• Journal of radiological science and technology
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• v.32 no.1
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• pp.33-38
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• 2009

Objective : This study was conducted to determine an association between aortic calcification viewed on plain chest radiography and obstructive coronary artery disease. Method : Retrospective review of all chest radiography obtained from consecutive patients undergoing coronary angiography. Chest PA images were reviewed by technical radiologist and radiologist. Considering the presence of aortic arch calcification, images were compared with the results of coronary angiography. In addition, the size of aortic arch calcification were divided into two groups - the smaller and the larger than 10 mm. Results : Among the total 846 patients, the number of the patients with obstructive coronary artery disease is total 417 (88.3%) in males and 312 (83.4%) in females. Considering the presence of aortic arch calcification, the positive predictive value of relation between aortic arch calcification and obstructive coronary artery disease was 91.4% and the relative risk of the group with aortic arch calcification to the opposite group was 1.10. According to the size of aortic arch calcification and obstructive coronary artery disease, the positive predictive value was 91.9% and the relative risk between two groups was 1.04. Conclusions : This study shows that aortic calcification was closely associated with obstructive coronary artery disease. If the aortic calcification is notified on plain chest radiography, we strongly recommend to consult with doctor.

• Journal of the Korean Society of Radiology
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• v.11 no.4
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• pp.221-225
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• 2017

To evaluate the performance of ultrasound imaging system, we investigated the change of spatial resolution according to changing sonic velocity change parameter provided by ultrasound equipment. Ultrasound phantom images were obtained using a 3.0 ~ 5.0 MHz convex transducer in an ultrasound diagnostic device used at a medical institution located at Iksan. N-365 multi-purpose ultrasound phantom was used to measure longitudinal distance measurement accuracy and longitudinal and transverse resolution. In the same manner, the sonic velocity of the ultrasound equipment was changed from 1580 m/sec to 1400 m/sec in six steps, and the full width at half maximum(FWHM) was measured using the image J program to determine whether the measured values were different. As a result, lateral resolution was measured from 1.91 mm to 5.3 mm according to the speed change, and the smallest FWHM was 1.91 mm at 1420 m/sec. The axial resolution was measured from 1.03 mm to 1.14 mm according to the speed change, and the smallest FWHM was 1.03 mm at 1400 m/sec. The slower the sound velocity of the ultrasound equipment, the shorter the length of longitudinal measurement.

• Journal of the Korean Society of Radiology
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• v.11 no.4
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• pp.197-203
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• 2017

This study purpose is propose the basic data for selecting the optimal target material by analyzing the photon characteristics of various materials which was located in the head of medical linear accelerator. In this study, energy spectrum of 6, 15 MV photon beams were compared and analyzed for 13 target materials using MCNPX of Monte Carlo method. The mean energy for the 6 MV energy spectrum was 1.69 ~ 1.84 MeV and that for the 15 MV was 3.38 ~ 3.56 MeV, according to the target material. The flux for the 6 MV energy spectrum was $1.64{\times}10^{-5}{\sim}1.80{\times}10^{-5}{\sharp}/cm^2/e$ and that for the 15 MV was $1.76{\times}10^{-4}{\sim}1.85{\times}10^{-4}{\sharp}/cm^2/e$. The analysis shows that the average energy and flux increase with higher atomic number of the target material. Based on this study, it is possible to present the basic data about the physical characteristics of the photon, and it will be possible to select the target later considering economic, efficiency and physical aspect.

• Journal of the Korean Society of Radiology
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• v.11 no.6
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• pp.483-491
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• 2017

This study investigates the perception of the general public through analysis of various potential risk factors reflecting nuclear power generation and nuclear power (radiation) and risks. A total of 293 copies of the data were collected from various strata in Busan. As a result, among the potential factors in everyday life, there was a high awareness of the risk to the fire. Next, the perception of risk for radiation terror and nuclear (nuclear) energy was relatively high compared to other risk factors. In the analysis according to age, educational background, and political ideological tendency, the results were contradictory to the necessity, risk and safety of nuclear power generation. The potential risk factors and the perception of nuclear power according to the tendency of political ideology were analyzed to be positive recognition of conservative ideology and negative recognition of progressive group. In other words, the perception of nuclear power was analyzed differently according to the tendency of political ideology. Therefore, it should be decided to reflect the opinions of experts and various opinions of the general public in the setting of nuclear radiation (radiation), it is believed that ordinary people need to take flexible action without having a vague sense of anxiety about various potential risks and nuclear power (radiation) based on objective and scientific grounds.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.459-465
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• 2015

Energy absorption distribution according to lead shielding for 511 keV ${\gamma}$ ray was evaluated using a Monte Carlo simulation in PET/CT. Experimental method was performed about the depth of skin surface(0.07), lens(3) and the depth(10) was conducted by using ICRU Slab phantom. Difference of energy absorption distribution according to lead thickness and effect of air gap according to distance of lead and phantom. As a result, study showed that using a lead shielding makes high energy distribution by backscatter electron. As a distance between lead and phantom increased, energy absorption distribution gradually decreased. 9 cm or more air gap should exist to prevent effect of backscatter electron which reaches skin surface, when 0.25 mmPb shielding is used. Also 1 cm or more air gap was needed to prevent the effect in 0.5 mmPb. If air gap was not concerned, 0.75 mm or more lead thickness was necessary to prevent effect of backscatter electron.

• Journal of the Korean Society of Radiology
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• v.11 no.2
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• pp.79-85
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• 2017

The purpose of this study is to investigate the cause analysis according to the difference between the pre exposure tube voltage and actual exposure tube voltage in mammography in connection with breast pressure thickness, breast size and body mass index and to find the improvement. The study tracked 377 women age 40 and older among the mammography examiners conducted by the National Health Insurance Corporation. It was analyzed that breast pressure thickness, breast size and body mass index according to the difference between the pre exposure tube voltage and actual exposure tube voltage among the parameters of dose report been sent to the picture archiving communication system with reference to the image with cranio-caudal projection in mammography. As are result, it shows that the thicker the breast thickness, smaller the breast size and lower body mass index, the higher the difference of tube voltage. In conclusion, the minimum tube voltage of mammography machine should be reset in order to set the tube voltage according to breast pressure thickness and breast size that are suitable for our country in mammography, in addition, it was considered that radiologist should make an effort to reduce radiation exposure and make a good quality image with reducing the difference of mammography condition by making a correct exposure condition in case of examining the patients with thin breast pressure and small breast size.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.663-669
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• 2017

In diagnostic medical imaging, it is essential to reduce the scattered radiation for the high medical image quality and low patient dose. Therefore, in this study, the influence of the scattered radiation on medical images was analyzed as the tube voltage increases. For this purpose, ANSI chest phantom was used to measure the scattering ratio, and the scattering effect on the image quality was investigated by RMS evaluation, RSD and NPS analysis. It was found that the scattering ratio with increasing x-ray tube voltage gradually increased to 48.8% at 73 kV tube voltage and to 80.1% at 93 kV tube voltage. As a result of RMS analysis for evaluating the image quality, RMS value according to increase of tube voltage was increased, resulting in low image quality. Also, the NPS value at 2.5 lp/mm spatial frequency was increased by 20% when the tube voltage was increased by 93 kV compared to the tube voltage of 73 kV. From this study, it can be seen that the scattering radiation have a significant effect on the image quality according to the increase of x-ray tube voltage. The results of this study can be used as basic data for the improvement of medical imaging quality.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.647-653
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• 2017

The purpose of this study is to provide basic data for policy making by understanding preparation plans and awareness of nuclear accidents and radiation terrorism among police officers in the vicinity of nuclear power plants. 221 police officers working in Busan metropolitan city were surveyed and their perception of disaster response was analyzed by organizational structure, command ability, and opinion management. As a result, there was no significant difference in disaster response perception by gender and command class (p>.05). There was statistically significant difference in the ability of command in age and ability according to work experience. As a result of the correlation analysis, there were statistically significant correlations among the three items of organizational structure perception, command ability, and opinion management (+0.5) (p<.01). Overall, it was positive for the police system, and it was well aware of the police work in case of radiation accidents and terrorist attacks. The purpose of this study is to provide basic data for policy making by understanding the coping and awareness of nuclear accidents and radiation terrorism among police officers in the vicinity of nuclear power plants.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.96-107
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• 2020

This study aimed to identify the associated factors of protective behaviors for radiation exposure among some radiology technologists using the Health Belief Model. The subjects of the study were 541 radiology technologists working at hospitals or clinics in Honam Province. Using the SPSS version 18.0 program, data were analyzed using a t-test, ANOVA, Pearson's correlation analysis, and hierarchical multiple logistic regression analysis. To modify the factors, the performance of subjects who had a higher level of education and nuclear medicine rooms were higher than those who worked in simple radiography rooms. The radiation protective behaviors performance of the subjects who had more exercise, medium-level stress, and worked in higher-quality protection facilities was higher. Regarding the personal perceptions, the cues to action (β=.292, p=.0001), and perceived seriousness (β =.075, p=.010) were factors that had effects on the performance of radiation protection behaviors. Regarding the likelihood of action, the benefits (β=.168, p<.0001), self-efficacy (β=.148, p=.007), and the performance of protective behaviors were higher. In conclusion, protection education as a cue to action should be provided to stimulate protective behaviors, and the benefits of protective behaviors should be emphasized. To increase the performance of protection behaviors, self-efficacy should be enhanced, and the subjects are offered appropriate information that helps perceive seriousness.

• Journal of the Korean Society of Radiology
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• v.14 no.2
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• pp.149-155
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• 2020

Most of radiation protection clothing is made of lead with excellent radiation shielding because it has excellent process ability and economic efficiency and has a high atomic number. However, lead is classified as a hazardous heavy metal, and there is a risk of lead poisoning. Recently, research to replace lead has been actively conducted. In this study, a research on a shielding sheet with improved physical properties while maintaining the radiation shielding ability equivalent to that of conventional materials by mixing two materials that are harmless to the human body, such as BaSO₄ and Bi₂O₃, and a silicone material binder Was performed. For comparison evaluation with the existing lead shielding sheet, the shielding rate was evaluated using a 40 degree shielding sheet having the highest porosity. As a result, it was analyzed that the shielding rate was superior to 9 % or more at the same thickness. In addition, as a result of studies to improve the physical properties of the shielding sheet, it was analyzed that the shielding sheet mixed with BaSO₄/nylon/Bi₂O₃ was the best.