• 대한방사선기술학회지:방사선기술과학
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• 제39권4호
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• pp.493-499
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• 2016

C-arm장비의 사용 시 시술자의 산란선에 의한 피폭선량을 확인하여 적절하고 효율적인 피폭선량 저 감화 방법을 알아보기 위해 본 연구를 진행하였다. Over Tube 방식에 비해 피폭선량이 적다는 Under Tube 방식의 C-arm 장비를 활용하여 연구한 결과 차폐도구가 두꺼울수록 시술자의 피폭선량은 감소하였고, 중심선에서 멀어질수록 피폭선량이 감소하였고, 조사시간이 길어질수록 피폭선량이 증가하였고, 세 곳의 선량계 부착위치 중 생식선에서 가장 많은 피폭선량이 측정되었고 흉부, 갑상선 순이었다. 그러나 실제 시술 중 피폭선량을 줄이기 위해 거리를 무한정 늘릴 수 없고, 조사시간을 무한정 단축시킬 수 없기 때문에 인위적으로 조절 가능한 차폐 두께를 달리하는 방법으로 시술자의 피폭선량을 감소시킬 수 있었다. C-arm장비를 사용할 경우 시술 중 불편하다는 이유로 방사선 차폐에 소홀히 하고 근접시술이 이루어지기 때문에 피폭량은 증가할 수밖에 없다. 이에 C-Arm장비의 특성상 조정실을 구비할 수 없으므로 Apron 등의 방사선 차폐도구의 적정두께 사용 등으로 시술 중 발생되는 방사선에 의한 시술자의 피폭선량을 경감시켜야 할 것으로 사료된다.

• Safety and Health at Work
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• 제8권2호
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• pp.130-142
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• 2017

Background: Osteoarthritis of the knee is considered to be related to knee straining activities at work. The objective of this review is to assess the exposure dose-response relation between kneeling or squatting, lifting, and climbing stairs at work, and knee osteoarthritis. Methods: We included cohort and case-control studies. For each study that reported enough data, we calculated the odds ratio (OR) per 5,000 hours of cumulative kneeling and per 100,000 kg of cumulative lifting. We pooled these incremental ORs in a random effects meta-analysis. Results: We included 15 studies (2 cohort and 13 case-control studies) of which nine assessed risks in more than two exposure categories. We considered all but one study at high risk of bias. The incremental OR per 5,000 hours of kneeling was 1.26 (95% confidence interval 1.17-1.35, 5 studies, moderate quality evidence) for a log-linear exposure dose-response model. For lifting, there was no exposure dose-response per 100,000 kg of lifetime lifting (OR 1.00, 95% confidence interval 1.00-1.01). For climbing, an exposure dose-response could not be calculated. Conclusion: There is moderate quality evidence that longer cumulative exposure to kneeling or squatting at work leads to a higher risk of osteoarthritis of the knee. For other exposure, there was no exposure dose-response or there were insufficient data to establish this. More reliable exposure measurements would increase the quality of the evidence.

• Journal of Radiation Protection and Research
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• 제45권2호
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• pp.81-87
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• 2020

Background: Kori unit #1 is permanently shut down after a 40-year lifetime. The Nuclear Safety and Security Commission recommends establishing initial decommissioning plans for all nuclear and radwaste treatment facilities. Therefore, the Korea Atomic Energy Research Institute (KAERI) must establish an initial and final decommissioning plan for radwaste-treatment facilities. Radiation safety assessment, which constitutes one chapter of the decommissioning plan, is important for establishing a decommissioning schedule, a strategy, and cost. It is also a critical issue for the government and public to understand. Materials and Methods: This study provides a method for assessing external radiation dose to workers during decommissioning. An external dose is calculated following each exposure scenario, decommissioning strategy, and working schedule. In this study, exposure dose is evaluated using the deterministic method. Physical characterization of the facility is obtained by both direct measurement and analysis of the drawings, and radiological characterization is analyzed using the annual report of KAERI, which measures the ambient dose every month. Results and Discussion: External doses are calculated at each stage of a decommissioning strategy and found to increase with each successive stage. The maximum external dose was evaluated to be 397.06 man-mSv when working in liquid-waste storage. To satisfy the regulations, working period and manpower must be managed. In this study, average and cumulative exposure doses were calculated for three cases, and the average exposure dose was found to be about 17 mSv/yr in all the cases. Conclusion: For the three cases presented, the average exposure dose is well below the annual maximum effective dose restriction imposed by the international and domestic regulations. Working period and manpower greatly affect the cost and entire decommissioning plan; hence, the chosen option must take account of these factors with due consideration of worker safety.

• Journal of Radiation Protection and Research
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• 제40권1호
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• pp.25-35
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• 2015

We analyzed the differential effects of histopathology, apoptosis and expression of radiation response genes after chronic low dose rate (LDR) and acute high dose rate (HDR) radiation exposure in spleen, lung and liver of rats. Female 6-week-old Sprague-Dawley rats were used. For chronic low-dose whole body irradiation, rats were maintained for 14 days in a $^{60}Co$ gamma ray irradiated room and received a cumulative dose of 2 Gy or 5 Gy. Rats in the acute whole body exposure group were exposed to an equal dose of radiation delivered as a single pulse ($^{137}Cs$-gamma). At 24 hours after exposure, spleen, lung and liver tissues were extracted for histopathologic examination, western blotting and RT-PCR analysis. 1. The spleen showed the most dramatic differential response to acute and chronic exposure, with the induction of substantial tissue damage by HDR but not by LDR radiation. Effects of LDR radiation on the lung were only apparent at the higher dose (5 Gy), but not at lower dose (2 Gy). In the liver, HDR and LDR exposure induced a similar damage response at both doses. RT-PCR analysis identified cyclin G1 as a LDR-responsive gene in the spleen of rats exposed to 2 Gy and 5 Gy gamma radiation and in the lung of animals irradiated with 5 Gy. 2. The effects of LDR radiation differed among lung, liver, and spleen tissues. The spleen showed the greatest differential effect between HDR and LDR. The response to LDR radiation may involve expression of cyclin G1.

• 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.

• 대한방사선기술학회지:방사선기술과학
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• 제47권3호
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• pp.167-173
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• 2024

This study purpose to establish an appropriate target exposure index(EIT) using dose area product(DAP) and exposure index(EI) based on chest radiography. First, the system response experiment was conducted with radiation quality of RQA5 to compare the dosimetry and dose area product of equipment. Next, EI and DAP were acquired and analyzed while varying the dose in the diagnostic at 70kVp using a human body model phantom. The signal to noise ratio(SNR) of the obtained results was analyzed in the diagnostic with in the diagnostic reference level(DRL) application range. The DRL at percentage 25% had a dose of 0.17 mGy and EI was 83, and at percentage 75% the dose was 0.68 mGy and EI was 344. As the dose increased, the SNR in the subdiaphragm increased. To set the EIT, calibration must first be performed using a dosimeter and set within the DRL range to reflect the needs of the medical institution.

• 한국방사선학회논문지
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• 제13권4호
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• pp.667-674
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• 2019

Technegas를 사용한 검사는 단순 확산 누적을 통해 폐 영상을 이미지화하기 때문에 검사를 마친 후에 검사실이 오염될 수 있다. 따라서 방사선 작업 종사자와 검사를 기다리는 환자는 technegas 흡입으로 인한 내부 피폭의 영향을 받게 된다. 이에 중력환기 전후의 시간경과에 따른 공간선량율 분포를 비교, 분석함에 따라 방사선사, 의료진, 대기 환자의 피폭선량 저감화 방법을 모색하고자 한다. 중력환기 전후 환자의 호흡기 위치에서 거리별, 각도별로 공간선량율을 10분 동안 측정하고 평균값, 표준 편차 및 감소율을 계산하였다. 실험 결과, 중력 환기 전후 감소율은 최고 95.31%였고 가장 높은 감소율은 1 ~ 3분 사이에서 나타났다. 중력환기를 통해서 방사선 작업종사자, 대기환자, 환자 보호자 및 간호사의 피폭선량을 감소시킬 수 있다. 결론적으로 중력환기를 통한 피폭선량 감소 결과는 방호 최적화를 이루는 역할을 할 것이며 ICRP 103에서 권고한 의료 피폭 저감화에 부합된다.

• 대한방사선기술학회지:방사선기술과학
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• 제40권3호
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• pp.355-361
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• 2017

소아는 성인보다 장기의 방사선에 대한 감수성이 크고 성장 중이기 때문에 더 민감하다. 피폭으로 인한 부작용을 겪는 기대수명이 길기 때문에 피폭선량의 관리가 어른의 경우보다 중요하게 다뤄진다. 본 연구는 10세 팬텀을 사용하여 현재 우리나라에 권고되어 있는 5세 소아의 촬영기준과 입사표면선량의 적합성을 확인하고 추가적으로 제시된 촬영기준으로 장기흡수선량을 측정해보았다. 임상에서 사용 중인 5세와 10세의 촬영조건과 장기흡수선량, 입사표면선량을 비교하였다. 임상 5세 촬영조건이 권고촬영조건보다 약간 높으며 임상 10세 촬영조건은 많이 높게 나타났다. 또한 권고 촬영조건으로 ESD를 측정한 결과 임상 촬영조건의 ESD가 43% 높게 나타났으며 10세의 ESD는 5세의 권고 촬영조건의 ESD 보다 126% 증가를 나타냈다. 5세의 권고된 ESD와 임상 촬영조건에 의한 ESD를 비교한 결과 31.6%의 차이를 나타냈다. 5세의 권고 촬영조건과 임상 촬영조건에 의한 장기흡수선량은 큰 차이는 없으나 흉부와 골반검사에서는 차이가 컸다. 그러나 10세의 임상 촬영조건에 의한 장기흡수선량을 비교하면 월등한 차이가 있었음을 알 수 있었다. 따라서 소아의 권고 선량에 대한 더욱 세분화된 기준안이 연구되어야 할 것으로 사료된다.

• Nuclear Engineering and Technology
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• 제38권3호
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• pp.231-238
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• 2006

Whole-body exposure to high-dose radiation causes injury involving multiple organs that depends on their sensitivity to radiation. This acute radiation syndrome (ARS) is caused by a brief exposure of a major part of the body to radiation at a relatively high dose rate. ARS is characterized by an initial prodromal stage, a latent symptom-free period, a critical or manifestation phase that usually takes one of four forms (three forms): hematologic, gastrointestinal, or cardiovascular and neurological (neurovascular), depending upon the exposure dose, and a recovery phase or death. One of the most important factors in treating victims exposed to radiation is the estimation of the exposure dose. When high-dose exposure is considered, initial dose estimation must be performed in order to make strategy decisions for treatment as soon as possible. Dose estimation can be based on onset and severity of prodromal symptoms, decline in absolute lymphocyte count post exposure, and chromosomal analysis of peripheral blood lymphocytes. Moreover, dose assessment on the basis of calculation from reconstruction of the radiation event may be required. Experience of a criticality accident occurring in 1999 at Tokai-mura, Japan, showed that ARS led to multiple organ failure (MOF). This article will review ARS and discuss the possible mechanisms of MOF developing from ARS.

• 한국콘텐츠학회논문지
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• 제17권7호
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• pp.498-504
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• 2017

치아를 칫솔질하거나 치약을 사용하는 것과 같은 구강 건강 행위는 구강 건강을 개선하며, 따라서 삶의 질을 향상시키는 중요한 부분이다. 그러나 화학 물질에 대한 연구도 필요한 실정이다. 따라서 본 연구는 구강 건강 행위로 인해 야기되어지는 불소 노출에 미치는 요인을 조사하여 정확한 구강 건강 지침을 제공하고자 한다. ConsExpo 5.0 모델에서 불소 화합물의 경구 노출을 적용한 결과, 일일 불소 인체노출량 추정은 성인남성의 모델 결과 oral external dose는 0.000196 mg/kg, oral acute(internal) dose는 0.000196 mg/kg, oral chronic(internal)dose는 0.000465 mg/kg/day로 추정되었다. 성인여성은 연구결과 oral external dose는 $4.1{\times}10^{-6}mg/kg$, oral acute(internal) dose $4.1{\times}10^{-6}mg/kg$, oral chronic(internal) dose $9.99{\times}10^{-6}mg/kg/day$로 추정되었다.