• Journal of The Korean Radiological Technologist Association
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• v.28 no.1
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• pp.34-38
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• 2002

As the radiation is widely used in atomic power generation and medical parts. If it was not very carefully treated, Especially, to consideration of the perspicacity ability of radiation or radionuclide will be caused cytogenetic damages. To evaluation of

• Tuberculosis and Respiratory Diseases
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• v.71 no.4
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• pp.259-265
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• 2011

Background: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, gefitinib and erlotinib, are effective therapies for non-small cell lung cancer (NSCLC) patients whose tumors harbor somatic mutations in EGFR. The mutations are, however, only found in about 30% of Asian NSCLC patients and all patients ultimately develop resistance to these agents. Ionizing radiation has been shown to induce autophosphorylation of EGFR and activate its downstream signaling pathways. In the present study, we have tested whether the effect of gefitinib treatment can be enhanced after ionizing radiation. Methods: We compared the PC-9 and A549 cell line with its radiation-resistant derivatives after gefitinib treatment with cell proliferation and apoptosis assay. We also analyzed the effect of gefitinib after ionizing radiation in PC-9, A549, and NCI-H460 cells. Cell proliferation was determined by MTT assay and induction of apoptosis was evaluated by flow cytometry. Caspase 3 activation and PARP cleavage were evaluated by western blot analysis. Results: PC-9 cells having mutated EGFR and their radiation-resistant cells showed no significant difference in cell viability. However, radiation-resistant A549 cells were more sensitive to gefitinib than were their parental cells. This was attributable to an increased induction of apoptosis. Gefitinib-induced apoptosis increased significantly after radiation in cells with wild type EGFR including A549 and NCI-H460, but not in PC-9 cells with mutated EGFR. Caspase 3 activation and PARP cleavage accompanied these findings. Conclusion: The data suggest that gefitinib-induced apoptosis could increase after radiation in cells with wild type EGFR, but not in cells with mutated EGFR.

• Radiation Oncology Journal
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• v.30 no.1
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• pp.27-35
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• 2012

Purpose: To evaluate the effect of common three photon energies (6-MV, 10-MV, and 15-MV) on intensity-modulated radiation therapy (IMRT) plans to treat prostate cancer patients. Materials and Methods: Twenty patients with prostate cancer treated locally to 81.0 Gy were retrospectively studied. 6-MV, 10-MV, and 15-MV IMRT plans for each patient were generated using suitable planning objectives, dose constraints, and 8-field setting. The plans were analyzed in terms of dose-volume histogram for the target coverage, dose conformity, organs at risk (OAR) sparing, and normal tissue integral dose. Results: Regardless of the energies chosen at the plans, the target coverage, conformity, and homogeneity of the plans were similar. However, there was a significant dose increase in rectal wall and femoral heads for 6-MV compared to those for 10-MV and 15-MV. The $V_{20Gy}$ of rectal wall with 6-MV, 10-MV, and 15-MV were 95.6%, 88.4%, and 89.4% while the mean dose to femoral heads were 31.7, 25.9, and 26.3 Gy, respectively. Integral doses to the normal tissues in higher energy (10-MV and 15-MV) plans were reduced by about 7%. Overall, integral doses in mid and low dose regions in 6-MV plans were increased by up to 13%. Conclusion: In this study, 10-MV prostate IMRT plans showed better OAR sparing and less integral doses than the 6-MV. The biological and clinical significance of this finding remains to be determined afterward, considering neutron dose contribution.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.140-145
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• 2009

All organisms are being exposed to harmful factors present in the environmental. The combined action of various factors is a distinguishing feature of modern life. An interaction between two chemicals is considered as synergistic when the effect produced is greater than the sum of the two single responses. The biological effects due to the combined action of ionizing radiation with the other factor are hard to estimate and predict in advance. In the current study, we investigated the synergistic effects between ionizing and $HgCl_2$ using fish hepatoma cells (PLHC-1 cells). The results showed a dramatic decrease of cell viability after simultaneous treatment of PLHC-1 cells with ionizing radiation and $HgCl_2$. Neiither of the two had any cytotoxic effect when treated alone. The cytotoxicity of ionizing radiation was enhanced in the presence of $HgCl_2$. The synergistic effects were observed after exposure of the PLHC-1 cells to ionizing radiation combined with $HgCl_2$. The synergistic interaction was due to an increase of irreversibly damaged cells after the combined exposure. Analysis of the extent of synergistic interaction enables to make quantitative estimation of irreversibly damaged cells after the combined exposure. The present study suggests that PLHC-1 cells can serve as rapid screening tools for detecting the toxicity of harmful factors.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.162-166
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• 2009

This study evaluated glucose effect on Listeria monocytogenes survival under gamma irradiation and NaCl stress. L. monocytogenes in phosphate buffered saline (PBS) plus glucose (0-4%) was treated with gamma irradiation (0-0.5 kGy), and the samples were then exposed to NaCl (0-9%) in tryptic soy agar plus 0.6% yeast extract. $D_{10}$ and $t_{3D}$ values were determined, and a model for prediction of $D_{10}$ values was developed. Cell counts of L. monocytogenes reduced as irradiation dose increased, and L. monocytogenes in PBS (no glucose) was more sensitive to irradiation and NaCl compared to those in PBS (2 or 4% glucose). $D_{10}$ values were 0.07-0.1, 0.12-0.16, and 0.13-0.15 kGy for 0, 2, and 4% glucose, respectively. The $t_{3D}$ values were 0.22-0.3 (0% glucose), 0.35-0.48 (2% glucose), and 0.40-0.44 (4% glucose). A model performance was acceptable. These results indicate that glucose in foods would increase the resistance of L. monocytogenes to gamma irradiation and NaCl stress.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.237-241
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• 2013

The gamma energy distributions at the major working places during refueling outage of Korean PWR nuclear power plants were measured. In order to estimate the dose reduction effect of a lead vest, Monte Carlo calculation method was used. For the simulations, the MIRD-V phantom with a lead vest was formed and exposed to the measured radiation field. The average measured gamma energy is lower than that of standard which is generally applied to radiation protection procedures. For the efficient use of a lead vest and achievement of radiation protection purpose, it is necessary to estimate the energy distribution of radiation field at working places.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.111-117
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• 2012

This study was conducted to improve organoleptic quality of gamma-irradiated Tarakjuk at 10 kGy with cheeses (Camembert, Cheddar, Gouda, and Edam) and flavors (Nurungji, cream, and vanilla-cream). Overall acceptability of gamma-irradiated Tarakjuk added each camembert cheese and vanilla-cream flavor was the highest among the all samples. In the effect of sterilization method on the quality of Tarakjuk, the autoclaved samples added with Edam cheese, Gouda cheese, and vanilla-cream flavor, respectively, were showed higher score on the overall acceptability than the irradiated samples, meanwhile the irradiated samples were superior in the other samples. In case of added mixture of Edam cheese and vanilla-cream flavor, irradiated Tarakjuk with mixture was showed the most of high score on overall acceptability. In conclusion, addition of mixture of cheese and flavor to Tarakjuk may help to improve organoleptic quality of sterilized Tarakjuk by gammairradiation.

• Journal of Radiation Industry
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• v.7 no.1
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• pp.81-85
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• 2013

This study was conducted to investigate the effect of fermented blackberry drinks (BD) on carbon tetrachloride ($CCl_4$)-induced liver injury in rats. Male Sprague-Dawley rats were randomly divided into four groups with 6 rats per group: control, $CCl_4$, $CCl_4$ plus BD $3ml\;kg^{-1}$, and $CCl_4$ plus BD $6ml\;kg^{-1}$. We found that the levels of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were significantly increased and the activity of antioxidant enzyme glutathione peroxidase (GPx) in the liver was decreased in rats treated with $CCl_4$ alone when compared with the control group. However, the administration of BD attenuated the levels of serum AST and ALT in $CCl_4$-treated rats. Moreover, the administration of BD significantly increased the activity of GPx in $CCl_4$-treated rat livers. Taken together, these results suggest that BD could protect the liver from $CCl_4$-induced hepatic damage.

• Journal of Radiation Industry
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• v.5 no.2
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• pp.169-173
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• 2011

This study investigated the effect of gamma irradiation on immune enhancing activity of Chaga mushroom extract (CME). CME was prepared by hot water extraction at $70^{\circ}C$ for 4 hours and lyophilized. Lyophilized CME powder was dissolved with deionized water at $10mg\;ml^{-1}$ and then irradiated at the doses of 10, 30 and 50 kGy by cobalt 60 gamma irradiator. The gamma-irradiated and non-irradiated CME were treated into the splenocyte separated from mouse. Cell proliferation and cytokine production of the immune cells were increased by gamma-irradiated CME and these increases were more prominent when CME was irradiated at higher doses. Therefore, it is considered that gamma irradiation can be an effective method for improvement of the immunomodulating activity Chaga mushroom extract.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.6
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• pp.1-13
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• 2018

Mapping radiation heat flux of urban area is essential for urban design and landscape planning. Because controlling urban geometry and generating green space are important urban design strategies for reducing urban heat, urban planner and designer need to recognize the micro urban heat distribution for adequate urban planning. This study suggests a new methodology for mapping urban radiation heat flux in a micro scale considering buildings and trees' shade. For doing that, firstly, we calculate net radiation for each urban surfaces (building, road (not shaded, building shaded, tree shaded), ground (not shaded, building shaded, tree shaded), tree (not shaded, building shaded)). Then, by multiplying the area ratio of surfaces to the net radiation, we can obtain the radiation heat flux in micro-scale. The estimated net radiation results were found to be robust with a $R^2$ of 90%, which indicates a strong explanatory power of the model. The radiation heat flux map for 12h $17^{th}$ August explains that areas under the building and tree have lower net radiation heat flux, indicating that shading is a good strategy for reducing incident radiation. This method can be used for developing thermal friendly urban plan.