• 한국의학물리학회지:의학물리
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• 제31권2호
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• pp.9-19
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• 2020

Purpose: This study aims to develop a multi-purpose electron beam irradiation device for preclinical research and material testing using the research electron linear accelerator installed at the Dongnam Institute of Radiological and Medical Sciences. Methods: The fabricated irradiation device comprises a dual scattering foil and collimator. The correct scattering foil thickness, in terms of the energy loss and beam profile uniformity, was determined using Monte Carlo calculations. The ion-chamber and radiochromic films were used to determine the reference dose-rate (Gy/s) and beam profiles as functions of the source to surface distance (SSD) and pulse frequency. Results: The dose-rates for the electron beams were evaluated for the range from 59.16 Gy/s to 5.22 cGy/s at SSDs of 40-120 cm, by controlling the pulse frequency. Furthermore, uniform dose distributions in the electron fields were achieved up to approximately 10 cm in diameter. An empirical formula for the systematic dose-rate calculation for the irradiation system was established using the measured data. Conclusions: A wide dose-rate range electron beam irradiation device was successfully developed in this study. The pre-clinical studies relating to FLASH radiotherapy to the conventional level were made available. Additionally, material studies were made available using a quantified irradiation system. Future studies are required to improve the energy, dose-rate, and field uniformity of the irradiation system.

• 전기학회논문지
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• 제56권12호
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• pp.2208-2213
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• 2007

In this study we have developed a hyperspectrum imaging system for highly sensitive and effective imaging analysis. An optical setup was designed using acoustic optical tunable filter (AOTF) for high sensitive hyperspectrum imaging. Light emitted by mercury lamp gets split in to diffracted and undiffracted beams while passing though AOTF. GFP transfected HEK-293 cell line was used as a model for in vitro imaging analysis. Cells were first, analyzed by fluorescence microscope followed by flow cytometric analysis. Flow cytometric analysis showed 66.31% transfection yield in GFP transfected HEK-293 cells. Various images of GFP transfected HEK-293 cell were grabbed by collecting the diffracted light using a CCD over a dynamic range of frequency of 129-171 MHz with an interval of 3 MHz. Subsequently, for in vivo image analysis of GFP transfected cells in mouse, a whole-body-imaging system was constructed. The blue light of 488 nm wavelength was obtained from a Xenon arc lamp using an appropriate filter and transmitted through an optical cable to a ring illuminator. To check the efficacy of the newly developed whole-body-imaging system, a comparative imaging analysis was performed on a normal mouse in presence and absence of Xenon arc irradiation. The developed hyperspectrum imaging analysis with AOTF showed the highest intensity of green fluorescent protein at 153 MHz of frequency and 494 nm of wavelength. However, the fluorescence intensity remained same as that of the background below 138 MHz (475 nm) and above 162 MHz (532 nm). The mouse images captured using the constructed whole-body-imaging system appeared monochromatic in absence of Xenon arc irradiation and blue when irradiated with Xenon arc lamp. Nevertheless, in either case mouse images appeared clearly.

• Asian Pacific Journal of Cancer Prevention
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• 제17권9호
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• pp.4409-4413
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• 2016

Background: Cervical cancer is the second most common of malignancy found in Thai women. Human papillomavirus (HPV) infection is a major cause. The objective of the present study was to evaluate the prevalence of HPV infection and association with abnormal cervical cytology in Thai women. Materials and Methods: This study was conducted at the Gynecologic Clinic, Thammasat University, Pathum Thani, Thailand. A total of 2,144 cases who underwent annual cervical cancer screening by co-testing (liquid based cytology and HPV testing, DNA versus mRNA) during the priod from July 2013 to June 2016 were recruited in this study. Results: Prevalence of positive high risk (HR) HPV DNA and mRNA test were 19.7 and 8.4%, respectively with a statistically significant difference. Majority of cases of abnormal cytology in this study were atypical squamous cells of undetermined significance (ASC-US). In patients with ASC-US, positive HR HPV DNA was greater than in the mRNA group (10.1 and 4.5%, p<0.001). Nonetheless, there was no significant difference in participants with cervical intraepithelial neoplasia (CIN). HPV mRNA test had slightly lower sensitivity but higher negative predictive value (NPV) than the DNA test to detect abnormal cytology during cervical cancer screening (p<0.001). Both HPV test (DNA and mRNA) had equally efficacy to detect high grade precancerous lesion or higher (CIN 2+). Conclusions: Prevalence of HR HPV DNA and mRNA were 19.7 and 8.4 percent, respectively. NPV of HPV mRNA was higher than DNA test. Both tests had equal efficacy to detect CIN 2+ with sensitivity and specificity of 63% vs 55.7% and 83% vs 92%, respectively.

• 대한골관절종양학회지
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• 제4권1호
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• pp.13-21
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• 1998

Taxol이 악성 골종양 세포에 어느 정도의 세포독성이 있는지를 평가하기 위해 한국세포주 은행에서 분양 받은 G-292, SaOS-2 및 HT-1080의 3가지 악성 골종양 세포들을 대상으로 기존의 항암제인 methotrexate, adriamycin, ifosfamide, cisplatinum과 함께 각각 투여하여 MTT분석법으로 정량 및 비교 분석하였으며, adriamycin과 taxol을 병용 투여하여 항암제의 상호작용을 isobologram 분석법으로 조사하여 다음과 같은 결과를 얻었다. 1. Taxol의 악성 골종양 세포 주들에 대한 $IC_{50}$는 G-292에서는 $2.7{\times}10^{-2}{\mu}g/ml$, $SaOS^{-2}$에서는 $1.0{\times}10^{-2}{\mu}g/ml$, $HT{\times}1080$에서는 $1.1{\times}10^{-3}{\mu}g/ml$이었다. 2. Taxol은 악성 골종양 세포주들에 대해 기존의 항암제들 보다 강한 세포독성을 보였으며, 기존 항암제의 세포 독성의 강도는 adriamycin이 제일 높은 역가를 보였으며 그 외 methotrexate, cisplatinum, ifosfamide순이었다. 3. Taxol과 adriamycin을 병용 투여하여 상호작용을 관찰한 결과 G-292와 SaOS-2 세포 주에서 상승효과가 관찰되었으며, HT-1080에서는 상승효과가 관찰되지 않았다.