• Journal of Soil and Groundwater Environment
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• v.18 no.4
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• pp.19-31
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• 2013

To figure out the decay characteristics of naturally occurring radionuclides, eight sampled groundwaters from a monitoring borehole having high levels of uranium and radon concentrations in a two mica granitic area have analyzed by liquid scintillation counters (LSC) for over 1 year. In December 2011, three groundwater samples (DJ1, DJ2, DJ3) were obtained from each aquifer system located at -20 m, -40 m, -60 m of the monitoring borehole below the ground surface, respectively. Five samples (DJ4, DJ5, DJ6, DJ7, DJ8) were additionally gained from each aquifer positioned -20 m, -40 m, -60 m, -100 m, -105 m of the borehole in February 2012, respectively. Temporal variation characteristics of uranium and radon concentrations have showed over maximum 2.1 times and 1.4 times fluctuations of the values in the same sampling intervals over time, respectively. The intervals of -40 m and -105 m in the borehole have the highest values of uranium and radon concentrations, respectively. This may imply that the concentrations of naturally occurring radionuclides such as uranium and radon in groundwater have been changed over time and indicate that the qualities of groundwaters from the aquifers developed at each interval in the borehole are different each other. This discrepancy, moreover, could be caused by behaviour differences between uranium which is in ionic status having a half life of 4.6 billion years and is transported along with the flowing groundwater, and radon which is in gaseous status having a 3.82 day's half life in the aquifer systems. Physicochemical characteristics of groundwaters from the aquifer systems could be identified by the results of the on-situ measuring items such as pH and Eh, and the major ionic contents. The CPM values of eight groundwater samples analysed by LSC over one year have shown not to follow the theoretical decay curve of the radon. The CPM values of the samples have ranged from 2 to 7.5 after it had passed two months when the theoretical CPM values of the radon started zero since the initial analysis. Alpha and beta particle spectrums have shown the peaks of radium-226, however they have not revealed any peaks of radon and it's daughter products such as polonium-218 and 214, bismuth-214 for the late stage of the analysis. This implies that the groundwater from the borehole may contain radium-226 having a half life of 1,600 years which decays continuously.

• Journal of the Korean Society of Radiology
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• v.1 no.3
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• pp.23-34
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• 2007

To find how much radiation was exposed the patients who visit emergency room, a measurement study was made for radiation amount toward 200 patients selected randomly among visitors to an emergency room in a university hospital from March 16 to 31st, 2006. The results are as follows ; 1. Among the subjects 50 person(25.0%) were transferred from other hospitals, 24 persons(8.3) come after traffic accident, 50 persons for other accident and 76 persons for general medical care. 2. The average frequency of X-ray taking was calculated as 6.4 time per person among transferred patients, 14.5 times per person among patients with traffic accident and 2.6 times per person among general medical care. 3. The radiation exposure amount by kind of X-ray showed 28.9mGyfor general X-ray diagnosis, 84.2mGy for CT scanning and 1.02mGy for other special radiation study. 4. Average radiation exposure amount was calculated as 24.6mGy by transferred patients, 55.2mGy by patients with traffic accident, 17.1mGy by patients with other accidents and 17.0mGy by general patients. 5. Through the comparison of radiation exposure amount among to subject with maximum allowance threshold by International Commission on X-ray Radium Protection, transferred patients exceeded 6 times than allowance in whole body except extremities and joints, blood forming organ, reproductive system, vitreous body of eye, bone, thyroid gland, skin and etc, Patient suffered from traffic accidents were exposed 10 times more than allowance. In conclusion, the radiation exposure amount during X-rat diagnosis re too much and exceeded allowance standard by International Commission on X-ray Radium Protection. So further study and preventive measure to decrease radiation exposure by patients who visit emergency room.

• Radiation Oncology Journal
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• v.18 no.1
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• pp.32-39
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• 2000

Purpose :The incidence of adenocarcinoma of the uterine cervix is low. Traditionally, Low Dose Rate (LDR) brachytherapy has been used as a standard modality in the treatment for patients with carcinoma of the uterine cervix. The purpose of this report is to evaluate the effects of the High dose rate (HDR) brachytherapy in the patients with adenocarcinoma of the uterine cervix compared with the LDR. : From January 1971 to December 1992, 106 patients of adenocarcinoma of uterine cervix were treated with radiation therapy in the Department of Radiation Oncology, Yonsei University with curative intent. LDR brachytherapy was carried out on 35 patients and 71 patients were treated with HDR brachytherapy. In LDR Group, 8 patients were in stage I, 18 in stage II and 9 in stage III. External radiation therapy was delivered with 10 MV X-ray, daily 2 Gy fractionation, total dose 40$\~$46Gy (median 48 Gy). And LDR Radium intracavitary irradiation was peformed with Henschke applicator, 22$\~$59 Gy to point A (median 43 Gy). In HDR Group, there were 16 patients in stage 1, 38 in stage II and 17 in stage III. The total dose of external radiation was 40$\~$61 Gy(median 45 Gy), daily 1.8$\~$2.0 Gy. HDR Co-60 intracavitary irradiation was peformed with RALS (Remote Afterloading System), 30 $\~$ 57 Gy(median 39 Gy) to point A, 3 times a week, 3 Gy per fraction. Conclusion : The 5-year overall survival rate in LDR Group was 72.9$\%$, 61.9$\%$, 45.0$\%$ in stage I, II, III, respectively and corresponding figures for HDR were 87.1$\%$, 58.3$\%$, 41.2$\%$, respectively (p>0.05). There was no statistical difference in terms of the 5-year overall survival rate between HDR Group and LDR Group in adenocarcinoma of the uterine cervix. There was 11$\%$ of late complication rates in LDR Group and 27$\%$ in HDR Group. There were no prognostic factors compared HDR with LDR group. The incidence of the late complication rate in HDR Group stage II, III was higher than that in LDR Group(16.7$\%$ vs. 31.6$\%$ in stage II, 11.1$\%$ vs. 35.3$\%$ In stage III, p>0.05). Although the incidence of radiation induced late complication rate was higher in HDR Group stage II and III patients than that in the LDR Group, statistical significance was not detected and within acceptable level. Conclusion : There was no difference in terms of 5-year survival rate and failure pattern in the patients with adenocarcinoma of the uterine cervix treated with HDR and LDR brachytherapy. Even late complication rates were higher in the HDR group It was an acceptable range. This retrospective study suggests that HDR brachytherapy seems to replace the LDR brachytherapy in the adenocarcinoma of the uterine cervix. However, further studies will be required to refine the dose rate effects.

• Analytical Science and Technology
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• v.12 no.5
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• pp.428-435
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• 1999

A method for measuring Rn-222 and Ra-226 in aqueous sample using liquid scintillation counting technique has been studied. The Rn-222 was extracted easily from the water sample (10 mL) by 12 mL of xylene based organic scintillant. After radioactive equilibrium between Rn-222 and its alpha emitting decay products for three hours, the alpha activity from Rn-222 and its decay products were measured in a scintillation vial using the Wallae $1220^{TM}$ Quantulus liquid scintillation counter. Ra-226 concentration in aqueous sample was determined, after isolation of Ra-226 from the sample matrix, by extraction the ingrowth of the Rn-222 and its alpha emitting decay products with xylene based organic scintillant. The optimum pulse-shape analysis (PSA) value was evaluated by the figure of merit (FM) criterion. Minimum detectable activity (MDA) is about 0.14 Bq/L (3.78 pCi) for the region of Rn-222 and its alpha emitting decay products and 0.06 Bq/L (1.63 pCi) for the region of Po-214 respectively, with 200 min, counting time at PSA level 100 in the low-diffusion polyethylene vial and xylene based cocktail solution. Experiment on the optimum sample-cocktail volume ratio, the influence of agitation and the diffusion of radon from vial were carried out.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.3
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• pp.216-223
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• 2000

In order to study origin and mixing ratio of surface water masses in the East China Sea (ECS), the South Sea of Korea and the Korea Strait, we use three end-member mixing equation. We use $^{228}$Ra/$^{226}$Ra activity ratio and salinity as two conservative tracer and the Changjiang Water (CW), the Yellow Sea Water (YSW), and the Kuroshio Water (KW) as three end members, Results show that ECS surface water includes all the three end member water, in the order of KW (50-90%), YSW (20-40%) and CW (0-20%) in August 1997. Also, the amount of CW can be approximately estimated by salinity alone. Surface water of the South Sea and the Korea Strait includes very small or almost no CW (below 2% except station 9) in May 1998. Thus in the Korea Strait mixing ratio could be estimated by $^{228}$Ra/$^{226}$Ra activity ratio tracer alone between two end-members, KW and YSW. However, in order to Set more accurate results or in case of rainy season, a mixing equation based on two tracers and three end-members is required.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.4
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• pp.23-36
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• 2000

Bottom sea waters in eight stations including from inner bay to outer bay to understand the importance of the submarine groundwater discharge for the environmental assessment of Chinhae Bay was collected in August 1999 and January 2000. Generally, /sup 222/Rn is very useful tracer to assess the submarine groundwater discharge because it is 2-4 orders of magnitude more concentrated in groundwater compared to surface water. The /sup 222/Rn activities ranged between about 33 to 182 dpm/100kg within the bay. Higher activities more than 100 dpm/100kg were found at the inner bay. The /sup 226/Ra activities, its parent, however, were little different between stations. /sup 222/Rn activities at the same station varied with season. It suggests that the major source of /sup 222/Rn is not from the bottom sediment, but from the change of submarine groundwater discharge by precipitation. The contents of Cl/sup -/ and SO/sub 4//sup 2-/ in the groundwater of Wonjeon-ri were very high as 1,312 and 369 ppm, respectively, indicating that this groundwater along the Chinhae coast was affected by seawater. Therefore, the submarine groundwater in the inner Bay may discharge to the overlying water. It indicates that these submarine groundwater discharges may play an important role as another important source of nutrients in the Chinhae Bay, because groundwater around the Chinhae Bay showed high concentration of dissolved inorganic nutrients (average , nitrate>174 μM, silicate>262 μM). Therefore, further studies are required to assess the contribution by the submarine groundwater discharge in the biogeochemical processes of the Chinhae Bay.

• The Journal of the Petrological Society of Korea
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• v.18 no.4
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• pp.279-291
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• 2009

Radon is a natural radionuclide originated from radioactive decay of radium in rocks and soil. It is colorless, odorless and tasteless elements that mainly distributed as gaseous phase in soil pore space. The present study analyzed the characteristics of long-term radon variation in granitic residual soil at Mt. Guemjeong in Guemjeong-gu, Busan and determined the effects of atmospheric temperature, rainfall and soil temperature and moisture. Periodic measurements of radon concentrations in soil gas were conducted by applying two types of in-situ monitoring methods (chamber system and tubing system). Radon concentration in soil gas was highest in summer and lowest in winter. The variations in soil temperature and atmospheric temperature were most effective factors in the long-term radon variations and showed positive co-relations. The air circulation between soil air and atmosphere by the temperature difference between soil and atmosphere was analyzed a major cause of the variation. However, other factors such as atmospheric pressure, rainfall and soil moisture were analyzed relatively less effective.

• Journal of Radiation Protection and Research
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• v.36 no.4
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• pp.223-229
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• 2011

Ba is the most useful element to get the $Ba(Ra)SO_4$ precipitate. However, when the high concentrations of ions such as sulfate, calcium are existed in the leachate of phosphogypsum stack, it is difficult to get the $Ba(Ra)SO_4$ precipitate. Since this reason, the developed method for the Ba coprecipitate using EDTA was performed to determine the $^{226}Ra$ concentration in the high sulfate sample. The average concentration of $^{226}Ra$ in a leachate of phosphogypsum using this method was 0.102 $Bq{\cdot}kg^{-1}$ and the minimal detectable activity is 3.4 $mBq{\cdot}kg^{-1}$. The $mBq{\cdot}kg^{-1}$ method was 0.102 $Bq{\cdot}kg^{-1}$ and the minimal detectable activity is 3.4 $mBq{\cdot}kg^{-1}$. The $^{226}Ra$ stock solution and the CRM (Certified Reference Material) were analyzed to verify this method. In analyzed $^{226}Ra$ stock solution, bias with added concentration was approximately 1% and the correlation curve between $^{226}Ra$ concentration in simulated standard sample and measured $^{226}Ra$ concentration showed good agreement with a correlation coefficient ($R^2$) of 0.99. In analyzed CRM, maximum bias with reference value was 5.8% (k=1) and the analytical results were in good agreement with the reference value.

• Journal of Radiation Protection and Research
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• v.37 no.3
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• pp.149-158
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• 2012

In this paper, we measured the variations of radon concentrations in groundwater using low-level Liquid Scintillation Counter (LSC), an instrument for analyzing the alpha and beta radionuclides at its 10 sites around the Kumjung-Gu, north-western of Busan. Optimization of Pulse Shape Analyzer (PSA) to determinate the highest value of figure of merit (FM) was decided using Quantulus 1200 LSC with radium-226 source, the optimal PSA level was shown in the range of 100 to 110. The results show that the Minimum Detectable Activity (MDA) of radon concentrations is 0.61 $Bq{\cdot}L^{-1}$ for 20 minutes in PSA level. We find that the average radon concentration in groundwater is high in granitic rock area and low in volcanic rock area. (Biotite granite : 191.39 $Bq{\cdot}L^{-1}$, Micro graphic granite : 141.88 $Bq{\cdot}L^{-1}$, Adamellite : 92.94 $Bq{\cdot}L^{-1}$, Andesite (volcanic) : 35.35 $Bq{\cdot}L^{-1}$). No significant seasonal variation pattern is observed from the long-term variation analysis from 10 selected sites. We have not seen the significant correlation of radon concentration to groundwater temperature, atmospheric temperature, atmospheric pressure and rainfall. The concentration variation is probably caused by more complex factors and processes.

• 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.