• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.571-575
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• 2006

To improve economic of solar power generation, stirling engine is required continuous operation and the receiver has to be provided with an additional combustion system. The hybrid receiver with a specially adapted combustion system is possible to 24 hr/day operation by solar and gas-fired. The inner cavity and external wall serve as absorber surfaces using collected irradiation and heat transfer surfaces for the gas heat flow, respectively. The hybrid receiver was designed and fabricated for the dish/stirling system. The analytical method for pridicting natural convective heat loss from receiver is used. The Koenig and Marvin model is used to estimate convection heat loss and heat transfer coefficiency.

• Bulletin of the Korean Chemical Society
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• v.5 no.6
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• pp.219-223
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• 1984

The 8-methoxypsoralen$<^{4',5'}_{5',6}>$ thymidine monoadducts are isolated from the irradiation mixture of 8-methoxypsoralen and thymidine in a dry film state by a flash column followed by lobar column chromatography. Some physical properties of the adducts were determined. The fluorescence maximum and quantum yield of the monoadduct are dependent on the solvent polarity and the phosphorescence to fluorescence quantum yield ratio was 2.10 which was significantly increased by external heavy atoms. The phosphorescence lifetime was 1.2s which is relatively large compared to other coumarin derivatives. Accurate spectral data of the monoadducts are presented.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.469-475
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• 1998

Purpose : To determine the role of Pelvic irradiation in stage I or IIA cervical carcinoma with pelvic nodal metastasis after hysterectomy and bilateral pelvic lymphadenectomy. Materials and Methods : This is a retrospective study of 68 cervical carcinoma patients who were found to have pelvic nodal metastasis at hysterectomy and received pelvic irradiation from 1983 to 1996 at Inje University Seoul Paik Hospital. External beam radiation therapy to pelvis was delivered using 4 MeV Linac and intracavitary irradiation was given via vaginal ovoids or cylinders. Five-year survival and disease-free survival were estimated by Kaplan-Meier Method and prognostic factors related to survival were analysed by log-rank test and Cox proportional hazards regression model. Results : Median length of follow-up was 52months. Five-year overall survival and disease-free survival (DFS) were 81.8$\%$ and 81.7$\%$ respectively. Patients with endometrial invasion had a 57.1$\%$ 5-year DFS compared to 87.5$\%$ for those without endometrial invasion (p=0.0074). Multivariate analysis revealed endometrial invasion as an only statistically significant prognostic factor for 5-year DFS. Among total 15 (22$\%$) recurrences. pelvic recurrences occurred in 4 cases and distant metastases occurred in 13 cases. Conclusion : We have been able to confirm previous results demonstrating marked decrease in local recurrence after pelvic irradiation. In view of the high proportion of distant metastasis found in this study, a trial of aggressive adjuvant systemic therapy and irradiation in early stage cervical carcinoma patients with pelvic nodal metastasis, especially with endometrial invasion, appears to be warranted.

• Radiation Oncology Journal
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• v.11 no.2
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• pp.267-275
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• 1993

Eighty five patients of oral cavity cancer, treated with radiation at the Department of Therapeutic Radiology, Korea Cancer Center Hospital, during the period from March 1985 to September 1990 were analyzed retrospectively. Among 85 patients, 37 patients were treated with radiation only and 48 patients were treated with radiation following surgery. And 70 patients received external irradiation only by $^{60}Co$ with or without electron, the others were 7 patients for external irradiation plus interstitial implantation and 8 patients for external irradiation plus oral cone electron therapy. Primary sites were mobile tongue for 40 patients, mouth floor for 17 patients, palate for 12 patients, gingiva including retromolar trigone for 10 patients, buccal mucosa for 5 patients, and lip for 1 patient. According to pathologic classification, squamous cell carcinoma was the most common (77 patients). According to AJC TNM stage, stage I + II were 28 patients and stage III+IV were 57 patients. Acturial overall survival rate at 3 years was $43.9\%,$ 3 year survival rates were $60.9\%$ for stage I + II, and $23.1\%$ for stage III+IV, respectively. As a prognostic factor, primary T stage was a significant factor (p<0.01). The others, age, location, lymph node metastasis, surgery, radiation dose, and cell differentiation were not statistically significant. Among those factors, radiation plus surgery was more effective than radiation only in T3+T4 or in any N stage although it was not statistically sufficient (p<0.1). From those results, it was conclusive that definitive radiotherapy was more effective than surgery especially In the view of pertainig of anatomical integrity and function in early stage, and radiation plus surgery was considered to be better therapeutic tool in advanced stage.

• Radiation Oncology Journal
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• v.13 no.4
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• pp.377-383
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• 1995

Purpose : To obtain the optimal treatement method in patients with endometrial carcinoma(clinical stage FIGO I, II) by comparative analysis between preoperative radiotherapy (pre-op RT) and postoperative radiotherapy (post-op RT). Material and Methods : A retrospective review of 62 endometrial carcinoma patients referred to the Yonsei Cancer Center for radiotherapy between 1985 and 1991 was undertaken. Of 62 patients, 19 patients(Stagel : 12 patients. Stagell;7 patients) received pre-op RT before TAH(Total Abdominal Hysterectomy) and BSO (Bilateral Salphingoophorectomy) (Group 1) and 43 patients(Stage 1;32 patients, Stage 2; 11 patients) received post-op RT after TAH and BSO (Group 2). Pre-op irradiation was given 4-6 weeks prior to surgery and post-op RT administered on 4-5 weeks following surgery. All patients except 1 patient(Group 2: ICR alone) received external irradiation. Seventy percent(13/19) of pre-op RT group and 54 percent(23/42) of post-op RT group received external pelvic irradiation and intracavitary radiation therapy(ICR). External radiation dose was 39.6-55 Gy(median 45 Gy) in 5-6. 5weeks through opposed AP/PA fields or 4-field box technique treating daily, five days per week, 180 cGy per fraction. ICR doses were prescribed to point A(20-39.6 Gy, median 39 Gy) in Group 1 and 0.5cm depth from vaginal surface (18-30 Gy,median 21 Gy) in Group 2. Results : The overall 5 year survival rate was $95{\%}$. No survival difference between pre-op and post-op RT group.($89.3{\%}$ vs $97.7{\%}$, p>0.1) There was no survival difference by stage, grade and histology between two groups. The survival rate was not affected by presence of residual tumor of surgical specimen after pre-op RT in Group 1 (p>0.1), but affected by presence of lymph node metastasis in post-op RT group(P<0.5). The complication rate of pre-op RT group was higher than post-op RT. ($16{\%}$ vs $5{\%}$) Conclusion : Post-op radiotherapy offers the advantages of accurate surgical-pathological staging and low complication rate.

• Radiation Oncology Journal
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• v.11 no.2
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• pp.355-361
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• 1993

Since May 1991, authors have conducted a pilot study to determine the feasibility and evaluate the effect of concurrent radiation therapy and chemotherapy with 5-FU and Cis-platinum for locally advanced cervical cancer (stage IIB-IVA). Radiation therapy consisted of external irradiation to whole pelvis (4140 cGy/23 fx) in 4.5 weeks followed by high dose rate intracavitary radiation therapy (HDR ICRT) to deliver a dose of 30 to 35 Gy to A point in 6 to 7 fractions. After the intracavitary radiation therapy, parametrial boost was delivered for B point dose of 60 Gy in Stage IIB and 65 Gy in stage IIIB. 5-FU (1000 $mg/m^2/24hr$ for 96 hour iv infusion) and Cis-platinum (20 $mg/m^2/day$ IV bolus for 3 days) were given during the second week of external RT and the second course chemotherapy administered at the first HDR ICRT with the same method as the first chemotherapy. Sixteen patients (10 stage IIB,4 stage IIIB,2 stage IVA) were registered to this protocol. Among these 16 patients, two refused treatment after 2 fractions of external irradiation, and one could not continue intracavitary irradiation because of treatment related genitourinary toxicity. So 14 patients were evaluated for toxicity and 13 patients were evaluated for response analysis. Five of 14 patients developed grade 3 gastrointestinal toxicity but 4 of them recovered at the completion of treatment. One stage IIIB patient with inguinal lymph node metastasis who received higher dose of radiation in spite of initial poor performance status did not recover from gastrointestinal toxicity at the completion of treatment. And she died of distant metastasis at one month after the completion of treatment. Two of 14 evaluable patients showed weight loss, more than $10\%$ of initial weight. One patient developed grade 3 leukopenia. In this study, the average total treatment period of completely treated patients was 75 days and three of them took more than 80 days (84, 84, 89 days). Toxicities were generally acceptable and there were no treatment related death. At the last follow-up, complete response was achieved in $62\%(8/13)$ and especially of nine patients with stage IIB, eight patients showed complete response. This study suggests that concurrent radiation therapy and chemotherapy (5-FU and Cis-platinum) is tolerable and effective. Further follow-up is needed to determine whether this protocol will have a favorable impact on survival and to evaluate the late effect on normal tissues. In future, prospective randomized trials are needed to compare the standard radiation therapy alone with concurrent chemotherapy and radiation therapy for locally advanced cervical carcinoma.

• Journal of radiological science and technology
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• v.41 no.2
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• pp.157-162
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• 2018

This study is a search for radiation protection effects of radiation exposure on the organogenic period during the prenatal period, which is known to be the most likely to have congenital malformations by radiation exposure. To study the radiation protection for the mixture of selenium that is strong antioxidant and folic acid that is essential vitamin for DNA synthesis, 2 Gy of radiation was irradiated to pregnant female rats. then, after 14 days of fetal birth, observing blood components, SOD(Superoxide Dismutase), histological changes and external malformations. There was a significant protective effect to reduce blood cell damage(p<0.05) in the irradiation group after selenium and folic acid mixture were administered than irradiation group, and the activation of SOD which is antioxidant enzymes was increased. In addition, confirmed the effect of suppressing the expression of apoptosis of small intestinal cells and the reduction of cerebral cortex layer reduction by radiation. thus, it was confirmed that the congenital malformations were reduced as a result of these protective effects. Based on these results, selenium and folic acid mixture may reduce the incidence of congenital malformations, and it will reduce the damage of the fetus caused by the exposure of the organogenic period due to accidents.

• Radiation Oncology Journal
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• v.12 no.3
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• pp.369-376
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• 1994

This is a retrospective analysis of 64 patients who was treated with postoperative radiation therapy after radical hysterectomy and bilateral pelvic lymphadenectomy (53 patients) or total abdominal hysterectomy(11 patients) for uterine cervix cancer between May 1980 and September 1991 at the Department of Radiation Oncology, Kyung Hee University Hospital. Most patients were FIGO IB (31 Patients) and IIA (25 patients), and median period of follow-up was 5.1 years. Of these patients,24 received adjuvant whole pelvis irradiation of 6000 cGy and 40 received 5000-5500 cGy whole pelvis irradiation and/or intracavitary radiation (7 Patients). The actuarial overall and relapse free 5 year survival rate were $71.0\%$, $68.3\%$ respectively. The survival rates by stage were $79.1\%$ in stage I, and $61.2\%$ in stage II. Treatment failure was noted in 18 of 64 patients ($28.1\%$), Iocoregional failure in 8 ($12.5\%$), distant metastasis in 8 ($12.5\%$), paraaortic node metastasis in 1 and one patient and concurrent locoregional and distant metastasis. The univariate analysis of prognostic factors affecting to overall survival rate represented lymph node status, the number and site of metastatic lymph node, parametrial invasion, the thichness of cervical wall invasion, and size of cancer mass. Histology, vessel invasion, endometrial extension, hemoglobin level. resection margin status, age, radiation dose were not significant prognostic factors. Complication relating to operation and postoperative radiation were variable according to radiation therapy method: 6000 cGy RT group 8/24($33.3\%$), 5000-5500 cGy+ICR 3/7 ($42.9\%$), 5000-5500 cGy external RT only group 3/33 ($9.1\%$). In conclusion, the results suggest that postoperative radiotherapy is necessary in high risk patients for locoregional control and improving survival rate, and higher dose does not improve results but only increases complication.

• Korean Journal of Head & Neck Oncology
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• v.18 no.1
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• pp.46-49
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• 2002

Background: Free flaps have become a very important role in the ablative head and neck surgery with functional preservation of defect sites. The forearm free flap has many advantage of lack of bulk, ease of dissection, vascularity, and malleability. Patients and Methods: A review of 51 radial forearm free flaps performed between may 1990 and feburary 2001 at the Korea University was undertaken to determine outcome. Patient age ranged 27 to 72 years (mean 56). There were 44 men and 7 women. The most prevalent neoplasm was squamous cell carcinoma. Results: The tans verse cervical artery and the external jugular vein were the most frequent receipient sites for microvascular anastomosis. Total flap loss occurred in 2 cases (4%) and other complications were seen in 42%. Fifteen patients received preoperative irradiation and the complication was higher than non-irradiation patients, but statistically not significant. Conclusion: The radial forearm free flap offers a variety of reconstructive options for head and neck. Its low flap loss and complication rates offer the best choice for reconstruction of defect of head and neck malignancy.

• Rapid Communication in Photoscience
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• v.3 no.1
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• pp.25-27
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• 2014

The relative importance of radiation dose, storage time, and temperature in radiation processing of spinach (Spinacia oleracea L.), was evaluated in terms of the postharvest quality through a model study using leaf disks. Physiological activity and chlorophyll and carotenoid contents were measured to represent the postharvest quality (in terms of external appearance) of spinach, a leafy green vegetable. At $22^{\circ}C$ and $30^{\circ}C$, the higher gamma-radiation dose caused a greater decrease in the physiological activity, depending on the storage time of 4 d. However, this decrease was not significant at $4^{\circ}C$ and $15^{\circ}C$. Total chlorophyll and carotenoid contents were substantially decreased by 3 kGy at $15^{\circ}C$, and dose-dependently by 0.5-3 kGy at $22^{\circ}C$. In contrast, the proportion of lutein in total carotenoid was significantly increased in the 2-3-kGy samples only at $22^{\circ}C$, while that of ${\beta}$-carotene was slightly decreased, indicating progression of leaf aging. These data suggest that the unfavorable effect of gamma irradiation on the postharvest quality of spinach could be avoided or controlled by the storage time or temperature rather than the radiation dose. The current study could be available to improve radiation processing of other leafy green vegetables.