from this technique is affected by conditions such as tube voltage, tube current, and exposure time, type of image acquisition medium, distance of the artifacts from the image acquisition medium, and thickness of artifacts. In this study, we evaluated the grayscale image obtained using GE's Computed Radiograhpy (CR) imaging system, the transmission characteristics of the X-ray source for each tree type (pine, chestnut, sawtooth oak, ginkgo) used in wooden Cultural Heritage, and the signal-to-noise ratio (SNR) and contrast. The GE's CR imaging were analyzed using the Duplex wire image quality indicator, line-pair gauges.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.207-227
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• 2001

스프린트는 치주처지료에서 부가적 처치법으로 널리 사용되고 있으며, 한편, 디지털 공제 활영술은 기존방사선촬영술의 한계점을 극복하기 위해 기발된 새로운 방법이다. 이번 연구에서는 치근활택술 단독시행시와 스피린트 병행 처치시의 효과를 임상적, 방사선학적으로 비교하였다. 중정도의 성인성 치주염을 가진 20명의 환자를 대상으로 하되 10명은 치근활택술 단독으로, 나머지 10명은 스프린트 병행처치로 처치하였다. 임상적, 방사선학적인 평가는 처치전, 처치후 6개월에 행하고, 임상적 평가의 경우 3개월에 추가로 실시하였다. 이번 연구에서 사용된 임상 지수로는 치태지수, 치은지수, 치은퇴축, 치주낭깊이, 임상부착수준, 임상부착증가, 탐침시출혈, 치아동요도 등이며, 방사선학적 평가는 기존 방사선촬영술에 의한 방법과 디지털 공제촬영수렝 의한 방법으로 행하였다. 디지털 공제 촬영술에 의한 평가시, 영상은 Digora 프로그램에 의해 획득하고 Emago 프로그램으로 처리 하여 다음과 같은 결론을 얻었다. 1. 처치후 3개월에 치태지수, 치은지수, 치은퇴축, 치주낭깊이, 임상적부착수준, 탐침시 출혈 등의 임상지수들이 변했으며, 특히 이러한 변화는 치주낭깊이, 치은퇴축, 탐침시출혈에서 유의성이 있었다. ( p<0.05 ) 그러나 두군간 차이는 인정되지 않았다. ( p>0.05 ) 2. 처치후 6개월에도 치태지수, 치은지수, 치은퇴축, 치주낭깊이, 임상적부착수준, 탐침시출혈, 치아동요도 등의 임상지수들이 변했으며, 특히 이러한 변화는 치주낭깊이, 치은퇴축, 탐침시출혈, 치태지수, 치아동요도에서 유의성이 있었다. ( p<0.05 ) 그러나 두 군간 차이는 인정되지 않았다. ( p>0.05 ) 3. 켄달 상관분석시, 임상적 평가와 기존 방사선 촬영술에 의한 평가사이의 관련성을 낮았으며 거의 0에 가까운 수치를 보였으며 (r=0.110, p=0.639 ) 임상적 평가와 디지털 공제 방사선 촬영술에 의한 평가사이에서 약간 높은 관련성을 보였다. ( r=0.257, p=0.315 ) 즉 치주치료후의 골변화는 디지털 공제 방사선 촬영술에 의한 평가시 기존 방사선 사진보다 임상적 부착증가와 더욱 긴밀한 관련성을 보여준다. 이상의 결과로 볼 때, 스프린팅 처치는 치주 치료에 있어 치근활택술에 부가적 표과를 제공하지 못한다.

• Journal of Korea Multimedia Society
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• v.8 no.4
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• pp.482-491
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• 2005

In this paper, we proposed the microcalcification detection algorithm which is based on wavelet transform and automatic thresholding method in the X-ray mammographic images. Digital X-ray imaging system is essential equipment in the field diagnosis and is widely used in the various fields such as chest, fracture of a bone, and dental correction. Especially, digital X-ray mammographic imaging is known as the most important method to diagnose the breast cancer, many researches to develop the imaging system are processing in country. In this paper, we proposed a microcalcifications detection algorithm necessary in the early phase of breast cancer diagnosis and showed that a algorithm could effectively detect microcalfication and could aid diagnosis-radiologist.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.645-650
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• 2018

This research aims at measuring images density of according to DAP(dose area product), and suggesting the need to quality control of exposure dose. When tube voltage was fixed as 80 kVp and tube current was set as 1, 25, 50, 80, and 100 mAs, with the increase of DAP from 25 mAs to 50 mAs, the dose also rose 1.88 times as much as before, and with the increase from 50 mAs to 100 mAs, it got 2.05 time higher than before. However, the images density obtained as film grew as much as 48% with the increase from 25 mAs to 50 mAs, and 29% with the increase from 50 mAs to 100 mAs. In addition, it has been found out that the higher the DR images density got from 25 mAs to 50 mAs, the bigger it became by 12%, and that it got bigger by 30% with the increase from 50 mAs to 100 mAs. In other words, the differences in the image density by the increase of the dose with the digital imaging equipment in a proper condition was proved to be less than in the film images. Based on the results of this research, medical institutions using a digital imaging equipment are expected to be able to reduce exposure dose of each region of interest than now through the quality control of radiation dose.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.30-41
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• 2011

In order to obtain more clear x-ray images, an antiscatter grid, which can absorb the scattered rays, is employed. In the high-resolution direct digital radiography, however, the artifacts due to the grid are visible. In this paper, within the methods of obtaining x-ray digital images by employing the rotated grids for the facility of grid artifact reduction, the previous work, where the frequencies of the artifact components on the boundary, is further analyzed and extended, and a min-max optimization for a given grid density is proposed. For practical grid densities, appropriate grid angles are provided and a grid artifact reduction algorithm is proposed for the appropriate grid angles. The proposed algorithm is tested for real x-ray digital images with a comparison, and can remove the grid artifacts while maintaining the resolution of the original image.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.131-139
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• 2023

In this study, we are purposed to find the educational effect of practical training using a 3D printed structure-based blind box on multidimensional radiographic image interpretation. The subjects were 83 (male: 49, female: 34) 2nd year radiological science students who participated in the digital medical imaging practice that was conducted for 3 years from 2020 to 2022. The learning method used 3D printing technology to print out the inside structure of the blind box designed by itself. After taking X-rays 3 times (x, y, z axis), the structure images in the blind box were analyzed for each small group. We made the 3D structure that was self-made with clay based on our 2D radiographic images. After taking X-rays of the 3D structure, it was compared whether it matches the structural image of the blind box. The educational effect for the practical training surveyed class faithfulness, radiographic image interpretation ability (attenuation concept, contrast concept, windowing concept, 3-dimensional reading ability), class satisfaction (interest, external recommendation, immersion) on a 5-point Likert scale as an anonymous student self-writing method. As a result, all evaluation items had high positive effects without significant differences between males and females. Practical education using blind boxes is a meaningful example of radiology education technology using 3D printing technology, and it is expected to be used as content to improve students' problem-solving skills and increase satisfaction with major subjects.