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[en] The intercomparison exercise on internal dose assessment has been carried out for the purpose of the evaluation for harmonization of internal dosimetry between the nuclear-related institutes in Korea. The exercises of 9 items on internal dose assessment have been developed for the unknown internal dosimetric parameters such as the intake pathway, absorption type, AMAD, and intake time of a radionuclide. Solutions to these exercises were reported by 7 participants from 5 institutes. The range of the ratio between the individual values and the geometric mean value of the evaluated doses for the exercises was 5.75x10-4 ∼ 9.81. But without the extreme partial solution, the range of the ratio was 0.216 ∼ 3.12
[en] A computed Radiography (CR) system by use of reusable Image Plate (IP) offers a convenient and reliable way to replace a conventional film-screen system for NDT (non-destructive testing) field. The quality of a radiography to detect a defect of welded objects depends on the procedure embracing several factors such as measurement conditions, image plate type/class, radiation energy, radiation type, and source to image plate distance. Also, the ability of images to detect a flaw reduces with increasing object thickness. In the study, the properties of gamma ray source were summarized for NDT field and inspection images of CR image system manufactured by FUJI were acquired using 75Se and 192Ir with welded objects. We analyzed the gray scale of hole defect image by using XCAP image processing program and calculated the image contrast and SNR in definition. Also the sesitivities of image quality indicator(IQI) were calculated for hot and cooling tube image of 75Se and 192Ir
[en] With the expanded use of radiation in modern medical practices, the most important issue in regards to efforts to reduce individual exposure dose is quality assurance. Therefore in order to study the present condition of quality assurance, the Gwangju Metropolitan City area was divided into five districts each containing ten hospitals. Four experiments were conducted: a reproducibility experiment for kVp, mA, and examination time (sec) intensity of illumination; half-value layer (HVL) measurement; and beam perpendicularity test matching experiment. The tube voltage reproducibility experiment for all fifty hospitals resulted in a 95.33% passing rate and mA and examination time both resulted in a 77.0% passing rate. The passing rate for intensity of illumination was 86.0% and 52.0% for HVL, which was the lowest passing rate of all four factors. For the beam perpendicularity test matching experiment, generally the central flux is matched to within 1.5.deg. . Of all fifty hospitals 30.0% were beyond 3.deg. . The results of the survey showed that 58% responded that they knew about quality assurance cycle. All fifty respondents stated that they have not received any training in regards to quality assurance at their current place of employment. Although quality assurance is making relative progress, the most urgent issue is awareness of the importance of quality assurance. Therefore, the implementation of professional training focusing on safety management and accurate quality assurance of radiation will reduce the exposure to radiation for radiologists and patients and higher quality imaging using less dosage will also be possible
[en] Conventional (SRS) and fractionated (FSRS) stereotactic radiosurgery necessarily require stringent overall target point accuracy and precision. We determine three-dimensional intracranial target point deviations (TPDs) in a whole treatment procedure using magnetic resonance image (MRI)-based polymer-gel dosimetry, and suggest a technique for overall system tests. TPDs were measured using a custom-made head phantom and gel dosimetry. We calculated TPDs using a treatment planning system. Then, we compared TPDs using mid bi-plane and three-dimensional volume methods with spherical and elliptical targets to determine their inherent analysis errors; finally, we analyzed regional TPDs using the latter method. Average and maximum additive errors for ellipses were 0.62 and 0.69 mm, respectively. Total displacements were 0.92 ± 0.25 and 0.77 ± 0.15 mm for virtual SRS and FSRS, respectively. Average TPDtotal at peripheral regions was greater than that at central regions for both. Overall system accuracy was similar to that reported previously. Our technique could be used as an overall system accuracy test that considers the real radiation field shape.
[en] Industrial radiography practice is usually employed in public domain. Over the years there are several radiation accidents reported in this practice. The accidents often result in severe or fatal exposures to occupational workers and public. The number of radiation accidents is also significant when compared with other industrial accidents. This paper describes practice specific training as one of the measures to the improve radiation safety and reduce the accidents. The efforts by International Atomic Energy Agency (IAEA) to disseminate information and to improve the radiation safety status in industrial radiography are also discussed.
[en] Recent domestic use of radiations has increased in the number of institutions and companies as well as operating as an investment, a variety of facilities and safety management are becoming increasingly complex. Despite the increase of radiation workers and facilities, the number of RSOs (Radiation Safety Officers) has not increased with a growing domestic radiation industry. The radiation safety management work (radiation workers management, radiation sources management, facilities management etc.) has been managed by insufficient number of the RSOs. These problems could be directly or indirectly related to causes of the radiation accidents. In this paper, we designed the Process Mapping of radiation safety management work for an efficient safety management of the radiation facilities and protection of radiation accidents. To develop the Process Mapping, we analyzed the radiation safety requirements of management issues and the individual procedures. Based on the Process Mapping, the work procedures for an appropriate radiation safety management of each institution can be configured clearly. Through this procedures, the safety risk factors in radiation facilities can be reduced, and the radiation safety management system will be improved. Depending on your needs, the Process Mapping could be modified and could be used for an efficient radiation safety management
[en] In this paper, we analyzed the Cognition of irradiated food and its relation with self-efficacy. The most important variables described behaviors based on health choices compared with the choice to choose irradiated food items. According to the survey, 33.1% of respondents said that the reason why irradiated food is considered to be a health risk is because 'radiation is dangerous'. 27.9% of respondents answered that 'eating irradiated food is like eating a radioactive substance', 21.1% said radiated food is comparable to a 'genetic variation in food' while 10.1% said 'food goes bad during the irradiation process'. On this basis, it is reasonable to conclude that respondents have a misunderstanding of irradiated food without reference to the general theory of irradiated knowledge. In this respect, it would be helpful to provide education showing that irradiated food is not related to eating harmful or genetically modified food to help high school students create informed opinions of irradiated food. In terms of relevance with health-specific self-efficacy, experience of acquiring information about irradiated food was marked at r=0.148 (p<0.01), experience of purchasing irradiated food was marked at r=0.077 (p<0.05), experience of eating irradiated food was marked at r=0.113 (p<0.01) while knowledge of irradiated food, attitude towards irradiated food and behavior was marked at r=0.103 (p<0.01), r=0.076 (p<0.05) and r=0.105 (p<0.01) respectively. This shows that self-efficacy is high when one has experience of acquiring information about irradiated food, purchasing or eating irradiated food resulting in a high level of knowledge, attitude and behavior. Education which serves to improve the level of self-efficacy needs to be provided along with an educational program which will increase the public's understanding of irradiated food. It is expected that if this education which increases the level of self-efficacy is provided together with correct information of irradiated food, behavior to choose and eat irradiated food will also improve
[en] A simple laboratory-made radioactive source to check the integrity of a gamma spectrometry system with HPGe detector was developed. The check source consists of radium-riched soil which was ground in size of less than 0.154mm and contained in air tight cylindrical vial, and provides photons with 12 distinct energies. The spectra of the check source were measured once a month during one year, analyzed the characteristics of their peaks. When the gamma spectrometry system was in normal state, the areas and FWHMs of the gamma rays with more than 3% gamma emission rate in radium and its decay products was constant within standard deviation 2% and 3%, respectively, except 77 keV peak. And it was found that this check source can play a sufficient role to check the integrity of a gamma spectrometry system using 10 peaks in the range of 77 to 2202 keV
[en] Urine bioassay has been widely used for internal dosimetry due to simple process of sampling and measurement. In this paper, we participated in the NRIP (NIST Radiochemistry Intercomparison Program) hosted by US NIST to carry out a reliable performance test of urine bioassay and introduced the measurement method and results of NRIP-2013. In customary exercise with 60 days of reporting time, bioassay results of 12 radionuclides in the synthetic urine samples were acceptable based on the performance criteria of ANSI N13.30. In emergency preparedness exercise with 8 hours of reporting time, bioassay results of 9 radionuclides showed that differences ranged from -35% to 45%. However, we concluded that urine bioassay applied for emergency preparedness exercise would be applicable for rapid screening and estimation of internal exposure within a difference of ±45% in the event of radiological accidents.
[en] We manufactured the Vac-lok that can be applied to patient of special body shape and need to special set-up position and evaluated the usefulness in the radiation therapy. The manufacture Vac-lok, It was used EVA resin and biobeadform of a diameter 1.5 mm. carried out the test of functionality, structural and analyzed the relative reproducibility of phantoms and patients. During the total period of radiation therapy, Vacuum pressure bring variety to a very small amount in the test of functionality of the manufacture Vac-lok. But It was a negligible quantity. The manufacture Vac-lok improved the relative reproducibility of phantoms than the existing Vac-lok and tolerance has a confidence less than 4% error. Also, relative reproducibility of patient increased error than phantom in the antero-posterior and lateral plan. However, the maximum set-up error was less than ± 2.3 mm. In conclusion, If tolerance set-up error of radiotherapy is less than ± 3 mm, the manufacture Vac-lok was enough possible to use and improvement of reproducibility, considering supply with the Vac-lok made to measure of special patient that produced at a low price and without delay