• Journal of Radiation Protection and Research
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• v.28 no.3
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• pp.189-197
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• 2003

The Level 3 PSA being termed accident consequence analysis is defined to assess effects on health and environment caused by radioisotopes released from severe accidents of nuclear power plants. In this study consequence analysis on health effects depending on release characteristics of radioisotopes has been peformed using the 3 MACCS code in severe accidents. The results of this study may contribute to identifying the relative importance of various parameters occurred in consequence analysis as well as to assessing risk reduction accident management strategies. Especially three parameters for the purpose of consequence analysis, such as the release height, the heat content, and the duration time, are used to analyze the variation of early fatalities and latent cancer fatalities. Also, in this study risk assessment using the concept, 'products of uncertainty and consequences', has been performed using consequence of MACCS and frequency on source term category 19 scenarios from IPE (Individual Plant Examination) analysis.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.68-73
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• 2002

In standard teletherapy, a treatment plan is generated with the aid of a treatment planning system, but it is common to perform an independent monitor unit verification calculation (MUVC). In exact analogy, we propose and demonstrate that a simple and accurate MUVC in Intensity Modulated Radiotherapy (IMRT) is possible. We introduce a concept of Modified Clarkson Integration (MCI). In MCI, we exploit the rotational symmetry of scattering to simplify the dose calculation. For dose calculation along a central axis (CAX), we first replace the incident IMRT fluence by an azimuthally averaged fluence. Second, the Clarkson Integration is carried over annular sectors instead of over pie sectors. We wrote a computer code, implementing the MCI technique, in order to perform a MUVC for IMRT purposes. We applied the code to IMRT plans generated by CORVUS. The input to the code consists of CORVUS plan data (e.g., DMLC files, jaw settings, MU for each IMRT field, depth to isocenter for each IMRT field), and the output is dose contribution by individual IMRT field to the isocenter. The code uses measured beam data for Sc, Sp, TPR, (D/Mu)$\_$ref/ and includes effects from MLC transmission, and radiation field offset. On a 266 MHZ desktop computer, the code takes less than 15 sec to calculate a dose. The doses calculated with MCI algorithm agreed within +/- 3% with the doses calculated by CORVUS, which uses a 1cm x 1cm pencil beam in dose calculation. In the present version of MCI, skin contour variations and inhomogeneities were neglected.

• Journal of Radiation Protection and Research
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• v.26 no.4
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• pp.357-365
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• 2001

Intervention levels for protection of the public in a radiological emergency are theoretically derived by the cost-benefit approach with the concept of justification and optimization. Intervention levels on the sheltering, evacuation, temporary relocation and permanent resettlement for protection of the public are estimated with the cost to protective countermeasures and the value from dose averted which are the site specific parameters. As a result, it is confirmed that IAEA guidelines for intervention levels are applicable to the radiological emergency in Korea. Optimum ranges of 5 - 10 mSv/2days for sheltering, 25 - 130 mSv/week for evacuation, 15 - 90 mSv/month lot temporary relocation and 600 - 3,500 mSv/lifetime for permanent resettlement for intervention levels are also provided. The result can be applied as useful data to update intervention levels under the theoretical background in Korea.

• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.118-123
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• 2015

The frequency of diagnostic radiation examinations in medical institutions has recently increased to 220 million cases in 2011, and the annual exposure dose per capita was 1.4 mSv, 51% and 35% respectively, compared to those in 2007. The number of chest radiography was found to be 27.59% of them, the highest frequency of normal radiography. In this study, we developed a shielding device to minimize radiation exposure by shielding areas of the body which are unnecessary for image interpretation, during the chest radiography. And in order to verify its usefulness, we also measured the difference in entrance surface dose (ESD) and the absorbed dose, before and after using the device, by using an international standard pediatric (10 years) phantom and a glass dosimeter. In addition, we calculated the effective dose by using a Monte Carlo simulation-based program (PCXMC 2.0.1) and evaluated the reduction ratio indirectly by comparing lifetime attributable risk of cancer incidence (LAR). When using the protective device, the ESD decreased by 86.36% on average, nasal cavity $0.55{\mu}Sv$ (74.06%), thyroid $1.43{\mu}Sv$ (95.15%), oesophagus $6.35{\mu}Sv$ (78.42%) respectively, and the depth dose decreased by 72.30% on average, the cervical spine(upper spine) $1.23{\mu}Sv$ (89.73%), salivary gland $0.5{\mu}Sv$ (92.31%), oesophagus $3.85{\mu}Sv$ (59.39%), thyroid $2.02{\mu}Sv$ (73.53%), thoracic vertebrae(middle spine) $5.68{\mu}Sv$ (54.01%) respectively, so that we could verify the usefulness of the shielding mechanism. In addition, the effective dose decreased by 11.76% from $8.33{\mu}Sv$ to $7.35{\mu}Sv$ before and after wearing the device, and in LAR assessment, we found that thyroid cancer decreased to male 0.14 people (95.12%) and female 0.77 people (95.16%) per one million 10-year old children, and general cancers decreased to male 0.14 people (11.70%) and female 0.25 people (11.70%). Although diagnostic radiation examinations are necessary for healthcare such as the treatment of diseases, based on the ALARA concept, we should strive to optimize medical radiation by using this shielding device actively in the areas of the body unnecessary for the diagnosis.

• Journal of the Korean earth science society
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• v.23 no.8
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• pp.676-682
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• 2002

The concept of sensible temperature in winter is an attempt to quantify the sensation of cold by dry-bulb temperature combined with wind speed. Siple-Passel’s windchill equivalent temperature originated in experiments that are not conformable to various human conditions. Therefore, many investigators have found the flaws which are listed. Steadman’s model is based on the concept of thermal equilibrium and more sound and more representative of human conditions. But no classifications exist for Steadman’s windchill equivalent temperature, yet. The JAG/TI-model which was developed by US and Canada is more accurate, easy to understand and reflects human beings by conducting experiments using human volunteers but didn't take into account solar radiation, wet condition and physical state of the individual. Because of individual differences in people’s age, activity, health, metabolic rate, etc., no experimental evidence exists to suggest whether Siple-Passel’s, Steadman’s and JAG/TI-model’s windchill equivalent temperature is more applicable to the majority of people. Therefore we need the windchill model which is best applicable to Korean Army.

• IMMUNE NETWORK
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• v.1 no.2
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• pp.126-134
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• 2001

Background : Paeonia japonica Miyabe is a medicinal plant which has been widely used as a component of blood-building decoctions (Chinese medicinal concept : Bu-Xie). The immunopharmacological characteristics of the extract of Paeonia japonica (PJ) were investigated. Methods : The effects of fractions of PJ extract on lymphocyte proliferation were measured by $H^3$-thymidine incorporation assay. The proliferated lymphocyte subsets were analyzed in flow cytometry. The subset cell populations of spleen cells were separated by magnetic cell separation system, and their proliferation by the extract were investigated. The effect of the extract on antibody production was determined in mice challenged with sheep red blood cells (SRBC) using hemolytic plaque forming cell assay. Results : Spleen cells were proliferated by water extract of PJ. Polysaccharide fraction (PJ-P) of the extract was most active in the proliferation. It was found in flow cytometry that the lymphocyte subset proliferated by PJ-P was B cell population. Among the separated subset cell populations, T cell-depleted cell population and macrophage-depleted cell population were most proliferated by PJ-P. However, positively selected populations of B cells and T cells were not proliferated by PJ-P. These results indicate that B cell proliferation by PJ-P may require the assistance of macrophages or T cells. These results suggest that firstly PJ-P may stimulate macrophages or T cells, and then B cells are activated. The number of antibody-secreting cells was increased by administration of PJ-P in mice immunized with SRBC as a T-dependent antigen. Conclusion : These results suggest that macrophages and accessory cells are directly activated by PJ-P and then helper T cells and B cells are indirectly activated. As the results, immune responses might be coordinately improved. In conclusion, PJ-P, a polysaccharide of P. japonica, may be a characteristic immunostimulator, which is analogous to polysaccharides such as lentinan, PSK and ginsan.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.5975-5979
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• 2012

Background: To investigate the influence of telomerase activity, apoptosis, radiosensitivity of cervical cancer after siRNA-mediated knockdown of telomerase RNA and evaluate in vivo growth with gene interference. Methods: We studied siRNA-targeting-telomerase RNA transfection into the Hela cell line. Expression of hTERC mRNA was detected by RT-PCR and telomerase activity was measured by the TRAP assay. Growth inhibition was determined by MTT assay and radiosensitivity of the cervical cancer cells was examined by colony formation assay. In addtion, effects of hTERC inhibition in vivo were studied by injection of siRNA-transfected Hela cells into nude mice. Results: The hTERC siRNA effectively downregulated the expression of hTERC mRNA and also reduced the telomerase activity to 30% of the untreated control vlaue. The viability of hTERC siRNA transfected Hela cells was reduced by 44.7% after transfection. After radiation treatment, the radiosensitivity of Hela cells with hTERC knockdown was increased. In vivo, the tumors developing from the hTERC siRNA-transfected cells were of reduced size, indicating that the hTERT siRNA also depressed the tumorigenic potential of the Hela cells. Conclusions: Our results supported the concept of siRNA-mediated inhibition of telomerase mRNA which could inhibit the expression of hTERC and telomerase activity. Furthermore, radiosensitivity was upregulated after knockdown the hTERC in vivo and in vitro.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1342-1349
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• 2023

The planning accuracy of charged particle therapy (CPT) is subject to the accuracy of stopping power (SP) estimation. In this study, we propose a method of deriving a pseudo-triple-energy CT (pTECT) that can be achievable in the existing dual-energy CT (DECT) systems for better SP estimation. In order to remove the direct effect of errors in CT values, relative CT values according to three scanning voltage settings were used. CT values of each tissue substitute phantom were measured to show the non-linearity of the values thereby suggesting the absolute difference and ratio of CT values as parameters for SP estimation. Electron density, effective atomic number (EAN), mean excitation energy and SP were calculated based on these parameters. Two of conventional methods were implemented and compared to the proposed pTECT method in terms of residuals, absolute error and root-mean-square-error (RMSE). The proposed method outperformed the comparison methods in every evaluation metrics. Especially, the estimation error for EAN and mean excitation using pTECT were converging to zero. In this proof-of-concept study, we showed the feasibility of using three CT values for accurate SP estimation. Our suggested pTECT method indicates potential clinical utility of spectral CT imaging for CPT planning.

• The Journal of the Korean dental association
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• v.54 no.2
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• pp.108-122
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• 2016

Prosthetic-driven implant placement is a concept considering the dental implant restoration first based on the final form of that prosthesis to be restored. The latest development of the imaging technology and digital dentistry was able to be obtained the high quality images of CBCT with low radiation exposure and it has also enabled the process to reconstruct the intraoral state in three dimensions due to the development of the intraoral, model and impression scanner. Computer-guided implant placement simulations and template production was able to be more widely used in this context. In this narrative review, the features and the types of implant surgical guides will be introduced. It will also be described the diagnosis and treatment plan using computerguided implant software to reduce the number of visit and to increase the accuracy of the implant surgery through the top-down approach based on the shape and location of the final prosthesis.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.103-109
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• 2013

Estimating the high tuber solids needs a simulation system on potato growth, and its development should be obtained by using agricultural elements which analyze the relationship between crop growth and agricultural factors. An accurate simulation to predict solids level against climatic change employs a calculation of in vivo energy consumption and bias for growth and induction shape in a slight environmental adaptation. So, to calculate in vivo energy consumption, this study took a concept of estimate of the amount of basal metabolism in each tuber. In the validation experiments, the results of measuring solid accumulation of potatoes harvested at dates suggested by simulation agreed with the actual measured values in each regional field during the growth period of years from 2006 till 2010. The mean values of tuber solids level and inter-annual level variation in validation experiments were predicted well by the simulation model. And also, the results of validation experiments represent that concentration of tuber solids were due mainly to the duration of sunshine, above 190 hours per a month, and the cumulative amount of radiation, above 2,200 $MJ{\cdot}m^{-2}$, of the effective growth period.