• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.598-608
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• 2017

A new radiation scale is proposed. With empathy toward the vast majority of people who are not well versed in radiation and related matters, and thus suffering from misunderstanding that breeds unnecessary fear of radiation, the aim of proposing a new radiation scale, radiation index (RAIN), is to put the general public at ease with the concept of radiation. RAIN is defined in dimensionless numbers that relate any specific radiation dose to a properly defined reference level. As RAIN is expressed in plain numbers without an attached scientific unit, the public will feel comfortable with its friendly look, which in turn should help them understand radiation dose levels easily and allay their anxieties about radiation. The expanded awareness and proper understanding of radiation will empower the public to feel that they are not hopeless victims of radiation. The correspondence between RAIN and the specific accumulated dose is established. The equivalence will allow RAIN to serve as a common language of communication for the general public with which they can converse with radiation experts to discuss matters related to radiation safety, radiation diagnosis and therapy, nuclear accidents, and other related matters. Such fruitful dialogues will ultimately enhance public acceptance of radiation and associated technologies.

• Toxicological Research
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• v.22 no.4
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• pp.417-422
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• 2006

Cytogenetic and hematological analysis was performed in peripheral blood obtained from cattle bred in the high background radiation areas (HBRA, Goesan-gun, Cheongwon-gun, Boeun-gun) and a control area. The frequencies of gamma-ray induced micronuclei (MN) in the cytokinesis-blocked (CB) lymphocytes at several doses were measured in 3 cattle. An estimated dose of radiation was calculated by a best fitting linear-quadratic model based on the radiation-induced MN formation from the bovine lymphocytes exposed in vitro to radiation over the range from 0 mGy to 1,969 mGy. The measurements performed after irradiation showed dose-related increases in the MN frequency in each donors. The results were analyzed using a linear-quadratic model with a line of best fit of $y=(0.0583{\pm}0.0137)D+(0.0366{\pm}0.0081)D^2+(0.0093{\pm}0.0015)$ (y=number of MN/CB cells and D=irradiation dose in Gy). MN rates per 1,000 CB lymphocytes of cattle from the Goesan-gun, Cheongwon-gun, Boeun-gun and the control area were $6.50{\pm}2.72,\;9.00{\pm}4.50,\;10.89{\pm}4.23\;and\;9.60{\pm}4.70$, respectively. The MN frequencies of CB lymphocytes from cattle bred in 4 areas mean that the values are within the background variation in this experiment. The MN frequencies and hematological values were similar regardless of whether the cattle were bred in the HBRA or the control area.

• Journal of Radiation Protection and Research
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• v.47 no.4
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• pp.214-225
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• 2022

Background: The conventional cerium-doped Gd₂Al₂Ga₃O₁₂ (GAGG(Ce)) scintillator-based gamma-ray imager has a bulky detector, which can lead to incorrect positioning of the gammaray source if the shielding against background radiation is not appropriately designed. In addition, portability is important in complex environments such as inside nuclear power plants, yet existing gamma-ray imager based on a tungsten mask tends to be weighty and therefore difficult to handle. Motivated by the need to develop a system that is not sensitive to background radiation and is portable, we changed the material of the scintillator and the coded aperture. Materials and Methods: The existing GAGG(Ce) was replaced with Bi₄Ge₃O₁₂ (BGO), a scintillator with high gamma-ray detection efficiency but low energy resolution, and replaced the tungsten (W) used in the existing coded aperture with lead (Pb). Each BGO scintillator is pixelated with 144 elements (12 × 12), and each pixel has an area of 4 mm × 4 mm and the scintillator thickness ranges from 5 to 20 mm (5, 10, and 20 mm). A coded aperture consisting of Pb with a thickness of 20 mm was applied to the BGO scintillators of all thicknesses. Results and Discussion: Spectroscopic characterization, imaging performance, and image quality evaluation revealed the 10 mm-thick BGO scintillators enabled the portable gamma-ray imager to deliver optimal performance. Although its performance is slightly inferior to that of existing GAGG(Ce)-based gamma-ray imager, the results confirmed that the manufacturing cost and the system's overall weight can be reduced. Conclusion: Despite the spectral characteristics, imaging system performance, and image quality is slightly lower than that of GAGG(Ce), the results show that BGO scintillators are preferable for gamma-ray imaging systems in terms of cost and ease of deployment, and the proposed design is well worth applying to systems intended for use in areas that do not require high precision.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.6441-6446
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• 2012

Background: Radiation therapy plays an important role in lung carcinoma treatment. However, the incidence of symptomatic radiation-induced lung injury is high. This study aimed to evaluate radioprotective effects of flavonoids extracted from Astragalus complanatus and mechanisms of action against radiation damage. Methods: Alteration in antioxidant status and levles of several cytokines were investigated in BABL/C mice treated with 4 mg/kg b.wt. flavonoids after exposure to 10Gy thoracic radiation. Results: Serum levels of SOD in the flavonoids+radiation group were significantly higher compared to the radiation control group, while TGF-${\beta}1$ and IL-6 were lower. Mice in the radiation control group displayed more severe lung damage compared with the flavonoids+radiation group. The expression of TGF-${\beta}1$ and TNF-${\alpha}$ in the radiation control group was markedly increased in alveolar epithelial cells and macrophages of the alveolar septum. Conclusions: From the results of the present study, flavonoids could be excellent candidates as protective agents against radiation-induced lung injury.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.72.2-72.2
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• 2011

We have performed the first self-consistent, large-scale simulation of cosmic reionization by stellar sources, including the Population III stars that emerged and were hosted by minihalos at very high redshifts (z~40). Based on this result, we calculate the redshifted radiation background from these stars and the relic H II regions which can be observed at near-infrared and infrared regime. Formation of the first stars inside minihalos are quenched by radiative feedback at z~15, while the relic H II regions have much longer lifetime due to the slow recombination rate. Therefore, the radiation output from the relic H II regions, dominated by Lyman alpha photons, will be observed both in the near-infrared and infrared regime. The estimated background from the first stars inside minihalos are still sub-dominant compared to that from stars inside larger halos, however, and thus complementary observations are necessary, such as redshifted 21-cm line observation.

• Journal of Radiation Protection and Research
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• v.49 no.1
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• pp.40-49
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• 2024

Background: This study aimed to prioritize policy measures to improve radiation safety management in medical institutions using the analytic hierarchy process. Materials and Methods: It adopted three policy options-engineering, education, and enforcement-to categorize safety management measures, the so-called Harvey's 3Es. Then, the radiation safety management measures obtained from the current system and other studies were organized into action plan categories. Using the derived model, this study surveyed 33 stakeholders of radiation safety management in medical institutions and analyzed the importance of each measure. Results and Discussion: As a result, these stakeholders generally identified enforcement as the most important factor for improving the safety management system. The study also found that radiation safety officers and medical physicists perceived different measures as important, indicating clear differences in opinions among stakeholders, especially in improving quality assurance in radiation therapy. Hence, the process of coordination and consensus is likely to be critical in improving the radiation safety management system. Conclusion: Stakeholders in the medical field consider enforcement as the most critical factor in improving their safety management systems. Specifically, the most crucial among the six specific action plans was the "reinforcement of the organization and workforce for safety management," with a relative importance of 25.7%.

• Journal of Korean society of Dental Hygiene
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• v.4 no.1
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• pp.15-29
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• 2004

The purpose of this study was to understand the relationship among knowledge, attitude, and behavior of dental personnel about the defense against dental radiation according to general features, and help them recognize the importance of defense against dental radiation. A questionnaire survey of 187 dental personnel who were working in 121 medical institutions such as university hospitals, general hospitals, hospitals, clinics, and public health centers in Seoul area was conducted from December 2002 to January 2003. Study findings are as follows: 1. The average knowledge score for the defense of radiation was 9.51(full score=14): By the demographic features, the know level for the defense of radiation was appeared to be different with the occupational category, age, academic background, workplace, year of working, and whether having the education of radiation or not. By questionnaire items, the knowledge for the defense of radiation was high in general, but for the item. 'the average amount of being bombed with radiation according occupations cannot be over 20mSv in a year for prescribed 5 years'. it was 18.7%: and for the item. 'the longer the length between focus and film. the less the amount of skin exposure', it was 40.6%. showing less knowledge for these two items. 2. The average attitude score for the defense of radiation was 64.24 (full score=75): By the demographic features, the attitude score was higher with respondents who were 31-35 years old. 11-15 years of working. and having radiation education. The attitude score by questionnaire items was generally high for all the items. 3. The average behavior score for the defense of radiation was 45.43: (a) By the demographic features, the behavior score for the defense of radiation was appeared to be higher with respondents who were dentists for occupational category, the aged for age, holding higher diploma for academic background, working in the university hospitals for workplace, and having longer occupational career for the year of working. (b) The behavior score for the defense of radiation by questionnaire items was lower than that of the attitude score for all the items. For the item, 'the amount of X-ray radiation is adjusted according to such conditions as patients' age, radiating areas, and kind of films', the score was 4.03; and for the item, 'Must receive the education of safety management of radiation periodically', the score was 1.73 and it was the lowest one. 4. As for the correlation among the knowledge, attitude, and behavior for the defense of radiation, the higher the level of knowledge and attitude, the higher the level of behavior.

• Journal of Radiation Protection and Research
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• v.42 no.4
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• pp.222-228
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• 2017

Background: On June 18, 2017, Korea's first commercial nuclear reactor, the Kori Nuclear Power Plant No. 1, was permanently suspended, and the capacity of nuclear power generation facilities will be adjusted according to the governments denuclearization policy. In these circumstances, it is necessary to assess the quality of radiation safety management in nuclear power plants in Korea by evaluating the radiation dose associated with them. Materials and Methods: The average annual radiation dose per unit, the annual radiation dose per person, and the annual dose distribution were analyzed using the radiation dose database of nuclear reactors for the last 5 years. The results of our analysis were compared to the specifications of the Nuclear Safety Act and Medical Law in Korea. Results and Discussion: The annual average per unit radiation dose of global major nuclear power generation was 720 man-mSv, while that of Korea's nuclear power plants was 374 manmSv. No workers exceeded 50 mSv per year or 100 mSv in 5 years. The individual radiation dose according to occupational exposure was 0.59 mSv for nuclear workers, 1.77 mSv for non-destructive workers, and 0.8 mSv for diagnostic radiologists. Conclusion: The radiation safety management of nuclear power plants in Korea has achieved the best outcomes worldwide, which is considered to be the result of the as-low-as-reasonably-achievable (ALARA) approach and strict radiation safety management. Moreover, the occupational exposures were also very low.

• Journal of Radiation Protection and Research
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• v.46 no.4
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• pp.213-217
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• 2021

Background: Radiation exposure can occur as a result of occupational activities utilizing sources of radiation. The average level of occupational exposure is generally similar to the global average, but some workers receive more than this. In this study, the occupational exposure data for workers in Korea to check the recent trend of radiation exposure. Materials and Methods: The data collection and analysis are carried out by two separate periods based on the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) survey. One is the year 2003 to 2014 for a recent survey, and the other is 2015 to 2019. All available data were collected by annual reports from radiation dose registry organizations. Results and Discussion: The annual dose over the record level to the total workers did not change much compared with the total increasing number of workers in this period. The dose to the nuclear fuel cycle field has a tendency to decrease. It resulted from the efforts of radiation dose reduction with high technology introduced to this area. Also, it is important result that the radiation dose to the workers in radiography is remarkably reduced. Conclusion: The number of radiation workers and average doses were analyzed for occupational categories in Korea. It still needs cooperative efforts between the dose registry organizations for the efficient dose management of Korean radiation workers.

• Korean Journal of Veterinary Research
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• v.45 no.4
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• pp.469-475
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• 2005

Cytogenetic and hematological analysis was performed in peripheral blood obtained from pigs bred in the high background radiation areas (HBRA) (Cheongwon-gun and Boeun-gun) and a control area. The frequencies of gamma-ray induced micronuclei (MN) in the cytokinesis-blocked (CB) lymphocytes at several doses were measured in three pigs. An estimated dose of radiation was calculated by a best fitting linear-quadratic model based on the radiation-induced MN formation from the swine lymphocytes exposed in vitro to radiation over the range from 0 mGy to 1,969 mGy. The measurements performed after irradiation showed dose-related increases in the MN frequency in each donors. The results were analyzed using a linear-quadratic model with a line of best fit of $y=0.0005404D^2+0.04237D+0.00833$ [y = number of MN/cytokinesis-blocked (CB) cells and D = irradiation dose in Gy]. MN rates per 1,000 CB lymphocytes of pig from the HBRA (Cheongwon-gun, Boeun-gun) and the control area were $6.70{\pm}2.36$, $9.00{\pm}3.50$ and $11.00{\pm}2.98$, respectively. The MN frequencies of CB lymphocytes from pigs bred in three areas means that the values are within the background variation in this experiment. The MN frequencies and hematological values were similar regardless of whether the pigs were bred in the HBRA or the control area.