• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.864-870
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• 2014

To propose a basis for the selection of personal dosimeters to measure radiation dose administration of radiation workers as a way to evaluate the usefulness dosimeter. For the dosimetry of the radiation workers 2012, during 1 year, 30 were radiation workers to measure personal dose. By personal exposure is measured cumulative dose, is investigated the performance of the TLD, PLD, OSLD. And comparing the measured value of each dosimeter dose and analyzed. Medical institutions, inspection work and quarterly confirmed the cumulative exposure dose of radiation workers. Using DAP and Ion-Chamber, to measure to compare TLD, PLD, OSLD dosimeter performance. A comparison of the directly through the X-ray dosimeter and The absolute value of the Ion-Chamber, OSLD more similar than in the TLD and PLD showed the dose values so the excellent ability to measure the results. Also in radiation generating area dose of radiation workers is higher than that in OSLD. Consequently, in terms of the individual exposure management OSLD is appropriated and beneficial than others.

• Journal of radiological science and technology
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• v.2 no.1
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• pp.45-50
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• 1979

For this study, 2,712 sheets of the chest x-ray films of neonatuses, infants and early children were observed statistically and then the following results were obtained: 1. Seasonal increment of patients was overwhelming in spring and summer in compare with in autumn and winter. 2. Males was majority in distribution by sex. Neonatal and infancy group was the largest in number by forming 29.46% in distribution by age group and then follows six-years group(14.75%), one-year group(13.64%) and five-years group(12.61%) 3. In radiographical projection for chest, a great proportion was P-A projection as 53.72%. But, almost all the neonatal and infancy group and emergency patients were by A-P projection 4. As for x-ray findings, 78.47% was normality while 21.53% was abnormality. Tuberculosis(176 cases), was the largest in number in abnormal cases and next in rank was pneumonia(128 cases)and then congenital heart disease(82 cases). 5. Adequacy of exposure was disclosed as follows: 57.01% in correct-exposure 29.20% in over-exposure, 13.79% in under-exposure. 6. The x-ray beam was not restricted in 77.10% of total films. 7. "Good" formed 30.01% in position immobilizing of the patient and "ordinary" formed 38.02%, "bad" 31.97%. Especially, "Bad" formed high percentage in neonatal and infancy group.

• Journal of radiological science and technology
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• v.42 no.6
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• pp.429-434
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• 2019

The gonads are directly affected by radiation exposure during radiography of the pelvis, abdomen, and spine. Exposure of the gonads to radiation can cause genetic mutations and can result in the occurrence of malignant tumors. In this study, we created three types of shielding material shapes for shielding of the ovaries, which are the gonads of female during radiography of the pelvis, and comparative evaluations using shadow shielding methods. The source surface distance(SSD) was 100 cm and the field size was 42 cm × 43 cm. The three types of shielding material shapes(type 1, 2 and 3) were assessed and the entrance surface dose in the ovaries were measured. The thickness of the shielding material was expanded from 0.3 mm to 2.4 mm and after five repetitions, radiation values were measured and mean values were calculated. The mean dose were 3.09 mGy for type 1, 3.54 mGy for type 2, and 3.19 mGy for type 3, indicating that the measurements were the lowest for type 1. When an additional filter of 0.2 Cu + 1 Al was used, the dose were 3.72 mGy for type 1, 5.43 mGy for type 2, and 4.05 mGy for type 3, indicating that the measurements were the lowest for type 1. The results show that, even if the shielding material is not thick, in other words, even with a thickness of 2.94 mGy for the SN 3(0.9 mm) of type 1, shielding can be achieved, with a patient dose lower than the diagnostic reference level(3.42 mGy). Additionally, among the three types of shielding material, the type 1 appeared to be the most appropriate shielding material. It is thought that the use of shielding material could reduce the risk factors for stochastic effects or critical effects of ionizing radiation during pelvic or lumbar radiography.

• Journal of the Korean Society of Radiology
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• v.14 no.4
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• pp.367-373
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• 2020

Most of the spatial scattered dose caused by the scattered rays generated by the collision between the object and X-rays is relatively easily absorbed by the human body as electromagnetic waves in the low energy region, thereby increasing the degree of radiation exposure. Such spatial scattering dose is also used as an indicator of the degree of radiation exposure of radiation workers and patients, and there is a need for a method to reduce exposure by reducing the spatial scattered dose that occurs indirectly. Therefore, in this study, a lead-free radiation shielding sheet was proposed as a way to reduce the spatial scattering dose, and a Monte Carlo (MC) simulation was performed based on a chest X-ray examination. The absorbed dose was calculated and the measured value and the shielding rate were compared and evaluated.

• Journal of Chest Surgery
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• v.29 no.6
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• pp.621-625
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• 1996

"Middle lobe syndrome" which was described y Graham and associates at first is always caused by ex- ternal bronchial compression by Iymph nodes. Although the patients may not present any symptom, the most common presenting symptoms were cough, dyspnea, fever, hemoptysis, and chest pain. Diagnostic procedures includ chest X-ray bronchoscopy, brochography, chest CT, and the principal finding is the contracted middle lobe which is usually airless. We experienced fifteen cases of middle lobe syndrome from April 1990 to May 1995. Eleven patients were treated surgically. The surgical candidates for middle lobe syndrome are suspicious malignancy, fixed bronchiectasis, bronchostenosis, intractable to medical treatment, recurrent infection. Operations were right middle lobectomy (8), right middle and lower bilobectomy (2), right upper and middle bilobectomy (1). Postoperative histological findings were tuberculosis in six, chronic inflammation in three, malignancy in one, and focal hemorrhage in one. There were two cases of postoperat ve complications which were postoperative atelectasis and hepatopathy.patopathy.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1983.05a
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• pp.7.1-7
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• 1983

Esophageal perforation occurred rarely, but it leads to a high mortality and morbidity. Main cause of esophageal perforation in Korea is instrumental perforation in patients with lye stricture of esophagus during diagnostic endoscopy or therapeutic bouginage. A case of 25-year-old male patient entered to outpatient clinic. Chief complaints were mild pain at swallowing, mild fever elevation and chest tightness with radiating pain to shoulder and interscapular region for 1 day. On the X-ray film with barium soaked cotton piece in esophagus, it was revealed that foreign body (fish bone) had been located on the level of 2nd vertebra with leakage of barium to mediastinum. The foreign body was removed with endoscopy in Dept. of otolaryngology, and cervical mediastinostomy was performed in Dept. of thoracic surgery.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.7
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• pp.112-117
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• 2003

The brazing of copper alloys and duplex stainless steels is an indispensable manufacturing technology for thrust chambers with regenerative cooling. For setting up the optimized brazing conditions, C18200 copper alloy plate with machined cooling channels and S31803 stainless steel plate are brazed with AMS4764 filler metals of which thickness is 50${\mu}m$ and 80${\mu}m$ They are tested by X-ray radiography, strength/leakage and fracture tests, and fracture surface inspection. The results obtained by the suggested conditions are that the specimen brazed with filler metal thickness of 50${\mu}m$ has good strength properties and brazed zone. However, the specimen with filler metal thickness of 80${\mu}m$ has the brazed zone with cooling channel obstruction and enlargement.

• Solar Energy
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• v.11 no.1
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• pp.41-49
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• 1991

In this study, the (P)SiC/(N)Si solar cell is fabricated by the vacuum evaporation method with the substrate temperature at about $200{\pm}5[5^{\circ}C]$ and its characteristics are investigated. The optimal thickness of $1.2[{\mu}m]$ of SiC film is derived from the relation between film thickness and conversion efficiency. The characteristics of solar cells are improved by the annealing. The optimum annealing temperature and duration are $420[^{\circ}C]$ and 12[min], respectively it is shown that the peak values of spectral response are shifted to the long wavelength region with increasing the annealing temperature. The X-ray diffraction patterns and the scanning electron micrographs show the grain grow thin SiC film as the annealing temperature and time is increased. The best conversion efficiency is 11.7[%] for a $2.5{\times}1[cm^2]$ cell.

• The Journal of the Korea Contents Association
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• v.19 no.8
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• pp.276-283
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• 2019

The purpose of this study is to evaluate the usefulness of automatic exposure control (AEC) by analyzing entrance surface dose (ESD) and entropy on using automatic exposure and manual exposure. The experimental method was to measure the dose by placing a semiconductor dosimeter on the Rando Phantom for the Pelvis, Abdomen, Skull, and Chest regions. The DICOM file was simultaneously acquired and then entropy was analyzed by using Matlab. As a result, when using the automatic exposure control, dose of all sites was lower than manual exposure's dose and entropy was high. In addition, paired t-test was performed for each item and p<0.05 was found in each item. In conclusion, the use of automatic exposure control can be a useful method to contribute to the optimization of the exposure dose and the image quality by reducing the amount of unnecessary radiation amount and information loss that can occur in X-ray examination.

• Journal of radiological science and technology
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• v.44 no.3
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• pp.205-210
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• 2021

The purpose of this study was to analyze the spatial dose according to the distance by location of medical workers when using a mobile X-ray fluoroscopy device in the operating room through a simulation experiment. The MCNPX program was used for the simulation, and the location of medical workers was set around the operating table, and the spatial dose distribution according to the distance and changes in imaging conditions was evaluated. As a result, The highest score was 2.74×10^-4 mGy, 2.72×10^-4 mGy, and 1.18×10^-4 mGy based on the 10 cm distance from the operating table. Spatial dose depending on the distance 100cm, A point 5.15×10^-5 mGy is decreased 19% of 10cm, D point 5.12×10^-5 mGy, 19 % of 10cm, and G pint, 1.73×10^-5 mGy is reduced by 15% of 10cm. Based on this study, medical-related workers directly or indirectly participating in surgery carry potential risks of radiation exposure during surgery, but there are difficulties in radiation protection due to the nature of their work. Therefore, efforts to reduce exposure suitable for the operating room environment will be required.