• Journal of Animal Science and Technology
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• v.47 no.5
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• pp.867-876
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• 2005

The microbial contamination of ice cream product commercially available in Korea was determined using ice bar, ice cream, ice milk and non-milk fat ice cream. Irradiation effect on enhancement of microbiological safety was also investigated at doses of 1, 3, and 5 kGy. In all products, yeast and molds were not detected, however, total aerobic and coliform bacteria were detected at 1-2 and 1-1.5 Log CFU/g level, respectively. According to the different flavor used in ice cream, total aerobic bacteria were detected as 2.30, 2.90, and 3.32 Log CFU/g level in vanilla, chocolate, and strawberry ice cream, respectively. Yeast and mold was not detected in vanilla ice cream but 2.30 and 2.70 Log CFU/g in chocolate and strawberry ice cream, respectively. Coliforms were also detected 1-2 Log CFU/g in the ice cream with different flavors. Listeria inocua and Escherichia coli were detected from 3 commercial samples but Salmonella spp. was not detected using API kit. Gamma irradiation significantly reduced the level of the contaminated total aerobic bacteria, yeast and molds and coliform population in the ice creams. These results indicated that irradiation(5kGy or less) is effective to ensure safety of ice cream.

• Journal of Radiation Protection and Research
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• v.21 no.4
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• pp.273-284
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• 1996

Embryos and fetuses are more sensitive to various environmental agents than are adults or children. The biological effects such as intrauterine death and malformation are closely connected with prenatal exposure very various agents. The sensitivity of these embryonic/fetal effects depends on the stage of pregnancy. From the viewpoint of fetal development, embryonic and fetal stages can be divided into three stages : Preimplantation, organogenetic and fetal. Each stage corresponds to 0 to 4.5days, 4.5 to 13.5days, and 13.5days of gestation in mice, respectively. Many studies on the biologcal effects of mice irradiated by ${\gamma}-rays$ at various stages during organogenesis and fetal period have been performed. Based on these results, the dose-effect and dose-response relationships in malformations, intrauterine death, or retardation of the physical growth have been practically modeled by the ICRP(International Commission on Radiological Protection) and other international bodies for radiation protection. Many experimental studies on mice have made it clear that mice embryos in the preimplantation period have a higher sensitivity to radiation for lethal effects than the embryos/fetuses on other prenatal periods. However, no eratogenic effects of radiation at preimplantation stages of mice have been described in many textbooks. It has been believed that 'all or none action results' for radiation of mice during the preimplantation period were applied. The teratogenic and lethal effects during the preimplantation stage are one of the most important problems from the viewpoint of radiological protection, since the preimplantation stage is the period when the pregnancy itself is not noticed by a pregnant woman. There are many physical or chemical agents which affect embryos/fetuses in the environment. It is assumed that each agents indirectly effects a human. Then, a safety criterion on each agent is determined independently. The pregnant ICR mice on 2, 48, 72 or 96 hours post-conception (hpc), at which are preimplantation stage of embryos, were irradiated whole body Cesium-gamma radiation at doses of 0.1, 0.25, 0.5, 1.5, and 2.5 Gy with dose rate of 0.2 Gy/min. In the embryos from the fetuses from the mice irradiated at various period in preimplantation, embryonic/fetal mortalities, incidence of external gross malformation, fetal body weight and sex ratio were observed at day 18 of gestation. The sensitivity of embryonic mortalities in the mice irradiated at the stage of preimplantation were higher than those in the mice irradiated at the stage of organogenesis. And the more sensitive periods of preimplantation stage for embryonic death were 2 and 48 hpc, at which embryos were one cell and 4 to 7 cell stage, respectively. Many types of the external gross malformations such as exencephaly, cleft palate and anophthalmia were observed in the fetuses from the mice irradiated at 2, 72 and 96 hpc. However, no malformations were observed in the mice irradiated at 48 hpc, at which stage the embryos were about 6 cell stage precompacted embryos. So far, it is believed that the embryos on preimplantation stage are not susceptible to teratogens such as radiation and chemical agents. In this study, the sensitivity for external malformations in the fetuses from the mice irradiated at preimplantation were higher than those in the fetuses on stage of organogenesis.

• Journal of Radiation Protection and Research
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• v.38 no.2
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• pp.68-77
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• 2013

Derived Investigation levels(DILs) were calculated to protect the workers from the effects of both radiological hazard and chemical toxicity by uranium intake. Investigation Levels(ILs) of committed effective dose of 2 mSv $y^{-1}-6$ mSv $y^{-1}$ and uranium concentration of 0.3 ${\mu}g$ $g^{-1}$ in kidney, based on Korean Nuclaer Safety Act, Korean Occupational Safety and Health Act and current scientific studies of uranium intake were assumed. DILs of radiological hazard and chemical toxicity were then calculated based on the concentration of uranium in air of workplace, the lung monitoring and urine analysis, respectively. As a result, in case of the nuclear fuel fabrication plant where 3.5% enriched uranium is handled, derived investigation level(DIL) for the control of the concentration of uranium in the air of workplace assumed with 15-min acute inhalation was 0.6 mg $m^{-3}$ for all types of uranium. DILs for the control of the average concentration of uranium in air of workplace, assuming an 8-hour workday, were 15.21 ${\mu}g$ $m^{-3}$ of Type F uranium, 0.41-1.23 Bq $m^{-3}$ and 0.13-0.39 Bq $m^{-3}$ for Type M and Type S uranium, respectively. DILs for the lung monitoring assumed with a period of 6-month interval were 0.37-1.11 Bq and 0.39-1.17 Bq in acute and chronic inhalation for Type M, respectively and 0.30- 0.91 Bq and 0.19-0.57 Bq in acute and chronic inhalation for Type S, respectively. Since a detection limit of typical germanium detector for the measurement of 235U activity is 4 Bq, DILs calculated for the lung monitoring were not appropriate. DILs for urine analysis, for which an interval was assumed to be 1 month, were 14.57 ${\mu}g$ $L^{-1}$ based on chemical toxicity after acute inhalation. In addition, acute and chronic inhalation of Type M were calculated 2.85-8.58 ${\mu}g$ $L^{-1}$ and 1.09-3.27 ${\mu}g$ $L^{-1}$ based on the radiological hazard, respectively.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.627-635
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• 2017

Brachytherapy is generally performed in conjunction with external radiation therapy, and the treatment course is very complicated, which can lead to radiation accidents. In order to solve this problem, we designed the process map by applying the failure mode and effects analysis (FMEA) method to the Brachytherapy and scored the risk priority number (RPN) for each treatment course based on this process map. The process map consisted of five steps, Patient consulting", "Brachytherapy simulation", "CT simulation", "Brachytherapy treatment planning" and "Treatment". In order to calculate the RPN, doctor, medical physicist, dose planners, therapist, and nurse participated in the study and evaluated occurrence, severity, and lack of detectability at each detail step. Overall, the process map is preceded by a patient identification procedure at each treatment stage, which can be mistaken for another patient, and a different treatment plan may be established to cause a radiation accident. As a result of evaluating the RPN for the detailed steps based on the process map, overall "Patient consulting" and "Brachytherapy treatment planning" step were evaluated as high risk. The nurses showed a tendency to be different from each other, and the nurses had a risk of 55 points or more for all the procedures except "Treatment", and the "Brachytherapy simulation" step was the highest with 88.8 points. Since the treatment stage differs somewhat for each medical institution performing radiotherapy, it is thought that the risk management should be performed intensively by preparing the process map for each institution and calculating the risk RPN.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.553-561
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• 2020

In this study aims to investigate the radiation protection effect of avocado peel extracts on the Sprague-Dawely rats. 52 male rats were randomly classified into 4 groups. NC Group was a normal control group, PA Group was a group injected avocado peel extracts, IR Group was irradiated group, and lastly PA+IR Group was set as an irradiated group after injected of avocado peel extracts. Avocado peel extract was administered orally at 200 mg/kg once a day for 14 days before irradiation, and the radiation dose was systemically irradiated with 6 MV X-ray of 7 Gy. On the 4 and 21 days after irradiation, the experimental animals were sacrificed to evaluate the change in blood cell composition, spleen index, and histopathological evaluation of the liver and small intestine. As a result, the PA+IR Group showed a significantly greater recovery of lymphocytes(p<0.01), red blood cells(p<0.01), and platelets(p<0.05) than the IR Group. It was also confirmed that the activation of Superoxide Dismutase(SOD) was further increased. Histopathologically, observed that nuclei aggregation and cytoplasmic expansion were slightly reduced in the PA+IR Group in the liver. and the damage was significantly reduce(p<0.01) in the change of villi length due to damage to the small intestine cells. Based on the above results, avocado peel extract can be expected to act as a radiation protection agent that can reduce damage to blood cells and major organs caused by irradiation.

• Journal of radiological science and technology
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• v.40 no.1
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• pp.41-47
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• 2017

Considering that the X-ray apron used in the department of radiology is also used in the department of nuclear medicine, the study aimed to analyze the shielding rate of the apron according to types of radioisotopes, thus ${\gamma}$ ray energy, to investigate the protective effects. The radioisotopes used in the experiment were the top 5 nuclides in usage statistics $^{99m}Tc$, $^{18}F$, $^{131}I$, $^{123}I$, and $^{201}Tl$, and the aprons were lead equivalent 0.35 mmPb aprons currently under use in the department of nuclear medicine. As a result of experiments, average shielding rates of aprons were $^{99m}Tc$ 31.59%, $^{201}Tl$ 68.42%, and $^{123}I$ 76.63%. When using an apron, the shielding rate of $^{131}I$ actually resulted in average dose rate increase of 33.72%, and $^{18}F$ showed an average shielding rate of -0.315%, showing there was almost no shielding effect. As a result, the radioisotopes with higher shielding rate of apron was in the descending order of $^{123}I$, $^{201}Tl$, $^{99m}Tc$, $^{18}F$, $^{131}I$. Currently, aprons used in the nuclear medicine laboratory are general X-ray aprons, and it is thought that it is not appropriate for nuclear medicine environment that utilizes ${\gamma}$ rays. Therefore, development of nuclear medicine exclusive aprons suitable for the characteristics of radioisotopes is required in consideration of effective radiation protection and work efficiency of radiation workers.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.158-167
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• 2016

The requirements for medical laboratories ISO 15189 is examined in organization and a quality management system, stressing the importance of evidence, document control, and control of records and clinical material. Medical services are provided from the areas of resource management, and pre-examination, examination and post-examination processes. The main goal of ISO 15189 accreditation is to improve the quality of laboratory services provided for patients and clinical users not only through compliance with consensually developed and harmonized requirements but also by adopting the philosophy of continual improvement using the Plan-Do-Check-Act cycle. Laboratory quality should be evaluated and improved in all steps of the testing process as the state-of-the art indicates that the pre- and post-analytical phases are more vulnerable to errors than the intra-analytical phase. The Korea Laboratory Accreditation Scheme (KOLAS), a national accreditation body, provides medical laboratory accreditations for appropriate approaches to evaluating the competence of a medical laboratory in providing effective services to its customers and clinical users. Adoption of ISO 15189 in 2010s as a government policy has been delayed, and only 5 laboratories have been accredited to date in Korea. The medical laboratories should seek the adoption of ISO 15189 with a positive attitude for quality improvement and strengthening of international competitiveness.

• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.301-308
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• 1982

Chungkook-jang Koji was fermented with rice straw at $40^{\circ}C\;and\;50^{\circ}C$ for 72 hours. The changes of proximate composition, pH, titrable acidity, nitrogen compounds, protease activity and free-amino acids during the fermentation were investigated. Moisture, lipid and protein contents remained essentially unchanged during the fermentation. The pH was gradually increased from 6.4 to 7.46 and 7.82 at $40^{\circ}C\;and\;50^{\circ}C$, respectively, after 72 hour fermentation. Amino type and water soluble nitrogen increased as fermentation progressed. however, the former slightly decreased after 60 hour fermentation. Chungkook-jang fermented at $40^{\circ}C$ showed somewhat higher protease activity than $50^{\circ}C$. However, protease activity at both fermentation temperatures showed the same trend; that is, it increased until 48 hour fermentation and thereafter decrease. Free amino acid content of Chung-kook-jang after 72 hour fermentation at $40^{\circ}C$ was 6 times greater than that of the steamed soybean, while it was 2.5 times greater at $50^{\circ}C$. Based on these results. it seems that the optimum fermentation conditions for Chungkook-jang were $40^{\circ}C$ and 72 hours.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.43-48
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• 2014

Purpose: In the PET/CT images, The SUV (standardized uptake value) enables the quantitative assessment according to the biological changes of organs as the index of distinction whether lesion is malignant or not. Therefore, It is too important to enter parameters correctly that affect to the SUV. The purpose of this study is to evaluate an allowable error range of SUV as measuring the difference of results according to input errors of Activity, Weight, uptake Time among the parameters. Materials and Methods: Three inserts, Hot, Teflon and Air, were situated in the 1994 NEMA Phantom. Phantom was filled with 27.3 MBq/mL of 18F-FDG. The ratio of hotspot area activity to background area activity was regulated as 4:1. After scanning, Image was re-reconstructed after incurring input errors in Activity, Weight, uptake Time parameters as ${\pm}5%$, 10%, 15%, 30%, 50% from original data. ROIs (region of interests) were set one in the each insert areas and four in the background areas. $SUV_{mean}$ and percentage differences were calculated and compared in each areas. Results: $SUV_{mean}$ of Hot. Teflon, Air and BKG (Background) areas of original images were 4.5, 0.02. 0.1 and 1.0. The min and max value of $SUV_{mean}$ according to change of Activity error were 3.0 and 9.0 in Hot, 0.01 and 0.04 in Teflon, 0.1 and 0.3 in Air, 0.6 and 2.0 in BKG areas. And percentage differences were equally from -33% to 100%. In case of Weight error showed $SUV_{mean}$ as 2.2 and 6.7 in Hot, 0.01 and 0.03 in Tefron, 0.09 and 0.28 in Air, 0.5 and 1.5 in BKG areas. And percentage differences were equally from -50% to 50% except Teflon area's percentage deference that was from -50% to 52%. In case of uptake Time error showed $SUV_{mean}$ as 3.8 and 5.3 in Hot, 0.01 and 0.02 in Teflon, 0.1 and 0.2 in Air, 0.8 and 1.2 in BKG areas. And percentage differences were equally from 17% to -14% in Hot and BKG areas. Teflon area's percentage difference was from -50% to 52% and Air area's one was from -12% to 20%. Conclusion: As shown in the results, It was applied within ${\pm}5%$ of Activity and Weight errors if the allowable error range was configured within 5%. So, The calibration of dose calibrator and weighing machine has to conduct within ${\pm}5%$ error range because they can affect to Activity and Weight rates. In case of Time error, it showed separate error ranges according to the type of inserts. It showed within 5% error when Hot and BKG areas error were within ${\pm}15%$. So we have to consider each time errors if we use more than two clocks included scanner's one during the examinations.