• Journal of Biomedical Engineering Research
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• v.8 no.2
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• pp.171-176
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• 1987

Wiener filtering method was applied to the dual energy imaging procedure in digital radiography(D.R.). A linear scanning photodiode arrays with 1024 elements(0.6mm H 1.3mm pixel size) were used to obtain chest images in 0.7 sec. For high energy image acquisition, X-ray tube was set at 140KVp, 100mA with a rare-earth phosphor screen. Low energy image was obtained with X-ray tube setting at 70KVp, 150mA. These measured dual energy images are represented in the vector matrix notation as a linear discrete model including the additive random noise. Then, the object images are restored in the minimum mean square error sense using Wiener filtering method in the transformed domain. These restored high and low energy images are used for computation of the basis image decomposition. Then the basis images are linearly combined to produce bone or tissue selective images. Using this process, we could improve the signal to noise ratio characteristics in the material selective images.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.682-684
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• 2005

현재 설러 병원에서 PACS 시스템을 도입해 유용하게 사용하고 있다. 병원 진료에서 방사선 영상 정보는 중요한 위치를 차지한다. 방사선 영상은 관전압(KVP)과 관전류(mAs)로 방사선량을 조절한 후 인체에 조사하여 얻게 되는데, KVP와 mAs, 인체의 두께에 따라 영상의 질이 변하게 된다. 이와 같이 장비에서 촬영된 영상은 판독을 거처 진료에 이용되고 일정한 시간이 지나면 압축하여 보관하게 되는데, 압축율을 높게 적용할수록 저장장치에 대한 경제적인 효과는 크다. 이에 저자는 1) CR, DR 촬영 조건별 흉부 영상을 얻어 JPEG 2000 압축방식을 적용해 촬영조건이 압축영상에 미치는 영향을 평가하였고, 2) MOS(Mean opinion score) 평가를 통해 영상판독에 영향을 주지 않는 유효 압축율을 제시하였다.

• Journal of the Korean Society of Radiology
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• v.7 no.3
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• pp.181-189
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• 2013

The optimum exposure parameters are found when examined using the automatic mode in FFDM. improve the image quality by applying denoising algorithm and propose methods to reduce AGD(Average Grandular Dose) a patient can receive. For the experiment, Nuclear Associates Model 18-222 phantom was the used, and the entrance dose and AGD were measured. And then, Signal, Noise, SNR and FOM(Figure of Merit) were measured, compared and analyzed image denoising before and after. As the experiment result, first, SNR was the highest at Mo/Mo 23kVp and W/Rh 35kvp was the lowest for the average glandular dose. It showed to use 28kVp of W/Rh to be the best through the result of FOM. SNR was the highest at Mo/Mo 23kVp(image denoising), and it showed to W/Rh and 28kVp to be the best in the FOM result which AGD was considered at the same time. By the image denoising, it is possible to reduce noise while maintain important information in the image.

• Journal of radiological science and technology
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• v.2 no.1
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• pp.31-35
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• 1979

A thorax is consisted of a heart, great vesseles, lungs, ribs, sternum and thoracic spine etc. The quality of chest radiogram is very important in order to find out abnormality in the lung field. The image has two major characteristics; density and contrast which directly influence the diagnostic quality of the roentgenogram. It is very hard to make excellent film image in the lung field because of overlapping bones and other soft tissues. To take a good radiogram of lung field, we studied the condition of chest P-A projection in adult and obtained results as follows: 1. The average chest radiographic condition is resulted as 62KVP, 16 mAs in hospitals around Kyung Ki-Do, Korea, 2. The density of the chest 20cm in thickness, is equal to the water phantom 8cm in thickness. 3. The best quality of chest radiogram is achieved in the condition of the lung field at 100KVP, 9.6mAs by use of Grid 8:1.

• Proceedings of the Korea Water Resources Association Conference
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• 1992.07a
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• pp.506-512
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• 1992

PET병에 넣어 시판되고 있는 일부 물중에서 일반세균과 대장균이 문제되고 있어 이러한 균을 멸균하기 위한 실험을 Cobalt-60과 X-ray를 이용하여 효과를 비교했다. 그 결과 Cobalt-60에 의해서 1.1KGY의 선량으로 물속의 모든 균은 멸균되었으나 X-ray에 의한 실험(56KVP 1mA 9초까지의 조사)에는 효과가 없었다. 앞으로 장기간 보관식품은 Cobalt-60에 의한 조사가 효과적이라고 생각되며 아울러 조사된 물은 인체에 하등의 영향을 주지 않는다.

• The Journal of the Korea Contents Association
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• v.11 no.9
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• pp.453-458
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• 2011

This study aimed to figure out the change of exposure dose to the radiologist according to the C-arm angle change. For the exam it was fixed with 101 kvp and 4.9mA for the exposure time with 3 seconds and 5 seconds respectively. C-arm Tube was located both under and over, then the average was taken after performing for 5 times with the change of angle from -30 degree to 0, 30, 60 and 90 degree. The detector measured in 160cm high from the position of the radiologist who operates the C-arm. The measurement was shown its highest result at -30 degree followed by 0, 30, 60, 90 from the highest order. Over tube method is higher than under tube method. Therefore, to reduce the exposure dose of the radiologist, it is required for using under tube method instead of over tube method. When the angle change is made, it is recommended to use the angle that tube is growing further apart from the radiologist. And it is also necessary to shorten exposed time as much as possible to create the same quality image and also to reduce the exposure dose.

• The Journal of Korean Society for Radiation Therapy
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• v.20 no.1
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• pp.17-23
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• 2008

Purpose: Cone-beam CT using linear accelerator attached to on-board imager is a image guided therapy equipment. Because it is to check the patient's set-up error, correction, organ and target movement. but imaging dose should be cause of the secondary cancer when taking a image. The aim of this study is investigation of appropriate cone beam CT scan mode to compare and estimate the image quality and skin dose. Materials and Methods: Measurement by Thermoluminescence dosimeter (TLD-100, Harshaw) with using the Rando phantom are placed on each eight sites in seperately H&N, thoracic, abdominal section. each 4 methods of scan modes of are measured the for skin dose in three time. Subsequently, obtained average value. Following image quality QA protocol of equipment manufacturers using the catphan 504 phantom, image quality of each scan mode is compared and analyzed. Results: The results of the measured skin dose are described in here. The skin dose of Head & Neck are measured mode A: 8.96 cGy, mode B: 4.59 cGy, mode C: 3.46 cGy mode D: 1.76 cGy and thoracic mode A: 9.42 cGy, mode B: 4.58 cGy, mode C: 3.65 cGy, mode D: 1.85 cGy, and abdominal mode A: 9.97 cGy, mode B: 5.12 cGy, mode C: 4.03 cGy, mode D: 2.21 cGy. Approximately, dose of mode B are reduced 50%, mode C are reduced 60%, mode D are reduced 80% a point of reference dose of mode A. the results of analyzed HU reproducibility, low contrast resolution, spatial resolution (high contrast resolution), HU uniformity in evaluation item of image quality are within the tolerance value by recommended equipment manufacturer in all scan mode. Conclusion: Maintaining the image quality as well as reducing the image dose are very important in cone beam CT. In the result of this study, we are considered when to take mode A when interested in soft tissue. And we are considered to take mode D when interested in bone scan and we are considered to take mode B, C when standard scan. Increasing secondary cancer risk due to cone beam CT scan should be reduced by low mAs technique.

• Journal of The Korean Association For Science Education
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• v.34 no.4
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• pp.407-415
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• 2014

Genetic determinism of human behaviors is considered as a philosophical perspective that genes in humans determine biological as well as social traits. However, many biologists agree that human traits are determined by interactions between genes and genes, as well as between genes and environments. In this context, genetic determinism still affect ideas of the general public as well as research directions of biologists. According to Cl$\acute{e}$ment's KVP model (Cast$\acute{e}$ra & Cl$\acute{e}$ment, 2012), teachers' conceptions of genetic determinism influence students' concepts of genetics. This study intends to investigate teachers' conceptions on genetic determinism of human behaviors. For this end, a questionnaire adopted from a previous research (Cast$\acute{e}$ra & Cl$\acute{e}$ment, 2012) has been administered to 308 teachers including 151 pre-service and 157 in-service. Factor analysis has been conducted to extract major factors and one-way ANOVA has been employed to find out differences in extracted factors among different groups of teachers. Four factors have been extracted from 14 items of questionnaire, including factor 1, a perspective of genetic determinism of gender differences in intellectual ability, social status, and emotional traits; factor 2, a perspective of genetic determinism of individual differences in intellectual ability; factor 3, a perspective of genetic determinism of individual differences in biological immune function and behavioral trait; and factor 4, a perspective of genetic determinism of ethnic differences. From the results of One-way ANOVA among teacher groups on four factors, first, it has shown a significant difference in factor 1 (F=3.325, p=.006), factor 3 (F=3.320, p=.006) and factor 4 (F=4.325, p=.001) due to their subject matters. In post-hoc comparison there have been no significant difference between biology teachers and other teachers. It has also been found that there was a significant difference between pre-service and in-service teachers in factor 1 (t=-3.938, p=.000) and factor 4 (t=-3.121, p=.002) and in-service teachers are more genetic deterministic than pre-service teachers. Finally, different religions have no influence on teachers' conceptions of genetic determinism of human behaviors.

• The korean journal of orthodontics
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• v.6 no.1
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• pp.55-63
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• 1976

This study was undertaken to establish the roentgenocephalometric standards of the Korean children in Hellman dental age III C. The subjects consisted of 33 males and 33 females with the normal occlusion and acceptable profile. The lateral cephalometric films were taken with the teeth in centric occlusion, the soft tissue outline of the nose, lips, and chin was made visible by the low-speed films, 70Kvp, 100Mas. Their linear and angular measurements were performed by Jarabak's methods. The following results were obtained; 1) The author made the tables of standard deviation from the measured values. 2) Each linear measurement of the skull was greater in males than in females. 3) The maxillary basal bones were more protrusive in Korean children than in Caucasian. 4) The degree of the facial convexity was larger in Korean children than in Caucasian. 5) The labial inclination of the upper & lower incisors was greater in Korean children than in Caucasian. The labial inclination of the upper incisor was greater in females, but the labial inclination of the lower incisor was greater in males.

• Journal of radiological science and technology
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• v.18 no.1
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• pp.71-75
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• 1995

In order to establish the photographic effects and sensitivity of various screens, fluorescence meter is used with convenience. When the radiation quality has been fixed the fluorescence has increased in proportion to X-ray dose. However, the response of fluorescence meter has the dependency of X-ray quality in accordance with KVP. as well as the difference of screen and scatter fraction can influence on the response of fluorescence meter. Using accurate fluorescence meter as a radiation detecter and as for a proper supervision the sensitive materials, we have to aware of the meter's dependency of X-ray quality and the scatter fraction.