• Journal of Radiation Protection and Research
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• v.39 no.1
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• pp.54-60
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• 2014

IAEA has employed various types of radiation detectors - HPGe, NaI, CZT - for accountancy of nuclear material. Among them, HPGe has been mainly used in verification activities required for high accuracy. Due to its essential cooling component(a liquid-nitrogen cooling or a mechanical cooling system), it is large and heavy and needs long cooling time before use. New hand-held portable HPGe has been developed to address such problems. This paper deals with results of performance evaluation test of the new hand-held portable HPGe prototype which was used during IAEA's inspection activities. Radioactive spectra obtained with the new portable HPGe showed different characteristics depending on types and enrichments of nuclear materials inspected. Also, Gamma-rays from daughter radioisotopes in the decay series of $^{235}U$ and $^{238}U$ and characteristic x-rays from uranium were able to be remarkably separated from other peaks in the spectra. A relative error of enrichment measured by the new portable HPGe was in the range of 9 to 27%. The enrichment measurement results didn't meet partially requirement of IAEA because of a small size of a radiation sensing material. This problem might be solved through a further study. This paper discusses how to determine enrichment of nuclear material as well as how to apply the new hand-held portable HPGe to safeguard inspection. There have been few papers to deal with IAEA inspection activity in Korea to verify accountancy of nuclear material in national nuclear facilities. This paper would contribute to analyzing results of safeguards inspection. Also, it is expected that things discussed about further improvement of a radiation detector would make contribution to development of a radiation detector in the related field.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.3
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• pp.142-149
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• 2005

This investigation was conducted to observe and verify the distribution and their occurrence between heavy metals and natural isotopes in the soil collected at the 40 locations from the abandoned coal mine areas to the sediment of Chungra reservoir located at Chungra-Myon Boryung city, Chungnam. The results of the investigation showed that there were distinctive differences of the contents for the heavy metals and the natural isotopes between the area influenced by the coal mine tailing and the non-influenced area. The amounts of the heavy metals were Pb ($1.32-29.96mg\;kg^{-1}$), Cd ($0.15-0.76mg\;kg^{-1}$), Cu ($0.28-49.67mg\;kg^{-1}$), and Cr ($1.31-13.18mg\;kg^{-1}$) while the averages were Cu ($12.43mg\;kg^{-1}$), Pb ($10.44mg\;kg^{-1}$), Cr ($4.87mg\;kg^{-1}$), Cd ($0.51mg\;kg^{-1}$). The standard deviations of Pb and Cu were significantly higher compared to other heavy metals investigated in this experiment. And the amounts of the natural isotopes measured from the dried soil samples were Pb-210 ($4.87dpm\;g^{-1}$), Th-234 ($3.52dpm\;g^{-1}$), Ra-226 ($2.88dpm\;g^{-1}$), Ra-228 ($7.30dpm\;g^{-1}$), K-40 ($58.06dpm\;g^{-1}$) for all locations whereas Cs-137 which is fall-out by nuclear experiment from atmosphere was rarely found. From these results we found that the amounts of natural isotopes such as Pb-210 (4.41%), Th-234 (3.60%), and Ra-226 (2.09%) were less than those found in the coal-tailing while the proportion of Ra-228 (266%) and K-40 (308%) were significantly higher than those in the coal-tailing. Also occurrence of correlations between the amounts of the heavy metals and the natural isotopes was proportionally related.

• The Korean Journal of Nuclear Medicine
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• v.5 no.1
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• pp.1-10
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• 1971

혈액질환(血液疾患), 특히 용혈성빈혈(溶血性貧血)을 수반(隨伴)한 경우(境遇)에 적혈구(赤血球)의 생성(生成) 및 파괴과정(破壞過程)을 정확(正確)히 파악(把握)하는 것은 중요(重要)하여 특히 적혈구수명측정(赤血球壽命測定)은 빈혈(貧血)의 본능(本能) 및 발생기전(發生機轉)을 이해(理解)하는데는 물론 병인적(病因的) 치료(治療) 및 예후(豫後)를 결정(決定)하는데 대단(犬端)히 유용(有用)하다. 적혈구수명측정(赤血球壽命測定)에는 1919년(年) Ashby가 개발(開發)한 differential agglutination법(法)이 이용(利用)되어 왔으나 수혈(輸血)에 따른 위험(危險)이 있고 방법(方法)이 복잡(複雜)하다는 단점(短點)을 가져 새로운 적혈구수명측정법(赤血球壽命測定法)이 연구(硏究)되어 왔다. 최근(最近)에 $^{51}Cr$이나, $^{32}DFP$같은 방사성동위원소(放射性同位元素)를 이용(利用)한 방법(方法)이 도입(導入)된 이래(以來) 임상적(臨床的)으로 적혈구수명측정(赤血球壽命測定)이 많이 시행(施行)되고 있지만 아직까지도 그 방법(方法)이나 결과(結果)의 해석(解釋)에 표준화(標準化)가 안되어 있다. 현재(現在) 임상영역(臨床領域)에서 가장 널리 이용(利用)되고 있는 적혈구수명측정법(赤血球壽命測定法)은 방사성(放射性) chromium($^{51}Cr$)법(法)으로 1950년(年) Gray와 Sterling에 의(依)해 창안(創案)된 이래(以來) 많은 학자(學者)들에 의(依)해 여러 가지 변법(變法)이 고안(考案)되어 왔는데, 이의 가장 큰 이유(理由)는 $^{51}Cr$이 적혈구표지(赤血球標識)에 가장 이상적(理想的)인 것만은 아니고 그 결과(結果)에 많은 요인(要因)들이 영향(影響)을 미치기 때문이다. 또 이런 변법(變法)의 사용(使用)은 각(各) 검사(檢査)에서 계산(計算)된 측정치(測定値)에 차이(差異)가 있어 그 결과(結果)의 해석(解釋) 및 비교(比較) 검토(檢討)에 적지않은 난점(難點)이 생겨 표준화(標準化)된 공통적(共通的)인 방법(方法)의 사용(使用)이 중요(重要)하다는 사실(事實)이 인식(認識)되게 되었다. 1966년(年) 호주(濠洲)의 Sydney에서 개최(開催)되었든 제11차(第11次) 국제혈액학회(國際血學會)때 열린 제4차(第4次) International Committee for Standardization in Haematology(ICSH)에서 Diagnostic Applications of Radioisotopes in Haematology에 관(關)한 expert panel을 갖을것을 의결(議決)하여 다음과 같은 12명(名)의 위원(委員)이 결정(決定)되었으며 위원회(委員會)의 의장(議長)에 Dr. Szur, 총무(總務)에 Dr. Glass가 각각(各各) 선임(選任)되었다. 그간(間) 1967년(年) 영경(英京) London에서 첫 회합(會合)이 있은후(後) New York, Vienna(IAEA후원(後援)) Brthesda(NIH후원(後援))에서 전문위원회(專門委員會)를 갖고 적혈구수명측정법(赤血球壽命測定法)에 관(關)한 의견(意見)의 일치(一致)를 보았다. ICSH와 국제혈액학회(國際血學會)에서는 이번에 결정(決定)된 적혈구수명측정법(赤血球壽命測定法)을 널리 소개(紹介)하며, 측정법(測定法)과 얻어진 결과(結果)의 해석(解釋)에 표준화(標準化)를 기(期)할 목적(目的)으로 이에 연관성(聯關性)있는 전문지(專門誌)에 게재(揭載)할 것을 요청(要請) 받었기에 이에 전문(全文)을 소개(紹介)하는 바이다. 이들은 방사성(放射性) chromium 법(法)의 모든 세부적(細部的)인 면(面)을 표준화(標準化)하고 있으며 그간(間) 가장 논란(論難)의 대상(對象)이 되었던, $^{51}Cr$-표지방법(標識方法)에 있어서의 세가지 변법(變法), 즉 ACD법(法), Citrate-wash법(法), ACD/ascorbic acid법(法)을 모두 인정(認定)하고 있다. 또한, DFP($DF^{32}P$ 또는 $^3H-DFP$) 표지법(標識法)의 표준방법(標準方法)도 기술(記述)하고 있으며, 더욱 중요(重要)한 것은 적혈구수명측정법(赤血球壽命測定法)으로서 현재(現在)까지 대부분(大部分)의 학자(學者)가 사용(使用)하여 왔던 지표(指標)인 $T_{50}Cr$ 대신(代身)에 mean red cell life span을 사용(使用)할 것을 권(勸)하고 있다.

• Progress in Medical Physics
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• v.20 no.1
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• pp.37-42
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• 2009

Proton therapy facility, which is recently installed at National Cancer Center in Korea, generally produces a large amount of radiation near cyclotron due to the secondary particles and radioisotopes caused by collision between proton and nearby materials during the acceleration. Although the level of radiation by radioisotope decreases in length of time, radiation exposure problem still exists since workers are easily exposed by a low level of radiation for a long time due to their job assignment for maintenance or repair of the proton facility. In this paper, the working environment near cyclotron, where the highest radiation exposure is expected, was studied by measuring the degree of radiation and its duration for an appropriate level of protective action guide. To do this, we measured the radiation change in the graphite based energy degrader, the efficiency of transmitted beam and relative activation degree of the transmission beam line. The results showed that while the level of radiation exposure around cyclotron and beam line during the operation is much higher than the other radiation therapy facilities, the radiation exposure rate per year is under the limit recommended by the law showing 1~3 mSv/year.

• Journal of Plant Biology
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• v.12 no.3
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• pp.26-34
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• 1969

Through immersing barley seeds (variety; Suwon No. 6) into different dilution of carrier-free P-32 original solution (Total activity; 90mc, To; 3/21) for 24 hours at room temperature, four groups of seeds (each group consists of 200 seeds) having activity levels of 1.6$\times$10-3$\mu$c 32P/grain, 2.3$\times$10-1$\mu$c 32P/grain 6.9$\times$100$\mu$c 32P/grain and 2.5$\times$101$\mu$c 32P/grain respectively, were obtained. To investigate the effects of various activity levels of P-32 absorbed upon the test plants, the seeds were germinated, transplant into the pots, and the growth was observed for three months after germination. After harvest, the inorganic contents in the leaves and the stems were also analyzed. The results: 1) Until four days after the beginning of germination, the rate of germination was found the lowest at the strongest activity level of 2.5$\times$101$\mu$c/grain. At the other P-32 levels treated, it showed generally higher than the control. 2) Before transplanting the seedlings of both 1.6$\times$103$\mu$c/grain and 2.3$\times$10-1uc/grain levels showed more vigorous growth than the control, whereas at the 6.9$\times$100 uc/grain level a retarded growth was conspicuous and all of plants belonging to the highest activity level of 2.5$\times$101$\mu$c/grain were withered owing apparently to the radiation damage. 3) This trend of growth promotion was continnually observed at the low activity levels even after transplanting the seeldings to the pots. As for the plants belonging to 6.9$\times$100$\mu$c/grain level, a clear sign of gradual recovery from the damage afflicted at the earlier stage was observable, and as a result the plants showed more growth than those of control two months after transplanting. 4) The number of stems diverged was found somewhat small in the blocks treated with P-32, compared with that of control until two months after germination. At the later stage of growth there seemed no significant difference among the themselves. 5) The dry weight of leaves and stems was proved that the lower the activity, the mroe it was produced. The relative increase of dry matter in each treatment compared with the control was 2% at 6.9$\times$105$\mu$c/grain level, 9% at 2.3$\times$10-1$\mu$c/grain and 35% at 1.6$\times$10-3$\mu$c/grain respectively. 6) The inorganic contents of the leaves and stems harvested were proved that: (1) Nitrogen was highest at the lowest activity level of 2.3$\times$10-1$\mu$c/grian. (2) Phosphorus showed generally higher contents in the treated blocks than in control, with the peak being at 2.3$\times$10-1$\mu$c/grain. (2) Phosphorus showed generally higher contents in the treated blocks than in contro, with the peak being at 2.3$\times$10-1$\mu$c/grain level in the leaves and at 6.9$\times$100$\mu$c/grain in the stems. (3) These was no significant difference in potassium contents in the leaves between treatment and control, whereas in the stem the treated blocks were higher than control roughly in propotion to the activity level. (4) Calcium in the lesves was richer in treated blocks than control while in the stem no difference was seen. (5) Magnesium contents both in leaves and in stems there was no difference among treatments.

• The Korean Journal of Nuclear Medicine Technology
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• v.21 no.2
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• pp.74-79
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• 2017

Purpose Proton therapy can deliver an optimal dose to tumor while reducing unnecessary dose to normal tissue as compared the conventional photon therapy. As proton beams are irradiated into tissue, various positron emitters are produced via nuclear fragmentation reactions. These positron emitters could be used for the dose verification by using PET. However, the short half-life of the radioisotopes makes it hard to obtain the enough amounts of events. The aim of this study is to investigate the effect of off-line PET imaging scan time on the PET image quality. Materials and Methods The various diameters of spheres (D=37, 28, 22 mm) filled with distilled water were inserted in a 2001 IEC body phantom. Then proton beams (100 MU) were irradiated into the center of the each sphere using the wobbling technique with the gantry angle of $0^{\circ}$. The modulation widths of the spread out bragg peak were 16.4, 14.7 and 9.3 cm for the spheres of 37, 28 and 22 mm in diameters respectively. After 5 min of the proton irradiation, the PET images of the IEC body phantom were obtained for 50 min. The PET images with different time courses (0-10 min, 11-20 min, 21-30 min, 31-40 min and 41-50 min) were obtained by dividing the frame with a duration of 10 min. In order to evaluate the off-line PET image quality with the different time courses, the contrast-to-noise ratio (CNR) of the PET image calculated for each sphere. Results The CNRs of the sphere (D=37 mm) were 0.43, 0.42, 0.40, 0.31 and 0.21 for the time courses of 0-10 min, 11-20 min, 21-30 min, 31-40 min and 41-50 min respectively. The CNRs of the sphere (D=28 mm) were 0.36, 0.32, 0.27, 0.19 and 0.09 for the time courses of 0-10 min, 11-20 min, 21-30 min, 31-40 min and 41-50 min respectively. The CNR of 37 mm sphere was decreased rapidly after 30 min of the proton irradiation. In case of the spheres of 28 mm and 22 mm, the CNR was decreased drastically after 20 min of the irradiation. Conclusion The off-line PET imaging time is an important factor for the monitoring of the proton therapy. In case of the lesion diameter of 22 mm, the off-line PET image should be obtained within 25 min after the proton irradiation. When it comes to small size of tumor, the long PET imaging time will be beneficial for the proton therapy treatment monitoring.

• Radiation Oncology Journal
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• v.19 no.4
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• pp.369-380
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• 2001

Purpose : By developing on-line statistics program to record the information of radiation oncology to share the information with internet. It is possible to supply basic reference data for administrative plans to improve radiation oncology. Materials and methods : The information of radiation oncology statistics had been collected by paper forms about 52 hospitals in the past. Now, we can input the data by internet web browsers. The statistics program used windows NT 4.0 operation system, Internal Information Server 4.0 (IIS4.0) as a web server and the Microsoft Access MDB. We used Structured Query Language (SQL), Visual Basic, VBScript and JAVAScript to display the statistics according to years and hospitals. Results : This program shows present conditions about man power, research, therapy machines, technics, brachytherapy, clinic statistics, radiation safety management, institution, quality assurance and radioisotopes in radiation oncology department. The database consists of 38 inputs and 6 outputs windows. Statistical output windows can be increased continuously according to user's need. Conclusion : We have developed statistics program to process all of the data in department of radiation oncology for reference information. Users easily could input the data by internet web browsers and share the information.

• Journal of Chest Surgery
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• v.35 no.3
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• pp.171-176
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• 2002

Background: Blood-foreign interaction cause activation of coagulation and inflammatory process that may lead to multiorgan dysfunction and determine the surgical outcomes. Of the methods for assessing the biocompatibility, the platelet adhesion study is considered as the most valuable evaluation step in blood-foreign interaction. As the most studies have used in-vitro or ex-vivo conditions, we have developed a technique of quantification for platelet adhesion on the blood contact surface by using in-vivo injection of radioactive platelets. Material and Method: A coupled bypass circuit was designed to connect the proximal and descending thoracic aorta in 6 piglets(20∼25 Kg). One side of the circuit tube was consisted of a heparin coated PVC tube(10mm in ID, n=6, Experimental group), and the other, a non-heparin coated PVC tube(10mm in ID, n=6, Control group). After cannulation, the blood was circulated through the circuit for 2 hours. Platelet concentrate was prepared from homologous pig blood 24 hours before the experiment. The platelet concentrate was incubated with Tc-99m-HMPAO for 30 min and then centrifuged for 10 min. The supernatant was discarded and the radio-labeling efficacy was measured. The radio-labeled platelet concentrate was mixed with the autologous plasma to make the volume 5 ml, and the mixture was injected intravenously into the experimental animal. After 2 hour circulation, 5 pieces of the specimen(10mm in length each) were obtained from each PVC tube. The radioisotopes were counted with a gamma counter(Cobra ll, Packard, USA), and the ratio of radioisotope count was compared between the control and experimental group. Result: The radioisotope count number was 537.3221.1 Ci/min in the control group and 311.1 184.5 Ci/min in the experimental group(p=0.0104). The ratio between the groups was 1 to 0.58 (p=0.004). Conclusion: In vivo quantification using technetium-99m-HMPAO labeled platelets is simple and reproducible in evaluating platelet adhesion on a foreign surface. We suggest this technique to be a useful tool for blood compatibility test.

• The Korean Journal of Nuclear Medicine
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• v.28 no.1
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• pp.98-105
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• 1994

The search for tumor-avid agents for use in nuclear medicine imaging or therapy is a field of ongoing importance. Metallothionein (MT) is an intracellular protein that binds many metals with isotopes having imaging or radiotherapeutic potential. The purpose of the study was to determine whether uptake of radioisotopes that bind to MT is increased in tumor. We measured the uptake of Cd-109 and Ga-67 in tumor and normal tissues of sarcoma-bearing mice. Tumors were grown subcutaneously in female Balb/C mice from cultured Balb/3T3 cells transformed by the Moloney murine sarcoma virus (MMSV). When the tumors reached about 1 cm in diameter, mice were injected subcutaneously with Cd-109 and Ga-67. Eighteen and seventy-two hours later, the mice were sacrified. Organs and tissues were removed, weighed, and activity per mg tissue determined by gamma well-counting. Uptake of Cd-109 by MMSV tumors exceeded that by normal tissues examined, with the exception of liver and kidney (the organs known to be richest in MT). The tumor-to-tissue ratios of uptake for Cd-109 were far greater than those for Ga-67 for many normal tissues of great importance in terms of background activity (bone, intestine, fat, muscle, and blood). We concluded that metals that bind to MT may be useful for oncologic imaging or rediotherapy of cancer.

• Journal of Radiation Protection and Research
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• v.33 no.1
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• pp.13-20
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• 2008

The flow rate measurements in a multi-phase flow pipeline were evaluated quantitatively by means of a clamp-on sealed radioisotope based on a cross correlation signal processing technique. The flow rates were calculated by a determination of the transit time between two sealed gamma sources by using a cross correlation function following FFT filtering, then corrected with vapor fraction in the pipeline which was measured by the ${\gamma}$-ray attenuation method. The pipeline model was manufactured by acrylic resin(ID. 8 cm, L=3.5 m, t=10 mm), and the multi-phase flow patterns were realized by an injection of compressed $N_2$ gas. Two sealed gamma sources of $^{137}Cs$ (E=0.662 MeV, ${\Gamma}$ $factor=0.326\;R{\cdot}h^{-1}{\cdot}m^2{\cdot}Ci^{-1}$) of 20 mCi and 17 mCi, and radiation detectors of $2"{\times}2"$ NaI(Tl) scintillation counter (Eberline, SP-3) were used for this study. Under the given conditions(the distance between two sources: 4D(D; inner diameter), N/S ratio: $0.12{\sim}0.15$, sampling time ${\Delta}t$: 4msec), the measured flow rates showed the maximum. relative error of 1.7 % when compared to the real ones through the vapor content corrections($6.1\;%{\sim}9.2\;%$). From a subsequent experiment, it was proven that the closer the distance between the two sealed sources is, the more precise the measured flow rates are. Provided additional studies related to the selection of radioisotopes their activity, and an optimization of the experimental geometry are carried out, it is anticipated that a radioisotope application for flow rate measurements can be used as an important tool for monitoring multi-phase facilities belonging to petrochemical and refinery industries and contributes economically in the light of maintenance and control of them.