• Title/Summary/Keyword: Gamma-ray protection

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Synergistic Effect of Green Tea EGCG Treatment with Gamma Radiation in Ieukemia Cell Necrosis (방사선조사와 병행 처리한 녹차 EGCG의 혈구암세포 사멸촉진 효과)

  • Lee, Hong-Soo;Kim, Jae-Man
    • Journal of radiological science and technology
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    • v.29 no.4
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    • pp.285-291
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    • 2006
  • During cancer therapy, gamma-ray irradiation and treatment of anti-cancer chemicals destroy the normal cells as well as cancer cells. In this study, we investigated the effect of epigallocathechin-gallate(EGCG) extracted from green tea, which is known to have anti-cancer and anti-oxident activities, in order to find out the feasible method to protect the normal cells and to kill the cancer cells efficiently. We investigated the effect of EGCG on the leukemia cell growth and cell necrosis, especially when treated along with gamma radiation. The EGCG inhibited the leukemia cell, HL-60, growth at the appropriate concentration while it exhibited no influence on the normal cell growth. More significantly, it enhanced leukemia cell necrosis when its treatment was combined with gamma irradiation. Simultaneous treatment of EGCG and gamma radiation increased leukemia cell necrosis up to 35% compared with separate treatments. These results suggest that drinking of green tea or co-treatment of EGCG during gamma irradiation therapy may result in better prognosis through enhancement of the tumor cell necrosis and protection of the normal cells.

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Protective Effects of a Herb, Menthae Herba, against Radiation-induced Oxidative DNA Damage

  • Jo, Sung-Kee;H, Heon-O;Uhee Jung;Kim, Sung-Ho;Byun, Myung-Woo
    • Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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    • 2003.10a
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    • pp.152-152
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    • 2003
  • As utilization of radiation in medicine, industry and biochemical research increases, the protection against radiation damage has become an important issue. Natural products such as herbal medicines are beginning to receive attention as modifiers on the radiation response. In the present study, the protective effect of a herb, Menthae Herba, against radiation-induced DNA damage was evaluated using alkaline single-cell gel electrophoresis (SCGE; comet assay) in the mouse peripheral blood Iymphocytes and the micronucleus formation test in the Chinese hamster ovary (CHO) cells. The tail moment, which was a marker of DNA damage in the SCGE, and the frequency of micronuclei was decreased in groups treated with Mentae Herba extract before exposure to 200 cGy of gamma-ray. We also confirmed its activities to scavenge DPPH and hydroxyl radicals. These experiments demonstrated that Menthae Herba was effective at reducing the radiation-induced damage of DNA and scavenging free radicals. It is plausible that scavenging of free radicals by Menthae Herba may have played an important role in providing the protection against the radiation-induced damage to the DNA. These results indicated that Menthae Herba might be a useful radioprotector and that radical scavenging appears to be one of the mechanisms of radiation protection.

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Induction of Micronuclei in Human and Mouse Lymphocytes Irradiated with Gamma Radiation and Effect of Panax ginseng C.A. Meyer (마우스와 사람 림프구에서 방사선에 의한 미소핵의 형성 및 고려인삼의 효과)

  • Kim, Sung-Ho;Oh, Heon;Lee, Song-Eun;Lee, Yun-Sil;Kim, Tae-Hwan;Jeong, Kyu-Sik;Ryu, Si-Yun
    • Journal of Radiation Protection and Research
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    • v.22 no.3
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    • pp.153-160
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    • 1997
  • The frequencies of ${\gamma}$-ray-induced micronuclei (MN) in cytokinesis-blocked (CB) lymphocytes at several doses were measured in three donors of human and C57BL/6 mice. Measurements performed after irradiation showed a dose-related increases in MN frequency in each of the donors studied. The relative sensitivity of mouse in spleen lymphocytes (SLs) compared with human peripheral blood lymphocytes (PBLs) was estimated by best fitting linear-quadratic model based on the radiation-induced MN data over the range from 0 cGy to 400 cGy. In the case of MN frequency with 0.2 per CB cell, the relative sensitivity of mouse SLs was 1.67. Compared with the radiation-induced MN formation in the PBLs of human, the SLs of mouse were more radiosensitive. Using this MN assay with human PBLs and mouse SLs, studies were performed to determine whether the water fraction of ginseng (Panax ginseng C.A.Meyer) against radiation-induced MN in human PBLs after in vitro irradiation (3Gy) and in SLs of C57BL/6 mice after in vivo irradiation (3Gy). The frequency of MN in human PBLs was reduced by water fraction of ginseng (0.5mg/ml of medium) both pre-and post treatment (p<0.0l) in vitro. In addition, the frequency of MN in mouse SLs was also reduced by pretreatment of ginseng (2mg/ml of drinking water for 7days) in vivo. The data suggested that the ginseng may reduce cell damage caused by ${\gamma}$-rays in vitro and in vivo. Further studies are needed to characterize better the protective nature of ginseng extract, its fractions and compounds.

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Gamma-ray-induced skin injury in the mini-pig: Effects of irradiation exposure on cyclooxygenase-2 expression in the skin (감마선조사에 의한 돼지 피부장애에 cyclooxygenase-2의 발현변화)

  • Kim, Joong Sun;Park, Sunhoo;Jang, Won Seok;Lee, Sun Joo;Lee, Seung Sook
    • Journal of Radiation Protection and Research
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    • v.40 no.1
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    • pp.65-72
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    • 2015
  • The basic concepts of radiation-induced skin damage have been established, the biological mechanism has not been studied. In this study, we have examined the effects of gamma rays on skin injury and cyclooxygenase(COX)-2 expression. Gamma irradiation induced clinicopathological changes in a dose- and time-dependent manner in mini-pig skin. The histological changes were consistent with the changes in gross appearance at 12 weeks after irradiation. After three days' irradiation, apoptotic cells in the basal layer were found more frequently in irradiated skin than in normal skin, with the magnitude of the effect being dose-dependent. The thickness of the epidermis transiently increased 3 days after irradiation, and then gradually decreased, although changes in the epithelial thickness of the irradiated field were not observed with irradiation doses over 50 Gy. In the epithelium, there was an initial degenerative phase, during which the rate of basal cell depletion was dependent on the radiation dose (20-70 Gy). One week after irradiation, COX-2 expression was mostly limited to the basal cell layer and was scattered across these cells. High COX-2 expression was detected throughout the full depth of the skin after irradiation. The COX-2 protein is upregulated after irradiation in mini-pig skin. These histological changes associated with radiation exposure dose cause the increased COX-2 expression in a dose-dependent fashion.

Statistical Analysis of Count Rate Data for On-line Seawater Radioactivity Monitoring

  • Lee, Dong-Myung;Cong, Binh Do;Lee, Jun-Ho;Yeo, In-Young;Kim, Cheol-Su
    • Journal of Radiation Protection and Research
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    • v.44 no.2
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    • pp.64-71
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    • 2019
  • Background: It is very difficult to distinguish between a radioactive contamination source and background radiation from natural radionuclides in the marine environment by means of online monitoring system. The objective of this study was to investigate a statistical process for triggering abnormal level of count rate data measured from our on-line seawater radioactivity monitoring. Materials and Methods: Count rate data sets in time series were collected from 9 monitoring posts. All of the count rate data were measured every 15 minutes from the region of interest (ROI) for $^{137}Cs$ ($E_{\gamma}=661.6keV$) on the gamma-ray energy spectrum. The Shewhart ($3{\sigma}$), CUSUM, and Bayesian S-R control chart methods were evaluated and the comparative analysis of determination methods for count rate data was carried out in terms of the false positive incidence rate. All statistical algorithms were developed using R Programming by the authors. Results and Discussion: The $3{\sigma}$, CUSUM, and S-R analyses resulted in the average false positive incidence rate of $0.164{\pm}0.047%$, $0.064{\pm}0.0367%$, and $0.030{\pm}0.018%$, respectively. The S-R method has a lower value than that of the $3{\sigma}$ and CUSUM method, because the Bayesian S-R method use the information to evaluate a posterior distribution, even though the CUSUM control chart accumulate information from recent data points. As the result of comparison between net count rate and gross count rate measured in time series all the year at a monitoring post using the $3{\sigma}$ control charts, the two methods resulted in the false positive incidence rate of 0.142% and 0.219%, respectively. Conclusion: Bayesian S-R and CUSUM control charts are better suited for on-line seawater radioactivity monitoring with an count rate data in time series than $3{\sigma}$ control chart. However, it requires a continuous increasing trend to differentiate between a false positive and actual radioactive contamination. For the determination of count rate, the net count method is better than the gross count method because of relatively a small variation in the data points.

Measurement of Growth Delay and the Oxygen Enhancement Ratio of Fast Neutron Beam Using Mouse Model System (마우스모델을 이용한 고속중성자선의 성장지연 및 산소증강비의 측정)

  • Eom, Keun-Yong;Park, Hye-Jin;Kwon, Eun-Kyung;Ye, Sung-Joon;Lee, Dong-Han;Wu, Hong-Gyun
    • Journal of Radiation Protection and Research
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    • v.32 no.4
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    • pp.178-183
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    • 2007
  • Neutrons are high LET (linear energy transfer) radiation and cause more damage to the target cells than x-rays or gamma rays. The damage from neutrons is generally considered fatal to a cell and neutrons have a greater tendency to cause cell death through direct interaction on DNA. We performed experiments to measure growth delay ratio and oxygen enhancement ratio (OER) in mouse model system. We inoculated EMT-6 cells to the right hind leg of BALB-c mouse and X-rays and neutron beams were given when the average volume of tumors reached $200-300mm^3$. We irradiated 0, 11, 15.4 Gy of X-ray and 0, 5, 7 Gy of fast neutron beam at normoxic and hypoxic condition. The volume of tumors was measured 3 times per week. In x-ray experiment, growth delay ratio was 1.34 with 11 Gy and 1.33 with 15.4 Gy in normoxic condition compared to in hypoxic condition, respectively. In neutron experiment, growth delay ratio was 0.94 with 5 Gy and 0.98 with 7 Gy, respectively. The OER of neutron beam was 0.97. The neutron beam was more effective than X-ray in the control of hypoxic tumors.

Assessment of Natural Radiation Exposure by Means of Gamma-Ray Spectrometry and Thermoluminescence Dosimetry (감마선분광분석(線分光分析) 및 열형광검출법(熱螢光檢出法)에 의한 자연방사선(自然放射線)의 선량측정연구(線量測定硏究))

  • Jun, Jae-Shik;Oh, Hi-Peel;Choi, Chul-Kyu;Oh, Heon-Jin;Ha, Chung-Woo
    • Journal of Radiation Protection and Research
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    • v.10 no.2
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    • pp.96-108
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    • 1985
  • A study for the assessment of natural environmental radiation exposure at a flat and open field of about $10,000m^2$ in area in CNU Daeduk campus has been carried out by means of gamma-ray scintillation spectrometry and thermoluminescence dosimetry for one year period of time from October 1984. The detectors used were 3'${\phi}{\times}$3' NaI(T1) and two different types of LiF TLD, namely, chip sealed in plastic sheet which tightly pressed on two open holes of a metal plate and Teflon disk. Three 24-hour cycles of in-situ spectrometry, and two 3-month and one 1-month cycles of field TL dosimetry were performed. All the spectra measured were converted into exposure rate by means of G(E) opertaion, and therefrom exposure rate due to terrestrial component of environmental radiation was figured out. Exposure rate determined by the spectrometry was, on average, $(10.54{\pm}2.96){\mu}R/hr$, and the rates of $(12.0{\pm}3.4){\mu}R/hr$ and $(11.0{\pm}3.6){\mu}R/hr$ were obtained from chip and disk TLD, respectively. Fluctuations in diurnal variation of the exposure rate measured by the spectrometry were noticeable sometime even in a single cycle of 24 hours. It is concluded that appropriately combined use of TLD with iu-sitn gamma-ray spectrometry system can give more accurate and precise measure of environmental radiation exposure, and further study for more adequate and sensitive TLD for environmental dosimetry, including improvement and elevation of accuracy in data assessment through inter-laboratory or international intercomparison is necessary.

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The Calculation of Response Matrix of 2-Dimensional Radiation Monitoring System Using EGS4 Simulation (EGS4 simulation을 이용한 2차원 방사선준위 분포측정 시스템의 Response Matrix 계산)

  • Kim, S.H.;Han, S.H.;Kang, H.D.;Kim, J.C.;Park, I.K.;Choi, Y.S.;Lee, Y.B.;Lee, J.M.
    • Journal of Radiation Protection and Research
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    • v.22 no.2
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    • pp.127-133
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    • 1997
  • In this study an EGS4 simulation code was used to calculate real energy spectrum from measured ${\gamma}$-ray energy spectrum obtained using 2-dimensional radiation monitoring system. As a result, the $39{\times}39$ response matrix was calculated the energy range of 0.1 to 2 MeV which energy interval of 50 keV The real energy spectrum for Co-60 radioisotope was calculated using inverse of response matrix. It was confirmed that the calculated response matrix was useful to the analysis of the measured energy spectrum for the radiation monitoring system.

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Development and Performance of a Hand-Held CZT Detector for In-Situ Measurements at the Emergency Response

  • Ji, Young-Yong;Chung, Kun Ho;Kim, Chang-Jong;Yoon, Jin;Lee, Wanno;Choi, Geun-Sik;Kang, Mun Ja
    • Journal of Radiation Protection and Research
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    • v.41 no.2
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    • pp.87-91
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    • 2016
  • Background: A hand-held detector for an emergency response was developed for nuclide identification and to estimate the information of the ambient dose rate in the scene of an accident as well as the radioactivity of the contaminants. Materials and Methods: To achieve this, the most suitable sensor was first selected as a cadmium zinc telluride (CZT) semiconductor and the signal processing unit from a sensor and the signal discrimination and storage unit were successfully manufactured on a printed circuit board. Results and Discussion: The performance of the developed signal processing unit was then evaluated to have an energy resolution of about 14 keV at 662 keV. The system control unit was also designed to operate the CZT detector, monitor the detector, battery, and interface status, and check and transmit the measured results of the ambient dose rate and radioactivity. In addition, a collimator, which can control the inner radius, and the airborne dust sampler, which consists of an air filter and charcoal filter, were developed and mounted to the developed CZT detector for the quick and efficient response of a nuclear accident. Conclusion: The hand-held CZT detector was developed to make the in-situ gamma-ray spectrometry and its performance was checked to have a good energy resolution. In addition, the collimator and the airborne dust sampler were developed and mounted to the developed CZT detector for a quick and efficient response to a nuclear accident.

Comparison of Non-Destructive Testing Images using $^{192}Ir$ and $^{75}Se$ with Computed Radiography System (Computed Radiography 시스템에 $^{192}Ir$$^{75}Se$ 동위원소를 적용하여 촬영한 비파괴검사 영상 비교)

  • Kang, Sang-Mook;Chol, Chang-Il;Lee, Seung-Kyu;Park, Sang-Ki;Kim, Yong-Kyun
    • Journal of Radiation Protection and Research
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    • v.35 no.1
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    • pp.26-33
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    • 2010
  • A computed Radiography (CR) system by use of reusable Image Plate (IP) offers a convenient and reliable way to replace a conventional film-screen system for NDT (non-destructive testing) field. The quality of a radiography to detect a defect of welded objects depends on the procedure embracing several factors such as measurement conditions, image plate type/class, radiation energy, radiation type, and source to image plate distance. Also, the ability of images to detect a flaw reduces with increasing object thickness. In the study, the properties of gamma ray source were summarized for NDT field and inspection images of CR image system manufactured by FUJI were acquired using $^{75}Se$ and $^{192}Ir$ with welded objects. We analyzed the gray scale of hole defect image by using XCAP image processing program and calculated the image contrast and SNR in definition. Also the sesitivities of image quality indicator(IQI) were calculated for hot and cooling tube image of $^{75}Se$ and $^{192}Ir$.