• The Korean Journal of Rheology
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• v.3 no.1
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• pp.22-29
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• 1991

In an effort to predict the long term durability of carbon fiber/epoxy composites in a space environ-ment interlaminar shear strength (ILSS) of the composites was measured as a function of 0.5 MeV electron radiation dosage. For the ILSS measurements a notch method (ASTM D3846) was used with and without side-supports. the supports were used to prevent peeling or bending during the test. The ILSS of both T300/ 5209 longitudinal composite system increases monotonically with radiation when the test is corried out without the support the ILSS of the composites increases initially but then decreases with further radiation. It is also observed that the ILSS of the unsupported case is much lower than that of the supported case. Measurement of epoxy modulus shows that the elastic modulus increases monotonically with radiation. But the breaking strength of the epoxy decreases with radiation. Electron Spectroscopy for Chemcal Analysis shows that the oxygen contents at both the pure epoxy surface and the composite fracture surface increase with radiation dose resulting in the increase of polarity at the interfacial region. This may be a supporting evidence for the increase in the ILSS of the composites.

• Journal of Ginseng Research
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• v.33 no.2
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• pp.132-138
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• 2009

Previous studies suggest that even low-dose irradiation can lead to progressive cognitive decline and memory deficits, which implicates, in part, hippocampal dysfunction in both humans and experimental animals. In this study, whether red ginseng (RG) could attenuate memory impairment was investigated through a passive-avoidance and object recognition memory test, as well as the suppression of hippocampal neurogenesis, using the TUNEL assay and immunohistochemical detection with markers of neurogenesis (Ki-67 and doublecortin (DCX)) in adult mice treated with a relatively low-dose exposure to gamma radiation (0.5 or 2.0 Gy). RG was administered intraperitonially at a dosage of 50 mg/kg of body weight, at 36 and 12 h pre-irradiation and at 30 minutes post-irradiation, or orally at a dosage of 250 mg! kg of body weight/day for seven days before autopsy. In the passive-avoidance and object recognition memory test, the mice that were trained for one day after acute irradiation (2 Gy) showed significant memory deficits compared with the sham controls. The number of TUNEL-positive apoptotic nuclei in the dentate gyrus (DG) was increased 12 h after irradiation. In addition, the number of Ki-67- and DCX-positive cells was significantly decreased. RG treatment prior to irradiation attenuated the memory defect and blocked apoptotic death as well as a decrease in the Ki-67- and DCX-positive cells. RG may attenuate memory defect in a relatively low-dose exposure to radiation in adult mice, possibly by inhibiting the detrimental effect of irradiation on hippocampal neurogenesis.

• Journal of Radiation Protection and Research
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• v.36 no.3
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• pp.140-147
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• 2011

Our purpose is to specify behavior and environmental factors aimed at reducing the exposed dosage caused by PET-CT and to develop radiation safety management guidelines adequate for domestic circumstances. We have used a multistep-multimethod as the methodological approach to design and to carry out the research both in quality and quantity, including an analysis on previous studies, professional consultations and a survey. The survey includes responses from 139 practitioners in charged of 109 PET-CTs installed throughout Korea(reported by the Korean Society of Nuclear Medicine, 2010). The research use 156 questions using Cronbach's ${\alpha}$ (alpha) coefficients which were: 0.818 for "the necessity of setting and installing the radiation protective environment"; 0.916 for "the necessity of radiation protection", "setting and installing the radiation protective environment"; and 0.885 for "radiation protection". The check list, derived from the radiation safety management guidelines focused on behavior and environment, was composed of 20 items for the radiation protective environment: including 5 items for the patient; 4 items for the guardian; 3 items for the radiologist; and 8 items applied to everyone involved; for a total of 26 items for the radiation protective behavior including: 12 items for the patient; 1 item for the guardian, 7 items for the radiologist; and 6 items applied to everyone involved. The specific check list is shown in(Table 5-6). Since our country has no safety management guidelines of its own to reduce the exposed dosage caused by PET-CTs, we believe the guidelines developed through this study means great deal to the field as it is not only appropriate for domestic circumstances, but also contains specific check lists for each target who may be exposed to radiation in regards to behavior and environment.

• Imaging Science in Dentistry
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• v.43 no.2
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• pp.63-69
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• 2013

After over one decade development, cone beam computed tomography (CBCT) has been widely accepted for clinical application in almost every field of dentistry. Meanwhile, the radiation dose of CBCT to patient has also caused broad concern. According to the literature, the effective radiation doses of CBCTs in nowadays market fall into a considerably wide range that is from $19{\mu}Sv$ to $1073{\mu}Sv$ and closely related to the imaging detector, field of view, and voxel sizes used for scanning. To deeply understand the potential risk from CBCT, this report also reviewed the effective doses from literatures on intra-oral radiograph, panoramic radiograph, lateral and posteroanterior cephalometric radiograph, multi-slice CT, and so on. The protection effect of thyroid collar and leaded glasses were also reviewed.

• Korean journal of food and cookery science
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• v.20 no.3
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• pp.256-264
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• 2004

The effects of irradiation on the functional and structural characteristics of soy protein isolates were studied. Soymilk was irradiated at 1, 5, and l0kGy, after which soy protein isolates were prepared. The functional properties of soy protein isolates were examined including solubility, emulsion capacity and stability, foam capacity and stability, structural properties as represented by SDS-PAGE pattern, and secondary and tertiary structures. The solubility and emulsion capacity were increased by radiation treatment at 1kGy however the values were adversely affected again as dosage was increased above 5kGy. As irradiation dosage increased, an increase of foaming capacity at 1kGy and a decreasing turnover afterwards were also noted in foaming capacity, although the differences were not statistically significant. The SDS-PAGE pattern showed fragmentation and aggregation of protein molecules as affected by irradiation in proportion to the dosage increase. The results of CD and fluorescence spectroscopy revealed increased aperiodic structure contents with the dosage increase. It was assumed that irradiation dosagefrom 5 to l0kGy could initiate minimal denaturation of protein in various foods compared to general heat treatment.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5631-5635
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• 2013

Cochlea hair cell death is regarded to be responsible for the radiation-induced sensorineural hearing loss (SNHL), which is one of the principal complications of radiotherapy (RT) for head and neck cancers. In this mini-review, we focus on the current progresses trying to unravel mechanisms of radiation-induced hair cell death and find out possible protection. P53, reactive oxygen species (ROS) and c-Jun N-terminal kinase (JNK) pathways have been proposed as pivotal in the processes leading to radiation hair cell death. Potential protectants, such as amifostine, N-acetylcysteine (NAC) and epicatechin (EC), are claimed to be effective at reducing radiation-inducedhair cell death. The RT dosage, selection and application of concurrent chemotherapy should be pre-examined in order to minimize the damage to cochlea hair cells.

• Restorative Dentistry and Endodontics
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• v.37 no.3
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• pp.160-164
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• 2012

Objectives: This study was aimed to investigate the methods to reduce operator's radiation dose when taking intraoral radiographs with portable dental X-ray machines. Materials and Methods: Two kinds of portable dental X-ray machines (DX3000, Dexcowin and Rextar, Posdion) were used. Operator's radiation dose was measured with an 1,800 cc ionization chamber (RadCal Corp.) at the hand level of X-ray tubehead and at the operator's chest and waist levels with and without the backscatter shield. The operator's radiation dose at the hand level was measured with and without lead gloves and with long and short cones. Results: The backscatter shield reduced operator's radiation dose at the hand level of X-ray tubehead to 23 - 32%, the lead gloves to 26 - 31%, and long cone to 48 - 52%. And the backscatter shield reduced operator's radiation dose at the operator's chest and waist levels to 0.1 - 37%. Conclusions: When portable dental X-ray systems are used, it is recommended to select X-ray machine attached with a backscatter shield and a long cone and to wear the lead gloves.

• Journal of Radiation Protection and Research
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• v.42 no.4
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• pp.205-211
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• 2017

Background: Radiation is used in a variety of areas, but it also poses potential risks. Although radiation is often used with great effectiveness in many applications, people perceive potential risks associated with radiation and feel anxious about the possibility of radiation exposure. Various methods of measuring radiation doses have been developed, but there is no way for the general public to measure their doses with ease. Currently, many people use smartphones, which provide information about the location of an individual phone through network connections. If a smartphone application could be developed for measuring radiation dosage, it would be a very effective way to measure individuals' radiation doses. Thus, we conducted a survey study to assess the social acceptance of such a technology by the general public and their intent to use that technology to measure radiation doses, as well as to investigate whether such an intention is correlated with anxiety and attitudes toward the use of radiation. Materials and Methods: A nationwide online survey was conducted among 355 Koreans who were 20 years old or older. Results and Discussion: Significant differences were found between the genders in attitudes, perceptions of radiation risk, and fears of exposure to radiation. However, a significant difference according to age was observed only in the intent to use a smartphone dose measurement application. Attitudes towards the use of radiation exerted a negative effect on radiation risk perception and exposure anxiety, whereas attitudes towards the use of radiation, risk perception, and anxiety about exposure were found to have a positive impact on the intent to use a smartphone application for dose measurements. Conclusion: A survey-based study was conducted to investigate how the general public perceives radiation and to examine the acceptability of a smartphone application as a personal dose monitoring device. If such an application is developed, it could be used not only to monitor an individual's dose, but also to contribute to radiation safety information infrastructure by mapping radiation in different areas, which could be utilized as a useful basis for radiation research.

• Food Science of Animal Resources
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• v.29 no.3
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• pp.302-309
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• 2009

This study investigated the effects of infrared (IR) radiation combined with air blast thawing on the physical properties of pork. Regardless of air velocity, increasing IR dosage produced an exponential increase in the thawing rate of pork. This rate increased further when air blast velocity was increased. IR treatments showed significantly lower thawing loss than that of 0 Watt treatment, while increasing air velocity significantly increased thawing loss of pork (p<0.05). Increasing both IR power and air velocity tended to decrease the cooking loss of pork. Moreover, increased IR power tended to decrease the water holding capacity and shear force of pork. The shear force changes were not significant (p>0.05). Shear force also increased with increasing air velocity. In addition, the higher the air velocity the higher the shear force of pork. In Commission Internationale de l'Eclairage (CIE) colour determination, control of temperature prevented discolouration from overheating of sample surface. The results suggest that IR dosage combined with air blast has potential in thawed meat quality aspects, and that humidity control could prevent surface drying.

• The Korean Journal of Pain
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• v.35 no.2
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• pp.129-139
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• 2022

C-arm fluoroscopy is a useful tool for interventional pain management. However, with the increasing use of C-arm fluoroscopy, the risk of accumulated radiation exposure is a significant concern for pain physicians. Therefore, efforts are needed to reduce radiation exposure. There are three types of radiation exposure sources: (1) the primary X-ray beam, (2) scattered radiation, and (3) leakage from the X-ray tube. The major radiation exposure risk for most medical staff members is scattered radiation, the amount of which is affected by many factors. Pain physicians can reduce their radiation exposure by use of several effective methods, which utilize the following main principles: reducing the exposure time, increasing the distance from the radiation source, and radiation shielding. Some methods reduce not only the pain physician's but also the patient's radiation exposure. Taking images with collimation and minimal use of magnification are ways to reduce the intensity of the primary X-ray beam and the amount of scattered radiation. It is also important to carefully select the C-arm fluoroscopy mode, such as pulsed mode or low-dose mode, for ensuring the physician's and patient's radiation safety. Pain physicians should practice these principles and also be aware of the annual permissible radiation dose as well as checking their radiation exposure. This article aimed to review the literature on radiation safety in relation to C-arm fluoroscopy and provide recommendations to pain physicians during C-arm fluoroscopy-guided interventional pain management.