• Nuclear Engineering and Technology
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• 제55권1호
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• pp.270-277
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• 2023

Exposure to ionizing radiation induces free radicals in human nails. These free radicals generate a radiation-induced signal (RIS) in electron paramagnetic resonance (EPR) spectroscopy. Compared with the RIS of tooth enamel samples, that in human nails is more affected by moisture and heat, but has the advantages of being sensitive to radiation and easy to collect. The fingernail as a biological sample is applicable in retrospective dosimetry in cases of localized hand exposure accidents. In this study, the dosimetric characteristics of fingernails were analyzed in fingernail clippings collected from Korean donors. The dose response, fading of radiation-induced and mechanically induced signals, treatment method for evaluation of background signal, minimum detectable dose, and minimum detectable mass were investigated to propose a fingernail-EPR dosimetry protocol. In addition, to validate the practicality of the protocol, blind and field experiments were performed in the laboratory and a non-destructive testing facility. The relative biases in the dose assessment result of the blind and field experiments were 8.43% and 21.68% on average between the reference and reconstructed doses. The results of this study suggest that fingernail-EPR dosimetry can be a useful method for the application of retrospective dosimetry in cases of radiological accidents.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.698-698
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• 2014

According to the analysis of special medical examination and work environment monitoring data, the rate of C1 and D1 on noise hazard exceeded 90% among those of total hazardous factors. The rate of company exceeding noise exposure limit was also more than 90%. The analysis result shows that main ages diagnosed with C1 and D1 was age of 50s. The majority scale company having workers diagnosed with C1 and D1 was the companies employing 5~49 workers. Types of industries which have a large number of companies exceeding noise exposure limit were automobile and trailer manufacturing, metal processing industry and primary metal manufacturing. A large number of work processes exceeding noise exposure limit were forming and processing work, cutting and bending work and grinding. To reduce the number of company exceeding noise exposure limit, the reduction counterplan should be focused on the type of industry and the work process which exceeded noise exposure limit frequently. However, the reduction counterplan is preemptively necessary to the type of industry and the work process which exceeded noise exposure limit consecutively if the purpose of reduction counterplan is not to merely reduce the number of company exceeding noise exposure limit but to abate workers' suffering from noise.

• 대한방사선기술학회지:방사선기술과학
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• 제44권2호
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• pp.109-115
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• 2021

In this study, a physical evaluation of internal radiation exposure in children was conducted using nuclear medicine test(Renal DTPA Dynamic Study) to simulate the distribution and effects of the radiation throughout the tracer kinetics over time. Monte Carlo simulations were performed to determine the internal medical radiation exposure during the tests and to provide basic data for medical radiation exposure management. Specifically, dose variability based on changes in the tracer kinetic was simulated over time. The internal exposure to the target organ (kidney) and other surrounding organs was then quantitatively evaluated and presented. When kidney function was normal, the dose to the target organ(kidney) was approximately 0.433 mGy/mCi, and the dose to the surrounding organs was approximately 0.138-0.266 mGy/mCi. When kidney function was abnormal, the dose to the surrounding organs was 0.228-0.419 mGy/mCi. This study achieved detailed radiation dose measurements in highly sensitive pediatric patients and enabled the prediction of radiation doses according to kidney function values. The proposed method can provide useful insights for medical radiation exposure management, which is particularly important and necessary for pediatric patients.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.725-733
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• 2023

The Korea Institute of Radiological and Medical Sciences has started a radiation epidemiological study, titled "Korean Radiation Worker Study," to evaluate the health effects of occupational exposure to radiation. As a part of this study, we investigated the methodologies and results of reconstructing organ-specific absorbed doses based on personal dose equivalent, H_p(10), reported from 1984 to 2019 for 20,605 Korean radiation workers. For the organ dose reconstruction, representative exposure scenarios (i.e., radiation energy and exposure geometry) were first determined according to occupational groups, and dose coefficients for converting H_p(10) to organ absorbed doses were then appropriately taken based on the exposure scenarios. Individual annual doses and individual cumulative doses were reconstructed for 27 organs, and the highest values were observed in the thyroid doses (on average 0.77 mGy/y and 10.47 mGy, respectively). Mean values of individual cumulative absorbed doses for the red bone marrow, colon, and lungs were 7.83, 8.78, and 8.43 mSv, respectively. Most of the organ doses were maximum for industrial radiographers, followed by nuclear power plant workers, medical workers, and other facility workers. The organ dose database established in this study will be utilized for organ-specific risk estimation in the Korean Radiation Worker Study.

• Asian Pacific Journal of Cancer Prevention
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• 제14권1호
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• pp.523-528
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• 2013

Background: The possibility that electromagnetic fields (EMF) exposure may increase male breast cancer risk has been discussed for a long time. However, arguments have been presented that studies limited by poor quality could have led to statistically significant results by chance or bias. Moreover, data fo the last 10 years have not been systematically summarized. Methods and Results: To confirm any possible association, a meta-analysis was performed by a systematic search strategy. Totals of 7 case-control and 11 cohort studies was identified and pooled ORs with 95% CIs were used as the principal outcome measures. Data from these studies were extracted with a standard meta-analysis procedure and grouped in relation to study design, cut-off point, exposure assessment method, adjustment and exposure model. A statistical significant increased risk of male breast cancer with EMF exposure was defined (pooled ORs = 1.32, 95% CI = 1.14-1.52, P < 0.001), and subgroup analyses also showed similar results. Conclusions: This meta-analysis suggests that EMF exposure may be associated with the increase risk of male breast cancer despite the arguments raised.

• Asian Pacific Journal of Cancer Prevention
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• 제14권2호
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• pp.811-816
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• 2013

Background: Pervious studies suggested occupational workers exposure to pentachlorophenol (PCP) might contribute to increased risk of cancer. However, few studies have focused on associations between PCP and cancer risk at the community level. Objective: The present study was to explore the cancer risk for the community population living long-term in a PCP contaminated area. Methods: All the cancer cases diagnosed in 2009-2011 in Tongling City were collected. The cancer patients' residencies were geo-referenced in each district. The historical PCP usage for each district of Tongling was calculated as the PCP pollution index, which was further used to divide into PCP exposure categories. Standardized rate ratios (SRRs) of cancer incidence were applied to detect the cancer risk as exposure grade elevated. Correlation analysis was performed to analyze the relationship between PCP pollution and cancer incidence. Results: A total of 5,288 cancer cases (3,451 male and 1,837 female) were identified. PCP usage was correlated with the incidence of leukemia (r=0.88, P=0.002) for males, and with cancer of the esophagus for males (r=0.83, P=0.008) and females (r=0.71, P=0.020). Compared with the low exposure category, significant SRRs for total cancer sites was obtained for high PCP exposure category (SRR=1.61, 95%CI=1.59-1.62). Most SRR values of the cancer sites were significantly increased as exposure grade elevated and exposure time extended. Conclusion: The present study found that community residents living in the PCP contaminated area had increased risk of cancers. Leukemias, lymphomas and nasopharyngeal and esophageal cancers are most possibly associated with PCP exposure.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.489-492
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• 2014

본 논문에서는 컴퓨터 단층활영(CT)을 통해 발생되는 방사선 노출량의 관리를 위한 시스템의 소프트웨어 설계를 제안한다. 방사선 피폭량은 환자의 각 신체 부위별로 민감성의 차이에 따라 다르기 때문에 방사선의 노출량을 관리할 수 있게 되면 결과적으로 환자의 방사선 피폭량을 추정할 수 있다. 최근 일본 원전의 방사선 누출 사건이 국제적으로 뉴스가 되었고 원전 뿐 만아니라 의료용 방사선 피폭까지 폭넓게 관심이 커지고 있다. 현재 방사선 안전관리는 방사선 관계 종사자에 대해서만 관리되고 있지만, 이제는 환자에 대한 피폭 관리까지 요구되고 있다. 우리나라에서 방사선을 이용한 검사와 시술이 증가하여 이에 따른 의료 피폭이 증가하였으나 의료 기관에서는 환자에게 가해지는 방사선 피폭 수치를 알지 못하는 실정이다. 따라서 의료 기관에서 환자의 방사선 피폭을 관리할 수 있는 시스템이 필요하다. 본 논문에서는 의료 기관에서 방사선을 이용하는 대표적인 촬영 도구인 CT의 방사선 노출량을 관리할 수 있는 소프트웨어 설계를 제시한다. 방사선의 노출량을 확인하고 선량의 한도를 설정함으로써 환자의 의료 피폭량을 최적화 하는데 도움이 되고자 한다.

• 의료법학
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• 제22권3호
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• pp.97-124
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• 2021

의료기관에는 진단용 방사선 발생장치를 취급하는 방사선사, 의사, 치과의사, 치과위생사 등 방사선 관계 종사자가 있다. 그리고 간호사, 간호조무사 등 방사선진료를 보조하거나 방사선 검사실로 환자이송 등을 하는 업무 보조자들이 있다. 방사선 관계 종사자는「의료법」 등에 의해 방사선 피폭관리가 이루어지고 있으나 방사선 진료업무 보조자 등은 이에 대한 법적 근거가 없는 실정이다. 또한 진단용 방사선 피폭관리는 의료법령에 의해 규율되고 있고, 치료용 방사선과 핵의학검사에 의한 방사선 피폭관리는「원자력안전법」의 규율을 받고 있다. 이에 진단용 방사선에 의한 피폭관리를 개선하기 위하여「의료법」 상 진단용 방사선 피폭관리에 관한 규정과「원자력안전법」 상 관련 규정들을 비교·검토하여 보았다. 그 결과로 얻은 주요 내용은 다음과 같다. 첫째, 진단용 방사선에 의한 피폭관리 대상으로 방사선 관계 종사자 외에 방사선 피폭 우려가 있는 간호사, 간호조무사, 임상실습 학생 등을 포함시켜 입법적으로 해결할 필요가 있다. 둘째,「원자력안전법」에서처럼 진단용 방사선 관계 종사자가 임신이 확인된 경우에는 피폭선량 한도를 명문으로 규정해야 한다. 셋째,「진단용 방사선 발생장치의 안전관리에 관한 규칙」의 개인피폭선량계의 종류에 관한 규정을 현실에 맞게 개정할 필요가 있다. 넷째, 방사선 관계 종사자, 방사선작업종사자와 수시출입자에 대한 건강진단의 검사항목은 동일해야 할 것으로 보인다. 다섯째, 의료기관에서 진단용 방사선뿐만 아니라 치료용 방사선과 핵의학을 포함한 의료용 방사선 전체를 하나의 법체계에서 통일하여 규율하는 것이 필요하다고 본다.

• Journal of Radiation Protection and Research
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• 제42권4호
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• pp.189-196
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• 2017

Background: The effects of radiation on tissues vary depending on the radiation type. In this study, a minipig model was used to compare the effects of ${\beta}$-rays from $^{166}Ho$ and ${\gamma}$-rays from $^{60}Co$ on the skin. Materials and Methods: In this study, the detrimental effects of ${\beta}$- and ${\gamma}$-irradiation on the skin were assessed in minipigs. The histopathological changes in the skin from 1 to 12 weeks after exposure to 50 Gy of either ${\beta}$- (using $^{166}Ho$ patches) or ${\gamma}$- (using $^{60}Co$) irradiation were assessed. Results and Discussion: The skin irradiated by ${\beta}$-rays was shown to exhibit more severe skin injury than that irradiated by ${\gamma}$-rays at 1-3 weeks post-exposure; however, while the skin lesions caused by ${\beta}$-rays recovered after 8 weeks, the ${\gamma}$-irradiated skin lesions were not repaired after this time. The observed histopathological changes corresponded with gross appearance scores. Seven days post-irradiation, apoptotic cells in the basal layer were detected more frequently in ${\beta}$-irradiated skin than in ${\gamma}$-irradiated skin. The basal cell density and skin thickness gradually decreased until 4 weeks after ${\gamma}$- and ${\beta}$- irradiation. In ${\beta}$-irradiated skin lesions, and the density and thickness increased sharply back to control levels by 6-9 weeks. However, this was not the case in ${\gamma}$-irradiated skin lesions. In ${\gamma}$-irradiated skin, cyclooxygenase-2 (COX-2) was shown to be expressed in the epidermis, endothelial cells of vessels, and fibroblasts, while ${\beta}$-irradiated lesions exhibited COX-2 expression that was mostly limited to the epidermis. Conclusion: In this study, ${\beta}$-rays were shown to induce more severe skin injury than ${\gamma}$-rays; however, the ${\beta}$-rays-induced injury was largely repaired over time, while the ${\gamma}$-rays-induced injury was not repaired and instead progressed to necrosis. These findings reveal the differential effects of ${\gamma}$- and ${\beta}$-irradiation on skin and demonstrate the use of minipigs as a beneficial experimental model for studying irradiation-induced skin damage.

• 대한임상독성학회지
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• 제19권1호
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• pp.38-43
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• 2021

Purpose: We investigated the association between defoliant exposure and survival to discharge after out-of-hospital cardiac arrest. Methods: This is a retrospective case-control study based on the cardiopulmonary resuscitation (CPR) registry. The electronic medical records of out-of-hospital cardiac arrest victims from 6/9/2008 to 12/31/2016 were analyzed statistically. The case patients group had a history of defoliant exposure while the control group did not. Among the 401 victims studied, a total of 110 patients were male out-of-hospital cardiac arrest patients. Baseline characteristics and the parameters involved in cardiac arrest were analyzed and compared between the two groups after propensity score matching. The primary outcome was survival to discharge, and secondary outcomes were sustained return of spontaneous circulation (ROSC) and survival to admission. Results: After propensity score matching a total of 50 patients (case=25, control=25) were analyzed. Primary outcome (survival to discharge) was not significantly different between case and control groups [(OR, 1.759; 95% C.I., 0.491-6.309) and (OR, 1.842; 95% C.I., 0.515-6.593), respectively]. In the subgroup analysis, there were also no significant differences between the control group and subgroups in primary and secondary outcomes according to defoliant exposure severity. Conclusion: There is no statistically significant association between defoliant exposure and survival of out-of-hospital cardiac arrest.