• Journal of Korean society of Dental Hygiene
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• v.17 no.6
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• pp.1095-1107
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• 2017

Objectives: This study was designed to provide raise awareness of the guidelines associated with radiation, including those associated with ensuring safety at dental clinics. Methods: A survey was conducted on the degree of awareness on dental radiation among adults over age 20 in Seoul and Gyeonggi Province from December 2016. The questionnaire copies from 21 respondents whose answers were insincere were excluded from analysis. A total of 320 copies, equivalent to 93.4% of the total data collected, were used in the analysis. Results: Dental radiography was found to have been experienced by 60. 5% of the subjects, and 83.4% of them did not receive any explanation to the radiation exposure, while 78.7% had no experience wearing protective equipment. As a result of investigating factors affecting the recognition of dental radiation, it was found that female subjects had a higher awareness of the hazards associated with dental radiation hazard and the necessity to provide information. Conclusions: It is necessary to educate the dental medical personnel to raise awareness on radiation exposure and the need for protective equipment, especially when checking for pregnancy.

• Journal of radiological science and technology
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• v.43 no.4
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• pp.259-264
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• 2020

Radiation causes radiation hazards in the human body. In Korea, a case of radiation necrosis occurred in 2014. In this study, the scatter and shielding efficiency according to lead shielding were classified into epidermis and dermis for 0.511 MeV used in nuclear medicine. In this study, experiments were conducted using the slab phantom that represents calibration and the dose of human trunk. Experimental results showed that the shielding rate of 0.25 mmPb was 180% in the epidermis and 96% in the dermis. Shielding at 0.5mmPb showed shielding rates of 158%in the epidermis and 82% in the dermis. As a result of measuring the absorbed dose by subdividing the thickness of the dermis into 0.5 mm intervals, when the shielding was carried out at 0.25 mmPb, the dose appeared to be about 120% at 0.5 mm of the dermis surface, and the dose was decreased at the subsequent depth. Shielding at 0.5 mmPb, the dose appeared to be about 101% at the surface 0.5 mm, and the dose was measured to decrease at the subsequent depth. This result suggests that when lead aprons are actually used, the scattering rays would be sufficiently removed due to the spaces generated by the clothes and air, Therefore, the scattered ray generated from lead will not reach the human body. The ICRU defines the epidermis (0.07), in which the radiation-induced damage of the skin occurs, as the dose equivalent. If the radiation dose of the dermis is considered in addition, it will be helpful for the evaluation of the prognosis for radiation hazard of the skin.

• Journal of Gynecologic Oncology
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• v.29 no.6
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• pp.97.1-97.12
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• 2018

Objective: Women with cervical cancer (CC) found to have positive surgical margins, positive lymph nodes, and/or parametrial invasion receive a survival benefit from postoperative chemoradiotherapy (CRT) vs. radiation therapy (RT) alone. However, older women may not benefit to the same extent, as they are at increased risk of death from non-oncologic causes as well as toxicities from oncologic treatments. This study sought to evaluate whether there was a survival benefit of CRT over RT in elderly patients with cervical cancer. Methods: The National Cancer Database was queried for patients ${\geq}70$ years old with newly diagnosed IA2, IB, or IIA CC and positive margins, parametrial invasion, and/or positive nodes on surgical resection. Statistics included logistic regression, Kaplan-Meier overall survival (OS), and Cox proportional hazards modeling analyses. Results: Altogether, 166 patients met inclusion criteria; 62 (37%) underwent postoperative RT and 104 (63%) underwent postoperative CRT. Younger patients and those living in areas of higher income were less likely to receive CRT, while parametrial invasion and nodal involvement were associated with an increased likelihood (p<0.05 for all). There were no OS differences by treatment type. Subgroup analysis by number of risk factors, as well as each of the 3 risk factors separately, also did not reveal any OS differences between cohorts. Conclusion: In the largest such study to date, older women with postoperative risk factor(s) receiving RT alone experienced similar survival as those undergoing CRT. Although causation is not implied, careful patient selection is paramount to balance treatment-related toxicity risks with theoretical outcome benefits.

• Journal of Radiation Industry
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• v.7 no.2_3
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• pp.155-159
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• 2013

Late effects of chronic exposure to gamma radiation are potential hazards to worker in radiation facilities as well as to the general public. Recently, chronic gamma radiation exposure effects have become a serious concern. Using a total of 60 mice, we studied the biological effects of medium-dose chronic exposure to gamma radiation. Sixty female 6-week-old specific pathogen free Balb/c mice were randomly divided into six groups (five groups irradiated and one non-irradiated control group). Irradiation was carried out for 7 days using gamma rays at dose rates of 119.65, 238.10, 357.14, 476.19 and $595.24mGy\;h^{-1}$ with total doses 20, 40, 60, 80 and 100 Gy. After irradiation, we determined survival rate of gamma radiation exposed mice during 1 week and 476.19 and $595.24mGy\;h^{-1}$ exposed group mice showed less 10% of survival rate. Otherwise, 119.65, 238.10 and $357.14mGy\;h^{-1}$ exposed group mice were survived each 100%, 80% and 70%. Half of survived mice after 1 week are immediately sacrifice and counted body and spleen weights. Compared with control non-irradiated group, total body weights and spleen weights isolated from 119.65, 238.10 and 357.14 irradiated group mice showed significant decreased. However, no significant alteration was observed between 119.65, 238.10 and $357.14mGy\;h^{-1}$ irradiated group. Overall, our results show for the first time that medium-dose chronic gamma radiation has the potential to stimulation of biological effects.

• The Korean Society of Law and Medicine
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• v.14 no.2
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• pp.119-142
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• 2013

It is not easy to regulate the amount of radiation used for the medical purpose as there usually is more good than harm to the patient's health and life caused by the medical exposure to the radiation. However, the rapid increase of the use of diagnostic radiation involves a high possibility of increasing the radiation hazard exposure. Therefore, it is imperative to implement effective regulations in order to secure the safety of diagnostic radiation. The one and only rule we currently have for the diagnostic radiation is "Medicine Act" with only one clause dedicated to regulate the safety management that does not include any rules for the medical radiation. A set of inclusive rules for the whole medical radiation inclusive of diagnostic radiation and therapeutic radiation need to be based on the "Medicine Act" rather than "Nuclear Safety Act" in order to protect the medical professionals, patients and the guardians of patients from the hazards of diagnostic and/or therapeutic radiation that was not used the purpose of medical treatment. If there is an administrative measure to be imposed to secure the safety of diagnostic radiation, it is considered as exertion of governmental authority of administrative agency. There must be clear and realistic legal guidelines for in-fringe on people's interests. The administrative measures for the safety management of the diagnostic radiation must be clearly and specifically based on the law and the detailed standards for the administrative measures must be dele-gated by the presidential decree or departmental ordinance. Accordingly, the restrictions imposed by the administrative measures to the "Safety Inspection Institute of Radiation along with Radiation Exposure Measuring Institutes" should have clear legal basis as well and the detailed standards for the administrative measures should be regulated by the Ministry of Health and Welfare decree instead of the notification by the Director of Korean Centers for Disease Control and Prevention. While securing the safety of radiation on one side, careful review and up-grade on our legal system for the safety management of the diagnostic radiation is required on the other side to guarantee the legality, interest balance and reliability of the administrative measures.

• Journal of Radiation Protection and Research
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• v.9 no.2
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• pp.67-75
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• 1984

As a part of studies on acute effects of high dose irradiation the present report was carried out to evaluate the changes of the leukocyte life span in the Newzealand white male rabbits by a single whole body exposure to gamma rays from $^{60}Co$ teleirradiation unit. The exposure was done in dose levels of 100, 300, 550 and 1,000 rad to each experimental group of 10 rabbits. The life span and apparent half survival time of leukocytes, and the elution rate of leukocytes in the circulating blood were measured by McMillan method using $^{51}Cr$. 1. As a critical indicator of radiation hazards of the Newzealand male rabbits, the LD 50/30 and LD 100/30 after whole body exposure was estimated as 550 and 1,000 rads respectively. 2. The life span of leukocyte in the circulation after irradiation was slightly shortened in the 100 rad irradiated group, as compared with the unirradiated control group, but markedly shortened in the 300, 550 and 1,000 rads irradiated group. 3. After irradiation, decrease of leukocyte half survival time in the circulation showed the same pattern as that of leukocytes life span. 4. As the irradiation doses increased, the elution rate of $^{51}Cr$ loss from $^{51}Cr$ tagged leukocytes in the circulation were markedly increased gradually. 5. The life span shortening of leukocytes in the circulation after irradiation seems to occure by two processes of senescence acceleration and early destruction.

• Imaging Science in Dentistry
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• v.43 no.4
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• pp.253-259
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• 2013

Purpose: Radiographs is an integral part of patient management in dentistry, despite their detrimental effects. As the literature pertaining to radiation protection among Indian dental practitioners is sparse, exploring such protection is needed. Materials and Methods: All private dental practitioners in Mangalore, India were included in the study. A structured, pre-tested, self-administered questionnaire was employed to assess the knowledge, attitudes, practices, previous training, perceptions towards the need to spread awareness, and willingness to gain and implement knowledge about radiation hazards and protection. Information regarding each respondent's age, gender, education, and type and duration of practice was collected. Results: Overall, 87 out of 120 practitioners participated in the study. The mean knowledge, attitude, and practice scores were $9.54{\pm}2.54$, $59.39{\pm}7.01$, and $5.80{\pm}3.19$, respectively. Overall, 25.3% of the respondents had undergone training in radiation protection, 98.9% perceived a need to spread awareness, and 94.3% were willing to improve their knowledge. Previous training showed a significant correlation with age, sex, and duration of practice; attitude was significantly correlated with education and type of practice; and knowledge scores showed a significant correlation with type of practice. Conclusion: Although the knowledge and practices of respondents were poor, they had a positive attitude and were willing to improve their knowledge. Age, sex, and duration of practice were associated with previous training; education and type of practice with attitude scores; and type of practice with knowledge scores. The findings of this study suggest a policy is needed to ensure the adherence of dental practitioners to radiation protection guidelines.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.325-336
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• 2019

The activity concentrations of $^{226}Ra$, $^{232}Th$, and $^{40}K$ from 102 building materials samples were determined using a high-purity germanium (HPGe) detector. The activity concentrations were evaluated for possible radiological hazards to the human health. The excess lifetime cancer risks (ELCR) were also estimated, and the average values were recorded as $0.42{\pm}0.24{\times}10^{-3}$, $3.22{\pm}1.83{\times}10^{-3}$, and $3.65{\pm}1.85{\times}10^{-3}$ for outdoor, indoor, and total ELCR respectively. The activity concentrations were further subjected to RESRAD-BUILD computer code to evaluate the long-term radiation exposure to a dweller. The indoor doses were assessed from zero up to 70 years. The simulation results were $92{\pm}59$, $689{\pm}566$, and $782{\pm}569{\mu}Sv\;y^{-1}$ for indoor external, internal, and total effective dose equivalent (TEDE) respectively. The results reported were all below the recommended maximum values. Therefore, the radiological hazards attributed to building materials under study are negligible.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.224-235
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• 2022

This study aimed to confirm the status of media reports on space hazards using topic modeling analysis of media articles that are related to space hazards for the past 12 years. Therefore, Latent Dirichlet Allocation (LDA) analysis was performed by collecting over 1200 space hazards articles between 2010 and 2021 on solar storm, artificial space objects, and natural space objects from BIGKins news platform. The articles related to solar storm focused on three topics: the effect of solar explosion on satellites; effect of solar explosion on radio communication in Korea, centered on the Korean Space Weather Center; and relationship between aircrew and space radiation. The articles related to artificial space objects focused on three topics: the threat of space garbage to satellite and space stations and the transition of useful objects into space junk; the relationship between space garbage and humanity as shown in movies; and the effort of developed countries for tracking, monitoring, and disposing of space garbage. The articles related to natural space objects focused on two topics: International Space Agency's tracking and monitoring of near-Earth asteroids and the countermeasures of collisions, and the evolution and extinction of dinosaurs and mammals, with a focus on the collisions of asteroids or comets. Therefore, this study confirmed that domestic media play a role in conveying dangers of space hazards and arousing the attention of public using a total of eight themes in various fields such as society and culture, and derived education method and policy on space hazards.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4253-4264
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• 2022

Since the implementation of the phosphate project in Bled El-Hadba (BEH) deposit, western region of Tébessa, no detailed study has been conducted to assess the natural radioactivity distribution and the associated radiological risk parameter for this open-pit mine. For the sake of determining a credible premining reference database for the region of interest, 21 samples were collected from different geological layers of the above-mentioned deposit. Gamma Spectrometry was applied for measuring radioactivity using a high resolution HPGe semiconductor detector. The obtained activity results have shown a significant broad variation in the radioactive contents for the different phosphate samples. The total average concentrations (in Bq·kg^-1) for ²²⁶Ra, ²³⁸U, ²³⁵U, ²³²Th and ⁴⁰K computed for the different type of phosphate layers were found to be 570 ± 169, 788 ± 280, 52 ± 18, 66 ± 6 and 81 ± 18 respectively. The mean activity concentrations of the measured radionuclides were compared to other regional and worldwide deposits. The ratios between the detected radioisotopes have been calculated for spatial distribution of natural radionuclides in the study area. Based on the aforementioned activity concentrations, the corresponding radiation hazard parameters were assessed. Correlations between the obtained parameters were drawn and a multivariate statistical analysis (Pearson Correlation, Cluster and Factor analysis) was carried out in order to identify the existing relationships.