• The Korean Journal of Nuclear Medicine
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• v.35 no.5
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• pp.324-333
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• 2001

Purpose: $^{123}I$-labeled fatty acids have been used in the evaluation of regional myocardial energy metabolism. This study aimed to evaluate the usefulness of $^{123}I$-BMIPP as a liposarcoma-imaging agent. Materials and Methods: We compared in vitro uptakes between liposarcoma(SW872) and glioma(9L) cell lines, and examined biodistribution and in vivo images of $^{123}I$-BMIPP in liposarcoma-bearing nude mice. Cold-BMIPP was labeled with $^{123}I\;using\;Cu^{2+}$ as catalyst. After purification by Sep-pak, radiochemical purity was determined by TLC. We compared cellular uptake between glioma and liposarcoma after incubation of 5, 10, 15, 30, 60, 120, and 180 mins with culture medium containing $^{123}I$-BMIPP. The difference in biodistribution was determined between non-feeding (water only) group for 18 hr and feeding group in normal mice (n=6/group) at 0.5, 2, and 24 hr. In liposarcoma-hearing nude mice model, liposarcoma, SW872, ceil lines were injected subcutaneously into the felt thigh of nude mice. The biodistribution of $^{123}I$-BMIPP was evaluated at 0.5, 2, and 24 hr (n:5 / group) and in vivo Image of $^{123}I$-BMIPP was obtained with gamma camera at 2 and 24 hr in liposarcoma-hearing nude mice. Results: Radiolabeling yield and radiochemical purity were 95% and above 99%, respectively. SW872 cell line showed more increased uptake than 9L with 1.5 times at 180 mins. The clearance of $^{123}I$-BMIPP in various tissues was more delayed in the non-feeding group than in the feeding group, especially at delayed time (24 hr) in normal mice, and the major excreting organ was the gastrointestinal tract. In liposarcoma-bearing nude mice, tumor/blood ratio of $^{123}I$-BMIPP was 0.94, 0.75, and 1.38 and tumor/muscle ratio was 0.66, 1.53, and 1.11 at 0.5, 2, and 24hr, respectively. $^{123}I$-BMIPP was selectively localized in liposarcoma at 24 hr image. Conclusions: These results suggest that $^{123}I$-BMIPP can be used as a liposarcoma-imaging agent.

• Radiation Oncology Journal
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• v.28 no.1
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• pp.50-56
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• 2010

Purpose: We report the results of an external audit on the absorbed dose of radiotherapy beams independently performed by third parties. For this effort, we developed a method to measure the absorbed dose to water in an easy and convenient setup of solid water phantom. Materials and Methods: In 2008, 12 radiotherapy centers voluntarily participated in the external auditing program and 47 beams of X-ray and electron were independently calibrated by the third party’s American Association of Physicists in Medicine (AAPM) task group (TG)-51 protocol. Even though the AAPM TG-51 protocol recommended the use of water, water as a phantom has a few disadvantages, especially in a busy clinic. Instead, we used solid water phantom due to its reproducibility and convenience in terms of setup and transport. Dose conversion factors between solid water and water were determined for photon and electron beams of various energies by using a scaling method and experimental measurements. Results: Most of the beams (74%) were within ${\pm}2%$ of the deviation from the third party's protocol. However, two of 20 X-ray beams and three of 27 electron beams were out of the tolerance (${\pm}3%$), including two beams with a >10% deviation. X-ray beams of higher than 6 MV had no conversion factors, while a 6 MV absorbed dose to a solid water phantom was 0.4% less than the dose to water. The electron dose conversion factors between the solid water phantom and water were determined: The higher the electron energy, the less is the conversion factor. The total uncertainty of the TG-51 protocol measurement using a solid water phantom was determined to be ${\pm}1.5%$. Conclusion: The developed method was successfully applied for the external auditing program, which could be evolved into a credential program of multi-institutional clinical trials. This dosimetry saved time for measuring doses as well as decreased the uncertainty of measurement possibly resulting from the reference setup in water.

• Journal of radiological science and technology
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• v.39 no.2
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• pp.237-246
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• 2016

This study is therefore aimed at measuring the surface dose rate and the spatial dose rate in and outside the radionuclide facility in order to ensure safety of the patients, radiation workers and family care-givers in their use of such equipment and to provide a basic framework for further research on radiation protection. The study was conducted at 4 restrooms in and outside the radionuclide facility of a general hospital in Incheon between May 1 and July 31, 2014. During the study period, the spatial contamination dose rate and the surface contamination dose rate before and after radiation use were measured at the 4 places-thyroid therapy room, PET center, gamma camera room, and outpatient department. According to the restroom use survey by hospitals, restrooms in the radionuclide facility were used not only by patients but also by family care-givers and some of radiation workers. The highest cumulative spatial radiation dose rate was 8.86 mSv/hr at camera room restroom, followed by 7.31 mSv/hr at radioactive iodine therapy room restroom, 2.29 mSv/hr at PET center restroom, and 0.26 mSv/hr at outpatient department restroom, respectively. The surface radiation dose rate measured before and after radiation use was the highest at toilets, which are in direct contact with patient's excretion, followed by the center and the entrance of restrooms. Unsealed radioactive sources used in nuclear medicine are relatively safe due to short half lives and low energy. A patient who received those radioactive sources, however, may become a mobile radioactive source and contaminate areas the patient contacts-camera room, sedation room, and restroom-through secretion and excretion. Therefore, patients administered radionuclides should be advised to drink sufficient amounts of water to efficiently minimize radiation exposure to others by reducing the biological half-life, and members of the public-family care-givers, pregnant women, and children-be as far away from the patients until the dose remains below the permitted dose limit.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.105-111
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• 2010

Purpose: There are various beam parameter in intensity modulated radiation therapy (IMRT). The aim of this study is to investigate how various dose rate affect the parotid in treatment plan of IMRT. Materials and Methods: The study was performed on 10 nasopharyngeal carcinoma patients who have undergone IMRT. CT images were scanned 3 mm of thickness in the same condition and the treatment plan was performed by Eclipse (Ver.7.1, Varian, Palo Alto, USA). The parameters for planning used 6 MV energy and 8 beams under the same dose volume constraint. The variation of dose rates were used 300, 400, 500 MU/min. The mean dose of both parotid was accessed from the calculated planning among the 10 patients. The mean dose of parotid was verificated by 2D diode array (Mapcheck from Sun Nuclear Corporation, Melbourne, Florida). Also, Total monitor unit (MU) and beam-on time was analysed. Results: According to the dose rate, the mean dose of parotid was increased by 0.8%, 2.0% each, when dose rate was changed from 300 MU/min to 400, 500 MU/min, moreover Total MU was increased by 5.4% and 10.6% each. There was also a dose upward trend in the dose measurement of parotid by 2D diode array. However, beam - on time difference of 1~2 minutes was no signigicant in the dose rate increases. Conclusion: From this study, when the dose rates increase, there was a signigicant increase of Total MU and the parotid dose accordingly, however the shortened treatment time was not significant. Hence, it is considered that there is a significant decrease of late side effect in parotid radiation therapy, if the precise dose rate in IMRT is used.

• The Korean Journal of Nuclear Medicine
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• v.35 no.6
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• pp.378-388
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• 2001

Purpose: In this study, we developed a new method for the determination of renal depth with anterior and posterior renal scintigrams in a dual-head gamma camera, considering the attenuation factor $e^{-{\mu}x}$ of the conjugate-view method. Material and Method: We developed abdomen and kidney phantoms to perform experiments using Technetium-99m dimercaptosuccinic acid ($^{99m}Tc$-DMSA). The phantom images were obtained by dual-head gamma camera equipped with low-energy, high-resolution, parallel-hole collimators (ICONf, Siemens). The equation was derived from the linear integration of omission ${\gamma}$-ray considering attenuation from the posterior abdomen to the anterior abdomen phantom surface. The program for measurement was developed by Microsoft Visual C++ 6.0. Results : Renal depths of the phantoms were derived from the derived equations and compared with the exact geometrical values. Differences between the measured and the calculated values were the range of 0.1 to 0.7 cm ($0.029{\pm}0.15cm,\;mean{\pm}S.D.$). Conclusion: The present study showed that the use of the derived equations for renal depth measurements, combined with quantitative planar imaging using dual-head gamma camera, could provide more accurate results for individual variation than the conventional method.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.5
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• pp.587-609
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• 2019

Short-and long-term stabilities of bentonite, favored material as buffer in geological repositories for high-level waste were reviewed in this paper in addition to alternative design concepts of buffer to mitigate the thermal load from decay heat of SF (Spent Fuel) and further increase the disposal efficiency. It is generally reported that the irreversible changes in structure, hydraulic behavior, and swelling capacity are produced due to temperature increase and vapor flow between $150{\sim}250^{\circ}C$. Provided that the maximum temperature of bentonite is less than $150^{\circ}C$, however, the effects of temperature on the material, structural, and mineralogical stability seems to be minor. The maximum temperature in disposal system will constrain and determine the amount of waste to be disposed per unit area and be regarded as an important design parameter influencing the availability of disposal site. Thus, it is necessary to identify the effects of high temperature on the performance of buffer and allow for the thermal constraint greater than $100^{\circ}C$. In addition, the development of high-performance EBS (Engineered Barrier System) such as composite bentonite buffer mixed with graphite or silica and multi-layered buffer (i.e., highly thermal-conductive layer or insulating layer) should be taken into account to enhance the disposal efficiency in parallel with the development of multilayer repository. This will contribute to increase of reliability and securing the acceptance of the people with regard to a high-level waste disposal.

• Imaging Science in Dentistry
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• v.50 no.2
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• pp.161-168
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• 2020

Purpose: The aim of this study was to evaluate the influence of voxel size and different post-processing algorithms on the analysis of dental materials using micro-computed tomography (micro-CT). Materials and Methods: Root-end cavities were prepared in extracted maxillary premolars, filled with mineral trioxide aggregate (MTA), Biodentine, and Intermediate Restorative Material (IRM), and scanned using micro-CT. The volume and porosity of materials were evaluated and compared using voxel sizes of 5, 10, and 20 ㎛, as well as different software tools(post-processing algorithms). The CTAn or MeVisLab/Materialise 3-matic software package was used to perform volume and morphological analyses, and the CTAn or MeVisLab/Amira software was used to evaluate porosity. Data were analyzed using 1-way ANOVA and the Tukey test(P<0.05). Results: Using MeVisLab/Materialise 3-matic, a consistent tendency was observed for volume to increase at larger voxel sizes. CTAn showed higher volumes for MTA and IRM at 20 ㎛. Using CTAn, porosity values decreased as voxel size increased, with statistically significant differences for all materials. MeVisLab/Amira showed a difference for MTA and IRM at 5 ㎛, and for Biodentine at 20 ㎛. Significant differences in volume and porosity were observed in all software packages for Biodentine across all voxel sizes. Conclusion: Some differences in volume and porosity were found according to voxel size, image-processing software, and the radiopacity of the material. Consistent protocols are needed for research evaluating dental materials.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.5
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• pp.370-376
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• 2016

Corrosion on the surface of a structure can generate cracks or cause walls to thin. This can lead to fracturing, which can eventually lead to fatalities and property loss. In an effort to prevent this, laser imaging technology has been used over the last ten years to detect thin-plate structure, or relatively thin piping. The most common laser imaging was used to develop a new technology for inspecting and imaging a desired area in order to scan various structures for thin-plate structure and thin piping. However, this method builds images by measuring waves reflected from defects, and subsequently has a considerable time delay of a few milliseconds at each scanning point. In addition, the complexity of the system is high, due to additional required components, such as laser-focusing parts. This paper proposes a laser imaging method with an increased scanning speed, based on excitation and the measurement of standing waves in structures. The wavenumber of standing waves changes at sections with a geometrical discontinuity, such as thickness. Therefore, it is possible to detect defects in a structure by generating standing waves with a single frequency and scanning the waves at each point by with the laser scanning system. The proposed technique is demonstrated on a wall-thinned plate with a linear thickness variation.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2_spc
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• pp.327-336
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• 2020

The high-flux advanced neutron application reactor (HANARO) is a research reactor with thermal power of 30 MW applied in various research and development using neutrons generated from uranium fission chain reaction. A degasifier tank is installed in the ancillary facility of HANARO. This facility generates gas pollutants produced owing to internal environmental factors. The degasifier tank is designed to maintain the gas contaminants below acceptable levels and is monitored using an analyzer in the gas sampling panel. If condensate water is generated and flows into the analyzer of the gas sampling panel, corrosion occurs inside the analyzer's measurement chamber, which causes failure. Condensate water is generated because of the temperature difference between the degasifier tank and analyzer when the gas flows into the analyzer. A heating system is installed between the degasifier tank and gas sampling panel to suppress condensate water generation and effectively remove the condensate water inside the system. In this study, we investigated the efficiency of the heating system. In addition, the variations in the pipe temperature and the amount of average condensate water were modeled using a wall condensation model based on the changes in the fluid inlet temperature, outside air temperature, and heating cable-setting temperature.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.4
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• pp.294-303
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• 2005

This paper describes the analysis results of a series f Round-Robin test that was performed to intercompare inspection and diagnosis techniques for characterization of pressure tube f a pressurized heavy water reactor under the Coordinated Research Project(CRP) of IAEA's nuclear Power Programme. For this test, six nations, Korea, Canada, India, Argentina, Rumania, and China that currently have pressurized heavy water reactors under operation involved, and the "KOR-1" pressure tube sample prepared by Korea was used. Two kinds of NDE technique, ultrasonic and eddy current test, were applied for these tests. The "KOR-1" pressure tube sample contains total 12 artificial flaws such as crack-like EDM notches, wear that is similar to the real flaws and can be produced on the pressure tubes during plant operation. Test results showed that seven laboratories from six nations detected all twelve flaws in "KOR-1" specimen by using ultrasonic and eddy current test methods, and ultrasonic test method was more accurate than eddy current test method in flaw detectin and sizing. ID flaws in pressure tube sample were more easily detected and accurately sized than OD flaws.