• Journal of radiological science and technology
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• v.33 no.2
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• pp.85-91
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• 2010

Digital radiography has been replacing rapidly the analog radiography for diagnosis of pneumoconiosis. The purpose of this study is to compare quality control of digital radiography (DR) and analog radiography (AR) for chest radiography in medical institution for pneumoconiosis (MIP) For the first time, we visited MIP to evaluate the chest radiography which is used for patients with pneumoconiosis, including equipment, technical parameters and reading environment. There were 33 institutions. DR and AR were installed in 24 and 9 institutions, respectively. Between DR and AR, we compared the radiological technique (RT), image quality (IQ) and reading environment (RE) to use the guideline published by Occupational Safety and Health Research Institute (OSHRI). The image quality was rated by two experienced chest radiologists for pneumoconiosis with certified from OSHRI. The chest radiography equipment was not significantly difference between AR and DR, but there were significantly difference in tube voltage and grid ratio used for chest radiography except to tube current, exposure time. Statistically, DR is significantly higher in RT(70.3 vs. 43.8, p = 0.009), RE(77.7 vs. 33.3, p = 0.004) than AR, but it's not significantly difference in IQ (65.6 vs. 52.8, p = 0.050). AR and DR in RT were passed 33.3%, 75.0% respectively (p = 0.044) and 44.4%, 79.2% (p = 0.090) in IQ and 44.4%, 91.7% (p = 0.009) in RE. In MIP, DR needs to replace AR in diagnosis of pneumoconiosis.

• Journal of the Korean Society of Radiology
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• v.10 no.7
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• pp.551-557
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• 2016

National competency standards, which are the contents of the knowledge, skills and attitudes required to perform a job in industry, is organized by the country. the job performance was evaluated based on the National competency standards from the third-year grade of radiology students by using field-based training courses. according to the evaluation results, students showed over 93% satisfactory ratio of job performance in all radiography projection methods. Therefore, it can be predicted that field-based training courses for students made a positive effect on improving their job performance. Exposure methods with CR equipment were evaluated the best rating, yet it has various problems. The standard deviation between students was very high, and the CR operation skill of students was insufficient. Film methods was evaluated also showed problems, due to the exposure condition setting and developing operation. although DR method was rated good to the students, it was evaluated that the operation skill of DR and the ancillary equipment operation skill was shortage. By supplementing the evaluation factors below proficiency levels to a course management in each exposure method, it could help students course achievement. Also, it could help students to improve job performance of clinical areas after graduation.

• Journal of Radiation Protection and Research
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• v.29 no.2
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• pp.129-139
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• 2004

Recently, much attentions are paid to the risk associated with increased uses of medium size radiation sources in medical and industrial fields. In this study, radiation risks to the worker and to the general public due to $^{99m}Tc$ generator were assessed for both normal and accident conditions. Based on the event tree technique, exposure scenarios for various situations were derived. Uncertainty analysis based on the Monte-Carlo technique was applied to the risk assessment for workers and members of the public in the vicinity of the work place. In addition, sensitivity analysis was performed on each of the five independent input parameters to identify importance of the parameters with respect to the resulting risk. Because the frequencies of normal tasks are fat higher than those of accidents, the total risk associated with normal tasks were higher than the accident risk. The annual dose due to normal tasks were $0.6mSv\;y^{-1}$ for workers and $0.014mSv\;y^{-1}$ for public, while in accident conditions $3.96mSv\;y^{-1}\;and\;0.0016mSv\;y^{-1}$, respectively. Uncertainty range of accident risk was higher by 10 times than that of normal risk. Sensitivity analysis revealed that source strength, working distance and working time were crucial factors affecting risk. This risk analysis methodology and its results will contribute to establishment of risk-informed regulation for medium and large radioactive sources.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.50-53
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• 2019

Purpose Yttrium-90 (Y-90) is high-energy beta emitters ($E{\beta}$, max = 2.28 MeV) with the mean penetration depth of 2.5 mm in tissue. Radioactive microspheres containing Y-90 is widely used for the transarterial radioembolization of hepatocellular carcinoma. However, bremsstrahlung radiation from Y-90 can cause the external radiation exposure to medical staff who handle the Y-90 microspheres. In this study, shielding device for Y-90 microspheres was developed to minimize the external radiation exposure. Materials and Methods Y-90 microsphere shielding device was made from 6 mm thicknesses of tungsten including the lead glass window. Radiation shielding ability of Y-90 microsphere shielding device was evaluated using 4 GBq of $SIR-Spheres^{(R)}$ Y-90 microspheres. The bremsstrahlung radiation was measured using radiation survey meter. Results The mean radiation dose of Y-90 microspheres in acrylic shield was $261.7{\pm}2.3{\mu}Sv/h$ (n=5) at 10 cm away from the shield. With the additional tungsten shielding device, it was $23.7{\pm}1.3{\mu}Sv/h$ (n=5). Thus, the bremsstrahlung radiation dose was decreased by 90.9%. At 50 cm away from the shield, bremsstrahlung radiation was reduced by 89.2% after using tungsten shielding device. Conclusion During the preparation and radioembolization of Y-90 microsphere, medical staff are exposed to external radiation. In this study, we demonstrated that the use of tungsten shielding device devices significantly reduced the amount of bremsstrahlung radiation. Y-90 microsphere tungsten shielding device can be highly effective in reducing the bremsstrahlung radiation.

• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.133-140
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• 2017

Increasing concerns on radioactive wastes have drawn much attention on the development of remediation technologies. Massive amounts of radioactive wastes generated from hospital and nuclear power plants were exposed to our environment. Although physicochemical removal methods were developed, an eco-friendly remediation method has not yet been demonstrated. Recently, an extremophilic bacterium has received much attention due to their extraordinary characteristics. Among them, Deinococcus radiodurans (D. radiodurans) strain was regarded as the best host organism for the removal of radioactive heavy metals and radionuclides, because of their superb characteristics like tolerance against the high level of radioactivity. In this article, we briefly introduced the extraordinary nature of D. radiodurans and also discussed the potential use of D. radiodurans strain for the removal of radioactive wastes.

• Journal of Veterinary Clinics
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• v.30 no.5
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• pp.380-383
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• 2013

This clinical report describes the dental treatment of canine teeth fractures in three cats. These animals were diagnosed by oral examination and dental radiography as having fractured teeth with pulpal exposure. After endodontic treatment was completed, root canal filling material was removed from the coronal access and a trial post placement was performed. The post was permanently cemented after shortening. Teeth were etched and a bonded composite resin core formed and then shaped using rotary instruments. Fractured canine teeth were treated without any complications observed during a six-month follow-up period, proving that fractured cat canine teeth can be treated successfully with root canal therapy followed by restorative treatment with posts and composite resin.

• The Korean Journal of Nuclear Medicine Technology
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• v.20 no.2
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• pp.32-35
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• 2016

Purpose The goal for this study is to figure out that medical staff except Nuclear Medicine Department could be exposed to radiation from the patients who take Nuclear Medicine examination. Materials and Methods Total 250 patients (Bone scan 100, Myocardial SPECT 100, PET/CT 50) were involved from July to October in 2015, and we measured patient dose rate two times for every patients. First, we checked radiation dose rate right after injecting an isotope (radiopharmaceutical). Secondly, we measured radiation dose rate after each examination. Results In the case of Bone scan, dose rate were $0.0278{\pm}0.0036mSv/h$ after injection and $0.0060{\pm}0.0018mSv/h$ after examination (3 hrs 52 minutes after injection on average). For Myocardial SPECT, dose rate were $0.0245{\pm}0.0027mSv/h$ after injection and $0.0123{\pm}0.0041mSv/h$ after examination (2 hrs 09 minutes after injection on average). Lastly, for PET/CT, dose rate were $0.0439{\pm}0.0087mSv/h$ after examination (68 minutes after injection on average). Conclusion Compared to Nuclear Safety Commission Act, there was no significant harmful effect of the exposure from patients who have been administered radiopharmaceuticals. However, we should strive to keep ALARA(as low as reasonably achievable) principle for radiation protection.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.253-264
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• 1990

The purpose of this study was to estimate the distribution of absorbed doses of each important organs of head and neck region in panoramic radiography. Radiation dosimetry at internal anatomic sites and skin surfaces of phantom (RT-210 Humanoid Head & Neck Section/sup R/) was performed with lithium fluoride (TLD-100/sup R/) thermoluminescent dosimeters according to change of kilovoltage (65kVp, 75kVp and 85kVp) with 4 miliamperage and 20 second exposure time. The results obtained were as follows; Radiation absorbed doses of internal anatomic sites were presented the highest doses of 1.04 mGy, 1.065 mGy and 2.09 mGy in nasopharynx, relatively high doses of 0.525 mGy, 0.59 mGy and 1.108 mGy in deep lobe of parotid gland, 0.481 mGy, 0.68 mGy and 1.191 mGy in submandibular gland. But there were comparatively low doses of 0.172 mGy and 0.128 mGy in eyes and thyroid gland that absorbed dose was estimated at 85kVp. Radiation absorbed doses of skin surfaces were presented the highest doses of 1. 263 mGy, 1.538 mGy and 2.952 mGy in back side of first cervical vertebra and relatively high doses of 0.267 mGy, 0.401 mGy and 0.481 mGy in parotid gland. But there were comparatively low doses of 0.057 mGy, 0.068 mGy and 0.081 mGy in philtrum and 0.059 mGy in middle portion of chin that absorbed dose was estimated at 85kVp. According to increase of kilovoltage, the radiation absorbed doses were increased 1.1 times when kilovolt age changes from 65kVp to 75kVp and 1.9 times when kilovolt age changes from 75kVp to 85kVp at internal anatomic sites. According to increase of kilovoltage, the radiation absorbed doses were increased 1.3 times when kilovolt age changes from 65kVp to 75kVp and 1.6 times when kilovoltage changes from 75kVp to 85kVp at skin surfaces.

• Journal of the Korean Society of Radiology
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• v.14 no.2
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• pp.77-83
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• 2020

This study investigated the radiation protection of therapeutic radiologists. Based on the change in X-ray energy and MU value, the space dose rate in the treatment room after the irradiation was measured. 6MV, 10MV and 15MV photon beams were exposed to radiation inside the treatment room based on 300MU, 600MU and 1000MU using a linear accelerator. And repeated 10 times under the same conditions. As a result of the experiment, 0.1555 μSv/h for 6MV 300MU, 0.157 μSv /h for 300sec, 0.152 μSv/h, 0.156 μSv/h for 600MU, and 0.157 μSv/h 0.152 μSv/h for 1000MU. 300MU of 10MV was 0.49 μSv/h, 0.309 μSv/h, and 0.69 μSv/h, 0.416 μSv/h for 600MU, respectively, and 1000MU was 0.977 μSv/h and 0.478 μSv/h, respectively. The 300MU of 15MV was 3.02 μSv/h, 1.2 μSv/h, 5.459 μSv/h at 600MU, 7.34 μSv/h at 1.836 μSv/h 1000MU, and 2.709 μSv/h. The average spatial dose rate of 6MV was not significantly different from the natural spatial dose rate in the treatment room. High spatial dose rates were measured at 10 MV and 15 MV and were attenuated over time. Therefore, entering the treatment room after a certain period of time (more than 60 seconds) is considered to be effective to prevent the exposure dose of radiation workers.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.4
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• pp.516-524
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• 2015

Objectives: This study aims to investigate the current status of knowledge, awareness and health risk concerns on occupational radiation exposures among firefighters in Korea. The results will provide basic information for developing a prevention program to minimize adverse health effects relating to radiation exposure among firefighters. Methods: A questionnaire was composed of general characteristics of participants, and their knowledge, awareness, health risk concerns relating to occupational radiation exposure. It was distributed by email to all of 307 firefighters in Jeollabukdo in April 2014 and 259 of them (response rate 84.3%) were responded. Answers were analyzed for descriptive statistics including frequencies and percentages. SPSS/WIN 18.0 program was utilized for statistical analysis of t-test, ANOVA and Pearson's correlation. Results: The average score of radiation protection knowledge was $5.83{\pm}1.77$ ($average{\pm}SD$) out of 10. The score of awareness and health risk concerns on radiation exposure were 4.27, 3.94 out of 5, respectively. The results indicated that the knowledge on the characteristics of radiation was marginal among the firefighters, while the awareness and health risk concerns relating to radiation exposures were relatively higher comparing to other professions. Conclusions: Knowing the characteristics of potential risks is the first step for minimizing the adverse health effects relating to the risks. Therefore, it is necessary to provide adequate training and information on radiation and exposure protection methods for firefighters.