• Korean journal of food and cookery science
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• v.24 no.1
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• pp.106-113
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• 2008

This study investigated the effects of gamma irradiation on microbial, physical, and sensory qualities as well as the antioxidant activity of cooked spinach. At 3 kGy of gamma irradiation, microbial growth was inhibited until 4 weeks and 5 days at storage temperatures of 4 and $25^{\circ}C$, respectively. The dose of 2 kGy did not significantly affect hardness; however, Hunter color system values for lightness, redness, and yellowness were changed. Low dose gamma-irradiation (up to 2 kGy) did not significantly affect the antioxidant activity of the cooked spinach. Also, based on a triangle sensory test, the gamma-irradiated cooked spinach was not significantly different from the control. These results, suggest that applying gamma irradiation to cooked vegetables at doses lower than 2 kGy can be recommended to extend shelf-life and maintain quality.

• Korean Journal of Food Science and Technology
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• v.15 no.3
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• pp.231-237
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• 1983

In order to develop the commercial storage method of chestnut by irradiation combined with natural low temperature, a chestnut variety Ok-gwang was stored in a natural low temperature storage room ($450{\times}650{\times}250$ cmH; year-round temperature change, $2-17^{\circ}C$; R.H., 80-85%) on batch scale followed by irradiation with optimum dose level. Sprouting rate of chestnut was 100% after seven month storage in control whereas that of 20-25 Krad irradiated group was only 5-15%. In comparison of rotting rate, weight loss and texture, 25 Krad irradiated group was better than that of control. Moisture and reducing sugar were increased in contrast with the decrease of total sugar during nine month storage and these changes were more remarkable in control. Ascorbic acid content was slightly decreased both in control and irradiated group; more decrement was noticed in control.

• Journal of dental hygiene science
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• v.5 no.3
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• pp.105-112
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• 2005

In spite of relatively low level of radiation dose used at dental clinics, long term exposure may be harmful, so radiation workers at dental clinics must be well aware of its danger. This study was to analyze the factors to have an influence on safety management behavior in the radiography chamber by understanding the relationship among the knowledge, attitudes and behavior in regard with radiation safety management by dental hygienists in order to take preventive measures for dental hygienists and suggest ideas to develop radiation safety training programs. For this, we contacted dental hygienists working at the local dental clinics for 4 months from December of 2003 to march of 2004 and obtained the following findings. 1. Concering the knowledge level of radiation safety management, $8.59{\pm}2.36$ was average score with the highest of 13 and the lowest of 3 from 15-scale test. In addition, knowledge level of radiation safety management by general characteristics showed statistically significant difference according to working experience (p < 0.001), marital status (p < 0.001), attendance rate of radiation safety management training program (p < 0.001), and type of clinic (p < 0.001). 2. Concering the attitude level of radiation safety management, $4.08{\pm}0.50$ is average score with the highest of $4.31{\pm}0.73$ and the lowest of $3.82{\pm}0.89$ by item from 5-scale test. Besides, attitude level of radiation safety management by general characteristics showed statistically significant difference according to age (p < 0.001), working experience (p < 0.05), attendance rate of radiation safety management training program (p < 0.01), and type of clinic (p < 0.001). 3. Concering the behavior level of radiation safety management, $2.89{\pm}0.77$ is average score from 5-scale test, which was relatively low in comparison with the level of attitude and the highest score was $3.82{\pm}0.94$ and the lowest $2.37{\pm}1.04$ by item. Behavior level of radiation safety management by general characteristics showed statistically significant difference according to working experience (p < 0.001) and type of clinic (p < 0.001). 4. From the survey of relationship among knowledge, attitude and behavior of radiation safety management was, we found that the higher the knowledge level of radiation safety management, the higher the level of attitude and behavior, and the higher the attitude level was, the higher the level of behavior.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.583-592
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• 2018

In this study, plans to apply 3D conformal radiotherapy, intensity modulated radiotherapy, and volumetric intensity modulated arc radiotherapy to esophageal cancer radiotherapy were compared. In particular, arc therapy was applied to reduce irradiated volume and spread of low-dose during intensity modulated radiation therapy and volumetric intensity modulated arc radiotherapy by limiting part of irradiated angle, in order to compare target doses and dose for surrounding normal tissues of the two methods and those of 3D conformal radiotherapy. No significant difference in target dose was found among the three methods. The 5 Gy volume(V5) of the lung showed 56.53% of conformal radiotherapy, 52.03% of intensity modulated radiotherapy, and 47.84% of volumetric modulated arc therapy(CRT-IMRT p=0.035, CRT-VMAT p<0.001, IMRT-VMAT p<0.001). The 10 Gy volume(V10) showed a significant difference in conformal radiotherapy 35.12%, intensity modulated radiotherapy 34.04%, and volumetric modulated arc radiotherapy 33.28%, showing significant difference in intensity modulated radiotherapy(p=0.018), volumetric modulated arc therapy(p=0.035), no significant difference in dose was found at 20 Gy volume. The mean dose and 20 Gy volume of the heart were not significantly different according to the treatment plan, but the 30 and 40 Gy volumes were 37.16% and 22.46% in the volumetric modulated arc radiotherapy, showing significant differences(p=0.028) in comparison with conformal radiotherapy. It is believed that, by limiting part of the irradiated angle during intensity modulated radiotherapy and volumetric intensity modulated arc radiotherapy, the irradiated volume and, thereby, the 5-10 Gy area and toxicity of the lung can be reduced while maintaining dose distribution of the target dose.

• Progress in Medical Physics
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• v.26 no.2
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• pp.93-98
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• 2015

The purpose of this study is to see the usefulness of lead apron for critical organs near the breast under examining. For clinical experiment, 30 female volunteers who agreed to their participation in the experiments, were chosen and divided into two groups, 15 in group A and 15 in group B respectively. group A is to see whether each side of breast under mammography affects to other side glandular on the critical organs is same, because it is not allowed to scan the both breast for same person or to scan repeatedly. Group B is to see the effectiveness of lead apron during the mammography of right breast. Glass dosimeters were placed on the thyroid, the contralateral breast, and lower abdomen where near the breast during examining. The average glandular doses on the surface in mammography of the thyroid gland, the contralateral breast, the lower abdomen were 0.0692 mGy, 0.6790 mGy, and 0.0122 mGy, respectively, which was an extremely low level of glandular dose. In group B, as to the thyroid gland, average dose was decreased from 0.0922 mGy to 0.0158 mGy. The average dose of contralateral breast was decreased from 0.8575 mGy to 0.0286 mGy. The average doses of lower abdomen was decrease 0.0150 mGy to 0.0173 mGy. As to the lower abdomen, dose decreased from 0.0150 mGy before the use of an apron down to 0.0173 mGy after the use. As p-value was under 0.05, statistically significant difference was observed between the two groups. Wearing an apron can have the protective effects on the thyroid gland up to 20 times lower than not wearing one. Besides, it is also necessary to protect the other breast during the examination by wearing one.

• Journal of Radiation Protection and Research
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• v.39 no.1
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• pp.38-45
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• 2014

This paper describes the results of assessment of radiological dose resulting from operation of the Daedeok nuclear facilities including the HANARO research reactor, which has been performed to assure whether or not to comply with the regulation standards of the radioactive effluents releases. Based on the meteorological data and the radiation source term, the maximum individual doses were evaluated from 2010 to 2012. The atmospheric dispersion and the deposition factors of gaseous effluents were calculated using the XOQDOQ computer code. ENDOS-G and ENDOS-L code systems were also used for maximum individual dose calculation from gaseous and liquid effluents, respectively. The results were compared with the regulation standards for the radioactive effluents presented by the Nuclear Safety and Security Commission (NSSC). The effective doses and the thyroid doses of the maximum individual were calculated at the maximum exposed point in the Daedeok site, and contributions of exposure pathways to the radiological doses resulting from gaseous and liquid radioactive effluents were evaluated at each facility of the Daedeok site. As a result, the maximum exposed age was analysed to be the child group, and the operation of HANARO research reactor had a major effect more than 90% on the individual doses. The main exposure pathways for gaseous radioactive effluent were from ingestion and inhalation. The effective doses and the thyroid doses were considerably influenced by tritium and iodine, respectively. The gaseous radioactive effluents contributed more than 90% on the total doses, whereas the contributions of the liquid radioactive effluents were relatively low. Consequently, the maximum individual dose due to radioactive effluents from the nuclear facilities within the Daedeok site were less than 3% of the regulation standard over 3 years; therefore, it can be concluded that radioactive effluents from the nuclear facilities were well managed, with the radiation-induced health detriment for residents around the site being negligible.

• Progress in Medical Physics
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• v.15 no.2
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• pp.94-99
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• 2004

Radiochromic film has several advantages; high spatial resolution, relatively low spectral sensitivity, near tissue equivalence and requires no special development procedure. The object of this study was to measure the anisotropy of an Ir-192 source (microSelectron manufactured by Nucletron) in a few mm regions from the source, using the GafChromic film. The GafChromic film was calibrated in the range of 0∼105 Gy, using a 4 MV photon beam, and the anisotropy function measured in an acrylic phantom using the GafChroimic film. The data obtained gave agreement to within 4.4% of the Monte Calro calculation, by J. F. Williamson, at a radial distance of 2.5 mm with polar angles of 50 to 130$^{\circ}$, while a maximum deviation of 17.6% was observed at angles near 140$^{\circ}$and agreement within 3.7% at a radial distance of 5 mm at polar angles between 35 to 150$^{\circ}$ and a maximum deviation of 7.6% was observed at angles near 30$^{\circ}$. A GafChromic film can be used as a more efficient detector for measuring the anisotropy of an HDR $^{192}$ Ir source at close distances than any other detector.

• Food Science of Animal Resources
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• v.29 no.1
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• pp.34-39
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• 2009

The objective of this study was investigated to apply the fucoidan and laminarin extract from low-grade Undaria pinnatifida to real food product, a pork patty. Pork patties added with fucoidan and laminarin showed lower lipid oxidation and the inhibition against lipid oxidation was shown to be dependent on the irradiation doses. The Hunter color values of pork patty added with fucoidan increased significantly with an increase of irradiation dose. The hardness profiles of the patties with fucoidan and laminarin was decreased, but the amount of water in the patties was increased. Also, the combination of gamma irradiation and addition of fucoidan and laminarin was shown to be effective for the microbiological control. These results suggested that gamma irradiation and fucoidan and laminarin treatment showed the positive effect on microbial stability and quality of the pork patty.

• Radiation Oncology Journal
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• v.34 no.1
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• pp.45-51
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• 2016

Purpose: The aim of this work was to assess the efficacy and tolerability of hypofractionated intensity-modulated radiotherapy (IMRT) in patients with localized prostate cancer. Materials and Methods: Thirty-nine patients who received radical hypofractionated IMRT were retrospectively reviewed. Based on a pelvic lymph node involvement risk of 15% as the cutoff value, we decided whether to deliver treatment prostate and seminal vesicle only radiotherapy (PORT) or whole pelvis radiotherapy (WPRT). Sixteen patients (41%) received PORT with prostate receiving 45 Gy in 4.5 Gy per fraction in 2 weeks and the other 23 patients (59%) received WPRT with the prostate receiving 72 Gy in 2.4 Gy per fraction in 6 weeks. The median equivalent dose in 2 Gy fractions to the prostate was 79.9 Gy based on the assumption that the ${\alpha}/{\beta}$ ratio is 1.5 Gy. Results: The median follow-up time was 38 months (range, 4 to 101 months). The 3-year biochemical failure-free survival rate was 88.2%. The 3-year clinical failure-free and overall survival rates were 94.5% and 96.3%, respectively. The rates of grade 2 acute genitourinary (GU) and gastrointestinal (GI) toxicities were 20.5% and 12.8%, respectively. None of the patients experienced grade ${\geq}3$ acute GU and GI toxicities. The grade 2-3 late GU and GI toxicities were found in 8.1% and 5.4% of patients, respectively. No fatal late toxicity was observed. Conclusion: Favorable biochemical control with low rates of toxicity was observed after hypofractionated IMRT, suggesting that our radiotherapy schedule can be an effective treatment option in the treatment of localized prostate cancer.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.547-553
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• 2017

In the current medical field, lead is widely used as a radiation shield. However, the lead weight is very heavy, so wearing protective clothing such as apron is difficult to wear for long periods of time and there is a problem with the danger of lethal toxicity in humans. Recently, many studies have been conducted to develop substitute materials of lead to resolve these problems. As a substitute materials for lead, barium(Ba) and iodine(I) have excellent shielding ability. But, It has characteristics emitting characteristic X-rays from the energy area near 30 keV. For patients or radiation workers, shielding materials is often made into contact with the human body. Therefore, the characteristic X-rays generated by the shielding material are directly exposured in the human body, which increases the risk of increasing radiation absorbed dose. In this study, we have developed the FLUKA transport code, one of the most suitable elements of radiation transport codes, to remove the characteristic X-rays generated by barium or iodine. We have verified the reliability of the shielding fraction of the structure of the structure shielding by comparing with the MCPDX simulations conducted as a prior study. Using the MCNPX and FLUKA, the double layer shielding structures with the various thickness combination consisting of barium sulphate ($BaSO_4$) and bismuth oxide($Bi_2O_3$) are designed. The accuracy of the type shown in IEC 61331-1 was geometrically identical to the simulation. In addition, the transmission spectrum and absorbed dose of the shielding material for the successive x-rays of 120 kVp spectra were compared with lead. In results, $0.3mm-BaSO_4/0.3mm-Bi_2O_3$ and $0.1mm-BaSO_4/0.5mm-Bi_2O_3$ structures have been absorbed in both 33 keV and 37 keV characteristic X-rays. In addition, for high-energy X-rays greater than 90 keV, the shielding efficiency was shown close to lead. Also, the transport code of the FLUKA's photon transport code was showed cut-off on low-energy X-rays(below 33keV) and is limited to computerized X-rays of the low-energy X-rays. But, In high-energy areas above 40 keV, the relative error with MCNPX was found to be highly reliable within 6 %.