• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.132-135
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• 2002

In this paper, a new method to implement the photopolymer-based VHOE using the optimized exposure time schedule is proposed. The cumulative grating strength dependence on the exposure energy is mathematically modeled by using the fourth-order polynomial function and then using this model, the optimized exposure-time schedule of the photopolymer for recording the given multiple gratings is calculated.

• 한국자기공명학회논문지
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• 제26권4호
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• pp.59-65
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• 2022

Benzo[a]pyrene (BaP), one of the polycyclic aromatic hydrocarbons (PAHs), is an endocrine disruptor and carcinogenic. This study was conducted to investigate the metabolic changes of zebrafish short-term exposure to BaP using nuclear magnetic resonance (NMR) spectroscopy. In our results, the multivariate analysis showed that the metabolic responses were differed according to the exposure concentration. Also, it was observed that exposure to high concentration of BaP (162 ㎍/L and 1620 ㎍/L) increased the levels of creatine, histidine, and inosine in zebrafish, which means high concentration of BaP exposure affected the energy metabolism and immune function in zebrafish.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.725-733
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• 2023

The Korea Institute of Radiological and Medical Sciences has started a radiation epidemiological study, titled "Korean Radiation Worker Study," to evaluate the health effects of occupational exposure to radiation. As a part of this study, we investigated the methodologies and results of reconstructing organ-specific absorbed doses based on personal dose equivalent, H_p(10), reported from 1984 to 2019 for 20,605 Korean radiation workers. For the organ dose reconstruction, representative exposure scenarios (i.e., radiation energy and exposure geometry) were first determined according to occupational groups, and dose coefficients for converting H_p(10) to organ absorbed doses were then appropriately taken based on the exposure scenarios. Individual annual doses and individual cumulative doses were reconstructed for 27 organs, and the highest values were observed in the thyroid doses (on average 0.77 mGy/y and 10.47 mGy, respectively). Mean values of individual cumulative absorbed doses for the red bone marrow, colon, and lungs were 7.83, 8.78, and 8.43 mSv, respectively. Most of the organ doses were maximum for industrial radiographers, followed by nuclear power plant workers, medical workers, and other facility workers. The organ dose database established in this study will be utilized for organ-specific risk estimation in the Korean Radiation Worker Study.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 추계학술발표회요약집
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• pp.304.1-304
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• 2001

• Journal of Radiation Protection and Research
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• 제32권1호
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• pp.27-34
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• 2007

본 논문에서는 일반인과 상대적으로 방사선피폭이 많은 핵의학 종사자들의 생체신호를 측정하여 방사선 피폭에 따른 생체신호 변화 정도를 비교 평가하고자 하였다. 핵의학과 종사자와 타부서 종사자들의 생체신호를 비교평가 하기 위하여 핵의학 종사자는 충북대학교 병원 핵의학과 종사자를 타부서 종사자는 전남대학교 병원 CT설, 일반촬영실, 의무기록실, 접수실 그리고 일반 사무실 종사자들에게 실험을 실시하였다. 실험에 쓰인 계측 장비들은 방사선량 계측을 위하여 Arrow -Tech사(社)의 poket dosimeter를 사용하였고, 생체신호인 심박수, 혈압을 측정하기 위하여 GE Medical Systems사(社)의 TONOPORT V, Heat flux, Skin temperature, Energy expenditure을 측정하기 위하여 Body Media사(社)의 Armband 인 SenseWare 2000을 사용하였다. 실험 결과 다음과 같은 결론을 얻었다. 1) 일일 장소에 따른 개인별 피폭 선량은 핵의학과가 3.05 uSv를 기록하였고, CT실, 일반촬영실, 병원 의무기록실, 병원 접수실, 일반 사무실, 교원 등이 뒤를 이었다. 핵의학과가 다른 장소(핵의학과를 제외한 나머지)에 비해 약1.4배 선량이 많았다. 2) 방사선 누적선량이 Heat flux, Skin temperature, Energy expenditure와는 별다른 관계가 없는 것을 알 수 있었다. 3) Blood pressure 에서는 Systolic blood pressure와 Diastolic blood pressure 이 핵의학과 종사자, 일반사무직 종사자, 일반인이 고르게 나타났다. 방사선선량이 상대적으로 많은 곳에서 근무하는 핵의학 종사자와 다른 직종에 종사하는 사람의 혈압을 비교해 왔을 때 변화가 없었다. 이 같은 결과로 볼 때 방사선 피폭이 상대적으로 많은 핵의학종사자들의 방사선 피폭에 따른 유해는 없다는 것을 알 수 있었다.

• Journal of Radiation Protection and Research
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• 제9권1호
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• pp.26-32
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• 1984

원자발전소의 가동에 따른 기체상 방사성물질의 방출로부터 주변주민이 받는 피해는 정상상태와 사고 경우로 나눠서 해석하게 된다. 정상상태 경우 방사성물질의 대기확산 모델은 주로 연평균 통계치를 사용하는 Gaussian식을 채택하나 사고결과 해석시에는 풍향 풍속의 변화를 추적하는 실시간(real time) 확산모델을 이용한다. 본고에서는 고려 원자력발전소의 정상가동에 따른 $1977{\sim}1982$년 6개년에 걸친 주변주민의 피복 선량을 Gaussian 직선제도 모델에 의한 대기확산인자치로 계산하였으며 사고경우에 대해서 요구되는 대상지역 주변의 대기확산계수 특성치를 구하는 간편한 영상처리방식을 실제 실험을 통해 제시하였다.

• Journal of Radiation Protection and Research
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• 제44권4호
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• pp.128-148
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• 2019

Massive environmental monitoring has been conducted continuously since the Fukushima Daiichi Nuclear Power accident in March of 2011 by different monitoring methods that have different features together with migration studies of radiocesium in diverse environments. These results have clarified the characteristics of radiological environments and their temporal change around the Fukushima site. At three months after the accident, multiple radionuclides including radiostrontium and plutonium were detected in many locations; and it was confirmed that radiocesium was most important from the viewpoint of long-term exposure. Radiation levels around the Fukushima site have decreased greatly over time. The decreasing trend was found to change variously according to local conditions. The air dose rates in environments related to human living have decreased faster than expected from radioactive decay by a factor of 2-3 on average; those in pure forest have decreased more closely to physical decay. The main causes of air dose rate reduction were judged to be radioactive decay, movement of radiocesium in vertical and horizontal directions, and decontamination. Land-use categories and human activities have significantly affected the reduction tendency. Difference in the air dose rate reduction trends can be explained qualitatively according to the knowledge obtained in radiocesium migration studies; whereas, the quantitative explanation for individual sites is an important future challenge. The ecological half-lives of air dose rates have been evaluated by several researchers, and a short-term half-life within 1 year was commonly observed in the studies. An empirical model for predicting air dose rate distribution was developed based on statistical analysis of an extensive car-borne survey dataset, which enabled the prediction with confidence intervals. Different types of contamination maps were integrated to better quantify the spatial data. The obtained data were used for extended studies such as for identifying the main reactor that caused the contamination of arbitrary regions and developing standard procedures for environmental measurement and sampling. Annual external exposure doses for residents who intended to return to their homes were estimated as within a few millisieverts. Different forms of environmental data and knowledge have been provided for wide spectrum of people. Diverse aspects of lessons learned from the Fukushima accident, including practical ones, must be passed on to future generations.

• 방사선산업학회지
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• 제7권2_3호
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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.

• 방사선산업학회지
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• 제7권2_3호
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• pp.135-139
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• 2013

Recently, chronic gamma radiation exposure on biological effects in middle dose-rates have become a serious concern. We investigated the biological effects of middle dose chronic exposure to gamma ray. Fifty male 6-week-old specific free Balb/c mice were randomly divided into five groups (four groups irradiated and one non-irradiated control group). Gamma radiation exposed in Gamma phytotron on Advanced Radiation Technology Institute (Jeongeup, Korea). Irradiation was carried out for 1 or 2 weeks using gamma rays at dose rates of 45 and $50mGy\;h^{-1}$ with total doses 7.56 Gy ($45mGy\;h^{-1}$, 1 week), 8.4 Gy ($50mGy\;h^{-1}$, 1 week), 15.12 Gy ($45mGy\;h^{-1}$, 2 weeks) and 16.8 Gy ($50mGy\;h^{-1}$, 2 weeks). After irradiation, immediately we sacrificed and counted body and organ weights. Moreover we counted spleen cell numbers. Compared with control non-irradiated group, all irradiated groups of body and spleen weights showed significant decreased. However, no significant alteration was observed between same irradiated period groups. In spleen cell numbers, reduced compared to the control group. However, significant alteration was observed between same irradiated period groups ($45mGy\;h^{-1}$, $50mGy\;h^{-1}$). These results demonstrated biological effects according to the radiation dose rate and irradiated period.

• 제어로봇시스템학회논문지
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• 제9권4호
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• pp.296-303
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• 2003

A personal portable type electronic dosimeter using silicon PIN photodiode and small GM tube is recently attracting much attention due to its advantages such as an immediate indication function of dose and dose rate, alerting function, and efficient management of radiation exposure history and dose data. We designed and manufactured a semiconductor radiation detector aimed to directly measure X-ray and v-ray irradiated in silicon PIN photodiode, without using high-priced scintillation materials. Using this semiconductor radiation detector, we developed an active electronic dosimeter, which measures the exposure dose using pulse counting method. In this case, it has a shortcoming of over-evaluating the dose that shows the difference between the dose measured with electronic dosimeter and the dose exposed to the human body in a low energy area. We proposed an energy compensation filter and developed a dose conversion algorithm to make both doses indicated on the detector and exposed to the human body proportional to each other, thus enabling a high-precision dose measurement. In order to prove its reliability in conducting personal dose measurement, crucial for protecting against radiation, the implemented electronic dosimeter was evaluated to successfully meet the IEC's criteria, as the KAERI (Korea Atomic Energy Research Institute) conducted test on dose indication accuracy, and linearity, energy and angular dependences.