• Nuclear Engineering and Technology
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• 제56권7호
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• pp.2732-2739
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• 2024

This study developed internal dose coefficients for radioiodine, tailored to the Korean population, by incorporating the Korean biokinetic model along with the Korean S values. The observed differences in dose coefficients for Koreans compared to the International Commission on Radiological Protection (ICRP) reference values noticeably varied depending on physical half-lives of iodine isotopes. For longer-lived isotopes such as I-125 and I-129, significant differences in thyroid dose coefficients were observed, with ratios (Korean/ICRP) from 0.30 to 0.55, indicating that actual doses for Koreans can be considerably lower than those evaluated based on the ICRP data. However, for short-lived iodine isotopes, such as I-131, the thyroid dose coefficients were comparable to the ICRP reference values (ratio = 0.95-0.98). These comparable dose coefficients resulted from the lower thyroidal iodine uptake in the Korean model being almost entirely offset by the higher thyroid self-absorption S values in the Korean phantoms. Additionally, this study delves into the substantial differences in absorbed dose coefficients for non-thyroidal regions and effective dose coefficients, which arose not only from physiological/anatomical variability but also technical differences in phantom design. The use of Korean-specific dose coefficients is advisable particularly in scenarios predicting elevated doses, yielding a more precise and clinically relevant dose assessment.

• Environmental Analysis Health and Toxicology
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• 제16권2호
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• pp.43-50
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• 2001

A daily newspaper in Korea addressed an controversial issue recently that the concentration of radon measured from the groundwater in Taejon was found out a relatively high level. The cancer risk arising from ingestion of such radon should be derived from calculation of the dose absorbed by the tissues at risk. The study performed by the National Research Council in United States confirmed that the use of a PBPK model for the ingested radon could provide the useful information regarding the distribution of radon among the organs of the body. This study presents an approach for the internal dose assessment of ingested radon for this case. At first, the study develops a PBPK model for ingested radon. However, the important issue is how to simulate a more realistic situation using the model associated with repeated oral doses rather than a single oral dose. The simulations are performed for repeated oral exposures per 8-hour interval using the PBPK model for a male adult. The concentration and cumulative value of radon concentration are calculated and analyzed for lung tissue and adipose group, respectively. The results could be used for the realistic prediction of the internal dose of radon in the human body for repeated oral exposures.

• Journal of Radiation Protection and Research
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• 제28권1호
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• pp.51-57
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• 2003

To assess the internal dose by $^3H\;&\;^{14}C$ in total diet of inhabitants near Wolsung Nuclear Power Plants, TFWT, OBT and $^{14}C$ concentration in total diet was analyzed for collection region and time. TFWT, OBT and $^{14}C$ concentrations were in the range of 3.19-42.2 Bq/L, 1.00-39.4 Bq/L, and 0.230-0.855 Bq/gC, respectively. The calculated annual effective dose with TFWT, OBT and $^{14}C$ is $6.10{\times}10^{-5}mSv/y,\;3.71{\times}10^{-5}mSv/y\;and\;7.08{\times}10^{-3}mSv/y$, respectively. And then annual internal dose with total diet for inhabitants near Wolsung NPPs is about $7.18{\times}10^{-3}mSv/y$, which is about 0.72% of annual effective dose limit 1 mSv/y.

• Journal of Radiation Protection and Research
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• 제41권3호
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• pp.291-300
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• 2016

Background: It is necessary to assess radiation dose to workers due to inhalation of airborne particulates containing naturally occurring radioactive materials (NORM) to ensure radiological safety required by the Natural Radiation Safety Management Act. The objective of this study is to develop an internal dose assessment procedure for workers at industries using raw materials containing natural radionuclides. Materials and Methods: The dose assessment procedure was developed based on harmonization, accuracy, and proportionality. The procedure includes determination of dose assessment necessity, preliminary dose estimation, airborne particulate sampling and characterization, and detailed assessment of radiation dose. Results and Discussion: The developed dose assessment procedure is as follows. Radioactivity concentration criteria to determine dose assessment necessity are $10Bq{\cdot}g^{-1}$ for $^{40}K$ and $1Bq{\cdot}g^{-1}$ for the other natural radionuclides. The preliminary dose estimation is performed using annual limit on intake (ALI). The estimated doses are classified into 3 groups ( < 0.1 mSv, 0.1-0.3 mSv, and > 0.3 mSv). Air sampling methods are determined based on the dose estimates. Detailed dose assessment is performed using air sampling and particulate characterization. The final dose results are classified into 4 different levels ( < 0.1 mSv, 0.1-0.3 mSv, 0.3-1 mSv, and > 1 mSv). Proper radiation protection measures are suggested according to the dose level. The developed dose assessment procedure was applied for NORM industries in Korea, including coal combustion, phosphate processing, and monazite handing facilities. Conclusion: The developed procedure provides consistent dose assessment results and contributes to the establishment of optimization of radiological protection in NORM industries.

• IMMUNE NETWORK
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• 제3권1호
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• pp.69-77
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• 2003

Background: Celecoxib, a COX-2 specific inhibitor, has recently been used for the treatment of rheumatoid arthritis. However, the molecular and cellular mechanisms of celecoxib against RA inflammation remain to be defined. To elucidate the action mechanism of celecoxib on inflammatory cells, we investigated the effect of celecoxib on the production of two important mediators of inflammation, nitric oxide and PGE2 Methods: RAW 264.7 cells stimulated with LPS were preincubated with various concentrations of celecoxib (from $10^{-8}$ to $10^{-5}$ M) and $10{\mu}M$ hydrocortisone, respectively. The production of NO and PGE2, the end products of iNOS and COX-2 genes, were estimated in culture supernatants by Greiss method and EIA, respectively. The expression of iNOS gene, COX-2 gene, $NF-{\kappa}B$, and $I-{\kappa}B$ were determined by RT-PCR and western blot analysis. Results: Celecoxib and hydrocortisone inhibited the production of NO and PGE2 in dose dependent manner, when RAW 264.7 cells were stimulated with LPS. The expression of iNOS was also down-regulated by celecoxib and hydrocortisone. Interestingly, COX-2 gene differentially expressed according to the dose of celecoxib, a decrease with lower dose ($10^{-8}$ M) but an increase with higher dose ($10^{-5}$ M). $NF-{\kappa}B$ binding activity was decreased by lower dose of celecoxib, whereas was not affected by higher dose of it. The expression of $I-{\kappa}B$ was suppressed by higher dose of celecoxib. Conclusion: The celecoxib strongly suppressed the production of NO and PGE2 in LPS-stimulated RAW264.7 cells. The decrease of NO seems to be linked to the inhibition of iNOS by celecoxib. The lower and higher dose of celecoxib differentially regulated the COX-2 expression and $NF-{\kappa}B$ activity.

• 대한한방내과학회지
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• 제34권4호
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• pp.349-361
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• 2013

Objectives : This study aimed to evaluate the single oral dose toxicity and four weeks repeated dose determination of Gamisasangja-tang (GST) in male and female Sprague-Dawley rats. Methods : In the single oral toxicity study, rats were orally administered a single dose of 0 and 5,000 mg/kg GST. There were 5 rats in each group. After single administration, mortality, clinical signs, body weight changes and gross pathological finding were observed for 14 days. In the 4-weeks repeated oral dose determination study, rats were orally administered a single dose of 0, 1,250, 2,500 or 5,000 mg/kg GST. There were 5 rats in each group. Mortality, clinical signs, body weight changes, food consumption and gross pathological finding were observed for 28 days. Organ weight, clinical chemistry and hematology were tested after 28 days. Results : There was no mortality in either of the two studies. There were also no significant differences in clinical sign, body weight, organ weights, hematological or serum chemical parameters between the GST and control groups. Conclusions : The results obtained in this study suggest that the 50% lethal dose of GST is over 5,000 mg/kg, so this finding would be expected to provide scientific evidence for the safety of GST.

• Journal of Yeungnam Medical Science
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• 제28권2호
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• pp.173-179
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• 2011

Polymyositis is diffuse, inflammatory myopathy with proximal-muscle weakness due to lymphocyte infiltration to the muscle layer. The exact cause of the muscle weakness is unclear but may be related with an immunologic mechanism. Using high-dose steroid is the treatment of choice for polymyositis. It is difficult to distinguish steroid-resistant polymyositis from steroid myopathy, however, in the course of high-dose steroid therapy. These authors encountered a steroid myopathy patient during polymyositis treatment with high-dose steroid. A 57-year-old woman was diagnosed with polymyositis and was treated with high-dose steroid. Her condition was initially improved, but in the course of the treatment, her symptom was aggravated without increasing the muscle enzymes. Her muscle weakness was improved by reducing the steroid dosage.

• Journal of Radiation Protection and Research
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• 제49권1호
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• pp.1-18
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• 2024

Exponential growth has been observed in nuclear medicine procedures worldwide in the past decades. The considerable increase is attributed to the advance of positron emission tomography and single photon emission computed tomography, as well as the introduction of new radiopharmaceuticals. Although nuclear medicine procedures provide undisputable diagnostic and therapeutic benefits to patients, the substantial increase in radiation exposure to nuclear medicine patients raises concerns about potential adverse health effects and calls for the urgent need to monitor exposure levels. In the current article, model-based internal dosimetry methods were reviewed, focusing on Medical Internal Radiation Dose (MIRD) formalism, biokinetic data, human anatomy models (stylized, voxel, and hybrid computational human phantoms), and energy spectrum data of radionuclides. Key results from many articles on nuclear medicine dosimetry and comparisons of dosimetry quantities based on different types of human anatomy models were summarized. Key characteristics of seven model-based dose calculation tools were tabulated and discussed, including dose quantities, computational human phantoms used for dose calculations, decay data for radionuclides, biokinetic data, and user interface. Lastly, future research needs in nuclear medicine dosimetry were discussed. Model-based internal dosimetry methods were reviewed focusing on MIRD formalism, biokinetic data, human anatomy models, and energy spectrum data of radionuclides. Future research should focus on updating biokinetic data, revising energy transfer quantities for alimentary and gastrointestinal tracts, accounting for body size in nuclear medicine dosimetry, and recalculating dose coefficients based on the latest biokinetic and energy transfer data.

• 대한한방내과학회지
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• 제34권1호
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• pp.46-58
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• 2013

Objectives : The object of this study was to obtain acute information (single oral dose toxicity) of Scutellariae Radix Aqueous Extracts (SR; yield = 27.20%) which traditionally have been used in Korean medicine for treating various diseases including inflammatory diseases. Methods : In order to observe the 50% lethal dose ($LD_{50}$), approximate lethal dosage (ALD) and target organs, SR Aqueous Extracts were once orally administered to female and male ICR mice at dose levels of 2,000, 1,000, 500 and 0 (control) mg/kg (body weight.) according to the recommendation of KFDA Guidelines. The mortality and changes on body weight, clinical signs and gross observation were monitored during 14 days after single oral treatment of SR according to KFDA Guidelines with organ weights and histopathological observations of 14 types of principle organs. Results : After single oral treatment of SR, we could not find any mortality and toxicological evidences up to 2,000 mg/kg treated group, the limited dosages in rodents, on the body and organ weights, clinical signs, gross and histopathological observations, except for some accidental findings. Conclusions : The results obtained in this study suggest that the $LD_{50}$ and ALD of SR in both female and male mice after single oral treatment be considered as over 2,000 mg/kg because no mortalities were detected up to 2,000 mg/kg that was the highest dose recommended by KFDA and OECD, and can be safely used in clinics.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2004년도 제29회 추계학술대회 발표논문집
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• pp.115-118
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• 2004

우리의 연구는 호흡에 의해 움직임의 영향을 받는 장기 및 종양에 대해서 조사된 선량분포를 측정하는 것이다. 이 연구를 수행하기 위해, 사전연구로 이전에 발표된 논문을 토대로 호흡에 의해 장기 및 종양의 움직임 변위를 조사하였다. 그리고 조사된 데이터를 활용하여 호흡에 따른 움직임을 구동 시스템을 적용하여 구현하였다. 내부 움직임에 의한 선량분포의 변화를 측정하기 위해서 이 구동 팬톰 시스템을 사용하였다. 이 결과로부터 호흡에 환자의 조사되는 선량분포의 부정확 정도를 평가할 수 있었다.