• Journal of the Korean Society of Radiology
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• v.11 no.6
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• pp.423-428
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• 2017

In this study, the calculation of the effective spatial dose distribution of the diagnostic imaging laboratory of K university was performed by the Monte Carlo simulation. The radiation generator has a maximum tube voltage of 150 kVp and a maximum current of 700 mA. Using the results, we compared the spatial effective dose distributions of diagnostic imaging laboratory when the shielding door was closed and opened. In conclusion, it was found that the effective dose in the operating room of the diagnostic imaging laboratory does not exceed the annual dose limit (6 mSv/y) of the student (occasional visitor) even when the door is opened. However, since the effective dose when the door is open is about 16 times higher in front of the lead glass window and about 3,000 times higher in front of the doorway than the case when the door is closed, closing the shielding door at the time of the practical exercising reduces unnecessary radiation exposure by great extent.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.289-294
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• 2020

In order to control the quality of X-ray images and patient exposure, it is necessary to document the output dose(air absorption dose(mGy)) output from the X-ray unit from the measurement. The purpose of this study is to find an equation that can calculate the output dose from the measurement of the output dose and output factor(Of) of the X-ray Unit. The output dose and output factors of the X-beam irradiated from the X-ray unit were measured using an XR multi-detector. The output dose calculation formula was obtained by fitting the measured output dose divided by the tube current-exposure time product(mAs) and the set tube voltage with Allometric1. The final output dose calculation formula was obtained by multiplying this formula with the output factor. It is considered that the obtained final output dose calculation formula will be useful for all tube voltages, tube currents, exposure times, field sizes, and distances.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.439-443
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• 2015

An electrical signals of a conventional radiation medical imaging sensor are obtained by charge integration method. In this study, the polycrystalline cadmium telluride(p-CdTe) film was fabricated by a thermal evaporation method for the photon counting sensor development with excellent resolution in low exposure dose. From the fabricated p-CdTe sensor, the physical properties(SEM, XRD) and the electrical properties(leakage current, x-ray sensitivity, SNR) were evaluated. As a result, the leakage current of below $5nA/cm^2$ and $7{\mu}C/cm^2-R$ of the X-ray sensitivity were showed in below $1V/{\mu}m$. In addition, the signal to noise ratio showed the values of above 5000 at operating voltage.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.655-661
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• 2017

Sparse view CT has been widely used to reduce radiation dose to patient in radiation therapy. In this work, we performed sinogram restoration from sparse sampling data by using inpainting method for simulation and experiment. Sinogram restoration was performed in accordance with sampling angle and restoration method, and their results were validated with root mean square error (RMSE) and image profiles. Simulation and experiment are designed to fan beam scan for various projection angles. Sparse data in sinogram were restored by using linear interpolation and inpainting method. Then, the restored sinogram was reconstructed with filtered backprojection (FBP) algorithm. The results showed that RMSE and image profiles were depended on the projection angles and restoration method. Based on the simulation and experiment, we found that inpainting method could be improved for sinogram restoration in comparison to linear interpolation method for estimating RMSE and image profiles.

• Journal of the Korean Society of Radiology
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• v.14 no.6
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• pp.833-839
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• 2020

Globally, infection prevention and social awareness have been greatly changed by the severe acute respiratory syndrome coronavirus, and as a result, the infection control guidelines and procedures for patients with high exposure to hospital-acquired infection are further strengthened and management and monitoring are more thorough. In order to prevent infection, sterilization should be carried out with the highest priority, and we will find a sterilization method that is low in cost, easy to install, and easy to operate, to present appropriate sterilization effects. In this study, the UV sterilizer was used to contaminate the caries bacteria with an output of 4 W and irradiation time of 60, 150, and 300 sec, and the laser was irradiated with outputs of 0.8 and 1.5 W at wavelengths of 266 and 355 nm, respectively. Ultraviolet sterilizer showed safety in infection prevention at over 150 sec, and laser showed safety in prevention at 1.5 W, 0.8 W, and 266 nm. As a result, the higher the output and the wavelength closer to 253.7 nm, the better the sterilization effect.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.545-552
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• 2020

The purpose of this study is to derive a lead thickness calculation formula for direct-shielded doors based on NCRP Report No.151 and IAEA Safety Report Series N0.47. After deriving the dose rate calculation formula for the direct shielded door, this formula was substituted for the lead shielding thickness calculation formula to derive the shielding thickness calculation formula at the door. The lead shielding thickness calculated from the derived direct shielded door shielding thickness calculation formula was about 6% lower than that calculated by the NCRP and IAEA secondary barrier shielding thickness calculation methods. This result is interpreted as meaning that the thickness calculation is more conservative from the NCRP and IAEA secondary barrier shielding thickness calculation methods and fits well for secondary beam shielding. In conclusion, it is thought that the formula for calculating lead shielding thickness of the direct shielded door derived in this study can be usefully used in the shield design of the door.

• Journal of radiological science and technology
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• v.40 no.3
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• pp.485-491
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• 2017

The purpose of this study was to develop a method to improve the job satisfaction of sonograpers by analyzing the factors affecting professional self-concept and job satisfaction. For data collection, total 141 sonographers working in Busan took part in the structured questionnaire survey. The collected data were analyzed by SPSS. For verification of the professional self-concept and job satisfaction, independent t-test and one way ANOVA were executed. When the statistical significance was verified, Sheffe was used for post hoc test. As a result, professional self-concept and job satisfaction were higher when got married, and also when a proper salary was paid according to work experience and professional qualification was acquired. In addition, the factors that have the greatest effect on the job satisfaction were analyzed as professional self concept. In conclusion, in order to improve the job satisfaction of sonographers, it is necessary not only to establish a professional qualification system for the job skill development but also to provide an appropriate compensation system according to work experience.

• Journal of the Korean Society of Radiology
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• v.14 no.1
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• pp.31-37
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• 2020

This study was conducted to examine the kinds and the frequency of incorrect outcomes occurring depending examiners' skills, in testing osteoporosis by using Dual Energy X-ray Absorptiometry(DXA) and improve frequently occurring errors by educating them. The results of an analysis show that the outcomes from the test of hips in patients with wrong postures or some regions with pressure fracture and degenerative changes were often included, even though they should be excluded, and that surgical instruments were also included in the analysis, though they should be excluded from resulting values. Of them, the errors most often found were those about patients' postures (n=56, 6 cases for spines and 50 cases for hips), followed by those about analytical processes (n=37, 35 cases for spines and 2 cases for hips), and then those about regions of interest (n=33, 28 cases for spines and 5 cases for hips). There were, however, no errors caused by the defectiveness of quality control.

• Journal of the Korean Society of Radiology
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• v.12 no.2
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• pp.185-191
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• 2018

The purpose of this study was to evaluate the usefulness of BMI application to Urography CT by applying different tube voltages in accordance with body mass index. Group A (n = 38) with body mass index of lower than 25 was examined with tube voltage of 100 kVp while Group B (n = 45) with a BMI of 25 and higher was examined with tube voltage of 120 kVp. C group (n = 37) with body mass index (BMI) of lower than 25 was examined with tube voltage of 120kVp. Although the difference in average dose between group A (100 kVp) and group C (120 kVp) with low body mass index (BMI) of lower than 25 was $214.8mGy{\cdot}cm$, there was no significant difference in qualitative evaluation and, compared with patient group with body mass index of 25 and higher, results obtained were rather good. Therefore, this study verified that the tube voltage of lower than 100 kVp does not have adverse effect on the quality of image for patients with body mass index (BMI) of lower than 25.

• Journal of the Korean Society of Radiology
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• v.12 no.2
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• pp.271-275
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• 2018

It is possible to do not use the Image Plate for a long time in the clinic. for the acquisition of reliable images the decommissioning process is very important. In this study, we would like to look at complex noises that may occur during Image Plate use depending on the frequency and time of day. first, we got the image from computer radiography. second, We calculate the noise changes using Peak Signal to Noise Ratio(PSNR) and Noise Power Spectrum(NPS). finally, we suggest that remove the noise from the IP for more than 4 hours. and It turned out to be better to remove the noise more than once. this study will be a quantitative reference for Image Plate management and use in the clinical trial.