• Journal of Radiation Protection and Research
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• v.5 no.1
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• pp.7-10
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• 1980

With the conceptual definition of the quotient(${\beta}$) of absorbed dose and the collision part of kerma for photon beams, the procedure of computing ${\beta}$ is briefly described. A series of calculations of ${\beta}$ was carried out for photons of 0.4, 0.5, 1 and 2 MeV in polystyrene, carbon, air and aluminum. Resultant values are tabulated and evaluated.

• Archives of Plastic Surgery
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• v.45 no.5
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• pp.403-410
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• 2018

Background Radiation-induced skin injury is a dose-limiting complication of radiotherapy. To investigate this problem and to develop a framework for making decisions on treatment and dose prescription, a murine model of radiation-induced skin injury was developed. Methods The dorsal skin of the mice was isolated, and irradiation was applied at single doses of 15, 30, and 50 Gy. The mice were followed for 12 weeks with serial photography and laser Doppler analysis. Sequential skin biopsy samples were obtained and subjected to a histological analysis, immunostaining against transforming growth factor beta (TGF-${\beta}$), and Western blotting with Wnt-3 and ${\beta}$-catenin. Increases in the levels of TGF-${\beta}$, Wnt, and ${\beta}$-catenin were detected after irradiation. Results All tested radiation doses caused progressive dermal thickening and fibrosis. The cause of this process, however, may not be radiation alone, as the natural course of wound healing may elicit a similar response. The latent appearance of molecular and histological markers that induce fibrosis in the 15 Gy group without causing apparent gross skin injuries indicates that 15 Gy is an appropriate dose for characterizing the effects of chronic irradiation alone. Thus, this model best mimics the patterns of injury that occur in human subjects. Conclusions This animal model can be used to elucidate the gross and molecular changes that occur in radiation-induced skin injury and provides an effective platform for studying this adverse effect without complicating the process of wound healing.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.369-376
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• 2008

In the present study, we investigated the radioprotective effect of cyclo(L-phenylalanyl-L-prolyl) on irradiated rat lungs to determine its potential as a radioprotective agent. We found that early lung damage induced by irradiation was reduced by treatment with 40mg/kg of cyclo(L-phenylalanyl-L-prolyl) in the latent and early pneumonitis phases. Expression of $TNF-{\alpha}\;and\;TGF-{\beta}1$ at 2 and TGF-${\beta}1$ at 8 weeks post-irradiation was decreased in animals that received both radiation and cyclo(L-phenylalanyl-L-prolyl) compared with animals that received radiation alone. Evidence indicated that the proinflammatory cytokine TNF-${\alpha}$ and the fibrogenic cytokine TGF-${\beta}1$ likely play a role in the radioprotective effect of cyclo(L-phenylalanyl-L-prolyl). However, besides TNF-${\alpha}$ and TGF-${\beta}1$ expressions, the precise mechanism by which cyclo(L-phenylalanyl-L-prolyl) ameliorates the induced radiation damage is not clear.

• Radiation Oncology Journal
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• v.22 no.1
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• pp.40-54
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• 2004

Purpose : Captopril (angiotension converting enzyme inhibitor) is known to have a radioproptective effect in the lungs, intestines and skin, but its effect in the heart is unclear. To investigate the radioprotectlve efiect and mechanism of captopril on the heart, the histopathological changes and immunohistochemical stains were compared with radiation alone, and radiation combined with captopril, in the rats. Materials and Methods : The histopathological changes and immunohistochemical stains ($TNF{\alpha}$, $TGF{\beta}1$, PDGF and FGF2) were examined in the radiation alone and the combined captopril and radiation groups, 2 and 8 weeks after irradiation. Each group consisted of 8 to 10 rats (Sprague-Dawley). Irradiation (12.5 Gy) was given to the left hemithorax in a single fraction. Captopril (50 mg/Kg/d) mixed with water, was given orally and continuously from the first week prior to, up to the 8th week of the experiment. Results : In the radiation alone group, the ventricle at 2 weeks after irradiation showed prominent edema (p=0.082) and fibrin deposit (p=0.018) compared to the control group. At 8 weeks, the edema was decreased and fibrosis increased compared to those at 2 weeks. The histopathological changes of the combined group were similar to those of the control group, due to the reduced radiation toxicity at 2 and 8 weeks. The endocardial fibrin deposit (p=0.047) in the atrium, and the interstitial fibrin deposit (p=0.019) and edema (p=0.042) of the ventricle were reduced significantly in the combined group compared to those in the radiation alone group at 2 weeks. The expressions of $TNF-{\alpha}$, $TGF-{\beta}1$, PDGF and FGF-2 in the radiation alone group were more increased than in the control group, especially in the pericardium and endocardium of the atrium at 2 weeks. At 8 weeks, the pericardial $TNF-{\alpha}$ and $TGF-{\beta}1$ in the radiation alone group continuously increased. The expressions of $TNF-{\alpha}$, $TGF-{\beta}1$ and PDGF were decreased in the combined group at 2 weeks. At 8 weeks, the expressions of $TNF-{\alpha}$ in the atrial and ventricular pericardia were markedly reduced (p=0.049, p=0.009). Conclusion : This study revealed that the early heart damage induced by radiation can be reduced by the addition of captopril in a rat model. The expressions of $TNF-{\alpha}$, $TGF-{\beta}1$ and PDGF were further decreased in the combined compared to the radiation alone group at both 2 and 8 weeks. From these results, it may be concluded that these cytokines probably play roles in the radioprotective mechanism of captopril from the radiation-induced heart toxicity, similarly to in other organs.

• Journal of Korean Clinical Nursing Research
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• v.20 no.2
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• pp.177-188
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• 2014

Purpose: This study was conducted to identify factors influencing endoscopy nurses' protective behavior against radiation exposure. Methods: Data were collected using self-report questionnaires from 122 endoscopy nurses in 21 hospitals located in Seoul, Gyeonggi province and six metropolitan cities in Korea. Collected data were analyzed using SPSS 18.0 program and included multiple regression analysis. Results: 1) There were significant relationships between protective behavior and protective environment (r=.74, p<.001), number of education sessions on radiation protection (r=.32, p<.001), number of protective devices (r=.28, p=.002), number of fellow nurses (r=.27, p=.003), and protective attitude (r=.18, p=.048). 2) Protective environment (${\beta}=0.79$, p<.001), type of hospital foundation (${\beta}=0.18$, p=.011) and marital status (${\beta}=-0.13$, p=.040) significantly predicted endoscopy nurses' protective behavior against radiation exposure (adjusted R square=.58, p<.001). The most powerful predictor for protective behavior against radiation exposure was a protective environment. Conclusion: Effective protective behavior of endoscopy nurses from radiation exposure requires improvement in their protective environment. Hospital administrators and managers should make efforts to increase protective facilities in endoscopy departments and provide endoscopy nurses with regular education on radiation protection.

• 전기의세계
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• v.14 no.3
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• pp.28-33
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• 1965

This experiment is based on "the feasible improvement studies for an eliminating device of the static electricity which applies the ionizing effect of beta radiation." In order to accomplish this object, the following problems were necessarily considered to investigate and to determine. The efficiency of the elimination of static electricity was determined by means of measuring the ion current between electrically charged plates with micro-ammeter. The effects of various factors, i.e., the distance between charged plate and radiation source, the activity of radiation source, the electric otential and the area of the charged plate, the shape of the source housing, the lining of backscattering material (Pb) on the source housing surface and blowing of ionized air, on the static electricity eliminating efficiency were studied. The beta radiation sources used in this experiment were S$^{35}$ and Sr$^{90}$ -Y$^{90}$ . It was revealed that ion current increased with source activity, the electric potential and area of the plates, the lead (Pb) lining on the surface of the source housing and the velocity of the ionized air blowing. As one could expect the S$^{35}$ was more effective to increase the ion current since it is known to be a higher specific ionization source than Sr$^{90}$ -Y$^{90}$ . The detailed result and performance of the eliminating device of the static electricity are described here.ibed here.

• ETRI Journal
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• v.42 no.6
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• pp.951-964
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• 2020

This paper presents a lightweight true random number generator (TRNG) using beta radiation that is useful for Internet of Things (IoT) security. In general, a random number generator (RNG) is required for all secure communication devices because random numbers are needed to generate encryption keys. Most RNGs are computer algorithms and use physical noise as their seed. However, it is difficult to obtain physical noise in small IoT devices. Since IoT security functions are required in almost all countries, IoT devices must be equipped with security algorithms that can pass the cryptographic module validation programs of each country. In this regard, it is very cumbersome to embed security algorithms, random number generation algorithms, and even physical noise sources in small IoT devices. Therefore, this paper introduces a lightweight TRNG comprising a thin-film beta-radiation source and integrated circuits (ICs). Although the ICs are currently being designed, the IC design was functionally verified at the board level. Our random numbers are output from a verification board and tested according to National Institute of Standards and Technology standards.

• Journal of radiological science and technology
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• v.45 no.5
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• pp.433-438
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• 2022

Targeted radionuclides treatment (TRT) requires the establishment of treatment plans that consider various factors, such as the type of radionuclides, target organs, and administration methods. For this reason, in this study, the absorption dose of a single cell was analyzed according to the type of radioisotope used to treat target radionuclides. In this study, a simulation was performed on beta rays used in the treatment of target radionuclides at the cell level using MCNPX (ver. 2.5.0). First, according to the calculation formula, the beam path according to the type of radioisotope for treatment was calculated. Second, the amount of self-radiation by beta rays emitted from cell diameters of 5 ㎛ and 10 ㎛ cell nuclei was evaluated. As a result, it showed a high range proportional to the maximum energy of the beta-ray, and the highest self-dose distribution from 177 Lu radiation sources among therapeutic radioisotopes. This was analyzed as a result that is inversely proportional to the maximum energy of the beta-ray, and it suggests that the selection of a nuclide considering the range of the beta-ray is necessary in the treatment of target radionuclides in the future.

• Environmental Mutagens and Carcinogens
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• v.25 no.3
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• pp.104-109
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• 2005

[ $7{\beta}$ ]-Hydroxycholesterol (cholest-5-ene-3, 7-diol, $7{\beta}$-OHC) showed the cytotoxicity on human cervical carcinoma cells (HeLa), $10{\mu}M$ of 50% inhibitory concentration. We evaluated $7{\beta}$-OHC as the possibility of radiation sensitizer. The combination effect of $7{\beta}-OHC\;and\;{\gamma}$-irradiation was measured using colony forming assay and flow cytometer with propidium iodide and $DiOC_6$ stained cells, respectively. The combined treatment of $7{\beta}-OHC\;and\;{\gamma}$-irradiation did not show significant enhancing effects on HeLa cells.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.6441-6446
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• 2012

Background: Radiation therapy plays an important role in lung carcinoma treatment. However, the incidence of symptomatic radiation-induced lung injury is high. This study aimed to evaluate radioprotective effects of flavonoids extracted from Astragalus complanatus and mechanisms of action against radiation damage. Methods: Alteration in antioxidant status and levles of several cytokines were investigated in BABL/C mice treated with 4 mg/kg b.wt. flavonoids after exposure to 10Gy thoracic radiation. Results: Serum levels of SOD in the flavonoids+radiation group were significantly higher compared to the radiation control group, while TGF-${\beta}1$ and IL-6 were lower. Mice in the radiation control group displayed more severe lung damage compared with the flavonoids+radiation group. The expression of TGF-${\beta}1$ and TNF-${\alpha}$ in the radiation control group was markedly increased in alveolar epithelial cells and macrophages of the alveolar septum. Conclusions: From the results of the present study, flavonoids could be excellent candidates as protective agents against radiation-induced lung injury.