• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.239-252
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• 2015

Purpose: Lead has been widely used in radiation shielding for its low price and high workability. Recently in several europe countries, use of lead was banned for environmental issues. Also lead can cause health problems like alergies. Alternative materials for lead are highly required. The purpose of this study was to propose lead free radiation shielding material. Methods: Research of radiation shielding in Korea is not easy for certain limits such as radiation materials, experimental facilities and places. The collected data through the research were simulated using MCNPX. The simulation tools used for this study were utilized Monte Carlo method. Results: we suggest new design of lead free radiation shielding material using MCNPX code comparing shielding performance of new composite materials to lead. Conclusion: This newly introduced nano-scale composite of metal and polymer makes new chance for highly lightened radiation protective garments with endurable shielding performance.

• Journal of radiological science and technology
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• v.47 no.4
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• pp.249-254
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• 2024

This study compared the X-ray shielding abilities of the shields using Computed Radiography(CR) System after manufacturing a lead-free boards using gypsum and BaSO₄, an eco-friendly X-ray shielding material. Total six lead-free boards were manufactured with BaSO₄ concentrations of 25 %, 50 % and thickness of 10 mm, 15 mm, 20 mm respectively, and additional thickness of 1.0 mm, 1.5 mm, 2.0 mm leads were prepared. In the experiment, Nine shields were placed on the Image Plate and placed in a Computed Tomography(CT) Room where CT scans were performed for 2 weeks. After that, the X-ray image of the shields were obtained through CR Reader, and Pixel Value(PV) were measured to evaluated the X-ray shielding abilities of the lead-free shields. The criterion for evaluating the shields was determined by comparing PV of lead-free board to that of the 1.5 mm thickness lead used in the CT rooms. As a result of the experiment, the PV of the lead-free boards within 25 % of the BaSO₄ concentration and within 10 mm of the thickness were not enough to be used as X-ray shields in the CT Room because they did not reach the PV of the 1.5 mm thickness lead. BaSO₄ concentration of 50 % at 20 mm thickness showed PV of 1.5 mm lead thickness or more indicating that it has an X-ray shielding ability to replace lead in the CT room

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2570-2575
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• 2024

The study aims to develop a novel, lead-free, flexible and lightweight composite shielding material against ionizing radiation. For this, it was used bismuth oxide (Bi₂O₃) in RTV-2 silicon matrix. The shielding tests were carried out in both diagnostic X-ray energies and intermediate gamma-ray energy range of up to 662 keV to determine the radiation attenuation properties of this material in terms of attenuation ratio, half value layer, tenth value layer, mean free path and lead equivalency of samples in weight of 30%, 40%, 50% in Bi₂O₃. In the diagnostic X-ray energy range, half value layer, tenth value layer and lead equivalency (in mm Pb) of the produced samples were measured at 80 and 100 kVp narrow beam conditions according to the requirements of EN IEC 61331-1 standard. The results show that lead equivalent values of the produced novel sheets was measured to be 0.16 mm Pb, corresponding to a 6 mm thickness of the flexible sample when it contains 30% wt. Bi₂O₃ in RTV matrix. The experimental findings for durability and flexibility also indicated that this new RTV-based flexible, lead -free shielding composite can be used safely for especially for manufacturing aprons, garments and thyroid guards used in mammography, radiology, nuclear medicine and dental applications in practice.

• Journal of the Korean Society of Radiology
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• v.18 no.6
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• pp.651-662
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• 2024

This study developed a lead-free shielding material using a filament made from a mixture of iron oxide and copper to address the toxicity issues associated with lead-based shielding. After creating the filaments, various thicknesses of shielding materials were printed using a FDM 3D printer. Shielding performance and dose measurements were taken by varying the tube voltage and current with a diagnostic X-ray generator, and data analysis was performed using SPSS (p < 0.05). The results showed that the iron oxide-copper mixed filament shielding exhibited better performance than a 0.25 mmPb lead-equivalent protection tool at thicknesses of 8 mm or more, except for the conditions of 120 kVp and 20 mAs. This research demonstrates that the mixed filament shielding can mitigate the drawbacks of lead while providing comparable shielding effectiveness, suggesting its potential as foundational data for further studies on lead-free shielding materials.

• Journal of the Korea Convergence Society
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• v.12 no.1
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• pp.105-110
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• 2021

Radiation shielding of affinity material, which is widely used in medical institutions, is made in sheet form and is mainly applied to apron. Shielding performance is presented based on lead equivalent, and is presented as 0.25-0.50mmPb. In the case of shielding materials where lead is used as the main material, the shielding performance can be adjusted by thickness due to the excellent machinability of lead. However, eco-friendly shielding sheets are difficult to control shielding performance based on thickness criteria as shielding performance varies depending on the content of shielding materials, the properties of polymeric materials that are base materials, and the technical differences in the process. In this study, shielding sheets were manufactured based on thickness to solve these problems and the shielding performance was compared in this study. As a result, it was shown that the laminated structure shielding sheet was more effective.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4708-4714
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• 2022

The novelty in the present search, the Soda-Lime-Silica (SLS) glass waste to prepare free lead glass shielding was used in order to limit the accumulation of glass waste, which requires extensive time to decompose. This also saves on the consumption of pure SiO₂, which is a finite resource. Furthermore, the combining of BaO with Bi₂O₃ into a glass network leads to increased optical properties and improved attenuation. The UV-Visible Spectrophotometer was used to investigate the optical properties and the radiation shielding properties were reported for current glass samples utilizing the PhysX/PDS online software. The optical property results indicate that when BaO content increases in glass structure, the Urbach energy ΔE, and refractive index n increases while the energy optical band gap E_opt decreases. The result of the metallisation criteria (M) revealed that the present glass samples are nonmetallic (insulators). Furthermore, the radiation shielding parameter findings suggest that when BaO was increased in the glass structure, the linear attenuation coefficient and effective atomic number (Z_eff) rose. But the half-value layer HVL declined as the BaO concentration grew. According to the research, the glass samples are non-toxic, transparent to visible light, and efficient radiation shielding materials. The Ba5 sample is considered the best among all the samples due to its higher attenuation value and lower HVL and MFP values, which make it a suitable candidate as transparent glass shield shielding.

• Nuclear Engineering and Technology
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• v.56 no.10
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• pp.4103-4114
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• 2024

This research aimed to develop lead-free polymer composites based on poly-methyl methacrylate (PMMA) and embedded with tungsten carbide (WC) micro and nanoparticles for use in radiation protection applications. PMMA was filled with 20 %, 40 %, and 60 % by weight of WC micro- and nanoparticles. The shielding features of the proposed polymer mixtures were evaluated at different radioactive sources of different energies using the HPGe detector. The results revealed that the investigated composites containing micro and nano-structured WC particles showed superior radiation shielding at 81 keV due to the K-edge of the W element occurring at 69.5 keV. The findings also demonstrated that composites loaded with WC nanoparticles were more effective in shielding gamma radiation than those loaded with WC microparticles, even at the same filler wt.%. Furthermore, the sample containing 60 % by weight of nano-WC, coded as P-60nWC, had superior shielding performance than other polymer-based composites reported in the literature. Thus, the proposed nano-WC/PMMA composites can be effectively employed in radiation facilities as alternative environmentally and lead-free radiation shielding materials to protect people and the environment from the harmful risks of gamma radiation.

• Progress in Medical Physics
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• v.21 no.2
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• pp.232-237
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• 2010

The shielding materials designed for replacement of lead equivalent materials for lighter apron than that of lead in diagnostic photon beams. The absorption characteristics of elements were applied to investigate the lead free material for design the shielding materials through the 50 kVp to 110 kVp x-ray energy in interval of 20 kVp respectively. The idea focused to the effect of K-edge absorption of variable elements excluding the lead material for weight reduction. The designed shielding materials composited of Tin 34.1%, Antimon 33.8% and Iodine 26.8% and Polyisoprene 5.3% gram weight account for 84 percent of weight of lead equivalent of 0.5 mm thickness. The size of lead-free shielder was $200{\times}200{\times}1.5\;mm^3$ and $3.2\;g/cm^3$ of density which is equivalent to 0.42 mm of Pb. The lead equivalent of 0.5 mm thickness generally used for shielding apron of diagnostic X rays which is transmitted 0.1% for 50 kVp, 0.9% for 70 kVp and 3.2% for 90 kVp and 4.8% for 110 kVp in experimental measurements. The experiment of transmittance for lead-free shielder has showed 0.3% for 50 kVp, 0.6% for 70 kVp, 2.0% for 90 kVp and 4.2% for 110 kVp within ${\pm}0.1%$. respectively. Using the attenuation coefficient of experiments for 0.5 mm Pb equivalent of lead-free materials showed 0.1%. 0.3%, 1.0% and 2.4%, respectively. Furthermore, the transmittance of lead-free shielder for scatter rays has showed the 2.4% in operation energy of 50 kVp and 5.9% in energy of 110 kVp against 2.4% and 5.1% for standard lead thickness within ${\pm}0.2%$ discrepancy, respectively. In this experiment shows the designed lead-free shielder is very effective for reduction the apron weight in diagnostic radiation fields.

• Journal of the Korean Society of Radiology
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• v.14 no.4
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• pp.367-373
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• 2020

Most of the spatial scattered dose caused by the scattered rays generated by the collision between the object and X-rays is relatively easily absorbed by the human body as electromagnetic waves in the low energy region, thereby increasing the degree of radiation exposure. Such spatial scattering dose is also used as an indicator of the degree of radiation exposure of radiation workers and patients, and there is a need for a method to reduce exposure by reducing the spatial scattered dose that occurs indirectly. Therefore, in this study, a lead-free radiation shielding sheet was proposed as a way to reduce the spatial scattering dose, and a Monte Carlo (MC) simulation was performed based on a chest X-ray examination. The absorbed dose was calculated and the measured value and the shielding rate were compared and evaluated.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.860-866
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• 2019

The lead element or its salts are good radiation shielding materials. However, their toxic effects are high. Due to less toxicity of bismuth salts, the radiation shielding properties of the bismuth salts have been investigated and compared to that of lead salts to establish them as a better alternative to radiation shielding material to the lead element or its salts. The transmission geometry was utilized to measure the mass attenuation coefficient (${\mu}/{\rho}$) of different salts containing lead and bismuth using a high-resolution HPGe detector and different energies (between 81 and 1333 keV) emitted from point sources of $^{133}Ba$, $^{57}Co$, $^{22}Na$, $^{54}Mn$, $^{137}Cs$, and $^{60}Co$. The experimental ${\mu}/{\rho}$ results are compared with the theoretical values obtained through WinXCOM program. The theoretical calculations are in good agreement with their experimental ones. The radiation protection efficiencies, mean free paths, effective atomic numbers and electron densities for the present compounds were determined. The bismuth fluoride ($BiF_3$) is found to have maximum radiation protection efficiency among the selected salts. The results showed that present salts are more effective for reducing the intensity of gamma photons at low energy region.