• Journal of Radiation Protection and Research
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• 제44권4호
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• pp.128-148
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• 2019

Massive environmental monitoring has been conducted continuously since the Fukushima Daiichi Nuclear Power accident in March of 2011 by different monitoring methods that have different features together with migration studies of radiocesium in diverse environments. These results have clarified the characteristics of radiological environments and their temporal change around the Fukushima site. At three months after the accident, multiple radionuclides including radiostrontium and plutonium were detected in many locations; and it was confirmed that radiocesium was most important from the viewpoint of long-term exposure. Radiation levels around the Fukushima site have decreased greatly over time. The decreasing trend was found to change variously according to local conditions. The air dose rates in environments related to human living have decreased faster than expected from radioactive decay by a factor of 2-3 on average; those in pure forest have decreased more closely to physical decay. The main causes of air dose rate reduction were judged to be radioactive decay, movement of radiocesium in vertical and horizontal directions, and decontamination. Land-use categories and human activities have significantly affected the reduction tendency. Difference in the air dose rate reduction trends can be explained qualitatively according to the knowledge obtained in radiocesium migration studies; whereas, the quantitative explanation for individual sites is an important future challenge. The ecological half-lives of air dose rates have been evaluated by several researchers, and a short-term half-life within 1 year was commonly observed in the studies. An empirical model for predicting air dose rate distribution was developed based on statistical analysis of an extensive car-borne survey dataset, which enabled the prediction with confidence intervals. Different types of contamination maps were integrated to better quantify the spatial data. The obtained data were used for extended studies such as for identifying the main reactor that caused the contamination of arbitrary regions and developing standard procedures for environmental measurement and sampling. Annual external exposure doses for residents who intended to return to their homes were estimated as within a few millisieverts. Different forms of environmental data and knowledge have been provided for wide spectrum of people. Diverse aspects of lessons learned from the Fukushima accident, including practical ones, must be passed on to future generations.

• 한국의학물리학회지:의학물리
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• 제25권4호
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• pp.193-198
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• 2014

본 연구의 목적은 새로 개발된 2차원 토모테라피 선량측정 시스템의 가능성을 알아보는 것이다. 방사선이 조사되면 가시광성을 내보내는 인광판을 원통형 물팬텀에 삽입하였다. 치료계획장치에서 원 모양, C자 모양, 다중표적 3종류의 가상의 표적을 만들고 각 표적에 10 Gy의 방사선을 전달하도록 하였다. 원통형 팬텀을 토모테라피 치료테이블위에 올려놓고 치료계획대로 방사선을 조사하였다. CCD카메라로 쵤영된 모든 프레임은 누적되었고 각 픽셀은 선량으로 변환되었다. 인광판으로부터 나온 영상은 치료계획장치에서 계산된 선량분포와 비교하였다. 선량기울기(dose rate)와 픽셀값의 관계그래프는 선량기울기 900 MU/min 까지 포화(saturated)되지 않았다. 인광판의 선형성 보정이 개선된다면 인광판과 CCD카메라를 이용한 토모테라피의 2차원 선량측정이 유용할 것으로 기대한다.

• Radiation Oncology Journal
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• 제26권2호
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• pp.104-112
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• 2008

목적: 기존치료에 반응하지 않는 다발성 간전이를 동반한 대장암 환자에서 방사선치료와 병합한 수지상세포 면역치료의 독성과 반응도를 조사하였다. 대상 및 방법: 2004년 5월부터 2006년 11월까지 다발성 간전이가 동반된 대장암 환자들 중에서 항암화학 요법에 반응하지 않은 환자 중 지원자를 대상으로 연구를 시행하였다. 본 임상 시험에 대하여 동아대학교병원과 부산대학교병원의 임상윤리심의위원회의 허가를 획득하였고, 동의서에 서명한 환자들을 임상 시험의 대상으로 등록하였다. 환자의 말초 혈액으로부터 수지상세포를 추출하여 배양하였다. 임상시험 일자에 맞추어서 $6{\times}10^6$개의 수지상세포를 바이알(0.5 ml)에 넣어서 디씨백/아이알 주사를 만들었다. 수지상세포 면역치료는 2주 간격으로 간전이암조직에 3회 주사하고, 5주에 내약성 평가를 하였다. 내약성 평가를 통과한 환자에게는 8주에 4번째 수지상세포 면역치료를 하였다. 병의 악화가 없거나 임상시험에 대한 환자의 동의 철회가 없는 경우에는 5, 6번째 수지상세포 면역치료를 각각 12, 16주에 시행하였다. 방사선치료는 수지상세포 면역치료를 주사할 간전이암 부위에 주사하기 전일 및 당일에 4 Gy씩을 조사하였다. 내약성 평가는 $3{\times}10^6$개의 수지상세포로부터 시작하여, $12{\times}10^6$개의 수지상세포까지 시행하였다. 내약성 평가의 최대 내성 용량으로 추가 임상시험을 하였다. 수지상세포 면역치료 주사를 맞은 모든 환자들에서 안전성 평가를 하였다. 4회 이상 주사를 맞은 환자들을 대상으로 10주에 치료 반응을 평가하여 유효성을 조사하였다. 결과: 임상시험에 등록한 24명 중 22명에서 수지상세포 면역치료를 시행하였다. 내성약 평가에는 14명이 등록하여 11명에서 평가를 완료하였다. 시험약과의 관련성이 있을 것으로 생각되는 grade 3 이상의 약물반응으로 인한 이상반응은 없었다. $12{\times}10^6$개의 수지상세포를 내성용량으로 확인하였고, 내성용량인 $12{\times}10^6$개 수지상세포 면역치료를 이용하여 8명에서 추가로 시험을 하였다. 치료에 대한 환자들의 내성은 양호하였고, grade 3을 초과하는 치명적인 부작용은 발생되지 않았다. 4회 이상의 수지상세포 면역치료 주사를 받은 환자가 17명이었고, 이 중의 15명에서는 종양의 반응도 평가가 이루어졌다. 본 연구의 목적은 안전성 평가이지만, 면역치료의 유효성 평가를 위해, 방사선치료와 수지상세포 면역치료 주사가 시행된 부위 외의 간전이암에서 반응도를 조사 하였다. 면역치료의 반응은 평가가 이루어진 환자들에서 정지성 병변이 4명, 진행성 병변이 11명 이었다. 결론: 수지상세포 면역치료와 병행한 방사선치료는 이론적으로 국소 및 전신 제어에 상승효과가 있을 것으로 기대할 수 있다. 하지만 기존 치료에 반응하지 않는 매우 진행된 직장암 환자들을 대상으로 한 본 연구에서는 방사선 치료와 병합한 수지상세포 면역치료로 인한 심각한 부작용의 발생은 없었다는 결과와 4예에서의 정지성 병변의 관찰을 보고한다. 수지상세포의 최대 투여 용량, 적절한 투여 방법, 적절한 방사선의 양, 방사선과 수지상 세포의 적절한 투여 간격 등에 관한 추가 연구를 통하여, 향후 제 2상, 3상 시험으로서의 진행 여부에 긍정적인 결과를 얻을 수 있다고 판단한다.

• 대한핵의학회지
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• 제33권4호
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• pp.422-429
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• 1999

목적: 근치적 절제술이 불가능하거나 전이를 동반한 악성 갈색세포종 환자의 I-131 MIBG 치료 시 흡수선량의 평가는 치료 효과 예측 및 치료용량 결정에 중요하다. 저자들은 갈색세포종 환자에서 I-131 MIBG 치료 후 감마카메라와 MIRD법을 이용하여 흡수선량을 평가하고자 본 연구를 시행하였다. 대상 및 방법: 종격동, 우측 신장 및 대동맥주위 림프절등에 전이가 확인된 악성 갈색세포종 환자에서 74 GBq I-131 MIBG 투여 후 양쪽 목옆에 37 MBq 와 74 MBq의 표준선원을 놓고 각각 0.5, 16, 24, 64, 145시간에 감마카메라로 전 후면영상 얻었다. 배후방사능 보정과 불응시간 보정 그리고 감쇠 보정후 MIRD법을 이용하여 표적조직의 흡수선량을 구하였다. 결과: 병소 각각에서 약 $32{\sim}63$ Gy/74 GBq의 흡수선량을 얻었으나 완전관해에 필요한 $150{\sim}200$ Gy에는 도달하지 못하였다. 치료 1달 후 X선 전산화 단층촬영상에서 병소의 감소를 확인하였고 치료 전과 비교한 I-123 MIBG 영상에서 MIBG 섭취감소를 확인하였다. 결론: 갈색세포종 환자에서 I-131 MIBG 치료 후 치료용량결정 및 치료계획을 수립하는 데 있어서 흡수선량평가가 필요하며 본 연구에서처럼 감마카메라와 MIRD법을 이용한 방법은 보다 간편하게 흡수선랑을 평가할 수 있어 임상적인 환경에서 유용할 것으로 여겨진다. 앞으로 본 연구에서 얻은 흡수선량의 정확성을 검증하고, 보다 많은 수의 환자에 적용하여 흡수선량과 치료 효과와의 관계를 규명하는 연구를 하여야 할 것이다.

• 지역사회간호학회지
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• 제26권2호
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• pp.169-177
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• 2015

Purpose: Previous studies focused on the negative effects of Internet use such as obesity, depression, and addiction. However, few studies investigated whether the Internet use for an appropriate time has positive effects on adolescents' health. Thus, the purpose of the study was to examine the dose-response relationship between Internet use for non-academic purposes (NAP) and happiness/stress in adolescents. Methods: This study used data from the 2013 Korea Youth Risk Behavior Web-Based Survey. A total of 72,435 adolescents were included. Rao-Scott ${\chi}^2$ and multiple logistic regression were conducted. To test the dose-response relationship, this study examined how happiness/stress changed with increase in the time of Internet use for NAP. Results: After controlling for general characteristics, the odds ratios for being unhappy and stressful were lowest in adolescents using the Internet for NAP for more than 0 hour and less than an hour a day. Interestingly, students who did not use the Internet for NAP had a significantly higher risk of being unhappy/stressful than those using for more than 0 hour and less than an hour a day. Conclusion: Internet use for NAP for more than 0 hour and less than an hour a day has positive effects on happiness/stress in adolescents.

• Radiation Oncology Journal
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• 제12권2호
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• pp.143-150
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• 1994

The damage which radiation produces in tissues such as the lungs can be discussed at the molecular, biophysical, cellular, and organ levels. The cellular effects of irradiating the lungs are related to the histologic and clinical sequelae. In the present study the right lung of rabbits were exposed to single dose of 20 Gy of X-irradiation. Animals from each group were sacrificed monthly for 6 months postexposure. Sections of lung were examined by light microscopy(LM) and by transmission electron microscopy(TEM). Multiple exudative lesions were seen at 2 months after the 20Gy irradiation,and they progressed to a proliferative and then reparative fibrotic lesion by 6 months. Changes in epithelial lining of lung components, particulary the presence of type II pneumocytes were found by both LM and TEM. Capillary endothelial damages were less pronounced. The possible implication of cellular components in radiation pneumonitis and fibrosis is discussed.

• 대한수의학회지
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• 제55권4호
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• pp.215-219
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• 2015

Cardiopulmonary depression of long-term constant rate infusion (CRI) administration of multiple analgesic drugs is important, especially in critically ill dogs. Therefore, this study was conducted to evaluate the effects of lidocaine, ketamine or combined lidocaine-ketamine combination CRI treatment on vital signs and left ventricular (LV) function in healthy dogs. Six adult Beagle dogs were administered either ketamine (initial loading dose of 0.5 mg/kg followed by $10{\mu}g/kg/min$ CRI), lidocaine (initial loading dose of 2 mg/kg followed by 0.025 mg/kg/min CRI), or combined lidocaine-ketamine intravenously. Arterial blood pressure (BP), heart rate (HR), respiratory rate (RR), body temperature (BT) and echocardiographic LV dimensions were measured before administration of medications, immediately after administration of drugs, and then every 10 min for 2 h. There were no significant changes in HR, RR, BT and BP after the administration of either lidocaine CRI, ketamine CRI, or combined lidocaine and ketamine CRI. There were also no significant changes in LV dimensions and stroke volume. The results revealed that treatment with either lidocaine, ketamine or combined lidocaine-ketamine may not cause cardiopulmonary suppression in healthy dogs.

• Nuclear Engineering and Technology
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• 제51권8호
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• pp.1998-2004
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• 2019

The Multi-Physics (MP) instrument is one of 20 neutron spectrometers planned in the China Spallation Neutron Source (CSNS). This paper presents a shielding calculation for the MP instrument using Monte Carlo codes MCNPX and FLUKA. First, the neutrons that escape from the CSNS decoupled water moderator and are delivered to the beam line of the MP instrument are calculated to use as the source term of the shielding calculation. Then, to validate the calculation method based on multiple variance reduction techniques, a cross check between MCNPX and FLUKA codes is performed by comparing the calculation results of the dose rate distribution on a simplified beam line model. Finally, a complete geometry model of the MP instrument is set up, and the primary parameters for the shielding design are obtained according to the calculated dose rate map considering different worst-case scenarios.

• Journal of Microbiology and Biotechnology
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• 제19권6호
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• pp.622-628
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• 2009

In the present study, the therapeutic potential of purified and well-characterized bacteriophages was evaluated in thermally injured mice infected with Klebsiella pneumoniae B5055. The efficacy of five Klebsiella phages (Kpn5, Kpn12, Kpn13, Kpn17, and Kpn22) was evaluated on the basis of survival rate, decrease in bacterial counts in different organs of phage-treated animals, and regeneration of skin cells as observed by histopathological examination of phage-treated skin. Toxicity studies performed with all the phages showed them to be non-toxic, as no signs of morbidity and mortality were observed in phage-treated mice. The results of the study indicate that a single dose of phages, intraperitoneally (i.p.) at an MOI of 1.0, resulted in significant decrease in mortality, and this dose was found to be sufficient to completely cure K. pneumoniae infection in the burn wound model. Maximum decrease in bacterial counts in different organs was observed at 72 h post infection. Histopathological examination of skin of phage-treated mice showed complete recovery of burn infection. Kpn5 phage was found to be highly effective among all the phages and equally effective when compared with a cocktail of all the phages. From these results, it can be concluded that phage therapy may have the potential to be used as stand-alone therapy for K. pneumoniae induced burn wound infection, especially in situations where multiple antibiotic-resistant organisms are encountered.

• 한국직업건강간호학회지
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• 제24권2호
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• pp.67-75
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• 2015

Purpose: The objective of the present study was to evaluate the effects of occupational exposure to low dose organic solvents on the prevalence of cardiovascular risk factors. Methods: Study design was retrospective cohort study subjected on 191 exposures and 118 controls working in a petrochemical manufacture company. The eight indicators related to CVD risk were followed up for five years from 2008 to 2012. The risk level was compared during the follow up years and subject's characteristics, and the change of risk level were analyzed with repeated measures ANOVA and multiple logistic regression analysis. Results: At the start year 2008, the rate over cutoff value (ROCV) of BS (p<.001) and mean systolic BP (p=.017) were higher in organic solvent exposure group and the others showed no difference. And by the subject's characteristics, odds ratio of the ROCV of BS were higher in organic solvent exposure group and work shift group as 2.51 and 3.07. Comparing the results in 2012 to those of 2008, cardiovascular disease risk in organic solvent exposure group was about 1.5 times higher than that of in the control group. Conclusion: Gradual increase in the CVD risk was identified in organic solvent exposure group. However, the risk might be influenced by shift work and bad behaviors rather than organic solvent exposure.