• Journal of Radiation Protection and Research
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• v.15 no.2
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• pp.75-85
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• 1990

The dose calculations were carried out using environmental montoring data around Karlsruhe Nuclear Research Center(KfK). Ingestion of plant foods was the most important pathway, and the K-40 and Pb-210 natural radioisotopes in food were the most effective radiation source to man. The dose received from artificial nuclides were mostly emitted by gamma irradiation of Cs-134 and Cs-137 deposited on the ground. The effective dose equivalent in the KfK environment was far less than the dose equivalent limit recommended by ICRP.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.577-582
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• 1998

In nuclear power plant, it has been the important object to reduce the occupational radiation exposure (ORE). Recently, the optimization concept of management science has been studied to reduce the ORE in nuclear power plant. In optimization of the worker allocation, the collective dose, working time, individual dose, an total number of worker must be considered and their priority orders must be thought because the main constraint is necessary for determining the constraints variable of the radiological worker allocation problem. The ultimate object of this study s to look into the change of the optimal allocation of the radiological worker as priority order changes. In this study, the priority order is the characteristic of goal programming that is a kind of multi-objective linear programming. From a result of study using goal programming, the total number of worker and collective dose of worker have changed as the priority order has changed and the collective dose limit have played an important role in reducing the ORE.

• Toxicological Research
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• v.18 no.1
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• pp.65-71
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• 2002

A benchmark dose (BMD) approach has been evaluated us a replacement for the traditional NOAEL methodology currently being wed to assess the noncancer effects of toxicants. The endocrine disrupt-ing effect of endosulfan which showed decrement of sperm count and testicular testosterone level in animals, was currently reported. The amount of endosulfan used as pesticide in the country has been continuously increased. The aim of this study was to suggest the permissible intake level (PIL), corresponding to Accept-able Daily Intake (ADI), based on endocrine disrupting effect wing BMD. Various animal data were collected by consideration of critical effect showing endocrine disruption and an animal data for reproductive toxicity was selected. The Power model from BMD software for induction of $BMD_10$ having meaning which is the dose at the 95% lower confidence limit on a 10% response was used due to that the form of selected dose-response animal data was continuous data. The $BMD_10$ was estimated to be 0.393 mg/kg/day based on reproductive toxicity showing decrement of sperm count. The permissible intake level (PIL) was calculated by dividing the $BMD_10$ by the uncertainty factors of 100 with consideration of from animal to human and human variability. The PIL as 0.004 mg/kg/day was compared with traditional ADI as 0.006 mg/kg/day based on the incidence of marked progressive glomerulonephrosis and blood vessel aneurysm in males.

• Journal of Radiation Protection and Research
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• v.28 no.1
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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 radiological science and technology
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• v.41 no.6
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• pp.573-580
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• 2018

The Nuclear Safety Commission amended the Nuclear Safety Act by strengthening the safety management system for the frequent workers to the level of radiation workers. And students entering radiation management zones for testing and practical purposes are subject to frequent workers. It is inevitable that this will incur additional costs. In this paper, the validity of the amendment to the Nuclear Safety Act was to be assessed in terms of radiation protection. Study subjects are from 2014 to 2016, among university students in Seong-nam Korea and comparisons for analyses were made taking into account variables that are differences in annual, practical types, on-class and clinical practice students exposure dose. The analysis showed that exposures between on-class and clinical practice received were less than the annual dose limit of 1 mSv for the public. Then, some alternatives that excluding from frequent workers during on-class practice or mitigating the frequent workers' safety regulation for only on-class frequent workers can be considered. Optimization is how rational is the reduction in exposure dose to the costs required. Therefore, the results are hardly considered for optimization. If the data accumulated, it could be considered that the revision of the act could be evaluated and improved.

• Journal of radiological science and technology
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• v.41 no.6
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• pp.603-610
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• 2018

This study examined the following: accuracy of the exposure conditions in the inverter device and three-phase device; output waveform over the exposure conditions; and average and standard deviation of the output waveform. After assessing whether the dose corresponding to the theoretical dose was presented, the following conclusions were obtained: 1. The accuracy of the tube voltage(kVp) and tube current(mA) exposure time(sec) was within the tolerable level prescribed in Korea's Safety Management Standards. In the error, Inverter device was large the tube voltage and exposure time, the three-phase device was large the tube current. 2. In terms of the output waveform of the exposure conditions and the average and standard deviation of the output waveform, the higher tube voltage and larger tube current resulted in greater standard deviation in pulsation. Moreover, the standard deviation of pulsation was shown to be greater in the inverter device than the three-phase device; there was also greater standard deviation in the inverter device considering the exposure time. 3. Regarding the exposure conditions over the output dose, all linearity showed the coefficient of variation which had an allowable limit of error within 0.05. Although the output dose ratio for the inverter device was 1.00~1.10 times no difference that of the three-phase device, there was almost no difference in dose ratio between the tube currents.

• Progress in Medical Physics
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• v.25 no.1
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• pp.23-30
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• 2014

The purpose of this study is to evaluate the developed dose verification program for in vivo dosimetry based on transit dose in radiotherapy. Five intensity modulated radiotherapy (IMRT) plans of lung cancer patients were used in the irradiation of a homogeneous solid water phantom and anthropomorphic phantom. Transit dose distribution was measured using electronic portal imaging device (EPID) and used for the calculation of in vivo dose in patient. The average passing rate compared with treatment planning system based on a gamma index with a 3% dose and a 3 mm distance-to-dose agreement tolerance limit was 95% for the in vivo dose with the homogeneous phantom, but was reduced to 81.8% for the in vivo dose with the anthropomorphic phantom. This feasibility study suggested that transit dose-based in vivo dosimetry can provide information about the actual dose delivery to patients in the treatment room.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.153-156
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• 2004

Korea Food and Drug Administration(KFDA) has peformed the calibration of therapy level dosimeters for Co-60 radiation since 1979. The reference standard ionization chamber has been calibrated at BIPM in France. The uncertainty on the KFDA calibration coefficients is 0.9 %(k=2) for air kerma and absorbed dose to water. Since 1999 a national quality audit program for ensuring dosimetry accuracy in Korea radiotherapy centers has been performed by the KFDA. The uncertainty associated with the determination of the absorbed dose to water from the TLD readings for high energy x-ray is 1.6 %(k=1). The correction factors for energy, non-linearity dose response, and TLD holder are used in the dose determination. Agreement between the user stated dose and KFDA measured dose within ${\pm}$ 5 % is considered acceptable. KFDA TLD postal dose quality audit program was peformed for 71 beam qualities of 53 domestic radiotherapy centers in 2003. The results for quality assurance showed that 63 out of 71 beam qualifies (89 %) satisfied the acceptance limit. The second audit was carried out for the centers outside the limit and ail of them have been corrected.

• Toxicological Research
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• v.20 no.1
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• pp.83-88
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• 2004

The present study was carried out to investigate the potential adverse effects of CKD-602 by a 5-day repeated intravenous dose in Sprague-Dawley rats. The test article, CKD-602, was administered intravenously to male and female rats at dose levels of 0.07, 0.22, 0.67, 2.0 and 6.0 mg/kg/day for 5 days consecutively. Mortalities, clinical findings, and body weight changes were monitored for the 14-day period after cessation of the administration. At the end of 14-day observation period, all animals were sacrificed and complete gross postmortem examinations were performed. There were 2 and 5 treatment related deaths in the 0.67 and 2.0 mg/kg/day dose groups of both genders, respectively. Treatment related clinical signs, including hair loss, skin paleness, decreased locomotor activity, emaciation, and changes in stool were observed in a dose-dependent manner from the third day after initiation of the injection. Decrease or suppression of body weight was also observed dose-dependently in males and females of the treated groups. Gross postmortem examinations revealed a dose-dependent increase in the incidence and severity of atrophy or hypertrophy and white membrane formation in the spleen, atrophy of the thymus, diffuse white spots and paleness of the liver, paleness of the lung, kidney and adrenal gland, and dark red discoloration and dark red contents in the alimentary tract. Based on these results, it was concluded that the 5-repeated intravenous injection of CKD-602 to male and female rats resulted in increased incidence of abnormal clinical signs and death, decreased or suppressed body weight, and increased incidence of abnormal gross findings. In the present experimental conditions, the $LD_{50}$ value was 2.07 (95% confidence limit not specified) mg/kg/day in both genders and the $LD_{10}$ value was 1.72 (95% confidence limit not specified) mg/kg/day in both genders.

• Journal of the Korean Society of Radiology
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• v.15 no.3
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• pp.355-359
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• 2021

In this study, the purpose of this study was to analyze the degree of exposure of radiation workers assigned to the Department of Radiology and frequent visitors during on-campus practice, and to conduct a basic study on the feasibility and optimization of the radiation protection of the Nuclear Safety Act for the Department of Radiology. . The average exposure dose of occupational workers by year was 0.01 mSv, the lowest in 2014 and 2016. The highest figure was 0.12 mSv in 2018. The average exposure dose of frequent visitors by year was the lowest at 0.013 mSv in 2018, and the highest at 0.022 mSv in 2016. According to this study, the annual exposure dose received by professors, practical assistants, and students in the department of radiology (department) who use only radiation generators in the course of in-school practice is less than 1 mSv, which is the dose limit for the general public. Therefore, at the time when the radiation dose of students in the Department of Radiology is lower than the dose limit of the general public, the current safety regulation of the Nuclear Safety law is judged to be excessive regulation. Therefore, it is considered necessary to revise the regulations for radiation generators in the current Nuclear Safety law or to revise the radiation safety management system for university students.