• Journal of radiological science and technology
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• v.36 no.3
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• pp.193-200
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• 2013

There are many concerns about radiation exposure in Korea after Fukushima Nuclear Plant Accident on 2011 in Japan. As some isotope materials are detected in Korea, people get worried about the radioactive material. In addition, the mass media create an air of anxiety that jump on the people's fear instead of scientific approach. Therefore, for curbing this flow, health, medical institute from the world provide a variety of information about medical radiation safety and hold the campaign which can give people the image that medical radiation is safe. At this, the Korean Food and Drug Administration(KFDA) suggested that make the alliance of medical radiation safety and culture on August, 2011. Seven societies and institutions related medical radiation started to research and advertise the culture of medical radiation safety in Korea. In this report, mainly introduce the activities of the Korean Alliance for Radiation Safety and Culture in Medicine(KARSM) for spreading culture of medical radiation safety from 2011 to 2012.

• Journal of radiological science and technology
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• v.34 no.2
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• pp.141-147
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• 2011

We developed an alternative radiation shielding material which is economical and has high protection efficiency. We validated the material in the form of sheet to make an apron. We increased the rate of barium and mixed tourmaline into silicon to improve the flexibility and protection rate of the sheet. The results showed that the shielding effect at low radiation energy is good enough with both 5 mm and 7 mm thickness. In the future, we will perform a quantitative evaluation of the reproducibility, volumetric efficiency, and porosity in mixing the ingredients.

• Journal of radiological science and technology
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• v.32 no.2
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• pp.147-151
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• 2009

In general, the discrete confidence judgments that use five-step assessment method have been used to assess the medical images by ROC. TPF or FPF can be computed easily with this independent reading test. However, during experiments, it happens frequently that adequate distribution for observers is required to smoothly estimate the ROC curve. In addition, data becomes invalid for distribution of the created categories. To solve such problems or to apply the ROC interpretation to data that is not obtained from the experimental observation, the continuous confidence judgements (CCJ) has been proposed, which implements ROC interpretation using continuously-distributed experimental results without category classification has been used. As the use of CCJ to assess medical images was barely reported in Korea, we applied it to the assessment of chest digital images in this study. The results showed that a smooth ROC curve was obtained conveniently by the commercialized program and the characteristic value was measured easily. Therefore, it is recommended that this method can be applied to the assessment of digital medical images.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.537-543
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• 2020

The elderly population in the modern society is growing rapidly due to advance medical technology and minimally invasive surgery. Therefore, as the tendency to use medical device is increasing, pathogenic infection is a concern. Therefore, the first aim of modern medicine is infection prevention in medical place. Recently, patient implants are increasing using 3D printing. Hydroxyapatite is used as a representative material. And, there haven't had currently absorbed dose standard for sterilization of hydroxyapatite discs. Escherichia coli and Streptococcus mutans contaminated on the surface of hydroxyapatite discs were irradiated at each absorbed dose of 0, 0.5, 1.0, 3.0, 5.0 kGy using Gamma-ray of cobalt and Electron-beam of linear accelerator. Then, the number of bacteria was measured in the sample by the decimal dilution method. After sterilization, a non-parametric testing method was performed to compare the survival of Escherichia coli and Streptococcus mutans. As a result, Escherichia coli was sterilized at 1 kGy or more and Streptococcus mutans at 3 kGy or more on absorbed dose. It is considered possible to perform sterilization at a lower value than the recommended absorbed dose of radiation sterilization.

• Journal of radiological science and technology
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• v.30 no.3
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• pp.245-250
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• 2007

This research measured the shielding rates of apron 0.25 and 0.5 mmPb for X-ray energy in diagnosis radiation system and gamma-ray energy of $^{99m}Tc$-MDP and $^{18}F$-FDG. X-ray energies were measured on effective energy of $26.2{\sim}45.6\;keV$ when additional filtering plate of 0, 2 mmAl is used within the range of tube voltage $40{\sim}120\;kVp$, and at this time, apron 0.5 mmPb has shown about 5.5% of increase in its shielding rate over 0.25 mmPb at the highest quality. Besides, the aprons of the two types have shown high shielding rate of over 90% for direct X-ray and spatial dose rate. And, in case 0.25 and 0.5 mmPb aprons were used at 140keV of $^{99m}Tc$-MDP, the shielding effects were between 30 and 53%, and at high energy of 511 keV, $^{18}F$-FDG, the shielding effects of apron, $1.3{\sim}3.6%$, were very small.

• Journal of radiological science and technology
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• v.33 no.2
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• pp.121-126
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• 2010

Traditionally, lead has been primarily used to shield the radiation in the hospital, because of its soft texture, durability and cost effectiveness. However, lead can be dangerous because of its toxicity when exposed to the human body, and it is classified as a heavy metal like cadmium, mercury, and arsenic etc. In order to compensate its noxious properties on the human body, researchers are trying to develop a radiation shield which has similar shielding efficiency and can also be manufactured in any form. In this study, sulfuric acid barium was mixed with fiber, rubber, and silicon all of which are harmless to the human body, tested, and evaluated for its ability of medical radiation shield. The result of this study showed that the sheet containing silicon and barium has the strongest shielding abilities.

• Journal of radiological science and technology
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• v.41 no.1
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• pp.39-45
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• 2018

The purpose of this study is to evaluate the usefulness of a software-based quality assurance system based on Volumetric Modulated Arc Therapy treatment plan. Evaluate treatment plan through the D VH analysis, PTV mean dose ($D_{mean}$) and PTV 95% dose($D_{95}$) compare the MFX based on original treatment plan, Average error rate was $0.9{\pm}0.6%$, $1.0{\pm}0.8%$, respectively. Measuring point dose using phantom and ion chamber, the average error rate between the ionization chamber and MFX was $0.9{\pm}0.7%$, $1.1{\pm}0.7%$ (high dose region), $1.1{\pm}0.9%$, $1.2{\pm}0.7%$ (low dose region). The average gamma though of MFX and $Delta^{4PT}$ is $98.7{\pm}1.2%$, $98.4{\pm}.3%$, respectively. Through this study, A software based QA system that simplifies hardware based QA procedures that involve a lot of time and effort. It can be used as a simple and useful tool in clinical practice.

• Journal of radiological science and technology
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• v.44 no.4
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• pp.367-373
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• 2021

A quality assurance of computed tomography(CT) have done seven items that were water attenuation coefficient, noise, homogeneity, spatial resolution, contrast resolution, slice thickness, artifact using by standard phantom. But there is no quality assurance items and methods for CT simulator at domestic institutions yet. Therefore the study aimed to access the CT dose index(CTDI), table tilting, image distortion, laser accuracy, table movement accuracy and CT seven items for CT simulator quality assurance. The CTDI at the center of the head phantom was 0.81 for 80 kVp, 1.55 for 100 kVp, 2.50 for 120 mm, 0.22 for 80 kVp at the center of the body phantom, 0.469 for 100 kVp, and 0.81 for 120 kVp. The table tilting was within the tolerance range of ±1.0° or less. Image distortion had 1 mm distortion in the left and right images based on the center, and the laser accuracy was measured within ±2 mm tolerance. The purpose of this study is to improve the quality assurance items suitable for the current situation in Korea in order to protect the normal tissues during the radiation treatment process and manage the CT simulator that is implemented to find the location of the tumor more clearly. In order to improve the accuracy of the CT simulator when looking at the results, the error range of each item should be small. It is hoped that the quality assurance items of the CT simulator will be improved by suggesting the quality assurance direction of the CT simulator in this study, and the results of radiation therapy will also improve.

• Journal of radiological science and technology
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• v.20 no.2
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• pp.28-33
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• 1997

For the Evaluation of X-ray image intensifier, we measured radiation dose at input of I. I., brightness and fluorescence at output of I. I. by using X-ray exposure meter, optometer and fluorescence meter for the relative conversion factor. Especially, by using fluorescence meter, we could easily get relative conversion factor without having regulated machine by JIS. Since using, the quality of image intensifier is going down. Consequently, it needs continuous quality maintenance.

• Journal of The Korean Radiological Technologist Association
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• v.25 no.1
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• pp.38.1-38.1
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• 1999

This study is to develop a curvi linear filter for density compensation when making whole spine X-ray image. It was difficult for radiological technologists to make a desirable image for Whole-spine. X-ray film due to the difference between cervical verte