• Journal of the Korean Society of Radiology
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• v.14 no.2
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• pp.105-109
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• 2020

Intensity-modulated radiotherapy(IMRT) has disadvantages such as increasing the low doses of irradiation to normal tissues and accumulated dose for the whole volume by leakage and transmission of the Multi Leaf Collimator (MLC). The accumulated dose and low dose may increase the occurrence of secondary malignant neoplasms. For this reasons, the jaw tracking function of the TrueBeam (Varian Medical Systems, Palo Alto, CA) was developed to reduce the leakage and transmission dose of the MLC with existing linear accelerators. But quantitative analysis of the dose reduction has not been verified. Therefore, in the present study, we intended to verify the clinical possibility of utilizing the jaw tracking function in brain tumor with comparison of treatment plans. To accomplish this, 3 types of original treatment plans were made using Eclipse11 (Varian Medical Systems, Palo Alto, CA): 1) beyond 2 cm distance from the Organs At Risk (OARs); 2) within 2 cm distance from the OARs; and 3) intersecting with the OARs. Jaw tracking treatment plans were also made with copies of the original treatment planning using Smart LMC Version 11.0.31 (Varian Medical Systems, Palo Alto, CA). A comparison between the 2 types of treatment planning methods was performed using the difference of the mean dose and maximum dose to the OARs in cumulative Dose Volume Histogram (DVH). In the DVH comparison, the maximum difference of 0.5 % was observed between the planning methods in the case of over 2 cm distance, and the maximum of 0.6 % was obtained for within the 2 cm distance. For the case intersecting with the OAR, the maximum difference of 2 % was achieved. According to these results, it could be realized that the differences of mean dose and maximum dose to the OARs was larger when the OARs and PTV were closer. Therefore, treatment plans with the jaw tracking function consistently affected the dose reduction and the clinical possibility could be verified.

• Food Science and Preservation
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• v.18 no.3
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• pp.294-301
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• 2011

The aim of this study was to investigate the changes in identification markers of irradiated foods after treatment of the full-overlapped gravitational field energy (FGFE). Wheat and soybean samples were irradiated at 0-5 kGy of Co-60 gamma energy, and analyzed for photostimulated and thermo luminescence characteristics (PSL and TL) and sprouting rate at 0 and 6th month after FGFE treatment. As a screening method for irradiated samples, PSL photon counts (PCs) for the non-irradiated samples appeared negative (<700 PCs), while irradiated samples gave positive (>5,000 PCs). But FGFE-treated irradiated samples appeared intermediate (700-5,000 PCs), showing decreased PCs during storage. The TL analysis on irradiated samples exhibited glow curve peaks in range of $150-200^{\circ}C$ and TL ratio ($TL_1/TL_2$) was also >0.1. Therefore, identification of irradiated samples was possible using thermoluminescence. But the glow curve range of FGFE-treated irradiated samples shifted from $150-200^{\circ}C$ to $180-230^{\circ}C$ and TL intensity was decreased 37-60% resulting from FGFE treatment. After 6 months of storage, all the samples showed a decrease in TL intensity, but identification was still possible. The sprouting rate of irradiated samples decreased by about 72%, whereas that of FGFE-treated irradiated samples showed by about 85%, as compared to non-irradiated samples. More detailed study is required to investigate sprouting phenomena for FGFE-treated samples.

• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.258-266
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• 2013

This study was conducted to determine the PSL and TL properties of foods irradiated with electron beam and gamma-ray. 5 kinds of food including cereal, pulse, fish powder, dried vegetable and tea were irradiated at 0 to 10 kGy by electron beam accelerator or $^{60}Co$ gamma-ray irradiator. The PSL analysis showed negative results for most of the non-irradiated samples. Non-irradiated shrimp powder showed intermediate result. Irradiated samples gave negative or intermediate or positive value which presented the limitation of PSL technique. In TL analysis, there were TL glow curves at around $300^{\circ}C$ with low intensity on non-irradiated samples. Maximum peak in the range of $150-250^{\circ}C$ was appeared on irradiated samples. TL ratio obtained by re-irradiation with 1 kGy was less than 0.1 on non-irradiated samples and higher than 0.1 on irradiated samples. Therefore, in PSL measurement, electron-beam irradiated samples could obtain more clear results. TL analysis showed obvious difference between non-irradiated and irradiated samples. But the identification was impossible for the sample of rice and lemon tea. Because of it's low contents of mineral.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.211-217
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• 1997

The physical and chemical stability of anthocyanins from a Korean pigmented rice variety was investigated at various conditions of pH, temperature, metal ion, sugar, organic acid and light. The anthocyanin pigments were relatively stable with half-lives of 36 days (pH 2.0) and 17 days (pH 3.0), while they were decomposed in a day at neutral and basic pH of 7.0 and 9.0 at $25^{\circ}C$. The anthocyanins also showed high thermal stability at pH 3.0; the half-lives were 7.4 hr, 23.6 hr and 96.3 hr at $95^{\circ}C,\;75^{\circ}C\;and\;50^{\circ}$, respectively. Addition of di- and tri-valent metal ions at pH 3.0 resulted in the increase of color intensity and stability throughout 21 days of storage periods at $25^{\circ}C$. Most sugars added accelerated the degradation of anthocyanin pigments, so that fructose showed the greatest degradation effect on the pigments. Addition of citric acid at pH 3.0 increased stability of anthocyanins, while tartaric acid decreased stability. The anthocyanins were very sensitive on light irradiation with a degradation half-life of 14 hr under 20,000 lux-light dosage at pH 3.0.

• Radiation Oncology Journal
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• v.20 no.1
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• pp.24-33
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• 2002

Purpose : In order to improve dose homogeneity and to reduce acute toxicity in tangential whole breast radiotherapy, we evaluated two treatment techniques using multiple static fields or universal compensators. Materials and Methods : 1) Multistatic field technique : Using a three dimensional radiation treatment planning system, Adac Pinnacle 4.0, we accomplished a conventional wedged tangential plan. Examining the isodose distributions, a third field which blocked overdose regions was designed and an opposing field was created by using an automatic function of RTPS. Weighting of the beams was tuned until an ideal dose distribution was obtained. Another pair of beams were added when the dose homogeneity was not satisfactory. 2) Universal compensator technique : The breast shapes and sizes were obtained from the CT images of 20 patients who received whole breast radiation therapy at our institution. The data obtained were averaged and a pair of universal physical compensators were designed for the averaged data. DII (Dose Inhomogeneity Index : percentage volume of PTV outside $95\~105\%$ of the prescribed dose) $D_{max}$ (the maximum point dose in the PTV) and isodose distributions for each technique were compared. Results : The multistatic field technique was found to be superior to the conventional technique, reducing the mean value of DII by $14.6\%$ (p value<0.000) and the $D_{max}$ by $4.7\%$ (p value<0.000). The universal compensator was not significantly superior to the conventional technique since it decreased $D_{max}$ by $0.3\%$ (p value=0.867) and reduced DII by $3.7\%$ (p value=0.260). However, it decreased the value of DII by maximum $18\%$ when patients' breast shapes fitted in with the compensator geometry. Conclusion : The multistatic field technique is effective for improving dose homogeneity for whole breast radiation therapy and is applicable to all patients, whereas the use of universal compensators is effective only in patients whose breast shapes fit inwith the universal compensator geometry, and thus has limited applicability.

• Tuberculosis and Respiratory Diseases
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• v.47 no.5
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• pp.650-659
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• 1999

Background/Aims: It is well recognized that all aerobic cells have the protective mechanisms in order to minimize the tissue damage induced by various reactive oxygen species(ROS). Thioredoxin peroxidase(TPX) which has been recently identified and characterized functions to convert peroxide to water. The protein is also found in various subtypes(TPX-A & B, MER5, HS22 and HORF-06) and is known to be ubiquitous in most human cells. Especially, ischemic brain injuries, partial hepatectomy and radiation induced DNA damages. In treating lung cancer, radiation therapy has a major place in the local control and the relief of symptoms, but radiation induced free radical injury and resulting pulmonary fibrosis has been the major drawback of the therapy. However, little is known about the protective mechanisms and biologic modulations against radiation-induced tissue damages. Methods: Eighteen mice were divided into six groups, 3 in each group, and fifteen had received 900cGy of radiation. The mice were sacrificed according to the pre determined time schedule; immediate, 1, 2, 3 and 6 weeks after irradiation. Extracts were made from the lungs of each mice, Western blot analysis of various subtypes of TPX were done after SDS-P AGE. Examination of H & E stained slides from the same irradiated specimens and the control specimens were also performed. Results: No difference in the intensity of the immunoreactive bands in the irradiated lung samples of the mice compared to the unirradiated control was observed regardless of the time intervals, although H & E examination of the sample specimens demonstrated progressive fibrotic changes of the irradiated lung samples. Conclusion: In conclusion, according to our data, it is suggested that various thioredoxin peroxidase subtypes and catalase which are known to be increased in many repair processes may not be involved in the repair of the radiation injury to the lung and subsequent fibrosis.

• Journal of Food Hygiene and Safety
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• v.28 no.2
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• pp.130-137
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• 2013

In this study, we investigated the applicability of the photostimulated luminescence (PSL), thermoluminescence (TL), electron spin resonance (ESR) and gas chromatography/mass spectrometry (GC/MS) methods for 5 seeds which are not allowed to be irradiated in Korea. All 5 seeds including evening primrose seed, safflower seed, rape seed, sunflower seed and flax seed were analyzed. Samples were irradiated at 1~10 kGy using a $^{60}Co$ gamma-ray irradiator. In PSL study, the photon counts of all the unirradiated samples showed negative (lower than 700). The photon counts of irradiated (1, 5, 10 kGy) samples showed positive (higher than 5,000). In TL analysis, results showed that it is possible to apply TL method to all foods containing minerals. In ESR measurements, the ESR signal (single-line) intensity of irradiated foods was higher than non-irradiated foods. The hydrocarbons 1,7-hexadecadiene ($C_{16:2}$) and 8-heptadecene ($C_{17:1}$) from oleic acid were detected only in the irradiated samples before and after the treatment at doses ${\geq}$ 1 kGy, but they were not detected in non-irradiated samples before and after treatment. These two hydrocarbons could be used as markers to identify irradiated safflower seed, rape seed, Sunflower seed and flax seed. And then, the hydrocarbons 1,7,10-hexadecatriene ($C_{16:3}$) and 6,9-heptadecadiene ($C_{17:2}$) from linoleic acid were detected in the evening primrose seed, safflower seed and sunflower seed. According to the results, PSL, TL and GC/MS methods were successfully applied to detect the irradiated foods. It is concluded that PSL, TL and GC/MS methods are suitable for detection of irradiated samples and a combined method is recommendable for enhancing the reliability of detection results.

• Radiation Oncology Journal
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• v.26 no.2
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• pp.96-103
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• 2008

Purpose: To conduct a nationwide academic hospital patterns of the practice status and principles of radiotherapy for prostate cancer. The survey will help develop the framework of a database of Korean in Patterns of Case Study. Materials and Methods: A questionnaire about radiation treatment status and principles was sent to radiation oncologists in charge of prostate cancer treatment at thirteen academic hospitals in Korea. The data was analyzed to find treatment principles among the radiation oncologists when treating prostate cancer. Results: The number of patients with prostate cancer and treated with radiation ranged from 60 to 150 per academic hospital in Seoul City and 10 to 15 outside of Seoul City in 2006. The primary diagnostic methods of prostate cancer included the ultrasound guided biopsy on 6 to 12 prostate sites(mean=9), followed by magnetic resonance imaging and a whole body bone scan. Internal and external immobilizations were used in 61.5% and 76.9%, respectively, with diverse radiation targets. Whole pelvis radiation therapy(dose ranging from 45.0 to 50.4 Gy) was performed in 76.9%, followed by the irradiation of seminal vesicles($54.0{\sim}73.8$ Gy) in 92.3%. The definitive radiotherapy doses were increased as a function of risk group, but the range of radiation doses was wide(60.0 to 78.5 Gy). Intensity modulated radiation therapy using doses greater than 70 Gy, were performed in 53.8% of academic hospitals. In addition, the simultaneous intra-factional boost(SIB) technique was used in three hospitals; however, the target volume and radiation dose were diverse. Radiation therapy to biochemical recurrence after a radical prostatectomy was performed in 84.6%; however, the radiation dose was variable and the radiation field ranged from whole pelvis to prostate bed. Conclusion: The results of this study suggest that a nationwide Korean Patterns of Care Study is necessary for the recommendation of radiation therapy guidelines of prostate cancer.

• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.231-238
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• 2018

Chlorophyll fluorescence, chlorophyll content, graft-taking and growth of grafted cucumber seedlings as affected by photosynthetic photon flux (PPF) of LED lamps were analyzed in this study. Four PPF levels, namely 25, 50, 100, $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ were provided to investigate the effect of light intensity on the chlorophyll fluorescence, chlorophyll content, graft-taking and growth of grafted cucumber seedlings. Air temperature, relative humidity, and photoperiod for graft-taking were maintained at $25^{\circ}C$, 90%, $16h{\cdot}d^{-1}$, respectively. Maximum quantum yield (Fv/Fm) of rootstock as affected by PPF was found to be 0.84-0.85 and there was no significant change in Fv/Fm. Even though Fv/Fm of scion measured at 2 days after grafting was lowered to 0.81-0.82, after then it gradually increased with increasing PPF. At 4 days after grafting, the chlorophyll content extracted from scion increased with increasing PPF. Graft-taking ratio of grafted cucumber seedlings was 90-95% as PPF was ranged from $25{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ to $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. However, the graft-taking ratio of grafted seedlings healed under PPF of $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ was decreased to 80%. Maximum PPF measured required for smooth joining of rootstock and scion was assumed to be $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. At healing stage of grafted cucumber seedlings, Fv/Fm of scion decreased and at least two days after grafting were required for rooting of grafted seedlings. Chlorophyll fluorescence response of rootstock and scion was linked to light irradiation. Therefore, it was concluded that physical environment including light and humidity during healing process of grafted seedlings should be controlled more precisely to facilitate root formation and to prevent scion from lowering Fv/Fm. Further studies are required to investigate the effects of root development and joining of vascular bundles of grafted seedlings on the chlorophyll content of scion.

• Journal of Radiation Industry
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• v.7 no.1
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• pp.15-21
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• 2013

The detection characteristics of irradiated spices were investigated depending on radiation sources and doses by photostimulated luminescence (PSL) and Thermoluminescence (TL). 6 kinds of spices (turmeric, onion powder, red pepper, basil, parsley, black pepper) were irradiated at 0 to 10 kGy under ambient conditions by both a $^{60}Co$ gamma irradiator and an electron beam (EB) accelerator, respectively. The PSL analysis showed negative results for non-irradiated spices, while irradiated spices gave intermediate and positive value, which presented the limited potential of PSL technique. In TL measurement, TL glow curves on non-irradiated samples appeared at about $300^{\circ}C$ with low intensity. All irradiated samples were easily distinguishable through radiation-specific strong TL glow curves with maximum peak in range of $150{\sim}200^{\circ}C$. TL ratio ($TL_1/TL_2$) obtained by a re-irradiation step could verify the detection result of $TL_1$ glow curves, showing ratios lower than 0.1 in the non-irradiated sample and higher than 0.1 in irradiated ones. Therefore, in PSL measurement, the identification of irradiated spices showed more clear results in electron beam irradiated samples. TL analysis showed obvious difference between non-irradiated and irradiated samples in gamma ray and electron beam irradiated samples.