• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.905-917
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• 2022

This study was conducted to evaluate the use of the MAR function and the image quality of the image when examining with each radiation dose. A simple Periapical phantom was made to set up an implant, and images were obtained and analyzed according to the presence or absence of MAR function for each radiation dose using CBCT equipment. In this study, MEAN, SNR, and CNR values were obtained using the Image J program, and through statistical analysis, images were the most quantitative and suitable values when the Abutment of Implant was 100 kVp and 8 mA, and when the Center of Implant and Apex of Implant were 100 kVp and 9 mA. As a result, it was confirmed that if the radiation dose increased, the Pixel Value, SNR, and CNR values of the image rose up so that the quality of the image improved, and using the MAR function reduced artifacts.

• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.443-451
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• 2022

In this case, non-rheumatic GLA was observed and it was intended to report a case of ultrasound examination. The case patient, a 60-year-old male, visited the emergency room for dyspnea and palpitations. For radiology examination, chest X-ray examination and CT examination were performed, and a giant left atrium was confirmed. Echocardiography was performed to find the cause of the giant left atrium. Echocardiography The size and volume of the left atrium were evaluated by Simpson's method, and the giant left atrium with LVEDVI 6 times larger than that of the general giant left atrium could be evaluated. Also, a giant left atrium in a patient without rheumatic heart disease is evaluated as a very rare case. Since non-rheumatic giant left atrium could be caused by functional mitral regurgitation, diastolic dysfunction. It was confirmed that ultrasonography, which allowed both morphological and hemodynamic examinations, could be a useful case.

• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.463-470
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• 2022

The purpose of this study was to investigate the perception of Air Force human resources (Civilian defense manpower, Officer, Noncommissioned officer, Solder) for the radiation perception. The subjects were 259 men and women who visited at the Aerospace Medical Center. As for the method, a survey study was conducted using a questionnaire with a total of 14 questions about radiation perception (risk, benefit, management). For statistical analysis, an independent sample T-test and one-way analysis of variance (ANOVA) were used to compare the average of confirm a significant difference among groups. The correlations between variables were tested with Pearson and Spearman correlation coefficients. As a result, in the air force human resources, perception of radiation risk of females had a significantly higher awareness than male. Radiation benefits had a significantly higher awareness among married people, military officers, officers, and non-commissioned officers. Radiation control was significantly higher in men, married men, and those with more than 16 years of military experience.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.809-817
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• 2023

Single source and dual source measurements using anthropomorphic phantoms in which the phantoms are lined up in human body equivalents use OSLD (Optically Stimulated Luminescence Dosimeter), so the effective dose is calculated using OSLD. For hospital images, SNR (Signal to Noise Ratio) and CNR (Contrast to Noise Ratio) were measured in MCA (Middle Cerebral Artery) for single source and dual source, and for phantom images, SNR and CNR were measured for brain parenchyma of single source and dual source. For hospital imaging, SNR and CNR were measured in MCA for both single-source and dual-source, and for phantom images, SNR and CNR were measured for brain parenchyma from single-source and dual-source. As a result of comparing the SNR and CNR of the hospital image and the phantom image, there was no statistical difference. Comparing patient doses in hospital images, the effective dose of the dual source was 53.53% less and the effective dose of the dual energy phantom was 57.94% less. The dose can be increased in other areas, but the cerebrovascular area is useful because the dose is small.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.761-766
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• 2023

In this paper, TI was measured to classify the presence or absence of mild left ventricular diastolic dysfunction. Of the total 306 data, 206 were used as training data and 100 were used as test data, and the machine learning models used for classification used SVM and KNN. As a result, it was confirmed that SVM showed relatively higher accuracy than KNN and was more useful in diagnosing the presence of left ventricular diastolic dysfunction. In future research, it is expected that classification performance can be further improved by adding various indicators that evaluate not only TI but also cardiac function and securing more data. Furthermore, it is expected to be used as basic data to predict and classify other diseases and solve the problem of insufficient medical manpower compared to the increasing number of tests.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.9-14
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• 2021

Recently, magnetic resonance imaging (MRI), which can acquire images with good contrast without exposure to radiation, has been widely used for diagnosis. However, noise that reduces the accuracy of diagnosis is essentially generated when acquiring the MR images, and by adjusting the parameters, the noise problem can be solved to obtain an image with excellent characteristics. Among the parameters, the number of excitation (NEX) can acquire images with excellent characteristics without additional degradation of image characteristics. In contrast, appropriate NEX setting is required since the scan time increases and motion artifacts may occur. Therefore, in this study, after fixing all MRI parameters through the MRiLab simulation program, we tried to evaluate the tendency of image characteristics according to changing NEX through quantitative evaluation of brain T2 weighted images acquired by adjusting only NEX. To evaluate the noise level and similarity of the acquired image, signal to noise ratio (SNR), contrast to noise ratio (CNR), root mean square error (RMSE) and peak signal to noise ratio (PSNR) were calculated. As a result, both noise level and similarity evaluation factors showed improved values as NEX increased, while the increasing width gradually decreased. In conclusion, we demonstrated that an appropriate NEX setting is important because an excessively large NEX does not affect image characteristics improvement and cause motion artifacts due to a long scan.

• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.283-287
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• 2011

In this study, fine $Gd_2O_2S$:Tb powder was synthesized by using a low temperature solution-combustion method for a high-resolution digital x-ray imaging detector. From the fabricated phosphor power, the fine scintillator films was fabricated by particle sedimentation method and was investigated the luminescent property. From the experimental results of relative light output as a function of terbium concentration, the highest luminescent efficiency has at 5 wt% Tb concentration, and luminescent intensity decreased rapidly according to quenching effect about higher Tb concentration. Also, the relative light output of $270{\mu}m$-$Gd_2O_2S$:Tb film has 2945 pC/$cm^2$/mR. And light intensity was saturated at higher film thickness. Finally, to evaluate an image acquisition performance of fabricated phosphor, images were obtained by using commercial CMOS sensor and measured the MTF, NPS, and DQE. DQE(0 lp/mm) of fine phosphor film has 37%. But, DQE improvement of fine phosphor film is possible by resolving problem of film fabrication process and has a significant potential in the application of digital radiation imaging system later.

• Journal of the Korean Society of Radiology
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• v.14 no.1
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• pp.39-44
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• 2020

The purpose of this study was learning about chest X-ray image classification and accuracy research through Deep Learning using big data technology with Convolution Neural Network. Normal 1,583 and Pneumonia 4,289 were used in chest X-ray images. The data were classified as train (88.8%), validation (0.2%) and test (11%). Constructed as Convolution Layer, Max pooling layer size 2×2, Flatten layer, and Image Data Generator. The number of filters, filter size, drop out, epoch, batch size, and loss function values were set when the Convolution layer were 3 and 4 respectively. The test data verification results showed that the predicted accuracy was 94.67% when the number of filters was 64-128-128-128, filter size 3×3, drop out 0.25, epoch 5, batch size 15, and loss function RMSprop was 4. In this study, the classification of chest X-ray Normal and Pneumonia was predictable with high accuracy, and it is believed to be of great help not only to chest X-ray images but also to other medical images.

• Journal of the Korean Society of Radiology
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• v.6 no.6
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• pp.483-487
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• 2012

In 1895, the discovered X-ray is used for not only in this field of medicine wide but also field. The detection of radiation after, people realized the risk of the radiation exposured recommended the principle about the protection of radiation by the part of the effort for lowering the radiation exposure. In this recommendation, all unnecessary radiation exposure have to be prevented by All doses include the protection of radiation, general idea of applicable two kinds of that it has to low maintain. Presently, in the General X-ray room of the clinical, the lead (Pb) was used for the shielding, However, because it had the problem of the lead poisoning which is fatal in the human body, the alternatives was showed. and Among them, the material that it is the tungsten was presented. in this research, the absorbed spectrum according to the thickness in the continuous X-ray energy of the tungsten which is not harmful to the human body through the Monte Carlo simulation, tried to compare with the absorbed spectrum of the lead (Pb). The tungsten confirmed that simulation presumption than result lead in the whole domain that absorbed probability was higher and it is considered that tungsten shows the absorbed efficiency higher than the lead in particularly, 70 keV ~ 90 keV and the tungsten is more useful to the X-ray energy cover of the high energy diagnostic area.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.53-64
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• 2018

Using the AUDIT-K (Korean versions of alcohol use disorders identification test), it was able to select a large number of potential danger drinkers who routinely live. There were no statistically significant differences in age, religion, marital status, occupation, family history of alcohol drinking, age at onset of alcohol use, smoking, and BMI (body mass index). However, only education and drinking periods were statistically significant. These results are consistent with the previous study, which suggests that alcohol consumption is higher among men who are educated. The level of education also suggests that there is a need to look at the differences depending on what you learned and how. Alcohol consumption by education also shows different results. Also, drinking at a young age will lead to a longer drinking period, which is consistent with previous studies on the age at onset of drinking. In this study, drinking period was the most important factor of alcohol use disorder and it is considered that measures and education of national government system which can delay drinking age as much as possible is needed as a method to shorten drinking period.