• Radiation Oncology Journal
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• v.27 no.2
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• pp.55-63
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• 2009

Purpose: This study was performed to objectively evaluate the rate of tumor response to hypofractionated radiotherapy for advanced squamous cell carcinomas of the head and neck. Materials and Methods: Thirty-one patients with advanced squamous cell carcinoma of the head and neck, who were treated by hypofractionated radiotherapy with 3 Gy per fraction for palliative purpose between 1998 and 2008, were reviewed retrospectively. Every tumor-volume was measured and evaluated from CT (computed tomography) images obtained before and 2~3 months after radiotherapy. The radiation toxicity was assessed during and after radiotherapy. A statistical analysis was performed to investigate overall survival, progressionfree survival, and the prognostic factors for survival and response. Results: The median age of the study patients was 70 years. In addition, 85% of the patients were in stage 4 cancer and 66.7% had an ECOG performance status of 1~2. The mean tumor-volume was 128.4 cc. Radiotherapy was administered with a total dose of 24~45 Gy (median: 36 Gy) over 10~25 days. Twenty-nine patients were treated with 30 Gy or more. The observed complete response rate was 12.9% and the partial response rate was 61.3%. Median survival time was 8.9 months and the 1-year progression-free survival rate was 12.9%. The treatment response rate was confirmed as a prognostic factor in the rate of survival. The primary site, stage, tumor-volume, radiotherapy field and overall radiation-dose showed a significant relationship with survival and treatment response. No grade 4 toxicity was observed during and after radiotherapy. Conclusion: There was an objective tumor-regression in about 74% of patients treated by hypofractionated radiotherapy. Further evaluation is needed to select the appropriate fraction-size and patient who may require the additional radiotherapy.

• 대한핵의학회:학술대회논문집
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• 1997.05a
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• pp.166-166
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• 1997

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.427.1-427
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• 2002

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2007.05a
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• pp.526-529
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• 2007

본 연구에서는 일정선량(600kGy)에서 전자빔 에너지(0.7, 1, 2 MeV)를 달리하여 조사한 $Ni/g-Al_2O_3$ 촉매를 이용하여 세 가지 다른 종류의 합성가스 전환반응(메탄의 이산화탄소 개질반응, 메탄의 수증기 개질반응, 메탄의 부분산화반응)을 수행하였다. 전자빔 조사는 He 분위기, 실온에서 수행하였으며, 조사된 촉매의 표면상태 변화를 살펴보기 위하여 XRD, XPS 분석을 수행하였다. 고에너지 전자빔 처리된 $Ni/g-Al_2O_3$ 촉매의 표면 특성분석 결과 촉매 표면의 Ni종은 metallic Ni, NiO, $NiAl_2O_4$의 3가지 상태로 존재함을 알 수 있었으며, 전자빔 에너지 증가에 따라 촉매 표면의 전체적인 Ni 함량과 촉매 표면의 Ni 분산도를 나타내는 Ni/Al ratio가 증가하였다. 또한, 전자빔 에너지 증가에 따라 Ni에 결합된 산소가 더 크게 감소되어 표면에서 산소 vacancy가 증가하는 결과를 가져왔으며, 이는 결국 세 가지 Ni의 상태 중 metallic Ni과 $NiAl_2O_4$를 증가시켰다. 이러한 결과들은 메탄의 이산화탄소 개질 반응과 메탄의 수증기 개질반응에서 반응물($CH_4$, $CO_2$)의 전환율과 생성물(CO, $H_2$)의 수득율을 증가시켰으며 메탄의 부분산화반응은 반응의 특성상 메탄의 전환율은 증가하나 생성물인 CO, $H_2$는 오히려 감소하는 결과를 가져옴을 알 수 있었다.

• Progress in Medical Physics
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• v.15 no.2
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• pp.105-111
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• 2004

The parallel plate detector with dielectric film for dosimetry was designed to measure detection characteristic of 6 MV X-ray with medical linear accelerator. PTFE film was inserted into FEP films that are made by two one-side metal coated materials for ion source. The thicknesses of PTFE dielectric film was 100 ${\mu}{\textrm}{m}$ and the thickness of FEP dielectric film was 100 ${\mu}{\textrm}{m}$, respectively. This detector was fixed by two acrylic plate for physical hardness ad geometrical consistency. The geometrical condition for measurement with parallel-plate for detector was below; SSD=100 cm and the 5 cm depth between detector and phantom surface The major parameter of detector characteristics such as zero drift current, leakage current, charge response by applied voltage, reproducibility, linearity, TMR measurement, dose rate effect were measured. The zero drift currents are 8.3 pA and leakage currents are 10 pA. The charge response of applied voltage is showing linearity in 414 voltage. The measurement deviation of reproducibility in this detector is within 1% for dose and the linearity of applied dose shows in this detector. The TMR curves in phantom between this parallel plate detector and reference detector are matched within 3% deviation from maximum dose depth to 7.5 cm depth. It is considered that this dosimetric system is satisfactory for the purpose of the constancy check of the 6 MV x-ray from medical linear accelerator.

• Journal of radiological science and technology
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• v.40 no.1
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• pp.87-92
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• 2017

The weight of small animal dosimetry has been continuously increased in pre-clinical studies using radiation in small animals. In this study, three-dimensional(3D) small animal phantom was fabricated using 3D printer which has been continuously used and studied in the various fields. The absorbed dose of 3D animal phantom was evaluated by film dosimetry. Previously, the response of film was obtained from the materials used for production of 3D small animal phantom and compared with the bolus used as the tissue equivalent material in the radiotherapy. When irradiated with gamma rays from 0.5 Gy to 6 Gy, it was confirmed that there was a small difference of less than 1% except 0.5 Gy dose. And when small animal phantom was irradiated with 5 Gy, the difference between the irradiated dose and calculated dose from film was within 2%. Based on this study, it would be possible to increase the reliability of dose in pre-clinical studies using irradiation in small animals by evaluating dose of 3D small animal phantom.

• Journal of Radiation Protection and Research
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• v.38 no.1
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• pp.44-51
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• 2013

ICRP recommended that cosmic ray exposure to the pilot and cabin crew would be considered as an occupational exposure due to their relatively high exposure. Since 2012 with the Act No. 10908 (Natural radiation management), the guideline of cosmic ray exposure to the pilot was established in Korea. The applicability of the solid-state nuclear track detector for personal dose assessment of pilot and cabin crew was evaluated. Dose linearity and angle dependence of dosimeters to the neutron were evaluated by $^{252}Cf$ neutron emitting source. The track density has a good agreement with the dose ($r^2$=0.99) and highly dependent on the degree of an angular of the dosimeter to the neutron source. In addition, the dosimeters (SSNTD) were exposed to cosmic ray in an aircraft during its cruising for more than two months in collaboration with Airline Pilots Association of Korea. Although the correlation between the track density from aircraft cruising altitude and expected neutron dose is low, however RSNS dosimeter could be used for personal neutron dosimeter. For application of RSNS as a personal dosimeter for pilot and cabin crew, additional studies are required.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.211-216
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• 2022

In radiation therapy, accurate Quality Assurance (QA) is required to irradiate tumor tissue while minimizing damage to normal tissue. Therefore, a dosimeter that can accurately measure radiation is needed. The purpose of this study is to develop a highly efficient radiation dosimeter with high sensitivity by applying a particle in binder method that can reduce manufacturing costs and simplify processes to perovskite materials that are cheaper and simpler to manufacture. By evaluating the response characteristics to high-energy photon, the applicability of QA dosimeter to radiation therapy was evaluated. As a result of reproducibility evaluation, RSD at 6 MV energy was presented as 1.178% and 15 MV energy was presented as 1.141%. As a result of linearity evaluation according to linear regression analysis, R² values of 0.9999 were presented under each condition of 6 MV and 15 MV energy. It was found that the CsPbBr₃ dosimeter manufactured based on the results of reproducibility and linearity evaluation is highly applicable as a QA dosimeter in the field of therapeutic radiation. The CsPbBr₃ dosimeter manufactured in this study presented more than the standard performance in the evaluation of reproducibility and linearity, and it can be used as a radiotherapy QA dosimeter through improvement.

• Nuclear Engineering and Technology
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• v.12 no.1
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• pp.1-8
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• 1980

The grafting studies were concentrated on working out the methodology for radiation of flame retardants to polyester/cotton (65/35) blend fabric. The Fyrol 76 was used as a flame retardant in develping methodology for localizing flame retardants on the surface of the blend fabric. By judicious control of the swelling conditions, time_of contact with the monomer, and dose rate, locating the graft in the fiber became possible. The yield of the graft polymerization was depended upon the total dose and the preswelling conditions. Oxygen Index was used to evaluate the effect of the location of Fyrol 76 and other flame retardants within the surface upon the flame retardance efficiencies. To get a better flame retardance efficiency by :the localized grafting of Fyrol 76 to polyester/cotton blend fabric, a technique of one step processing at room temperature was developed substituting the ordinary two-step processing at high temperature.

• Radiation Oncology Journal
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• v.4 no.1
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• pp.67-73
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• 1986

To access the result of radiation therapy for 8 years experiences, 21 patients who were treated with superior vena cava syndrome had been analysed according to dose fractionation and total dose. The results are as follows; 1. In high fractionate dose group, six of eleven patients $(54.5\%)$ exhibited relief of symptoms in 1-2 days, and additional three patients of nine $(81.7\%)$ within 34 days, while standard fractionated dose treatment is not effective to achieve initial relief of symptoms. 2. Graded response by total dose was correlated with total dose rather than dose fractionation. 3. Overall one year survival rate with superior vena cava syndrome was $9.1\%$ and mean survival was 4.2 months.