• Journal of Radiation Protection and Research
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• v.34 no.1
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• pp.31-36
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• 2009

The purpose of this study is to measure the tube voltage, the tube current/volume, exposure time and exposure dose of diagnostic X-ray unit in each doctor offices, hospitals and general hospitals for evaluating the performance of such device, to learn the method and technology of its measurement and to suggest its importance. Research subjects were total 30 X-ray units and divided into groups of 10 X-ray units each. The tube voltage, the tube current/volume, exposure time and exposure dose were measured using percentage average error, and then reproducibility of exposure dose was measured through calculating coefficient of variation. The results are like followings; The tube voltage correctness examination showed that incongruent devices among total 30 X-ray units were 5 devices (16.7%). The tube current correctness examination showed that incongruent X-ray units were 3 devices (10.0%). The tube current volume correctness examination showed that incongruent X-ray units were 4 devices (13.3%). Finally, according to exposure time correctness examination, incongruent X-ray units were 5 devices (16.7%) and according to reproducibility examination of exposure dose, incongruent X-ray units were 7 devices (23.3%). Above results showed serious problem in performance management based on management regulation of diagnostic X-ray unit; it means that regular checkout and safety management are required, and as doing so, patients will be able to receive good quality of medical service by the reduction of radiation exposure time, image quality administration, unnecessary retake and etc. Therefore, this study suggests that the performance of diagnostic X-ray units should be checked regularly.

• Journal of the Korean Wood Science and Technology
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• v.34 no.1
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• pp.23-31
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• 2006

X-ray transit materials with straight path and the its intensity is proportional to the density of materials. Therefore, X-ray has been extensively used as a nondestructive evaluation (NDE) method in various fields. This study was carried out for development of a portable X-ray CT (computed-tomography) system to detect deteriorations of wood members in buildings. Based on the results of our previous study, a procedure of CT image reconstruction was established In order to verify the applicability of developed system, CT images of three wood disks were reconstructed by newly developed procedure and compared with the prototypes. From the results of this study, it was shown that the newly developed system could be used not only to determine the shape, size, and position of defects, but also to find the density distribution in cross section of wood structure members. The density distribution may be utilized to clarify the reason of wood deterioration and to provide the preventive method on how to treat or repair wood buildings. Because it was initial stage of system development, there were some limitations concerned with measuring equipment and image reconstruction algorithm. Especially, measuring time including equipment setup time was longer and measuring accuracy was lower than we expected. Therefore, we planned some additional studies on improvement of equipment and algorithm to enhance the capability of X-ray CT system.

• The Journal of the Korea Contents Association
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• v.9 no.3
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• pp.250-255
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• 2009

This study performed and evaluated the performance test in 40 general X-ray units among diagnostic X-ray units, which were being used in hospitals of gyeongsangnam-do gimhae-si through X-ray tube variable limiting device ability test, the light field and X-ray field alignment test and collimation and beam alignment test of diagnostic X-ray unit. The results are as followings: In a variable beam limiting device ability test, the result of maximum X-ray field test showed that 4(10%) of were incongruent while the result of minimum X-ray field test represented that 5(12.5%) of were incongruent. The result of the light field and X-ray field alignment test showed 23(57.5%) of were within 2% of maximum permissible level and the other 17(42.5%) units were misalignment. The result of beam alignment test represented that 11(27.5%) coincided and another 11(27.5%) within $0.5^{\circ}$ respectively, 10(25%) were $0.6^{\circ}-1.5^{\circ}$ intervals, 7(17.5%) were $1.6^{\circ}-3^{\circ}$ and 1(2.5%) were more than $3^{\circ}$.

• Journal of Radiation Protection and Research
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• v.27 no.3
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• pp.155-164
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• 2002

Methodology to evaluate the effective doses to adults undergoing various diagnostic x-ray examinations were established by Monte Carlo simulation of the x-ray examinations. Anthropomorphic mathematical phantoms, the MIRD5 male phantom and the ORNL female phantom, were used as the target body and x-ray spectra were produced by the x-ray spectrum generation code SPEC78. The computational procedure was validated by comparing the resulting doses to the results of NRPB studies for the same diagnostic procedures. The effective doses as well as the organ doses due to chest, abdomen, head and spine examinations were calculated for x-rays incident from AP, PA, LLAT and RLAT directions. For instance, the effective doses from the most common procedures, chest PA and abdomen AP, were 0.029 mSv and 0.44 mSv, respectively. The fact that the effective dose from PA chest x-ray is far lower than the traditional value of 0.3 mSv(or 30 mrem), which results partly from the advances of technology in diagnostic radiology and partly from the differences in the dose concept employed, emphasizes necessities of intensive assessment of the patient doses in wide ranges of medical exposures. The methodology and tools established in this study can easily be applied to dose assessments for other radiology procedures; dose from CT examinations, dose to the fetus due to examinations of pregnant women, dose from pediatric radiology.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.879-886
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• 2018

A 3-dimensional (D) printer is a device capable of outputting a three-dimensional solid object based on data modeled in a computer. These features are utilized in the bone model X - ray phantom production etc using CT data by fusing with the radiation science field. A bone model phantom was made using data obtained by CT scan of an existing Pelvis phantom, using PLA, Wood, XT-CF20, Glow fill, Steel filaments which are materials of Fused Filament Fabrication (FFF) 3D printer.Measure Hounsfield Unit (HU) with images obtained by CT scan of the existing Pelvis phantom and five material phantoms made with 3D printer under the same conditions,SI and SNR were measured using a diagnostic X-ray generator, and each phantom was compared and analyzed.As a result, the X - ray phantom in the X - ray examination condition of the limb was found to be most suitable for the glow fill filament.The characteristics of the filament can be known to the base of this research and the practicality of X - ray phantom fabrication was confirmed.

• Journal of radiological science and technology
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• v.27 no.4
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• pp.55-60
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• 2004

The purpose of this study was to examine both patient exposure dose during mammography and the utility status of mammograpy equipments. The data of this study were collected through questionnaire survey for 278 medical facilities registered at Korean Hospital Association and finally 161 medical facilities's data were analyzed. According to data analysis, medical facilities of 14.9% used the average glandular dose of less than 0.5 mGy, $0.51{\sim}1.0\;mGy$ 8.6%, $1.01{\sim}1.5\;mGy$ 14.9%, $1.51{\sim}2.0\;mGy$ 11.1%, $2.01{\sim}2.5\;mGy$ 9.8%, $2.51{\sim}3.0\;mGy$ 33.3%, and 7.4% more than 3.01 mGy. It was found that medical facilities of 92.6% used less than 3 mGy, showing that this figure is similar to the limit value of 3 mGy recommended by Korea Food & Drug Administration(KFDA). Recently, international organizations such as ICRP associated with radiation protection suggests that less than 3 mGy of average mammary gland dose be used during mammography in case of using Mo target+Mo filter, film/screen system and craniocaudal projection with the breast pressed to 4.2 cm. The standard dose is being strictly observed and that of the limits is going down to 2 mGy or 1.5 mGy. The major results of this study indicate that interests and a counterplan to reduce patient dose during mammography should be considered. Based on this study, the authors of this study will continue to measure exposure dose to set a new standard for patient exposure dose during mammography.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.09a
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• pp.170-174
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• 2005

본 연구는 산업용과 의료용에 사용되는 비파괴 검사용 X 선 영상시스템에 이용되는 X 선을 직접 감지하는 방식의 센서를 실리콘 반도체 재료를 사용하여 개발하는데 목적이 있다. 이를 위해서 실리콘 반도체를 기본 물질로 하는 X-선 센서를 제작하고, 광범위한 영역에서 응용이 가능한 비파괴 시험용으로 제품화하기 위해 센서 어레이와 주변회로 및 구동회로 시스템과의 연관기술을 검토한다.

• Tuberculosis and Respiratory Diseases
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• v.43 no.3
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• pp.388-402
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• 1996

Background : To compare the diagnostic accuracies of High-resolution CT(HRCI) and chest radiography in the diagnosis of diffuse infiltrative lung disease(DILD). Methods : This study included ninety-nine patients with a diagnosis of acute or chronic DILD, representing 20 different diseases. Twelve normal subjects were included as control. The disease state was confirmed either pathologically or clinically. Radiographs and CT scans were evaluated separately by three independent observers without knowledge of clinical and pathologic results. The observers listed three most likely diagnoses and recorded degree of confidence. Results : The sensitivity of HRCT in the detection of DILD was 98.9% compared to 97.9% of chest radiography. Overall, a correct first-choice diagnosis was made in 48% using chest radiographs and in 60% using HRCT images. The correct diagnosis was among the top-three choices in 64% when chest radiographs were used, and in 75% when HRCT images were reviewed. Overally a confident diagnosis was reached more often with HRCT(55%) than with chest radiography(26%). The correct first-choice diagnosis increased remarkably when the HRCT was used in usual interstitial pneumonia, miliary tuberculosis, diffuse panbronchiolitis and lymphangitic carcinomatosis. Conclusion : HRCT is confirmed to be superior to conventional radiography in the detection and accurate diagnosis of DILD. HRCT is especially valuable in the diagnosis of usual interstitial pneumonia, miliary tuberculosis, diffuse panbronchiolitis, and lymphangitic carcinomatosis.

• Journal of the Korean Society of Radiology
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• v.9 no.1
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• pp.17-21
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• 2015

Recently, As people's interest in the health of teeth is increased in the medical field changed into aging society, the number of times for the radiological diagnosis is increased. It can be said that the radiation exposure dose of Korean population is increased. It is also growing concern about radiation exposure. Therefore, the basic data for the dental panoramic X-ray system, its investigation and measuring the radiation dose is needed. In this study, we used ALOKA PDM-117 dosimeter and estimated a two-dimensional dose distribution of the dental panoramic X-ray system (VATEC Pax-400). Dose evaluation about the distribution is confirmed from the point of radiation exposure of a patient. Dose distribution of the dental panoramic X-ray system irradiated chin and the facial region to high dose as well as the parts of teeth. It was founded that the eye lens which are sensitive to radiation are exposed to unnecessary radiation, considering the effect of scattered radiation. The results of this study will be used more accurate dose assessment in a variety of object size and location of measuring dose.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.146-151
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• 2005

The coral is precious and organic gemstone. It is Beautifully Red color. Coral jewelry have been used for a long time in Asia. Especially in Korea, The Coral is an traditional and popular gemstone. It is significant to get the base data for the purpose of distinguishing natural coral from imitation coral by comparing about gemmological character in this study. Color, luster, transparency, streak color, refractive index, hardness, chemical reaction, ultraviolet fluorescence, specific gravity, observation of microscope and XRD analysis were conducted for identification of natural and imitation coral. As a result, natural coral has usually $CaCO_3$ composition and calcite structure. But, it is known that imitation coral impregnate calcic and dyeing materials with pigment. And they were distinguished also from not only XRD analysis but also a few simple experiments like specific gravity, refractive index and chemical reaction. Natural coral is harder and luster then imitation coral. In breaking method, the streak color is used certification.