• Analytical Science and Technology
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• v.16 no.1
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• pp.39-47
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• 2003

The measurement of radium ($^{226}Ra$) in the groundwater was established using ${\gamma}$-ray spectroscopy without sample preparation. The background interference by air borne radon daughter nuclides was reduced by $N_2$ gas flow into the counting chamber. Leakage of radon gas produced in the radioactive equilibrium with radium and its daughter nuclides was prevented by use of the air-tighted aluminium container. We investigated the effect of air layer in the counting container. Radioactivity variation due to emanation of radon into the air layer was within the counting error range 5%. When the nitrogen gas was flowed around the detector, peak counts of ${\gamma}$-rays from the daughters of airborne radon was decreased and detection limit was decreased to 0.02 Bq/L. The detection limit of detector was lower than 0.74 Bq/L, the $^{226}Ra$ Maximum Contaminant Level (MCL) in the groundwater proposed by US Environmental Protection Agency (EPA). It was confirmed that $^{226}Ra$ radioactivity in the groundwater could be determined by the ${\gamma}$-ray spectroscopy.

• The Journal of the Acoustical Society of Korea
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• v.28 no.2
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• pp.141-147
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• 2009

This paper presents a new fast algorithm, rotation-based method (RBM), for the reconstruction of 3 dimensional image for cone beam computerized tomography (CB CT) system. The system used cone beam has less exposure time of radioactivity than fan beam. The Three-Pass Shear Matrices (TPSM) is applied, that has less transcendental functions than the one-pass shear method to decrease a time of calculations in the computer. To evaluate the quality of the 3-D images and the time for the reconstruction of the 3-D images, another 3-D images were reconstructed by the radon transform under the same condition. For the quality of the 3-D images, the images by radon transform was shown little good quality than REM. But for the time for the reconstruction of the 3-D images REM algorithm was 35 times faster than radon transform. This algorithm offered $4{\sim}5$ frames a second. It meant that it will be possible to reconstruct the 3-D dynamic images in real time.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.277-294
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• 2012

The characteristics of temporal spacial radon variation in soil according to parent rock type and affecting factors were studied in Busan, Korea. The concentration of $^{222}Rn$ in soils and their parent elements ($^{226}Ra$,$^{228}Ra$, U and Th) in rocks and soils were measured at 24 sites in Busan area. The distribution and transportation behavior of these parent elements were analyzed and their correlations to radon concentration in soil were determined. Topographic effects were also evaluated. Two in-situ radon measurement (soil probe and buried tube) methods were applied to measure radon concentration in soil and their accuracies were evaluated. The spatial variation of radon in soil generally reflected U concentration in the parent rock. Average radon concentrations were higher in plutonic rocks than in volcanic rocks and were decreased in the order of felsic>intermediate>mafic rock. However, the radon concentrations were significantly varied in soils developed from same parent rocks due to the disequilibrium of U and $^{226}Ra$ between rock and soil. As results, the correlation of these element concentrations between rocks and soils was very low and radon concentrations in soils had highly co-related to the concentrations of these elements in soils. Th and $^{228}Ra$ show complex enrichment characteristics, differing significantly with U, in soils developed from same parent rock because the geochemical behavior of these elements during weathering and soil developing process was different with U. The radon concentrations in the same depth of soil in slope area were also different according to positions. The radon concentrations in soils developed from same parent rocks (19 sites at Pusan National University) varied 6.8~29.8Bq/L range because of small scale topographic variation. The opposite seasonal variation pattern of radon were observed according to soil properties. It was determined that buried tube method is more accurate method than soil probe method and was very advantageous application for the analysis for the characteristics of temporal spacial radon variation in soil.

• The Journal of Engineering Geology
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• v.26 no.2
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• pp.261-276
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• 2016

The occurrence of natural radioactive materials such as uranium and radon-222 in groundwater was examined with hydrogeochemistry and geology at ○○ village in the Yongin area. Two rounds of 19 groundwater and 5 surface water sampling were collected for analysis. The range of pH value in groundwaters was 5.81 to 7.79 and the geochemical types of the groundwater were mostly Ca(Na)-HCO₃ and Ca(Na)-NO₃(Cl)-HCO₃. Uranium and radon-222 concentrations in the groundwater ranged from 0.06 to 411 μg/L and from 5.56 to 903 Bq/L, respectively. Two deep groundwaters used as common potable well-water sources exceeded the maximum contaminant levels of the uranium and radon-222 proposed by the United States Environmental Protection Agency (US EPA). Three groundwater samples from residential areas contained unsuitable levels of uranium, and 12 groundwater samples were unsuitable due to radon-222 concentrations. Radioactive materials in the unsuitable groundwater are naturally occurring in a Jurassic amphibole- and biotite-bearing granitic gneiss. High uranium and radon-222 groundwater concentrations were only observed in two common wells; the others showed no relationship between bedrock geology and groundwater geochemical constituents. With such high concentrations of naturally occurring radioactive materials in groundwater, the affected areas may extend tens of meters for uranium and even farther for radon-222. Therefore, we suggest the radon-222 and the uranium did not originate from the same source. Based on the distribution of radon-222 in the study area, zones of higher radon-222 concentrations may be the result of diffusion through cracks, joint, or faults. Surface radioactivity and uranium concentrations in the groundwater show a positive relationship, and the impact areas may extend for ~200m beyond the well in the case of wells containing high concentrations of uranium. The highest uranium and thorium concentrations in rock samples were detected in thorite and monazite.

• The Journal of Engineering Geology
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• v.25 no.4
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• pp.557-576
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• 2015

Groundwaters in granite, gneiss, and two-mica granite formations, including faults, in the Hoengseong area are examined to determine the relationship between their uranium and radon-222 contents and rock types. The chemical compositions of 38 groundwater samples and four surface water samples collected in the study area were analyzed. Sixteen of the samples showing high uranium and radon-222 contents were repeatedly analyzed. Surface radioactivities were measured at 30 points. The uranium and radon-222 concentrations in the groundwater samples were in the ranges of 0.02-49.3 μg/L and 20-906 Bq/L, respectively. Four samples for uranium and 35 samples for radon had concentrations exceeding the alternative maximum contaminant level of the US EPA. The chemical compositions of groundwaters indicated Ca(Na)-HCO₃ and Ca(Na)-NO₃(HCO₃+Cl) types. The pH values ranged from 5.71 to 8.66. High uranium and radon-222 contents in the groundwaters occurred mainly at the boundary between granite and gneiss, and in the granite area. The occurrence of uranium did not show any distinct relationship to that of radon-222. The radon-222, an inert gas, appeared to be dissolved in the groundwater of the aquifer after wide diffusion along rock fractures, having been derived from the decay of uranium in underground rocks. The results in this study indicate that groundwater of neutral or weakly alkaline pH, under oxidizing conditions and with a high bicarbonate content is favorable for the dissolution of uranium and uranium complexes such as uranyl or uranyl-carbonate.

• Journal of the Korean Society of Radiology
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• v.8 no.4
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• pp.211-216
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• 2014

Radium is rock or soil of crust or uranium of building materials after radioactivity collapse process are created colorless and odorless inert gas that accrue well in sealed space like basement. It inflow to lung circulate respiratory organ and caused lung cancer because of deposition of lung or bronchial tubes. In this study, the air in the elementary school classroom nongdoeul tonkatsu place of measured values were compared using the calculated annual internal radiation exposure. La tonkatsu exposure measured in primary school classroom at least five schools when you close the windows in the average floor 0.56mSv 2 floors ground floor windows when opened 0.384mSv 048mSv 3 floors, 2 floor levels of the same three layers 0.31mSv 0.296mSv the human exposure to radon and radiation on the first floor of 3 floors above ground in a lot of exposure was moderate. When you close the window from the first floor up 0.384mSv 056mSv 3 floors with a minimum annual radiation exposure due to natural radiation in the 16 to 23.3 percent minimum 2.4mSv accounted for. When I opened the window to the maximum annual radiation exposure 2.4mSv 0.296mSv 0.31mSv least a minimum of 12.3 to 12.91% accounted for Results suggest that more than five chodeunghakgyoeun La tonkatsu domestic radon measurements conducted below regulatory requirements and internal exposure has also fall within the normal range. People The less the radiation exposure to the human body because it reduces the impact in the classroom in elementary school vent windows often reduced to the maximum radon concentration in the air, if called tonkatsu be able to reduce radiation exposure for the immune system is weak and elementary will be helpful to experiment more in the future for the school authorities called tonkatsu investigation is done to him if the action to establish a more secure school building facilities is thought would be helpful.

• Progress in Medical Physics
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• v.32 no.2
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• pp.25-39
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• 2021

Brachytherapy, along with external beam radiation therapy (EBRT), is an essential and effective radiation treatment process. In brachytherapy, in contrast to EBRT, the radiation source is radioisotopes. Because these isotopes can be positioned inside or near the tumor, it is possible to protect other organs around the tumor while delivering an extremely high-dose of treatment to the tumor. Brachytherapy has a long history of more than 100 years. In the early 1900s, the radioisotopes used for brachytherapy were only radium or radon isotopes extracted from nature. Over time, however, various radioisotopes have been artificially produced. As radioisotopes have high radioactivity and miniature size, the application of brachytherapy has expanded to high-dose-rate brachytherapy. Recently, advanced treatment techniques used in EBRT, such as image guidance and intensity modulation techniques, have been applied to brachytherapy. Three-dimensional images, such as ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography are used for accurate delineation of treatment targets and normal organs. Intensity-modulated brachytherapy is anticipated to be performed in the near future, and it is anticipated that the treatment outcomes of applicable cancers will be greatly improved by this treatment's excellent dose delivery characteristics.

• Journal of Radiation Protection and Research
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• v.26 no.4
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• pp.441-445
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• 2001

In this work we investigated distribution of the natural and artificial radioactive nuclides and level of the regional background in soil in Busan. For 45 points, the environmental radioactivity concentration of Busan surface soil is $14.38{\sim}57.03\;(mean\;:\;33.95)\;Bq{\cdot}kg^{-1}$ for $^{226}Ra,\;2.41{\sim}86.58\;(mean\;:\;51.08)\;Bq{\cdot}kg^{-1}$ for $^{228}Ra,\;223.64{\sim}1332.30\;(mean\;668.51)\;Bq{\cdot}kg^{-1}$ for $^{40}K$ and $<0.33{\sim}33.37\;(mean:13.74) Bq{\cdot}kg^{-1}$ for $^{137}Cs$. Also, in order to investigate vertical distribution for radioactivity, we examined radioactive concentration with mountain height. But there was no correlation between radiaoactivity distribution and mountain height. The $^{226}Ra/^{228}Ra$ and $^{226}Ra/^{40}K$ concentration ratios were $0.68{\pm}19 %$ and $0.06{\pm}34%$, respectively.

• Journal of Environmental Health Sciences
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• v.49 no.5
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• pp.251-261
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• 2023

Background: This paper deals with the study of natural radioactivity in rocks from Ogun State in Southwestern Nigeria. The aim is to determine radiation emissions from rocks in order to estimate radiation hazard indices. Objectives: The following objectives were targeted: 1. To determine radiation emissions from each type of rocks; 2. To estimate radiation hazard indices based on the rocks; 3. To correlate the activity concentrations of radionuclides with major oxides. Methods: The samples were analyzed using a NaI (Tl) gamma ray spectrometric detector and PerkinElmer AAnalyst 400 AAS spectrometer. Results: The activity of ⁴⁰K, ²²⁶Ra, and ²³²Th were found in order of decreasing magnitude from pegmatite>granite>migmatite. In contrast, lower concentrations were found in shale, phosphate, clay stone, sandstone and limestone. The mean absorbed doses were 125±23 nGyh^-1 (migmatite), 74±13 nGy/h (granite), 72±13 nGyh^-1 (pegmatite), 64±09 nGyh^-1 (quartzite), 45±16 nGyh^-1 (shale), 41±09 nGyh^-1 (limestone), 41±11 nGyh^-1 (clay stone), 24±03 nGyh^-1 (phosphate), and 21±10 nGyh^-1 (sandstone). The outdoor effective dose rates in all rock samples were slightly higher than the world average dose value of 0.34 mSvy^-1. The percentage composition of SiO₂ in the rock samples was above 50 wt% except for in the limestone, shale and phosphate. Al₂O₃ ranged from 4.10~21.24 wt%, Fe₂O₃ from 0.39~7.5 wt%, and CaO from 0.09-46.6 wt%. In addition, Na₂O and K₂O were present in at least 5 wt%. Other major oxides, including TiO₂, P₂O₅, K₂O, MnO, MgO and Na₂O were depleted. Conclusions: The findings suggest that Ogun State may be described as a region with elevated background radiation. It is recommended that houses should be constructed with good cross ventilation and residences should use home radiation monitoring instruments to monitor radon emanating from walls.