• International Journal of Contents
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• v.8 no.2
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• pp.60-66
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• 2012

This study was designed to detect and measure the concentration of radioactivity of natural radionuclides ($^{238}U$, $^{232}Th$, $^{40}K$) and artificial radionuclides ($^{137}Cs$, $^{60}Co$) present in the drinking water of the city of Busan and surrounding areas in South Korea, and also to measure the absorbed dose of radiation caused by these elements in the residents so as to help better manage the risk that these radionuclides pose in the future. For the purposes of the study, a total of 42 samples of water were collected from three key water sources (19 samples of groundwater, 4 samples of tap water, and 19 samples of surface water) and their contents were analyzed for radioactivity concentration. The results revealed that two natural radionuclides, $^{238}U$ and $^{232}Th$, exist in the groundwater with an average concentration of radioactivity of 3.34 Bq/L and $8.28{\times}10^{-5}Bq/L$ respectively, while the surface water was found to contain the same two radionuclides with mean concentrations of 0.849 Bq/L and $1.103{\times}10^{-4}Bq/L$ respectively. In addition, of the 19 samples of the groundwater, $^{137}Cs$ was found in eight of them and $^{60}Co$ was detected in ten. Of the four samples of the tap water, $^{137}Cs$ was detected in all samples and $^{60}Co$ was detected in three. Both $^{137}Cs$ and $^{60}Co$ were detected in all 12 samples of surface water. As far as $^{40}K$ is concerned, this element was detected in three of the 19 groundwater samples, but was not detected in any surface or tap water sample. In addition, the absorbed dose of $^{238}U$ from the groundwater was $7.94{\times}10^{-8}Sv/y$, while the absorbed dose of $^{232}Th$ from the surface water was $9.33{\times}10^{-13}Sv/y$. The absorbed dose of $^{137}Cs$ from the tap water was $7.33{\times}10^{-5}Sv/y$, while the absorbed dose of $^{60}Co$ from the surface water was the highest at $4.23{\times}10^{-6}Sv/y$.

• Journal of Radiation Protection and Research
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• v.22 no.2
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• pp.111-117
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• 1997

Recently, the conclusion of Comprehensive Test Ban Treaty(CTBT) is globally constructing a network system for nuclear test monitoring. The radionuclide experts of the Conference on Disarmament recommended that the detection of nuclear debris in the atmosphere was an essential factor of nuclear test monitoring and proposed the technical requirements. Based on those requirements, atmospheric radionuclide monitoring system to detect nuclear debris generated from the nuclear explosion test was composed. The system is comprised of high volume air sampler(HVAS), filter paper presser and high purity germanium detector(HPGe). Minimum detectable concentrations(MDCs) of the key nuclides requiring in CTBT monitoring strategies are determined by considering of decay time, counting time and flow rate of the high volume air sampler for the rapid explosion and the optimum measurement condition. The results were selected $10{\pm}$2h, $20{\pm}$2h and $850{\pm}50m^3$/h as parameters, respectively. The relation between the natural air-borne radionuclide concentration of $^{212}Pb$ and MDC were calculated which gave effect in the Compton continuum baseline due to those nuclides in the gamma-ray spectroscopy. These results can be used as an actually tool in the CTBT monitoring strategies.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.68.1-68.1
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• 2013

Infrared Medium-Deep Survey is a near-infrared imaging survey geared toward understanding the formation and the evolution of quasars and galaxies at high redshift, and studying transient and time-variable objects such as gamma-ray bursts, supernovae, and young stellar objects. The survey uses a multi-tier structure, with deep imaging survey of 100 $deg^2$ using UKIRT to the depth of 23 AB mag, and a shallower imaging of interesting sources using the CQUEAN camera on the 2.1m telescope at McDonald observatory. This talk will give an overview of the survey strategy, the instrument development, and science highlights. The science highlights will include the discovery of high redshift quasars, high redshift galaxy clusters, GRBs, and other interesting sources. At the end of the talk, we will also present the future prospects of our study.

• The Korean Journal of Nuclear Medicine
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• v.25 no.2
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• pp.286-293
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• 1991

$^{123}I$, which is applied for the thyroid and other in vivo kinetic study, has a special role in life sciences. The 159 KeV $\gamma-ray$ from $^{123}I$ is almost ideally appropriate for the current imaging instrumentation. Its decay mode (electron capture) and short half-life (13.3 hr) reduced the burden of radiation dose to the patients, and its chemical property makes it easy to synthesize the labelling compounds. In this experiment, the production of $^{123}I$ via the nuclear reaction $^{124}Te(p,2n)^{123}I$ with 28 MeV protons was sutdied. $TeO_2$ is used as a target material, because it has good physical properties. The target was prepared with $TeO_2$ powder and was molten into a ellipsoidal cavity (a=14 mm, b=10 mm, $270.8mg/cm^2$ thick) of pure platinum. The irradiation was carried out in the external proton beam with incident energies range from 28 MeV to 22 MeV, and current was $30{\mu}A$. The loss of $TeO_2$ target was significantly reduced by using $4\pi-cooling$ system in irradiation. The dry distillation method was adopted for the separation of $^{123}I$ from irradiated target, and when it was kept 5 minutes at $780^{\circ}C$, its result was quantitative. The loss of the target material $(TeO_2)$ was below 0.2% for each production run and $^{123}I$ from the dry distillation apparatus was captured with 0.01 N NaOH in $Na^{123}I$ form, then the pH of the solution was adjusted to $7.5\sim9.0$ with HC1/NaOH. The $Na^{123}I$ solution was passed through $0.2{\mu}m$ membrane filter, and sterilized under high pressure and temperature for 30 minutes. The production of $^{123}I$ is acceptable for clinical application based on the quality of USP XXI.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.399-407
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• 2013

Some groundwater in Korea contains high U concentrations, especially where two-mica granite occurs in the Daejeon area. The elemental U in the two-mica granite is lower than that in normal granites elsewhere in the world, and U-minerals have yet to be reported in the two-mica granite in the Daejeon area. This study focuses on investigating the occurrence of U-minerals serving as the U source in groundwater. In situ gamma ray spectrometry and mineralogical analyses using EPMA were performed. U-count anomalies were identified in a granitic dyke and in hydrothermally altered granite. Uraniferous granitic dykes occur along the contact zone between the two-mica granite and mica-schist. The uraniferous parts within the two-mica granite are developed in the hydrothermally altered zone, which contains numerous quartz veinlets within a fracture zone. Hydrothermal alteration is dominated by potassic and prophylitic alteration. Uraninite is a common U-mineral in granitic dykes and hydrothermally altered granite. Coffinite and uranophane occur in the hydrothermally altered granite. All of these U-minerals are commonly accompanied by hydrothermal alteration minerals such as muscovite, chlorite, epidote, and calcite. It is concluded that granitic dyke and hydrothermally altered granite are the main source rocks of U in groundwater.

• Korean Journal of Food Science and Technology
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• v.43 no.1
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• pp.30-38
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• 2011

Effects of depolymerization treatments of a carbohydrase mixture (CM), ultrasound, and irradiation on the physical properties of defatted mustard meal-based edible films (DMM films) were investigated. DMM hydrocolloids were added to CM (0.42% (w/w solution)), treated by ultrasound (500-700 W, 10-30 min) or ${\gamma}$-ray (40-100 kGy) to prepare film-forming solutions. Films were formed by drying. The CM treatment at 0.42% (w/w), pH 5.5, and 40-$50^{\circ}C$ with a 0.5 hr incubation time resulted in the highest colloidal stability in the film-forming solution. The depolymerization treatments did not dramatically change the water vapor permeability of the films. The solubility of the film decreased up to 53.1% by the CM treatment. The ultrasound treatment (700 W-30 min) decreased tensile strength and elongation. The ultrasound treatment (600 W-20 min) resulted in more compact and uniform structures of the films. Flavor profiles were differentiated by the power level and the time of the ultrasound treatment.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.637-643
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• 2018

A depth of interaction(DOI) detector module using a block scintillator and a pixellated scintillator was designed, and layer discrimination ability was calculated using DETECT2000. The block scintillator was used to improve the sensitivity and the spatial resolution was improved by measuring the DOI. The DOI was measured by analyzing the signal characteristics of each channel of the changed distribution of light. The detector module was composed to the block scintillator in the top layer and the pixellated scintillator in the bottom layer, which changes the distribution of light generated from a scintillator interacting with a gamma ray. In the flood image, the top layer was able to acquire the image at the position similar to the position of the bottom layer because the bottom layer consist of the pixellated scintillator. By using the Anger algorithm, the 16 channel signal was reduced to 4 channels to facilitate the analysis of the signal characteristics. The layer discrimination was measured using a simple algorithm and the accuracy was about 84% for each layer. When this detector module is used in preclinical PET, the spatial resolution at the outside of the field of view can be improved by measuring the DOI.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.28-34
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• 2018

Purpose With regard to the use of radioiodine in domestic medical institution, the case of exceeding the allowance of nuclear safety Act about radioactive concentration in drainage was found. Through understanding the cause of exceeding case and analyzing radioactive concentration in drainage, evaluating the relationship of the public waters in surroundings and usefulness. Materials and Methods From November 1, 2014 to April 30th, 2015, the research is aiming at domestic twenty hospitals for six months. By using a HPGe gamma-ray spectrometer(Canberra DSA-1000) and GENIE-2000 Analysis software for comparative analysis, measuring a radioactive concentration of radioiodine in drainage. Consequently, we confirm the excess of radioactive concentration of radioiodine in seven medical institutions. Results Conducting a survey of twenty hospitals and average radioactive concentration of radioiodine in drainage appears $42,100Bq/m^3$. The features of domestic hospitals where show a high radioactive concentration are a number of medical treatment patient when using radioactive iodine and the absence of private rest room. During I-131 whole body scan, the pretreatment procedure of urinating is considered emission of residual Iodine. In public waters, the cause of exceeding detect on radioactive concentration in drainage suppose a diagnostic radioactive iodine. Conclusion We confirm the importance of enhanced education, providing a safety control instructions and installing a private rest rooms for patients who injected a low capacity radioiodine. Also, constructing institutional and legal management system is considered about the Emission management standard in drainage.

• Biomolecules & Therapeutics
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• v.5 no.1
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• pp.100-105
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• 1997

DW-166HC ($^{166}$Holmium-chitosan) is a complex of $^{166}$Ho, $\beta$- and $\gamma$-ray emitter, and chitosan, a polymer of glucosamine, with radiotherapeutic potential. The current study was performed to determine the acute toxicities of $^{165}$Ho-chitosan in mice by two different routes of administration. The both sex mice were given a single intravenous bolus injection of $^{165}$Ho-chitosan complex at doses of 12, 10, 6, 5 and 4 mg/kg or subcutaneous administration at doses of 600, 500, 400 and 300 mg/kg. Chitosan was dosed to control animals as 16 and 800 mg/kg, intravenously and subcutaneously, respectively. The doses of $_{165}$Ho-chitosan complex were expressed as $_{165}$holmium nitrate pentahydrate and the ratio of $^{165}$Ho$(NO_3)_3$).$5H_2O$ to chitosan was 3/4 Severe convulsion and respiratory failure were followed by death within 10 min after intravenous dosing. Transient unilateral hindlimb hypokinesias were found in two mice of 5 mg/kg dosing group during the study period. No abnormalities were observed during the necropsy of survived animals in intravenous dosing group. Only one male animal was found dead in 500 mg/kg subcutaneously dosed group. Alopecia with or without cutaneous ulcer were found in most mice including control animals. During necropsy, omental adhesion was observed in all dose ranges and enlarged spleen was found in several animals including control group. It is suggested that the acute intravenous >).$LD_{50}s$ for male and female mice were 4.90 and 6.03 mg/kg, respectively. The lowest lethal dose in male was 500 mg/kg by subcutaneous administration.

• Pediatric Infection and Vaccine
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• v.23 no.2
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• pp.94-101
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• 2016

Purpose: This study aimed to describe the results of a contact investigation on health care workers after exposure to a house officer with smear-positive pulmonary tuberculosis (TB). Methods: Eighty nine out of 101 subjects who had close contact with the index patient agreed to be enrolled in the investigation. The first contact investigation was conducted approximately 30 days after the index patient's onset of symptoms, followed by the second investigation after 10 weeks. In both, clinical manifestations were studied, and chest X-ray and tuberculin skin test (TST)/QuantiFERON-TB Gold (QFT-G) in dual screening strategy were conducted. Results: The first TST resulted in positive in 34 subjects (38.2%). QFT-G was conducted on 16 subjects who tested positive in the first TST and aged under 36. Six of them (37.5%) were positive. The second TST was conducted on 41 subjects with negative results in the first TST. Seventeen (41.5%) were positive and among them, three (17.6%) showed positive QFT-G. None of the subjects were diagnosed with active TB. The probability of TB infection through contact with the index patient was 7.3% (3/41) in dual screening strategy while it was 41.5% (17/41) in TST strategy. Conclusions: This first hospital-setting contact investigation for tuberculosis in Korea revealed that latent tuberculosis infection (LTBI) rates vary depending on different diagnostic strategies. This indicates the need for systematic guidelines for diagnosing LTBI in health care workers who have professional exposure to TB.