• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2009년도 춘계 학술발표
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• pp.168-169
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• 2009

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• Journal of Radiation Protection and Research
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• 제26권3호
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• pp.249-253
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• 2001

Neutron dose assessment in criticality accidents using Whole Body Counter (WBC) was proved to be an effective method as rapid neutron dose estimation at the JCO criticality accident in Tokai-mura. The 1.36MeV gamma-ray of $^{24}Na$ in a body can be detected easily by a germanium detector. The Minimum Detectable Activity (MDA) of $^{24}Na$ is approximately 50Bq for 10miniute measurement by the germanium-type whole body counter at JNC Tokai Works. Neutron energy spectra at the typical shielding conditions in criticality accidents were calculated and the conversion factor, whole body activity-to-organ mass weighted neutron absorbed dose, corresponding to each condition were determined. The conversion factor for uncollied fission spectrum is 7.7 $[(Bq^{24}Na/g^{23}Na)/mGy]$.

• Journal of Radiation Protection and Research
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• 제47권3호
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• pp.143-151
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• 2022

Background: After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, biological alterations in the natural biota, including morphological changes of fir trees in forests surrounding the power plant, have been reported. Focusing on the terminal buds involved in the morphological formation of fir trees, this study developed a method for estimating the absorbed radiation dose rate using radionuclide distribution measurements from tree organs. Materials and Methods: A phantom composed of three-dimensional (3D) tree organs was constructed for the three upper whorls of the fir tree. A terminal bud was evaluated using Monte Carlo simulations for the absorbed dose rate of radionuclides in the tree organs of the whorls. Evaluation of the absorbed dose targeted ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs, the main radionuclides subsequent to the FDNPP accident. The dose contribution from each tree organ was calculated separately using dose coefficients (DC), which express the ratio between the average activity concentration of a radionuclide in each tree organ and the dose rate at the terminal bud. Results and Discussion: The dose estimation indicated that the radionuclides in the terminal bud and bud scale contributed to the absorbed dose rate mainly by beta rays, whereas those in 1-year-old trunk/branches and leaves were contributed by gamma rays. However, the dose contribution from radionuclides in the lower trunk/branches and leaves was negligible. Conclusion: The fir tree model provides organ-specific DC values, which are satisfactory for the practical calculation of the absorbed dose rate of radiation from inside the tree. These calculations are based on the measurement of radionuclide concentrations in tree organs on the 1-year-old leader shoots of fir trees. With the addition of direct gamma ray measurements of the absorbed dose rate from the tree environment, the total absorbed dose rate was estimated in the terminal bud of fir trees in contaminated forests.

• Journal of Radiation Protection and Research
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• 제45권2호
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• pp.69-75
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• 2020

Background: Dose conversion coefficients (DCCs) have been commonly used to estimate radiation-dose absorption by human organs based on physical measurements of fluence or kerma. The International Commission on Radiological Protection (ICRP) has reported a library of DCCs, but few studies have been conducted on their applicability to non-Caucasian populations. In the present study, we collected a total of 8 Korean pediatric and adult voxel phantoms to calculate the organ DCCs for idealized external photon-irradiation geometries. Materials and Methods: We adopted one pediatric female phantom (ETRI Child), two adult female phantoms (KORWOMAN and HDRK Female), and five adult male phantoms (KORMAN, ETRI Man, KTMAN1, KTMAN2, and HDRK Man). A general-purpose Monte Carlo radiation transport code, MCNPX2.7 (Monte Carlo N-Particle Transport extended version 2.7), was employed to calculate the DCCs for 13 major radiosensitive organs in six irradiation geometries (anteroposterior, posteroanterior, right lateral, left lateral, rotational, and isotropic) and 33 photon energy bins (0.01-20 MeV). Results and Discussion: The DCCs for major radiosensitive organs (e.g., lungs and colon) in anteroposterior geometry agreed reasonably well across the 8 Korean phantoms, whereas those for deep-seated organs (e.g., gonads) varied significantly. The DCCs of the child phantom were greater than those of the adult phantoms. A comparison with the ICRP Publication 116 data showed reasonable agreements with the Korean phantom-based data. The variations in organ DCCs were well explained using the distribution of organ depths from the phantom surface. Conclusion: A library of dose conversion coefficients for major radiosensitive organs in a series of pediatric and adult Korean voxel phantoms was established and compared with the reference data from the ICRP. This comparison showed that our Korean phantom-based data agrees reasonably with the ICRP reference data.

• 대한방사선기술학회지:방사선기술과학
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• 제33권3호
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• pp.185-192
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• 2010

거대핵세포(megakaryocyte)에서 유래된 혈소판은 백혈구와 더불어 방사선에 민감하여 가장 먼저 감소하므로 방사선장해의 지표로 활용된다. 따라서 혈소판이 부족하게 되면 점상출혈(dot hemorrhage)이 계속되고 혈구 수의 감소와 면역기능 저하로 이어진다. 특히, 전신조사(whole body irradiation)로 4~6 Gy를 받을 경우, 3주 후 혈소판이 최하로 감소되어 출혈과 빈혈에 의한 조혈기계 장해의 사망원인이 된다. 따라서 본 연구는 혈소판 장해의 메카니즘을 밝히고 방어효과를 알아보고자 하였다. 실험에 사용한 방어물질은 마늘 성분의 알리인(Alliin)을 사용하였으며, rat의 꼬리 정맥에 투여한 후 전자현미경(TEM)으로 관찰하였다. 연구 결과, 5 Gy 방사선조사(Irradiation) 후 10일 경과된 혈소판 조직에서는 세포막이 심하게 손상되어 풍선모양으로 부풀어 올랐으며, 당질층(glycocalyx)이 비후되었다. 조사 후 20일 경과된 혈소판에서는 소기관들의 형태를 알아볼 수 없을 정도로 손상되었으며, 세포질의 내용물이 간질부위로 유출되어 손상이 매우 심하였다. 또한 과립들의 형태도 관찰되지 않았다. 30일 경과된 혈소판에서는 가운데 부분에서 공포(vacuole)가 생기고 조직의 손상이 관찰되었다. 하지만 Alliin을 정맥 투여한 실험군에서는 과립(granules)들의 형태가 대조군과 같이 일정하게 유지되고 있었으며, 세포막의 손상도 확인되지 않았다. 따라서 Alliin의 혈관투여시 혈소판의 방사선방어 효과를 확인할 수 있었다.

• Journal of Radiation Protection and Research
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• 제28권1호
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• pp.35-42
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• 2003

진단 X선 촬영에 의한 소아 및 성인의 장기 등가선량과 유효선량을 구하는 방법론을 개발하였다. 연령에 따른 체격의 차이가 방사선량 분포에 미치는 영향을 평가하기 위해, 식도를 포함한 4개 연령군의 MIRD형 수학적 모의피폭체를 제작하였다. 두 가지의 전형적인 진단 X선 절차인 흉부 PA와 복부 AP 진단 X선 촬영을 모사하여, 연령별 선량을 계산하였다. 흉부 PA 진단 X선 촬영절차에 의해서 환자들은 대략 0.03mSv의 유효선량을 피폭하는 것으로 나타났다. 복부 AP 진단 X선 촬영절차의 경우 연령에 따라서 0.4에서 1.7mSv의 유효선량을 받는 것으로 나타났다. 한정된 조사장을 갖는 방사선에 대해서 선량을 평가했기 때문에, 장기의 위치와 크기, 모양, 그리고 방사선이 입사하는 표면으로부터의 필이 등이 선량 계산에 상당한 영향을 미쳤다. 따라서 진단 X선의 조사장이나 선질의 조절 등을 통해 방호의 최적화를 위한 노력이 중요한 것으로 나타났다. 본 연구에서 개발된 선량계측 절차는 의료방사선 방호의 최적화를 위한 수단으로 활용될 수 있다.

• Applied Microscopy
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• 제48권1호
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• pp.11-16
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• 2018

For Odontamblyopus lacepedii with small and turbid eyes, the gross structure and histology of the olfactory organ, which is important for its survival and protection of the receptor neuron in estuarial environment and its ecological habit, was investigated using a stereo, light and scanning electron microscopes. Externally, the paired olfactory organs with two nostrils are located identically on each side of the snout. These nostrils are positioned at the anterior tip of the upper lip (anterior nostril) and just below eyes covered with the epidermis (posterior nostril). Internally, this is built of an elongated olfactory chamber and two accessory nasal sacs. In histology, the olfactory chamber is elliptical in shape, and lined by the sensory epithelium and the non-sensory epithelium. The sensory epithelium of a pseudostratified layer consists of olfactory receptor neurons, supporting cells, basal cells and lymphatic cells. The non-sensory epithelium of a stratified layer has swollen stratified epithelial cells and mucous cells with acidic and neutral sulfomucin. From these results, we confirmed the olfactory organ of O. lacepedii is adapted to its ecological habit as well as its habitat with burrows at the muddy field with standing and murky waters.

• 대한디지털의료영상학회논문지
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• 제14권2호
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• pp.9-14
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• 2012

Exposed dose of young child should be managed necessarily. Young child is more sensitive than adult of a Radioactivity, especially, and lives longer than adult. Must reduce exposed dose which follows The ALARA(As Low As Reasonably Achievable)rule is recommended by ICRP(International Commission on Radiological Protection)within diagnostic useful range. Therefore, We have to prepare Pediatric DRL(Diagnostic Reference Level) in Korea as soon as possible. Consequently, in this study, wish to estimate organ dose and effective dose using PCXMC Program(a PC-Based Monte Carlo Program), and measure ESD(Entrance surface dose)and organ dose using Glass dosimeter, and then compare with DRL which follows EC(European Commission)and NRPB(National Radiological Protection Board). Using glass dosimeter and PCXMC programs conforming to the International Committee for Radioactivity Prevention(ICRP)-103 tissue weighting factor based on the item before the organs contained in the Chest, Skull, Pelvis, Abdomen in the organ doses and effective dose and dose measurements were evaluated convenience. In a straightforward way to RANDO phantom inserted glass dosimeter(GD352M)by using the hospital pediatric protocol, and in a indirect way was PCXMC the program through a virtual simulation of organ doses and effective dose were calculated. The ESD in Chest PA is 0.076mGy which is slightly higher than the DRL of NRPB(UK) is 0.07mGy, and is lower than the DRL of EC(Europe) which is 0.1mGy. The ESD in Chest Lateral is 0.130mGy which is lower than the DRL of EC(Europe) is 0.2mGy. The ESD in Skull PA is 0.423mGy which is 40 percent lower than the DRL of NRPB(UK) is 1.1mGy and is 28 percent lower than the DRL of EC(Europe) is 1.5mGy. The ESD in Skull Lateral is 0.478mGy which is half than the DRL of NRPB(UK) is 0.8mGy, is 40 percent lower than the DRL of EC(Europe) is 1mGy. The ESD in Pelvis AP is 0.293mGy which is half than the DRL of NRPB(UK) is 0.60mGy, is 30 percent lower than the DRL of EC(Europe)is 0.9mGy. Finally, the ESD in Abdomen AP is 0.223mGy which is half than the DRL of NRPB(UK) is 0.5mGy, and is 20 percent lower than the DRL of EC is 1.0mGy. The six kind of diagnostic radiological examination is generally lower than the DRL of NRPB(UK)and EC(Europe) except for Chest PA. Shouldn't overlook the age, body, other factors. Radiological technician must realize organ dose, effective dose, ESD when examining young child in hospital. That's why young child is more sensitive than adult of a Radioactivity.

• 대한수의학회지
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• 제36권3호
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• pp.699-707
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• 1996

This study was designed to examine the involvement of lead in function of target organ, and the protective effect of selenium in lead-treated guinea pigs for 8 weeks. The effects of exposure to 0.5% lead acetate(lead) and/or 4ppm sodium selenite(selenium) in feed on serveral aspects were evaluated by measuring thyroid stimulating hormone(TSH), triiodothyronine($T_3$), thyroxine($T_4$), serum biochemical activities, organ weights, and serum and organ lead concentrations in growing animals. The many indicators of endocrine function(TSH, $T_3$, and $T_4$ in serum), enzyme and biochemical activities(${\alpha}$-glutamyltranspeptidase, alkaline phosphatase, lactate dehydrogenase, triglyceride, creatinine, $Ca^{2+}$ in serum), and organ weights(kidney, spleen and testis) were correlated with lead exposure or showed significantly different mean values between the exposed and controls. These changes on some aspects were reversed by combination-fed of selenium, but did not statistically significant. The organ(kidney, liver, spleen, testis and brain) and serum lead concentrations of lead-fed group were clearly higher than that of controls. Selenium supplementation resulted in a significant protection against lead accumulation in liver and testis. These results suggest that lead can cause a toxic effect on several organ and that selenium seems to has a protective effect on specific reaction by lead-induced organic function toxicity.

• 한국방재학회 논문집
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• 제9권4호
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• pp.67-70
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• 2009

본 연구는 산업현장의 산업재해를 저감시키기 위한 근본적인 대책을 제시하기 위하여 수행되었으며, 우리나라 산업체에 재해 방지 기관으로 핵심적인 역할을 담당하고 있는 대행기관들을 중점 조사하였다. 그래서 각 대행기관들이 안고 있는 문제점들을 파악하여 대행기관 및 대행사업장에 대한 안전상의 문제점들을 제시하며 한편으로는 대행을 받고 있는 사업장에 대한 유용한 시책들은 더욱 권장하여 중소사업장의 산재예방 전도기관으로 거듭날 수 있도록 한다. 그래서 대행기관에 활성화를 위한 실질적인 대안을 제시하고자 하는 것이 본 연구의 주요 목적이다.