• 한국환경보건학회지
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• 제49권1호
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• pp.1-10
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• 2023

Low-dose radiation exposure has received considerable attention because it reflects the general public's type and level of exposure. Still, controversy remains due to the relatively unclear results and uncertainty in risk estimation compared to high-dose radiation. However, recent epidemiological studies report direct evidence of health effects for various types of low-dose radiation exposure. In particular, international nuclear workers' studies, CT exposure studies, and children's cancer studies on natural radiation showed significantly increased cancer risk among the study populations despite their low-dose radiation exposure. These studies showed similar results even when the cumulative radiation dose was limited to an exposure group of less than 100 mGy, demonstrating that the observed excess risk was not affected by high exposure. A linear dose-response relationship between radiation exposure and cancer incidence has been observed, even at the low-dose interval. These recent epidemiological studies include relatively large populations, and findings are broadly consistent with previous studies on Japanese atomic bomb survivors. However, the health effects of low-dose radiation are assumed to be small compared to the risks that may arise from other lifestyle factors; therefore, the benefits of radiation use should be considered at the individual level through a balanced interpretation. Further low-dose radiation studies are essential to accurately determining the benefits and risks of radiation.

• 한국산학기술학회논문지
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• 제19권6호
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• pp.432-439
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• 2018

본 연구는 치과위생사를 대상으로 방사선 관리에 대한 지식, 태도, 안전관리 행위, 방사선 피폭 불안감을 분석하고 이에 영향을 미치는 요인들을 분석함으로써 방사선 안전 관리 수준을 향상하고 방사선 취급에 대한 올바른 인식 전환과 불안감을 줄이는 방안을 도출하고자 연구하였다. 연구기간은 2017년 9월 10일부터 10월 31일까지 전라북도에 근무하는 치과위생사 280명을 대상으로 SPSS 12.0 프로그램을 사용하여 빈도, 기술통계, 다중회귀분석을 실시하여 분석하여 다음과 같은 결과를 얻었다. 방사선 질 관리에 대한 지식 정도의 평균은 8.07 였고, 정답률은 75.3% 였다. 태도 정도는 96.1%가 긍정적인 태도를 보였으며, 방사선 안전관리 행위는 촬영자는 4.11 였고, '방사선 촬영 시 항상 TLD(개인선량계)를 착용한다'는 4.58 로 가장 높았다. 환자 방사선 안전관리 행위는 3.86 였고, '방사선촬영 전 가임기 여성의 임신 여부를 확인한다'는 4.69 로 가장 높았다. 방사선 피복 뷸안감은 3.86 였고, '임신 중 일 때 태아의 건강 문제로 염려된다'는 4.13로 가장 높았다. 방사선 피폭 불안감에 영향을 미치는 요인으로는 방사선 안전관리 행위가 낮을수록, 연령이 낮을수록, 방사선 촬영경력이 낮을수록, 최종학력이 높을수록, 월 소득이 많을수록, 직위가 높을수록 유의한 영향을 미치는 것으로 나타났다(p<0.05). 이상의 연구결과를 토대로 치과위생사는 방사선 질 관리에 대한 지식, 태도, 안전관리 행위는 높았으나, 방사선 피폭 불안감은 높은 불안감을 가지고 있어 방사선 안전 관리 수준을 향상시켜 방사선 피폭 불안감을 줄일 수 있는 방안 마련이 이루어져야 할 것으로 사료된다.

• Journal of Radiation Protection and Research
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• 제34권2호
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• pp.49-54
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• 2009

Mitochondrial DNA (mtDNA) deletion is a well-known marker for oxidative stress and aging and also contributes to their unfavorable effects in cultured cells and animal tissues. This study was conducted to investigate the effect of ionizing radiation (IR) on mtDNA deletion and the involvement of reactive oxygen species (ROS) in this process in human lung fibroblast (IMR-90) cells. Young IMR-90 cells at population doubling (PD) 39 were irradiated with $^{137}Cs$ $\gamma$-rays and the intracellular ROS level was determined by 2',7'-dichlorofluorescein diacetate (DCFH-DA) and mtDNA common deletion (4977bp) was detected by nested PCR. Old cells at PD 55 and $H_2O_2$-treated young cells were compared as the positive control. IR increased the intracellular ROS level and mtDNA 4977 bp deletion in IMR-90 cells dose-dependently. The increases of ROS level and mtDNA deletion were also observed in old cells and $H_2O_2$-treated young cells. To confirm the increased ROS level is essential for mtDNA deletion in irradiated cells, the effects of N-acetylcysteine (NAC) on IRinduced ROS and mtDNA deletion were examined. 5 mM NAC significantly attenuated the IR-induced ROS increase and mtDNA deletion. These results suggest that IR induces the mtDNA deletion and this process is mediated by ROS in IMR-90 cells.

• Journal of Radiation Protection and Research
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• 제48권2호
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• pp.68-76
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• 2023

Background: In the process of discussion on the possibility of using radionuclide-contaminated soil and debris generated by radiation disasters, a strategy for the proper management of radiation exposure protection while considering the source of the contaminated materials is necessary. Materials and Methods: The radiological protection criteria that are likely to be applied to the source-related approach based on the International Commission on Radiological Protection recommendations and the International Atomic Energy Agency safety standards are summarized. We proposed five interpretations of radiation protection to contribute to the promotion of discussion on the possibility of using a part of low-level-radionuclide-contaminated soil and debris in the post-accident rehabilitation. Interpretations I to III are based on the idea of "using a reference level to protect the public in post-accident rehabilitation," whereas IV and V are based on the idea of "using the dose constraint to protect the public in the post-accident rehabilitation when the sources are handled in a planned activity." The former idea is subdivided into three based on the definition of the source, which is managed by the reference level, and the latter idea is divided into two depending on whether or not additional dose from using contaminated materials is deemed acceptable. Results and Discussion: To confirm the applicability of the five interpretations presented, we suggested the concrete values of protection criteria via two feasible cases. In this case study, we proposed radiation protection by the dose constraint based on the Interpretation IV and chose 1 mSv/yr for the public and 20 mSv/yr for workers dealing with radionuclide-contaminated materials. Conclusion: We concretely and systematically demonstrated how the concept of radiation protection can be applied to the process of discussion on the possibility of using radionuclide-contaminated materials within the framework of an international system of protection. This study's findings can provide necessary information to discuss the possibility of using radionuclide-contaminated materials as an alternative option for recovery and reconstruction after a radiation disaster from the viewpoint of radiation protection.

• 한국군사과학기술학회지
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• 제16권1호
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• pp.34-39
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• 2013

In this paper, we described the study on back-radiation level improvement of IFF antenna after briefly describing a design of IFF antenna to distinguish the target as the sub-antenna of surveillance radar. The proposed IFF antenna was minimized a size with use all-in-one power divider as a two-channel IFF antenna forming sum and difference pattern. The method for back-radiation level reduction was studied, and the identified method through the simulation confirmed the decrement throught the measurement.

• 방사선산업학회지
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• 제4권1호
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• pp.47-51
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• 2010

Centipedegrass is a warm season turfgrass in the world. Chlorogenic acid (CA) is one of the important compounds present in the leaf of centipedegrass and already known as an antioxidant, CA has become a key resistance against insect pests and bacteria pathogens of agricultural and horticultural plants during seedling stage. Furthermore, CA is accumulated by abiotic stress such as an UV irradiation. In present study, we investigated enhancement of the level of CA upon gamma irradiation in centipedegrass. The high performance liquid chromatography (HPLC) data analysis showed an approximately increasing of the CA levels from among the irradiated samples. However, plants irradiated at 50 Gy showed a constant increase in the CA level (0.0066 to $0.114mg\;ml^{-1}$ and 0.0258 to $0.2211mg\;ml^{-1}$, respectively) from $3^{rd}$ to $15^{th}$ day among one and three month irradiated plants compared to control. The present study, indicates an increase in the CA level upon gamma irradiation, suggests strategy for conferment of strong resistance in seedling stage plants by gamma irradiation as simplicity and cheaply method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.828-831
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• 1996

Radiation monitoring system is needed at nuclear power plant and nuclear facility. Manual survey techniques are commonly used, but they are time consuming and somewhat inaccurate. Automatic radiation surveys are very important because it provides significant savings in men-rem and wages. Unmanned, remote automatic radiation measurement system should be small and light-weighted in order to mount on robotic system. The system we have developed consists of detection parts, signal processing part, interface, and software part. Position information is provided by using of a collimator. The measurement process is achieved by the scanning of detector and image processing techniques are used to display radiation levels. We designed collimators, detectors, signal processing circuit, and constructed prototype system. The goal of this system is the mapping of camera image and radiation level distribution.

• 한국유체기계학회 논문집
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• 제5권1호
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• pp.49-54
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• 2002

HANARO, 30 MW of research reactor, was installed at the depth of 13m in an open pool. The $90\%$ of primary coolant was designed to pass through the core and to remove the reaction heat of the cote. The rest, $10\%$, of the primary coolant was designed to bypass the core. And the reactor coolant through and bypass the core was inhaled at the top of chimney by the coolant pump to prevent the radiated gas from being lifted to the top of reactor pool. But, the part of core bypass coolant was not inhaled by the reactor coolant pump and reached at the top of reactor pool by natural convection, and increased the radiation lovel on the top of reactor pool. To reduce the radiation level by protecting the natural convection of the core bypass flow, the hot water layer (HWL, hereinafter) was installed with the depth of 1.2 m from the top of reactor pool. As the HWL was normally operated, the radiation level was reduced to five percent ($5\%$) in comparing with that before the installation of the HWL. When HANARO was operated at a higher temperature than the normal temperature of the HWL by operating the standby heater, it was found that the radiation level was more reduced than that before operation. To verify the reason, the heat loss of the HWL was calculated by Visual Basic Program. It was confirmed through the results that the larger the temperature difference between the HWL and reactor hall was, the more the evaporation loss increased. And it was verified that the radiation level above was reduced mote safely by increasing the capacity of heater.

• Asian Pacific Journal of Cancer Prevention
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• 제16권3호
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• pp.1111-1116
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• 2015

Background: To investigate the relationship between pathologic tumor response to concurrent chemoradiotherapy and variation of serum VEGF in patients with esophageal cancer. Materials and Methods: Forty six patients with esophageal cancer who were treated with concurrent chemo-radiotherapy were enrolled. Endoscopic and pathologic examination was conducted before and four weeks afterwards. Serum level of VEGF was documented before, four weeks later and after chemo-radiotherapy. The relationship between pathologic response and the variation of serum level of VEGF and its influence on the prognosis were investigated. Results: Serum level of VEGF decreased remarkably during and after chemo-radiotherapy in patients whose pathologic response was severe (F=5.393, 4.587, P(0.05). There were no statistical differences of serum VEGF level before, during and after chemo-radiotherapy for patients whose pathologic response was moderate or mild. There were 18 (85.7%), 7 (53.8%) and 6 patients (50.0%) whose serum VEGF level dropped in the severe, moderate and mild group, respectively, with significant differences among these groups (p=0.046). Two year survival rates of patients with severe, moderate and mild pathologic response were 61.9%, 53.8% and 33.3% respectively, and no statistically difference between severe and mild group regarding OS (p=0.245) was tested. Conclusions: Tumor pathologic response during chemo-radiotherapy and the changes of serum VEGF lever could predict curative effects of chemo-radiotherapy in patients with esophageal cancer.

• Journal of Radiation Protection and Research
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• 제36권4호
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• pp.230-236
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• 2011

방사선이용의 사회적 수용성 제고 방안의 일환으로 일반대중 가운데 장기적인 관점에서 여론의 주도층 역할을 하게 될 대학생을 대상으로 전공자와 비전공자 사이에 방사선이용 분야별 필요성 인식 차이를 파악하여 방사선이용에 대한 국민이해 증진사업의 효율적인 전략구상에 필요한 근거자료를 제공하고자 한다. 2010년 11월 교육통계서비스(http://cesi.kedi.re.kr) 기준, 전국 4년제 대학교 177개교, 전문대학 146개교 중 전체 24.0%에 해당하는 78개교의 재학생을 표본으로 선정하여 방사선이용 분야별 필요성 인식수준을 설문조사 하였다. 그 결과 전공자와 비전공자 모두 의료분야의 필요성 인식수준이 높았고, 전공자와 비전공자 모두 농업분야의 필요성 인식수준이 가장 낮게 나타났다. 6개 방사선이용 분야 모두 전공자가 비전공자보다 필요성 인식수준을 높게 나타냈다. 각 분야별로 남학생, 의료방사선 경험이 있는 경우, 관련 교육을 받은 경우에 필요성 인식수준이 높았다. 이는 여학생, 의료방사선 경험이 없는 경우, 관련 교육경험이 없는 경우에 대해서는 보다 다양한 정보제공으로 필요성 인식 수준을 상대적으로 더 높일 필요가 있다고 본다. 각 지역별, 방사선이용 분야별 정책결정에 있어서 본 연구결과에 나타난 집단의 특성을 고려한다면 방사선이용에 대한 국민이해 증진사업을 효율적으로 달성하는데 도움이 될 것이라고 사료된다.