• Analytical Science and Technology
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• v.21 no.5
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• pp.403-411
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• 2008

Dimethyldibutyltetradecylmalonamide (DMDBTDMA) extractant was used in a solvent extraction process for a radioactive liquid waste treatment. For the study of radiolysis phenomena, DMDBTDMA was synthesized and the degradation compounds (n-methylbutylamine, tetradecane, 1-tetradecanol) in the DMDBTDMA extractant, irradiated with $^{60}Co$ gamma ray, were identified and determined as radiolysis products by a Fourier transform infrared (FT-IR), gas chromatograph/mass spectrometer (GC/MS) analysis and GC/MS with selected ion monitoring (SIM) mode. Retention behavior of n-methylbutylamine, n-dodecane, tetradecane and 1-tetradecanol in the total ion chromatogram with the standard materials and n-dodecane as the internal standard (ISTD) were 2.35 min., 8.83 min., 10.68 min. and 12.75 min., respectively. In the case of tetradecane, there was a linear relationship between the concentration of the tetradecane and the absorbed dose of the ${\gamma}$-ray irradiated DMDBTDMA.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.1
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• pp.17-23
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• 2009

Dihexyloctanamide(DHOA) was used as an extractant or phase modifier with the diamide extractants in a solvent extraction process for a radioactive liquid waste treatment. The degradation compounds of the DHOA extractant, irradiated with $^{60}Co$ gamma ray, were octanoic acid and dihexylamine which are identified by a Fourier transform infrared(FT-IR) and gas chromatograph/mass spectrometer(GC/MS) analysis, and determined by the GC/MS with selected ion monitoring(SIM) mode. Retention behavior of octanoic acid, tridecane (internal standard) and dihexylamine in total ion chromatogram (TIC) were 8.65 min., 9.79 min., and 10.27 min., respectively. With increasing the absorbed dose of the $\gamma$-ray irradiated DHOA, the concentration of octanoic acid was decreased and that of dihexylamine was increased.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2005.05a
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• pp.373-374
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• 2005

1. 조사량의 증가는 PVA의 분해를 향상시켰다. 2. PVA의 초기 농도가 50 mg/L일 경우 1 kGy에서 99% 이상의 분해효과를 나타내었으며, 250 mgh일 경우 39.2% 의 분해 효과를 나타내어, PVA의 방사선에 의한 분해는 PVA초기농도에 영향을 받고 있음을 알 수 있다. 2. PVA 자체는 방사선에 의해서 효과적으로 분해 되었지만, TOC의 경우 초기농도50mg/L의 PVA를 제외하고는 아주 미비한 제거 효과를 보였다. 하지만 생분해도가 증가함으로써 방사선 처리후 생물학적 처리의 연계는 PVA를 완전히 산화시키기 위한 효과적인 방안이 될 수 있을 것임을 예측할 수 있었다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1252-1256
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• 2004

Radiolytic characteristics of phytic acid by gamma irradiation were investigated, and the antioxidative activity between irradiated phytic acid and commonly used antioxidants including ascorbic acid, tocopherol and butylated hydroxyl anisole (BHA) was evaluated. Phytic acid sodium salt dissolved in a deionized distilled water was irradiated at 0, 5, 10, 15 and 20 kGy. It was found that the level of irradiation had an effects on the degree of degradation. After irradiation, stable DPPH radical scavenging capacity of phytic acid was newly observed, and it was significantly increased by dose-dependent manners (p<0.05). Antioxidant activity of phytic acid in the oil models was higher than that of the other antioxidant during storage, and phytic acid (400 $\mu\textrm{g}$/mL) irradiated at 20 kGy especially showed the highest antioxidative ability among the antioxidants tested during 3 weeks. Results indicated that irradiation induced the radiolysis of phytic acid in an aqueous model system, and the antiradical and antioxidative activities of irradiated phytic acid increased.

• Radiation Oncology Journal
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• v.21 no.1
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• pp.10-18
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• 2003

Purpose : To evaluate the role of fractlonated sterotactic radiotherapy (FSRT) in the management of benign brain tumors, we reviewed the clinical, and radiographic responses of patients treated. Methods and Materials : Between March 1995 and March 2002, 36 patients with benign brain tumors were treated by FSRT. The pathological diagnoses consisted of pituitary adenomas (12 patients), cranio-pharyngiomas (5 patients), meningiomas (10 patients), and acoustic neurinomas (9 patients). Radiotherapy doses of 25 to 35 Gy (3~6 Gy/fraction, 5~10 fractions) were prescribed to the 85~90% isodose line, depending upon the location, size and volume of the tumors. The median clinical and radiographical follow up periods were 31 (range, 2~74) and 21 (range, 4~56) months, respectively. Results : In the 35 patients that could be evaluated for their clinical response, 13 (37.1%) were considered improved, 16 (45.7%) stable and 6 (17.2%) worse. Of the 33 patients who had radiographic studies, tumor shrinkage was noted in 17 (51.5%), tumor stabilization in 13 (39.4%), and tumor progression in 3 (9.1%). Of the 17 tumor shrinkage patients, 7 (21.2%) showed a complete response. Acute radiation-induced complications occurred iin 11 (30.6%) patients. Conclusions : FSRT is considered a safe and effective treatment method for begin brain tumors, but large numbers of patients, with relatively long follow-up periods are needed to assess the exact role or effect of FSRT.

• Radiation Oncology Journal
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• v.10 no.1
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• pp.15-20
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• 1992

A total of 20 patients (male: female=10:10, adult:children=8:12) with brainstem tumors had been received radiation therapy in the Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine between 1980 and 1990. Thirteen of 20 patients were treated with conventional radiation therapy (before 1989, 180~200 cGy per fraction, 5 days a week, total dose 4680~5400 cGy), and seven patients were treated with hyperfractionated radiation therapy (in 1990, 100 cGy per fraction, twice daily 10 fractions a week, total dose 7200 cGy). Median follow up Periods for conventional radiation therapy group and hyperfractionated radiation therapy group were 36 months and 10 months, respectively. Four of 20 Patients had histopathologic diagnosis prior to treatment; 3 cases were low grade astrocytoma and 1 case was high grade astrocytoma. Overall 2-year actuarial survival rate was 30%. The prognosis of patients with a longer duration of symptom and sign was better (60%, vs 12%), and the adult (52%) was better than children (14%). There was no significant difference between the focal (29%) and diffuse (26%) type. The initial clinical response was better in the hyperfractionated radiation therapy group. Because of the relatively small number of Patients and short follow up Period in hyperfractionated radiation therapy group, there was no comparison between two group.

• Radiation Oncology Journal
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• v.12 no.1
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• pp.9-16
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• 1994

Hypothesis that hypoxic tumors should be more responsive to the addition of preferential hypoxic cell cytotoxin SR 4233 (tirapazamine) to fractionated irradiation was tested in the mouse SCCVll carcinoma and RIF-1 sarcoma, Model of hypoxic tumor was established using the tumor bed effect: tumors growing in the preirradiated tissue (preirradiated tumors) were more hypoxic than tumors growing in the unirradiated tissue (unirradiated tumors). When the tumors reached a mean volume of 100 $mm^{3}$, both unirradiated and preirradiated tumors were treated with a fractionated course of 6${\times}$2 Gy in 3 days or 8${\times}$2.5 Gy in 4 days with SR 4233 (0.08 mmol/kg/injection) given 30 minutes before each irradiation or without SR 4233. Compared to the unirradiated tumors, hypoxic preirradiated tumors were approximately 5 times more resistant to fractionated irradiation alone but were approximately 5 times more responsive to SR 4233. Addition of SR 4233 Potentiated the effect of fractionated irradiation in both unirradiated and preirradiated tumors. Potentiation in the preirradiated tumors was morequal to or greater than that in the unirradiated tumors and seemed to be higher for more fractionated treatment. We confirm the hypothesis in a transplantable mouse tumor. Present results suggest that radioresistance of some hypoxic tumors can be overcome with hypoxic cytotoxin.

• Radioisotope journal
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• v.20 no.2
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• pp.20-24
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• 2005

• 대한방사선방어학회:학술대회논문집
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• 2011.04a
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• pp.166-167
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• 2011

• 대한방사선방어학회:학술대회논문집
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• 2010.04a
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• pp.182-183
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• 2010