• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.295-303
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• 2023

Whole-body counters are widely used to assess internal contamination after a nuclear accident. However, it is difficult to determine radioiodine activity due to limitations in conventional calibration phantoms. Inhaled or ingested radioiodine is heterogeneously distributed in the human body, necessitating time-dependent biodistribution for the assessment of the internal contamination caused by the radioiodine intake. This study aims at calculating counting efficiencies considering the biodistribution of ¹³¹I in whole-body counting measurement. Monte Carlo simulations with computational human phantoms were performed to calculate the whole-body counting efficiency for a realistic radioiodine distribution after its intake. The biodistributions of ¹³¹I for different age groups were computed based on biokinetic models and applied to age- and gender-specific computational phantoms to estimate counting efficiency. After calculating the whole-body counting efficiencies, the efficiency correction factors were derived as the ratio of the counting efficiencies obtained by considering a heterogeneous biodistribution of ¹³¹I over time to those obtained using the BOMAB phantom assuming a homogeneous distribution. Based on the correction factors, the internal contamination caused by ¹³¹I can be assessed using whole-body counters. These correction factors can minimize the influence of the biodistribution of ¹³¹I in whole-body counting measurement and improve the accuracy of internal dose assessment.

• Journal of Radiation Industry
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• v.9 no.4
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• pp.199-207
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• 2015

Typical radiation cross-linked hydrogels has the characteristic that high water content, but low emission efficiency of active ingredients. Therefore, the hydrogel was prepared by the addition to collagen, which is closely related to the formation of skin wrinkles in biocompatibility and highly water-soluble carboxymethyl cellulose sodium salt (CMC) in order to preparation of hydrogels has excellent emission efficiency of active ingredients. Hydrogels were prepared by dissolving CMC and collagen each of 0.5%, 10% concentration in deionized water. Then, prepared hydrogels are performed by gamma-radiation at 1, 3, 5 kGy irradiation dose. The results showed that the gel fraction of after irradiated 3 kGy hydrogel was higher than before irradiated gelation as long as the 55.3%. The swelling rate of irradiated 3 kGy hydrogel was lower than the non-irradiated sample. The compressive strength of 3 kGy irradiated hydrogel was the highest. The visco-elastic did not show any significant differences, even after irradiation. The CMC hydrogel in this study suggested a potential use as a material for the mask pack for improved emission efficiency of the active ingredient and anti-wrinkles.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.103-106
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• 1998

본 논문은 상용 FEM-BEM 프로그램을 사용하여 점-조화 가진(harmonic point excitation)에 의한 자유지지 경계 조건을 갖는 원통 셸(cylindrical shell)의 방사 효율(radiation efficiency) 실험의 결과와 비교하였다. 우선 충격 해머 실험(impact hammer test)을 통한 모드 시험(modal testing)으로 원통 셸의 공진 주파수(natural frequency)와 모드 형상(mode shape)의 특징을 살펴보고 다음으로 점-조화 가진에 의한 원통 셸의 방사 효율을 SYSNOISE와 ANSYS로 해석해 보았다. 동시에 음향 세기 실험을 통한 방사 효율을 측정하여 전산 해석의 결과와 실험의 결과를 비교해 보았다.

• Journal of radiological science and technology
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• v.44 no.6
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• pp.629-633
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• 2021

This article is designed to look into the radiation exposure dose to each body part and the shielding effect for workers using an additional shielding to reduce their radiation exposured by scattering radiation which is generated in a space between the operating table and lead curtain during interventional radiology(IR) procedures. After placing a human phantom on the table of SIEMENS' angiography machine, the following measurements were taken, depending on the presence of an additional shield of lead equivalent of 0.25 mmPb, manufactured for this purpose: dose to gonad, dose to an area where the personal dosimeter is placed, and dose to an area of eye lens is located. An ion chamber(chamber volume 1,800 cc) was utilized to measure scattering radiation. The two imaging tests were carried out as follows: fluoroscopy of the abdomen (66 kV, 100 mA, 60 seconds) and of the head (70 kV, 65 mA, 60 seconds); and digital subtraction angiography(DSA) of the abdomen (67 kV, 264 mA, 20 seconds) and of the head (79 kV, 300 mA, 20 seconds). In all the experiments, the shielding efficiency of the gonad position was the largest at 59.8%. In case an additional shielding was used as protection against scattering radiation that came through the operating table and the lead curtain during an IR, the radiation shielding efficiency was estimated to be up to 59.8%, leading to a conclusion that its presence may effectively reduce the radiation exposure dose of medical staffs.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.274-281
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• 2016

Background: Whole-body counters are widely used to evaluate internal contamination of the internal presence of gamma-emitting radionuclides. In internal dosimetry, it is a basic requirement that quality control procedures be applied to verify the reliability of the measured results. The implementation of intercomparison programs plays an important role in quality control, and the accuracy of the calibration and the reliability of the results should be verified through intercomparison. In this study, we evaluated the reliability of 2 whole-body counting systems using 2 calibration methods. Materials and Methods: In this study, 2 whole-body counters were calibrated using a reference male bottle manikin absorption (BOMAB) phantom and a Radiation Management Corporation (RMC-II) phantom. The reliability of the whole-body counting systems was evaluated by performing an intercomparison with International Atomic Energy Agencyto assess counting efficiency according to the type of the phantom. Results and Discussion: In the analysis of counting efficiency using the BOMAB phantom, the performance criteria of the counters were satisfied. The relative bias of activity for all radionuclides was -0.16 to 0.01 in the Fastscan and -0.01 to 0.03 in the Accuscan. However, when counting efficiency was analyzed using the RMC- II phantom, the relative bias of $^{241}Am$ activity was -0.49 in the Fastscan and 0.55 in the Accuscan, indicating that its performance criteria was not satisfactory. Conclusion: The intercomparison process demonstrated the reliability of whole-body counting systems calibrated with a BOMAB phantom. However, when the RMC-II phantom was used, the accuracy of measurements decreased for low-energy nuclides. Therefore, it appears that the RMC-II phantom should only be used for efficiency calibration for high-energy nuclides. Moreover, a novel phantom capable of matching the efficiency of the BOMAB phantom in low-energy nuclides should be developed.

• Progress in Medical Physics
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• v.28 no.3
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• pp.122-128
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• 2017

Eclipse Scripting Application Programming Interface (ESAPI) was devised to enhance the efficiency in such treatment related workflows as contouring, treatment planning, plan quality measure, and data-mining by communicating with the treatment planning system (TPS). It is provided in the form of C# programming based toolbox, which could be modified to fit into the clinical applications. The Scripting program, however, does not offer all potential functionalities that the users intend to develop. The shortcomings can be overcome by combining the Scripting programming with user-executable program on Windows or Linux. The executed program has greater freedom in implementation, which could strengthen the ability and availability of the Scripting on the clinical applications. This work shows the use of the Scripting programming throughout the simple modification of the given toolbox. Besides, it presents the implementation of combining both Scripting and user-executed programming based on MATLAB, applied to automated dynamic MLC wedge and FIF treatment planning procedure for promoting the planning efficiency.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.1 s.94
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• pp.132-140
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• 1999

This paper suggests a monitoring method for the pulsed laser spot welding of the thin metal sheets using a point IR(InfraRed) sensor. A new criterion was introduced and the experimental results guaranteed the efficiency. The ideal radiation feature was derived from the mathematical model and was simulated. The radiation feature is robust to withstand the change of measuring condition and can be used to detect the absorbed laser energy. In an experiment, the radiation feature was examined for the differect laser energy. The pulse width and the laser power was variated and the radiation feature was examined. In the other experiment, the relationship between the weld strength and radiation feature was examined. Artificial Neural Network(ANN) was employed to find out the relationship. The correlation coefficient between the real strength and the estimated strength is high as 0.94 and the mean square error is low as 0.64 kgf learned parts. Another group of the welds was used to appraise the learning efficiency. The correlation coefficient between the measured and the estimated weld strength is high as 0.91.

• 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.

• The Korean Journal of Food & Health Convergence
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• v.4 no.3
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• pp.1-5
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• 2018

In today's technological development of human society more and more influence on the lives of biological organisms different electromagnetic radiation. Therefore, the study and analysis of the mechanisms of their effects is an urgent task. The purpose of research - the study of the primary mechanisms of interaction of photons of optical radiation with the structures of biological objects, using the laws of quantum mechanics and biophysics. Photobiological basis of the mechanism of action of EMR optical range is the energy absorption of light quanta (photons) by atoms and molecules of biological structures (law Grotgus-Draper), which resulted in the formation of electronically excited states of these molecules with the transfer of photon energy (internal photoeffect). This is accompanied by electrolytic dissociation and ionization of biological molecules. The degree of manifestation of photobiological effects in the body depends on the intensity of the optical radiation, which is inversely proportional to the square of the distance from the source to the irradiated surface. Accordingly, in practice, determine not the intensity and irradiation dose at a certain distance from the source of exposure by the exposure time.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.67.1-67.1
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• 2011

Knowledge of the solar radiation components and classified wavelength are essential for modeling many solar energy systems. This is particularly the case for applications that concentrate the incident energy to attain high photo-dynamic efficiency achievable only at the higher intensities. In order to estimate the performance of concentrating solar systems, it is necessary to know the intensity of the beam radiation, as only this components can be concentrated, and The new solar system can generate electricity from ultraviolet and infrared light as well as visible light. The Korea Institute of Energy Research(KIER) has began collecting solar radiation components data since January, 1988, and solar radiation classified wavelength data since November, 2008. KIER's solar radiation components and classified wavelength data will be extensively used by concentrating solar system users or designers as well as by research institutes.