• Imaging Science in Dentistry
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• v.37 no.1
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• pp.9-14
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• 2007

Purpose : To determine the more valuable information to detect the mandibular canal and the mental foramen in panoramic radiographs of a selected Korean population for the implant. Materials and Methods : This study analysed 288 panoramic radiographic images of patients taken at the Dental hospital of Chosun University retrospectively. Indirect digital panoramic X-ray machine (ProlineXC, PLANMECA, Finland) with processing by using Directview $CR950^@$ (Kodak, U.S.A.) and Direct digital panoramic X-ray machine (Promax, PLANMECA, Finland) were used for all exposures. All images were converted into Dicom format. Results : The common position of the mental foramen was in line with the longitudinal axis of the second premolar (68.1%). The mental foramen was symmetrical in 81.8% of cases. The mandibular canal was not identified at anterior portion and discontinued with the mental foramen in 27.8% of all cases, in 42.4% identified with lower border line continued with the mental foramen, in 14.6% with both upper and lower border lines, and in 15.3% unilaterally identified with lower border line. Conclusion : Clinicians can estimate the upper border line of the mandibular canal from the confirmation of the mental foramen and the lower border line of the mandibular canal symmetrically on the panoramic radiography taken in adjusted midsaggital plane of patient's head.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.11a
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• pp.117-120
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• 2006

뼈 나이 평가는 소아 뼈의 골화정도, 내분비선 장애 등을 쉽게 알아 볼 수 있어 소아 방사선 의학에서 자주 사용되는 방법이다. 뼈 나이 평가를 위해서는 골단판과 손마디 뼈의 길이 넓이 등 뼈 정보가 필요하기 때문에 골단판 영역의 추출이 선행되어야 한다. 하지만 골단판의 성장이 많이 진행되어 손마디 뼈 부분과 붙어 있는 경우 골단판 추출이 어려운 점이 있다. 본 논문에서는 골단판 성장 여부와 상관없이 다양한 나이의 디지털 X-ray 영상에서 손가락의 골단판을 추출하는 알고리즘을 제안한다. 손가락 경계선의 레이블링 처리를 이용하여 정확한 손가락 영역을 추출하고 골단판 위치의 통계적 특성을 사용하여 골단판의 후보 지역을 생성한다. 그리고 골단판 영역에서는 손가락 영상의 수직 투영 미분값이 크기 때문에 후보 지역 내에서 수직 투영 미분값의 변화량으로 골단판의 위치를 정확하게 추출한다. 다양한 나이에 대해 실험해 본 결과 제안한 방법은 골단판의 성장 여부와 상관없이 골다판과 손가락 뼈가 붙은 곳에서도 골단판의 통계적 특성을 사용해 정확한 골단판 영역을 추출할 수 있었다.

• Journal of the Korean Society of Radiology
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• v.2 no.4
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• pp.5-9
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• 2008

Antiscatter grids are widely used in radiography to remove scattered X-rays and thus improve the image contrast. However, the use of grids makes moir$\acute{e}$ artifact in the digital image, and this can be a critical reason for a mistaken diagnosis. In this paper, we examined that moire artifacts are how to relate with grid frequency, pixel pitch and grid rotation angle. To experiment we prepared 6 grids having different line frequencies (4.0 to 8.5lines/mm) and tested with a DR imager having a $139{\mu}m{\times}139{\mu}m$ pixel size. In the result of this experiment, we could get data about moir$\acute{e}$ artifact that could be make solution to remove the line artifact for the successful use of the grid in digital radiography. The acquired data and theory through this experiment, are expected to make contribution to the elimination of moir$\acute{e}$ artifact in the DR system.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.555-561
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• 2014

For five diagnostic X-ray generators (DR), four units turned out to be appropriate in tests on the reproducibility of radiation output suggested in the IEC 60601-2-54 standard, but in one unit of the X-ray equipment, an item measured in a combination of 50% of the highest tube voltage of the diagnostic X-ray equipment, the test setting of Group C with authorized output doses between $1{\mu}Gy$ and $5{\mu}Gy$ of mAs turned out to be inappropriate. As a result, the radiation dose to the IEC 60601-2-54 standard for quantification standards proposed by the radiation output from diagnostic X-ray imaging device reproducibility of performance management should be aware that an important evaluation factor.

• Journal of the Korea Safety Management & Science
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• v.6 no.3
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• pp.303-309
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• 2004

Many system devices for fluoroscopic and general X-ray studies in diagnostic radiographic system have been being changed from analog mode to digital mode. In addition, among diagnostic imaging and radiologic examinations, fluoroscopic studies that requires functional diagnosis is being widely used. The video recording method of fluoroscopic studies has been useful in functional image diagnosis and dynamic image observation, but the utility of its image quality is being reduced because of limitation in setting play segments of the video player, inconvenience of play, difficulties in preserving reproduced images, the change of image quality, etc. In order to complement these shortages, it is necessary to facilitate access to patient diagnosis information such as storing, editing and sharing functional diagnosis images in response to the trend of the digitalization of digital radiographic & fluoroscopic system(DRF). Thus this study designed and implemented a device of storing functional dynamic images real time using a computer rather than existing video recording, aiming at contribution to functional image diagnosis.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.637-645
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• 2017

The objective of this study was to find the optimum test device for the cerebral blood vessels by comparing and analyzing the SNR and CNR methods for images of three devices (i.e., MRA, CTA, and DSA). The study targeted 90 patients who underwent cerebral angiography from November 2016 to May 2017. The measuring parts were measured by using Rt MCA, Lt MCA, and ACA Image J. The results of quantitative analysis showed that the mean SNR of MRA, the CNR of MRA, the signal strength of MRA, the mean SNR of CTA, the CNR of CTA, the signal strength of CTA, the SNR of DSA, the CNR of DSA, and the signal strength of DSA were evaluated as 254.87, 178.13, 326.81, 74.75, 62.2, 356.66, 26.85, 25.89, and 4400.69, respectively (p<0.05). As a result, both SNR and CNR methods measured it in the order of MRA>CTA>DSA. Statistical significance was determined by using ANOVA analysis at p<0.05 and Bonferroni method was used as a post-hoc analysis SPSS. In conclusion, the results of this study revealed that the optimum imaging devices were MRA, CTA, and DSA after evaluating randomly selected patients with cerebrovascular disease.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.2
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• pp.158-168
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• 2015

This article describes how to use digital system in a fully edentulous case that diagnosis to definitive prosthesis fabrication. While proceeding oral scan and CBCT taking, digital markers were attached on maxillary palate and lower existing denture. Using CBCT image and oral scan image, the bone contour and anatomical structures were analyzed and flapless surgical guide, customized abutment and prosthesis were made. After the osseointegration, the definitive prosthesis was fabricated using the oral scan image with scan body. It provides clinicians with a fast workflow and improves clinical efficiency.

• Journal of Radiation Protection and Research
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• v.29 no.4
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• pp.231-236
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• 2004

An imaging plate(IP) detector, a two-dimensional digital radiation detector that can acquire image of radioactivity distribution in a sample, has been applied in many fields; for industrial radiography, medical diagnosis, X-ray diffraction test, etc. In this study, the possibility of IP detector to be used lot measuring radioactivity of sample is explored using its high sensitivity, higher spatial resolution, wider dynamic range and screen uniformity for several kinds radiations. First, the IP detector is applied to measure the surface uniformity for area source. Surface uniformity is measured rapidly and nondestructively by measuring the radioactivity distribution of common standard area source$(^{241}Am)$. Next, the IP is employed to study the possibility of measuring an extremely low-level activity of environmental sample. For this study the screen uniformity, shield effect of background radiation, linear dynamic range and fading effect of the IP detector is investigated. The potato, banana, radish and carrot samples are chosen to measure ultra low-level activity of $^{40}K$ isotope. The efficiency calibration of IP detector is carried out using the standard source.

• Journal of Digital Convergence
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• v.11 no.6
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• pp.269-273
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• 2013

Exposure dose to the examinee was measured using glass dosimeter in the test using panorama device at the time of dental treatment. As a result of measuring expose dose to lens according to the different sizes of Pb banding of own manufacturing to reduce exposure dose to lens especially sensitive to radiation, it was verified that exposure dose to lens varied depending on the size of the Pb banding. With the size of Pb banding of $3{\times}20{\times}0.2cm$, exposure dose tended to increase higher than normal value, and with the size of or more than $5{\times}20{\times}0.2cm$, it decreased. And also, the obtained image with the size of $7{\times}20{\times}0.2cm$ was not suitable for diagnosis. Therefore, it is expected that exposure dose would be reduced by using Pb banding of the size of not less than $5{\times}20{\times}0.2cm$ and not more than $6{\times}20{\times}0.2cm$ in the test, to minimize exposure dose and conduct panorama test efficiently.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.185-193
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• 2011

There is no exact standard of detecting pulmonary tuberculosis(TB) in digital image of simple chest radiography. In this study, I experimented on the principal components analysis(PCA) algorithm in the past and suggested six other parameters as identification of TB lesions. The purpose of this study was to develop and test computer aided diagnosis(detection) method for the detection and measurement of pulmonary abnormalities on digital chest radiography. It showed comparatively low recognition diagnosis rate using PCA method, however, six kinds of texture features parameters algorithm showed similar or higher diagnosis rates of pulmonary disease than that of the clinical radiologists. Proposed algorithms using computer-aided of texture analysis can distinguish between areas of abnormality in the chest digital images, differentiate lesions having pulmonary disease. The method could be useful tool for classifying and measuring chest lesions, it would play a major role in radiologist's diagnosis of disease so as to help in pre-reading diagnosis and prevention of pulmonary tuberculosis.