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Optimization Study for the CRC PIXE System Beam Transport Line
정철기,이경진 한국방사선산업학회 2014 방사선산업학회지 Vol.8 No.1
Proton Induced X-ray Emission (PIXE) is a MeV ion beam analysis method for usewith particle accelerators. PIXE uses low-energy charged particles as an excitation mechanism togenerate characteristic x-ray emission from each element in a target. In PIXE analysis, the beamcurrent used is from a few nA to several tens of nA. Chosun University (Cyclotron ResearchCenter) designed a 50 μA beam line from the 13 MeV cyclotron for use with a PIXE analysissystem, as well as performing beam transport line optimization research. In this study, the beamline operation conditions for the optimization process of beam transport and beam characteristicsare shown.
정철기,이경진,허민구,장홍석,민영돈 한국방사선산업학회 2011 방사선산업학회지 Vol.5 No.4
[18F]FDG (2-[18F] Fluoro-2-deoxy-D-Glucose), which is required Automated SyntheticModule for production, is most often used Radiopharmaceuticals in nuclear medicine. In this study,an Automated Synthesis Module was developed to produce FDG in two consecutive time when F-18 feds continuously by modifying a domestic FDG Automated Synthetic Module on structuralgeometry and control system. The results were showed that the Average Synthesis Yields on thedeveloped Automated Synthetic Module were 45±3% (n=20), 50±3% (n=20) respectively. TheQuality Control results, such as Radio TLC, Radiochemical purity, Gamma-counter, pH, LALTest, Micro bacteria test, showed in same level with domestic [18F]FDG Auto-Synthetic modules. Therefore, if some features were improved by considering the components life time and appearance,commercial sales can be expected because of low price and easy maintenance comparedwith foreign products.
Evaluation of 18F Radioactive Concentration in Exhaust at Cyclotron Facility at Chosun University
정철기,장한,이경진 (사)한국방사선산업학회 2016 방사선산업학회지 Vol.10 No.1
The recent prevalence of PET examinations in Korea has led to an increase in thenumber of cyclotrons. The medical isotope 18F produced in most cyclotron facilities currentlyoperating in Korea is emitted into the environment during the production of [18F]FDG, a cancerdiagnosisreagent. The amount of [18F]FDG synthesized determines the radioactive concentrationof 18F in the exhaust. At some facilities, this amount temporarily exceeds the emission limit. In thisstudy, we evaluated the 18F radioactivity concentration in the exhaust from the cyclotron facilityat Chosun University. The 18F radioactivity concentration was measured using an air sampler anda HPGe semiconductor detector. The measurements showed that the radioactive concentration of18F in the exhaust at the cyclotron facility at Chosun University was the highest during [18F]FDGsynthesis but remained under the legal limit of 2,000 Bq m-3.
조선대학교 사이클로트론 시설의 RI 배기필터 성능평가 및 18F 배출저감 연구
정철기,장한,이경진 (사)한국방사선산업학회 2017 방사선산업학회지 Vol.11 No.1
Recently, the number of PET cyclotrons has increased in Korea. A cyclotron mainly produces 18F, which is used for the production of [18F]FDG, a cancer diagnostic radiopharmaceutical. For radiation protection, the discharge control standard under the Nuclear Safety Act limits the radioactive concentration of 18F in the exhaust discharged from a nuclear power utilization facility to below 2,000 Bq m-3. However, the radioactive concentration of 18F discharged during [18F]FDG production at the cyclotron facility at Chosun University is maintained at about 1,500 Bq m-3 on average, which is 75% of the concentration limit of the discharge control standard, and temporarily exceeds the standard as per the real-time monitoring results. This study evaluated the performance of the exhaust filter unit of the cyclotron facility at Chosun University by assessing the concentration of 18F in the exhaust, and an experiment was conducted on the discharge reduction, where 18F is discharged without reacting with the FDG precursors during [18F]FDG synthesis and is immediately captured by the [18F]FDG automatic synthesis unit. Based on the performance evaluation results of the exhaust filter at the cyclotron facility of Chosun University, the measured capture efficiency before and after the filter was found to be 92%. Furthermore, the results of the discharge reduction experiment, where the exhaust 18F was immediately captured by the [18F]FDG synthesizer, showed a very satisfactory 94.3% reduction in the concentration of discharge compared to the existing discharge concentration.
鄭哲基 광주대학교 1986 광주개방대학 논문집 Vol.3 No.-
Though modern bank of our country was established about a century ago, our country's financial industry has been making progress for only recent 20 years. It is truth that our country's financial industry has been growing distinctly from its formal point, it is likely not to be enough in the growth of real economy. The reason why financial industry is inferior to real economy is : First, because of continuing inflation, household and enterprise are reluctant to hold financial asset including money. Second, there was no financial innovation. Third, antrepronoors frequently failed to invest the capital ??복사불량. Fourth, government controlled financial industry too strongly. Our country's financial industry of future must be established on the proposition that the proposition that the principle of chance and the principle of market economy should be ??복사불량. First, the direction and contents that finance Self-control should be rooted, must be established. Second, according to business cycle, government should content interest eiastically. Third, financial authorities should pursue profit maximizing for the officiency of financial industry. Fourth, financial industry should adapt the principle of competition and promote to develop the financial industry. I put emphasis on financial improvements in this article. But what is important is that government and authorities of financial field should have strong will to improve and carry out strenuously.