• Radiation Oncology Journal
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• v.32 no.3
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• pp.163-169
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• 2014

Purpose: To report the results of stereotactic body radiotherapy (SBRT) for unresectable primary or recurrent cholangiocarcinoma. Materials and Methods: From January 2005 through August 2013, 58 patients with unresectable primary (n = 28) or recurrent (n = 30) cholangiocarcinoma treated by SBRT were retrospectively analyzed. The median prescribed dose was 45 Gy in 3 fractions (range, 15 to 60 Gy in 1-5 fractions). Patients were treated by SBRT only (n = 53) or EBRT + SBRT boost (n = 5). The median tumor volume was 40 mL (range, 5 to 1,287 mL). Results: The median follow-up duration was 10 months (range, 1 to 97 months). The 1-year, 2-year overall survival rates, and median survival were 45%, 20%, and 10 months, respectively. The median survival for primary group and recurrent group were 5 and 13 months, respectively. Local control rate at 1-year and 2-year were 85% and 72%, respectively. Disease progression-free survival rates at 1-year and 2-year were 26% and 23%, respectively. In univariate analysis, ECOG performance score (0-1 vs. 2-3), treatment volume (<50 vs. ${\geq}50mL$), and pre-SBRT CEA level (<5 vs. ${\geq}5ng/mL$) were significant in overall survival rate. In multivariate analysis, ECOG score (p = 0.037) and tumor volume (p = 0.030) were statistically significant. In the recurrent tumor group, patients with >12 months interval from surgery to recurrence showed statistically significant higher overall survival rate than those with ${\leq}12$ months (p = 0.026). Six patients (10%) experienced ${\geq}$grade 3 complications. Conclusion: SBRT can be considered as an effective local modality for unresectable primary or recurrent cholangiocarcinoma.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.149-154
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• 2001

Calculational models to evaluate radiation doses resulting from the medical use of high energy beta-ray sources are presented. The radioactive sources considered are Sr-90/Y-90 used as ophthalmic applicator, Re-188 used for treating restenosis of coronary artery, and Ho-166 used for treating hepatic tumors. Typical therapeutic situations which might induce relatively high radiation doses the medical person involved were considered to compute by using MCNP-4C Monte Carlo code the radiation doses. The calculation results suggest that for all of the cases considered, the evaluated radiation doses are negligible compared to the dose limits. It is also found that the effect of Bremsstrahlung radiations on the total dose is insignificant, and hence the conventional lead gown is also effective in shielding beta-rays.

• Journal of Photoscience
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• v.9 no.3
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• pp.37-40
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• 2002

Astronauts are constantly exposed to space radiation at a low-dose rate during long-tenn stays in space. Therefore, it is important to determine correctly the biological effects of space radiation on human health. Space radiations contain various kinds of different energy particles, especially high linear energy transfer (LET) particles. Therefore, we have to study the relative biological effectiveness (RBE) of space radiation under microgravity environment which may change RBE from a stress for cells. Furthermore, the research about space radiation might give us useful information about birth and evolution of life on the earth. We also can realize the importance of preventing the ozone layer from depletion by use of exposure equipment to sunlight at International Space Station (ISS).

• Journal of the Korean Society of Radiology
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• v.83 no.4
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• pp.783-791
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• 2022

The radiation emitted during radiological examinations can be harmful to the human body, but the technique is still used because it is helpful to the patient. Therefore, radiologic examinations must follow radiation protection principles such as justification and optimization, and only minimal required re-examinations should be performed. Proper use of radiation in the medical field can be achieved by proper education of individuals from multiple medical fields.

• Advances in Traditional Medicine
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• v.5 no.1
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• pp.48-56
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• 2005

We studied the protective effect of Echinacea purpurea against radiation by evaluating changes in the peripheral blood cell count and peripheral blood antioxidant activity. Echinacea purpurea administration had a suppressive effect on radiation-induced leukopenia, especially on lymphocytes and monocytes and resulted in a faster recovery of blood cell counts. Mouse peripheral blood antioxidant activity was increased by Echinacea purpurea, and a relationship between the suppressive effect on radiation-induced leukopenia and the antioxidant effect was suggested.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.81-81
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• 2006

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.49-51
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• 1996

We have developed the prototype Multi-leaf Collimator(MLC) for Medical linear acclerator. In this study, we have examined the mechanical characteristics of newly developed multileaf collimator. The leaf movement in clinical situation and the modification of accessories is good. such as the block tray mount and the wedges, due to the new MLC installation are efficient. But it was that bolts and nuts for the leaf control should have better performance.

• Korean Journal of Health Education and Promotion
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• v.19 no.2
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• pp.99-113
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• 2002

While the use of radiation in the medical field provides diagnosis and treatment with important benefits, we cannot deny that the radiation bombing causes some hindrances. The expansion of radiation use in modem medicine is essential, so the radiation use and preparation of proper measure for safety management has risen as a pressing subject. Therefore, in order to make defensive plans for the prevention of health obstacles to general users of radiation and for the provision of basic data of the health education programs to radiation workers by grasping the knowledge, attitude and behavior towards the radiation safety management of radiation workers in each medical institution and by analyzing the factors that affect the actions of radiation safety management, in this study we conducted questionnaires from September 26 to November 5, 2001 targeting 805 radiation workers in 108 medical institutions including university hospitals, general hospitals, hospitals, clinics and public health centers etc. located in Seoul, four metropolitan cities and small and medium cities, and has obtained the following results. 1. The average point of knowledge on the radiation safety management was 10.96 out of 15. As for the general characteristics, the level of knowledge on radiation safety management was higher with older age, high education background and longer career. 2. The average point of attitude on the radiation safety management was 66.36 out of 75. The attitude point for general characteristics were higher with higher education background, longer career and in case of universities, the level of attitude on the radiation safety management was high. 3. The average of action points on the radiation safety management was 56.09 out of 75. In general characteristics, the action level of radiation safety level was higher with older age, longer career, and the reception of radiation education and in case of university hospitals. 4. It is analyzed that the relation of knowledge, attitude and behavior on the radiation safety management is higher as the levels of knowledge and attitude on the radiation safety management is higher. 5. As a result of analyzing the factors that affect the knowledge on the radiation safety management, the variables that can be explained best was in the order of ‘the behavior on the radiation safety management’, ‘work career’, ‘the attitude on the radiation safety management’, and ‘school career’. 6. As a result of analyzing the factors that affect the attitude on the radiation safety management, the variables that can be explained best was in the order of ‘the behavior on the radiation safety management’, ‘the knowledge on the radiation safety management’, and ‘school career’. 7. As a result of analyzing the factors that affect the behavior on the radiation safety management, the variables that can be explained best was in the order of ‘the attitude on the radiation safety management’, ‘the knowledge on the radiation safety management’, and ‘the frequency of radiation education

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3395-3402
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• 2015

Background: Preoperative 5-fluorouracil (5-FU)-based chemoradiotherapy is a standard treatment for locally advanced colorectal cancer (CRC). However, CRC cells often develop chemoradiation resistance (CRR). Recent studies have shown that long non-coding RNA (lncRNA) plays critical roles in a myriad of biological processes and human diseases, as well as chemotherapy resistance. Since the roles of lncRNAs in 5-FU-based CRR in human CRC cells remain unknown, they were investigated in this study. Materials and Methods: A 5-FU-based concurrent CRR cell model was established using human CRC cell line HCT116. Microarray expression profiling of lncRNAs and mRNAs was undertaken in parental HCT116 and 5-FU-based CRR cell lines. Results: In total, 2,662 differentially expressed lncRNAs and 2,398 mRNAs were identified in 5-FU-based CRR HCT116 cells when compared with those in parental HCT116. Moreover, 6 lncRNAs and 6 mRNAs found to be differentially expressed were validated by quantitative real time PCR (qRT-PCR). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis for the differentially expressed mRNAs indicated involvement of many, such as Jak-STAT, PI3K-Akt and NF-kappa B signaling pathways. To better understand the molecular basis of 5-FU-based CRR in CRC cells, correlated expression networks were constructed based on 8 intergenic lncRNAs and their nearby coding genes. Conclusions: Changes in lncRNA expression are involved in 5-FU-based CRR in CRC cells. These findings may provide novel insight for the prognosis and prediction of response to therapy in CRC patients.

• Nuclear Engineering and Technology
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• v.38 no.3
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• pp.285-292
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• 2006

Thermoresistant (TR) clones of radiation-induced fibrosarcoma (RIF) cells have been reported to show an adaptive response to 1cGy of low dose radiation, and HSP25 and inducible HSP70 are involved in this process. In this study, to further elucidate the mechanism by which HSP25 and inducible HSP70 regulate the adaptive response, HSP25 or inducible HSP70 overexpressed RIF cells were irradiated with 1cGy and the cell cycle was analyzed. HSP25 or inducible HSP70 overexpressed cells together with TR cells showed increased G1 phase after 1cGy irradiation, while RIF cells did not. $[^3H]-Thymidine$ and BrdU incorporation also indicated that both HSP25 and inducible HSP70 are involved in G1 arrest after 1cGy irradiation. Molecular analysis revealed upregulation of p27Cip/Kip protein in HSP25 and inducible HSP70 overexpressed cells, and cotransfection of p27Cip/Kip antisense abolished the induction of the adaptive response and 1cGy-mediated G1 arrest. The above results indicate that induction of an adaptive response by HSP25 and inducible HSP70 is mediated by upregulation of p27Cip/Kip protein, resulting in low dose radiation-induced G1 arrest.