• Journal of radiological science and technology
• /
• v.42 no.1
• /
• pp.47-51
• /
• 2019

This study was conducted from July 1 to September 30, 2018 using Optically Stimulated Luminescence Dosimeter(OSLD) and photoluminescent glass dosimeter(PLD) to measure the 3-month exposure dose and the cumulative dose in the active working area of the nuclear medicine worker Respectively. As a result, the cumulative dose for three months in the worker and work area was measured as 1.97 mSv and 2.02 mSv in the PLD. The mean surface dose and the mean depth dose of the OSLD were measured to be 2.04 mSv. The difference in the total surface dose measured by the PLD and the OSLD was 0.66mSv and the total mean surface dose was 0.07mSv. The difference between the total depth dose and the total depth dose was 0.1mSv and 0.02mSv, respectively. It was found that the dose value of the OSLD was higher than that of the PLD. In addition, it was found that the maximum difference of 0.01mSv was observed between the PLD and the OSLD of the worker. For the dose measurement of the two dosimetry systems, there was no significant difference between the PLD and the OSLD in the surface dose of 0.239 (p>0.05). Also, the significance of PLD and OSLD in the deep dose was 0.109, which was not statistically significant (p>0.05).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.12
• /
• pp.1158-1166
• /
• 2013

SAR calculation method following the Mobi-Kids study protocol is analyzed and evaluation method of cumulative RF dose from mobile phones which have been used by a subject of case and control groups is proposed. An SAR database is built by calculating SAR distributions in 4 head models at different ages for representative phone models with the same conducted power. To obtain SAR distribution in a subject's head for a specific commercial phone which had/have been used by him/her, an SAR correction factor using SAR compliance test results is determined. Cumulative dose is calculated by considering mobile phone characteristics and use pattern such as call time and laterality(right and left).

• Journal of the Korean Society of Radiology
• /
• v.15 no.6
• /
• pp.803-811
• /
• 2021

In this study, the exposure amount of IASCC test worker was evaluated by applying the process simulation technology. Using DELMIA Version 5, a commercial process simulation code, IASCC test facility, hot cells, and workers were prepared, and IASCC test activities were implemented, and the cumulative exposure of workers passing through the dose-distributed space could be evaluated through user coding. In order to simulate behavior of workers, human manikins with a degree of freedom of 200 or more imitating the human musculoskeletal system were applied. In order to calculate the worker's exposure, the coordinates, start time, and retention period for each posture were extracted by accessing the sub-information of the human manikin task, and the cumulative exposure was calculated by multiplying the spatial dose value by the posture retention time. The spatial dose for the exposure evaluation was calculated using MCNP6 Version 1.0, and the calculated spatial dose was embedded into the process simulation domain. As a result of comparing and analyzing the results of exposure evaluation by process simulation and typical exposure evaluation, the annual exposure to daily test work in the regular entrance was predicted at similar levels, 0.388 mSv/year and 1.334 mSv/year, respectively. Exposure assessment was also performed on special tasks performed in areas with high spatial doses, and tasks with high exposure could be easily identified, and work improvement plans could be derived intuitively through human manikin posture and spatial dose visualization of the tasks.

• Journal of Environmental Science International
• /
• v.25 no.8
• /
• pp.1107-1114
• /
• 2016

This research, sponsored by the Korean Ministry of Environment in 2014, was the first epidemiological study in Korea that investigated the health impact assessment of radon exposure. Its purpose was to construct a model that calculated the annual mean cumulative radon exposure concentrations, so that reliable conclusions could be drawn from environment-control group research. Radon causes chronic lung cancer. Therefore, the long-term measurement of radon exposure concentration, over one year, is needed in order to develop a health impact assessment for radon. Hence, based on the seasonal correction model suggested by Pinel et al.(1995), a predictive model of annual mean radon concentration was developed using the year-long seasonal measurement data from the National Institute of Environmental Research, the Korea Institute of Nuclear Safety, the Hanyang University Outdoor Radon Concentration Observatory, and the results from a 3-month (one season) survey, which is the official test method for radon measurement designated by the Korean Ministry of Environment. In addition, a model for evaluating the effective annual dose for radon was developed, using dosimetric methods. The model took into account the predictive model for annual mean radon concentrations and the activity characteristics of the residents.

• Current Photovoltaic Research
• /
• v.6 no.3
• /
• pp.81-85
• /
• 2018

The photovoltaic modules installed in the actual field are affected by various external environments and the electrical performance output value is generally lowered compared to initial output value. The most of photovoltaic modules consists of low iron glass, encapsulant (EVA), back sheet, frame and junction box assembly based on the solar cells. In this paper, the characteristics of encapsulant which is an important constituent material of photovoltaic module were verified by maximum power determination, electro luminescence images, yellowness index measurement, and gel content measurement after ultraviolet (UV) irradiation exposure. The most commonly installed 72 cells crystalline photovoltaic modules were tested after various UV exposure of 0, 15, 30, and $60kWh/m^2$ and compared with the reference module. After UV exposure of $15kWh/m^2$, which is the current international test condition, a small amount of change was observed in yellowness index and electroluminescence, while a gell content rapidly increased. At a cumulative dose of $60kWh/m^2$, which will be a new international test condition in the near future, however, the yellowness index increased sharply and showed the greatest output power drop.

• Journal of IKEEE
• /
• v.23 no.4
• /
• pp.1457-1460
• /
• 2019

In this paper, we proposed the development of a mixed sensor parts for integrated radiation exposure protection fireman's life-saving alarm that can be location-tracked and irradiated. To measure radiation exposure dose, we use the PIN-Diode radiation measurement sensor module, a semi-conductive radiation measurement sensor that can minimize size and weight. The design for removing leakage current is carried out to enhance the characteristics of the radiation measurement sensor using PIN-Diode. The IMU sensor module is used to estimate the location of the current fireman at the same time as the accident estimate by adding together the data and the values for acceleration on the three axis. Experiments were conductied by an authorized testing agency to determine the efficiency of the proposed mixed sensor parts for integrated radiation exposure protection fireman's life-saving alarms. The cumulative dose measurement range was measured in the range of 10 μSv to 10 mSv, the highest level in the world. The accuracy was measured from ±6.3% to ±9.0% (137 Cs) and normal operation was found at the international standard of ±15%. In addition, positional accuracy was measured within ±10%, resulting in a high level of results, demonstrating its effectiveness. Therefore, it is expected that more firemen will be able to provide with superior performance integrated radiation exposure protection fireman life-saving alarm.

• Journal of Preventive Medicine and Public Health
• /
• v.29 no.1 s.52
• /
• pp.27-41
• /
• 1996

This study described methods to predict human health risk associated with exposure to environmental carcinogens using animal bioassay data. Also, biological assumption for various dose-response models were reviewed. To illustrate the process of risk estimate using relevant dose-response models such as Log-normal, Mantel-Bryan, Weibull and Multistage model, we used four animal carcinogenesis bioassy data of chloroform and chloroform concentrations of tap water measured in large cities of Korea from 1987 to 1995. As a result, in the case of using average concentration in exposure data and 95% upper boud unit risk of Multistge model, excess cancer risk(RISK I) was about $1.9\times10^{-6}$, in the case of using probability distribution of cumulative exposure data and unit risks, those risks(RISK II) which were simulated by Monte-Carlo analysis were about $2.4\times10^{-6}\;and\;7.9\times10^{-5}$ at 50 and 95 percentile, respectively. Therefore risk estimated by Monte-Carlo analysis using probability distribution of input variables may be more conservative.

• Environmental Analysis Health and Toxicology
• /
• v.31
• /
• pp.1.1-1.13
• /
• 2016

Objectives To investigate the accuracy and scientific validity of the current very low risk factor for hereditary diseases in humans following exposures to ionizing radiation adopted by the United Nations Scientific Committee on the Effects of Atomic Radiation and the International Commission on Radiological Protection. The value is based on experiments on mice due to reportedly absent effects in the Japanese atomic bomb (A-bomb) survivors. Methods To review the published evidence for heritable effects after ionising radiation exposures particularly, but not restricted to, populations exposed to contamination from the Chernobyl accident and from atmospheric nuclear test fallout. To make a compilation of findings about early deaths, congenital malformations, Down's syndrome, cancer and other genetic effects observed in humans after the exposure of the parents. To also examine more closely the evidence from the Japanese A-bomb epidemiology and discuss its scientific validity. Results Nearly all types of hereditary defects were found at doses as low as one to 10 mSv. We discuss the clash between the current risk model and these observations on the basis of biological mechanism and assumptions about linear relationships between dose and effect in neonatal and foetal epidemiology. The evidence supports a dose response relationship which is non-linear and is either biphasic or supralinear (hogs-back) and largely either saturates or falls above 10 mSv. Conclusions We conclude that the current risk model for heritable effects of radiation is unsafe. The dose response relationship is non-linear with the greatest effects at the lowest doses. Using Chernobyl data we derive an excess relative risk for all malformations of 1.0 per 10 mSv cumulative dose. The safety of the Japanese A-bomb epidemiology is argued to be both scientifically and philosophically questionable owing to errors in the choice of control groups, omission of internal exposure effects and assumptions about linear dose response.

• Nuclear Engineering and Technology
• /
• v.40 no.7
• /
• pp.539-550
• /
• 2008

Lung cancer is the most prevalent global cancer, ${\sim}90%$ of which is caused by cigarette smoking. The LNT hypothesis has been inappropriately applied to estimate lung cancer risk due to ionizing radiation. A threshold of ${\sim}1\;Gy$ for lung cancer has been observed in never smokers. Lung cancer risk among nuclear workers, radiologists and diagnostically exposed patients was typically reduced by ${\sim}40%$ following exposure to <100 mSv low LET radiation. The consistency and magnitude of reduced lung cancer in nuclear workers and occurrence of reduced lung cancer in exposed non-worker populations could not be explained by the HWE. Ecologic studies of indoor radon showed highly significant reductions in lung cancer risk. A similar reduction in lung cancer was seen in a recent well designed case-control study of indoor radon, indicating that exposure to radon at the EPA action level is associated with a decrease of ${\sim}60%$ in lung cancer. A cumulative whole-body dose of ${\sim}1\;Gy$ gamma rays is associated with a marked decrease in smoking-induced lung cancer in plutonium workers. Low dose, low LET radiation appears to increase apoptosis mediated removal of $\alpha$-particle and cigarette smoke transformed pulmonary cells before they can develop into lung cancer.

• Safety and Health at Work
• /
• v.12 no.2
• /
• pp.174-183
• /
• 2021

Background: Toluene diisocyanate (TDI) is a highly reactive chemical that causes sensitization and has also been associated with increased lung cancer. A risk assessment was conducted based on occupational epidemiologic estimates for several health outcomes. Methods: Exposure and outcome details were extracted from published studies and a NIOSH Health Hazard Evaluation for new onset asthma, pulmonary function measurements, symptom prevalence, and mortality from lung cancer and respiratory disease. Summary exposure-response estimates were calculated taking into account relative precision and possible survivor selection effects. Attributable incidence of sensitization was estimated as were annual proportional losses of pulmonary function. Excess lifetime risks and benchmark doses were calculated. Results: Respiratory outcomes exhibited strong survivor bias. Asthma/sensitization exposure response decreased with increasing facility-average TDI air concentration as did TDI-associated pulmonary impairment. In a mortality cohort where mean employment duration was less than 1 year, survivor bias pre-empted estimation of lung cancer and respiratory disease exposure response. Conclusion: Controlling for survivor bias and assuming a linear dose-response with facility-average TDI concentrations, excess lifetime risks exceeding one per thousand occurred at about 2 ppt TDI for sensitization and respiratory impairment. Under alternate assumptions regarding stationary and cumulative effects, one per thousand excess risks were estimated at TDI concentrations of 10 - 30 ppt. The unexplained reported excess mortality from lung cancer and other lung diseases, if attributable to TDI or associated emissions, could represent a lifetime risk comparable to that of sensitization.