• Journal of Radiation Protection and Research
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• 제45권4호
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• pp.154-162
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• 2020

Background: Several studies have reported that wild mushrooms contain high amounts of radioactive cesium (137Cs). After the Fukushima Daiichi Nuclear Power Plant Accident, a significantly high concentration of 137Cs has been detected in wild mushrooms, and their consumption may be the cause of the chronic internal exposure of local consumers to radioactivity. Therefore, an accurate evaluation of the internal radioactivity resulting from mushroom ingestion is needed. Materials and Methods: The 137Cs elution rate through the cooking and digestion stages was evaluated using in vitro experiments. The edible mushroom Pleurotus djamor was taken as a sample for the experiments. The mushrooms were cultivated onto solid media containing 137Cs. We evaluated the internal dose based on the actual conditions using the elution rate data. For various cooking methods, the results were compared with those of other wild edible mushrooms. Results and Discussion: From the elution experiment through cooking, we proved that 25%-55% of the 137Cs in the mushrooms was released during soaking, boiling, or frying. The results of a simulated digestion experiment after cooking revealed that almost all the 137Cs in the ingested mushrooms eluted in the digestive juice, regardless of the cooking method. The committed effective dose was reduced by 20%-75% when considering the dissolution through the cooking process. Conclusion: We found that cooking lowers 137Cs concentration in mushrooms, therefore reducing the amount of radioactivity intake. Besides, since there were differences between mushroom types, we demonstrated that the internal exposure dose should be evaluated in detail considering the release of 137Cs during the cooking stages.

• 한국콘텐츠학회논문지
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• 제16권7호
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• pp.451-456
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• 2016

방사선방호목적의 두부용 수학적 모의 피폭체를 제작하여 두부 CT촬영 시 시각기관(눈, 각막, 수정체)의 흡수선량을 분석하였다. 이후 안구차폐에 따른 방사선량 감소효과를 분석하였다. 그 결과 안구의 흡수선량은 에너지가 증가 할수록 높은 선량을 나타냈으며, 선량이 높은 장기는 두부를 제외하고 눈(eye), 각막(cornea), 수정체(lens) 순으로 평가되었다. 또한 눈의 경우 차폐체 전 후 선량 감소율을 약 38%에서 55%까지, 각막은 약 35%에서 52%를, 끝으로 수정체는 전면만 차폐한 경우 약 51%를 전면과 측면을 동시에 차폐한 경우 약 67%의 감소율을 나타냈다.

• 한국산학기술학회논문지
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• 제13권9호
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• pp.3822-3826
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• 2012

소형 UV 챔버 내부온도 및 챔버 내 체류시간이 Urethane Acrylate 의 경화속도에 미치는 영향을 조사하였다. UV 램프에 가해지는 Power를 60, 80, 100% 로 조절하여 UV 조사량 (UV dose)를 변경하였고 필름이 지나가는 챔버 내부의 가이드롤 (또는 패턴롤)에 냉각수를 투입하여 롤 자체의 온도에 변화를 주었다. 또한 코팅속도를 조절하여 챔버 내부에서의 체류 시간을 변경시켰는데 이들 조건들이 Urethane Acrylate 의 경화에 어떠한 영향을 미치는지를 알아보기 위하여 경화된 필름의 gel 분율을 측정, 비교하였다. 본 연구를 통해 Power가 증가 할수록 경화기 내부의 온도는 상승 하였으며 냉각수 투입에 따라 경화기 내부의 온도는 감소하였는데 이러한 경화기 내부의 온도변화는 UV 경화에 큰 영향을 미치지 않음을 알 수 있었다. 반면에 코팅속도가 증가할수록 경화필름의 gel 분율은 감소하였는데 이는 충분한 경화를 위해서는 경화기내부에서의 체류시간이 일정 이상이 되어야 함을 의미하였다. 한편, 체류시간에 따른 UV dose 측정 및 UV 램프주변의 열유동 해석을 통하여 램프주변의 온도분포 해석을 시도하였는데 이러한 결과들을 바탕으로 UV 경화기 구조 및 운전 조건이 UV 경화된 제품의 특성에 어떠한 영향을 미치는지 알 수 있었다.

• Radiation Oncology Journal
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• 제1권1호
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• pp.95-102
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• 1983

The radical treatment of uterine cervical cancer by interacavitary radium or cesium, in combination with teletherapy are well known. Although the result of such treatment should not give rise to complacency, problem of radiation exposure to medical staff had not been resolved. Fortunately, many attempts have been made to reduce this hazard, most of which take the form of afterloading applicators with a suitably shielded radioisotope. In order to avoid hazardous radiation exposure to staffs concerned with brachytherapy, RALS using high intensity source of Co-60, have been employed at Yonsei Cancer Center since May, 1979. It allows rectal and bladder doses to be kept low, while maintaining a satifactory usual dose distribution of the other type of applicators, and the short treatment time allow four or five patients to be treated per hour. It also removes much patient's discomfort and the difficulties of nursing these patients. Since the first introduction in Korea, over seven hundred cases with various stage of uterine cervical cancer have been treated on a radical basis at this center last 4 years. These authors have strongly attracted attention to the results in terms of local control rate, survival s and morbidity compared with those of conventional low dose rate radiotherapy. Retrospective interim analysis of data was preliminarily accomplished through the labored follow-up study of 340 cases treated during initial 2 years and the radiobiologic standpoint of high dose rate intracavitary irradiation will be discussed.

• 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.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8171-8175
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• 2014

Background: To study the radioprotective effects of flavonoids from Rosa roxburghii Tratt (FRT). Materials and Methods: The radioprotective effects of FRT were investigated by examining cell viability, 30-day survival of mice and the number of colony-forming units in spleen (CFU-S) after total-body 60Co irradiation. Results: The survival rates of irradiated cells gradually increased with increasing concentrations of FRT. The survival rate was the highest at 87% with a concentration of $30{\mu}g/mL$. Pretreatment with FRT was needed to realize its radioprotective activity in mice at the dose of 60 mg/kg. With the increasing doses of 30 mg/kg, 60 mg/kg and 120 mg/kg, the numbers of CFU-S increased, and were significantly different compared with the control group. Conclusions: Pretreatment with FRT prior to irradiation resulted in significantly higher cell survival at 24 h after 5 Gy radiation, increased 30-day survival in mice after exposure to a potentially lethal dose of 8 Gy, and resulted in a higher number of CFU-S in mice after exposure to a dose of 6 Gy. These results collectively indicate that FRT is an effective radioprotective agent.

• 한국환경과학회지
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• 제15권4호
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• pp.311-317
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• 2006

The purpose of this study was to investigate Rn concentration and annual radiation exposure level in the basement and first floor. The Rn Cup monitors were placed in different environments such as shopping stage, office building, Apartment, Hospital, house in Seoul from Match 1996 to April 1997 and CR-39 films were collected every two months. The mean radon concentration in the basement of house($88.6\;Bq/m^3$) showed the highest level among the areas, while radon concentration on the first floor of house($50.5\;Bq/m^3$) showed the higher than other areas. The annual radiation exposure dose that person on the floor / in the basement of differential place in the seoul can be exposed during living was estimated from 24.11 to 87.64 mRem/yr. This radiation dose is significantly lower than 130mRem maximum radiation dosage from the radon nuclide prescribed by the ICRP, with respect to the overall average exposure of the working adult. this study indicated that possible radon sources on the first floor / in the basement areas are radon intrusion from soil gas, construction materials, or ground water leaking. Further study is needed to quantitatively assess major contributions of radon-222 and health effect to radon exposure.

• 대한방사선기술학회지:방사선기술과학
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• 제39권4호
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• pp.509-516
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• 2016

저선량 장시간(15초 내외) X선을 조사하는 치과 파노라마 촬영장치는 교육 목적의 사용에는 원자력안전법의 규제를 받으며, 이에 따라 방사선안전 설비(경보장치, 인터록)를 설치해야 한다. 본 연구에서는 치과 파노라마 촬영에서 방사선량 및 공간선량률을 측정하여 방사선안전 설비의 실효성을 확인하고 방사선작업종사자 및 수시출입자 등의 방사선방호를 위한 기초자료를 제공하고자 하였다. 치과 파노라마 전용팬텀의 직접 피폭부위인 치아와 간접 피폭부위인 수정체와 갑상선에서 유리선량계 소자(GD-352M)를 부착한 후 X선을 3회 반복 조사하여 형광유리선량계 시스템으로 선량을 판독하였다. 팬텀 절치부를 중심으로 한 수평면을 $45^{\circ}$ 각도로 분류하여 7방향으로 구획하여 각 방향마다 30, 60, 90, 120 cm의 거리에서 공간선량률을 측정하였다. 직접 피폭부위는 최대 $984.5{\mu}Gy$가 측정되었다. 공간선량률은 30 cm에서 가장 높게 나타났으며, 120 cm로 거리가 증가할수록 선량이 감소하였다. 방향에 따라서는 30 cm 거리에서 회전 시작부위의 공간선량률이 $3,840{\mu}Sv/h$로 가장 낮은 부위인 $778{\mu}Sv/h$에 비해 4배 차이가 났다. 방사선작업종사자가 위치할 수 있는 60 cm 거리에서의 공간선량률은 평균 $408{\mu}Sv/h$로 측정되었다. 보수적인 관점에서 방사선관리구역 내에 의도하지 않은 피폭이 발생하는 경우를 대비하여 피폭선량 예측이 가능하도록 공간선량률에 대한 방사선안전 교육이 필요하지만, 현재 의료법에 의해 의료기관에서는 설치하지 않아도 되는 인터록 등의 설비는 교육용 치과 파노라마 촬영실의 공간선량률이 낮은 것을 감안할 때 원자력안전법에서 의무화 되어 있는 것은 과한 규제로 사료된다.

• 한국환경보건학회지
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• 제48권3호
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• pp.151-158
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• 2022

Background: Chemical emissions in the environment have rapidly increased with the accelerated industrialization taking place in recent decades. Residents of industrial complexes are concerned about the health risks posed by chemical exposure. Objectives: This study was performed to suggest modeling methods that take into account multimedia and multi-pathways in human exposure and risk assessment. Methods: The concentration of benzene emitted at industrial complexes in Daesan, South Korea and the exposure of local residents was estimated using the Caltox model. The amount of human exposure based on inhalation rate was stochastically predicted for various activity stages such as resting, normal walking, and fast walking. Results: The coefficient of determination (R²) for the CalTOX model efficiency was 0.9676 and the root-mean-square error (RMSE) was 0.0035, indicating good agreement between predictions and measurements. However, the efficiency index (EI) appeared to be a negative value at -1094.4997. This can be explained as the atmospheric concentration being calculated only from the emissions from industrial facilities in the study area. In the human exposure assessment, the higher the inhalation rate percentile value, the higher the inhalation rate and lifetime average daily dose (LADD) at each activity step. Conclusions: Prediction using the Caltox model might be appropriate for comparing with actual measurements. The LADD of females was higher ratio with an increase in inhalation rate than those of males. This finding would imply that females may be more susceptible to benzene as their inhalation rate increases.

• Journal of Radiation Protection and Research
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• 제29권1호
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• pp.57-63
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• 2004

원자력발전소 가동중 검사의 일부로서 계획예방정비 기간중 수행되는 ECT 검사작업은 작업자의 과피폭 우려로 인해 방사선안전관리 대상으로 비중을 두고 관리감독이 이루어지고 있다. 정기적으로 반복되는 검사수행경험 사례 분석의 결과, ECT 검사작업 완료후 피폭결과가 방사선안전관리 목표선량을 상회하는 경우가 상당수 나타나고 있어서 개인별 피폭선량관리가 쉽지않고 방사선작업허가서 발급에도 지장을 초래하는 것으로 나타났다. 검사자의 피폭선량 저감을 위한 세심한 방사선작업계획 수립과 최적화된 방사선방호대책마련을 위한 지속적인 방사선작업 관련 자료 축적도 중요하다고 판단되나, ECT검사 방사선작업계획의 기본요소인 작업내용 및 작업소요시간, 작업인원에 대한 검토와 논의는 미미한 실정이다. 방사선작업계획 수립의 근간을 이루는 예상피폭선량표에 포함될 검사작업내용과 검사자 작업소요시간에 대하여 반복시험과 사례분석 결과를 제시하였다.