• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.271-281
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• 2019

This study investigated the shielding efficiency of various types of shielding materials and measured the dose by organ using the phantom. Results of Shielding Efficiency Measurement Using Personal Radiation Meter. Among the various shielding materials, 1.1 mm RNS-TX composed of nano tungsten showed the highest shielding efficiency and 0.2 mm lead shielding showed the lowest shielding efficiency. 99mTc 30 mCi was exposed to the phantom for 120 minutes and the result of the measurement of the organs. 20.53 mSv without radiation protective clothing, 8.75 mSv when wearing 0.25 mm Pb protective clothing, 6.03 mSv when wearing 0.5 mm Pb protective clothing. 131I 2 mCi mCi was exposed to the phantom for 120 minutes and the result of the measurement of the organs. 7.71 mSv without radiation protective clothing, 4.88 mSv when wearing 0.25 mm Pb protective clothing, 2.79 mSv when wearing 0.5 mm Pb protective clothing. 18F 5 mCi was exposed to the phantom for 120 minutes and the result of the measurement of the organs. 16.39 mSv without radiation protective clothing, 15.84 mSv when wearing 0.25 mm Pb protective clothing, 12.52 mSv when wearing 0.5 mm Pb protective clothing. None of the radiation workers working in the nuclear medicine department exceeded the dose limit. However, when compared with other workers in the hospital, they showed a relatively high dose. Therefore, it is necessary to prepare measures to reduce and manage the dose of radiation workers in the nuclear medicine department through the wearing of radiation protective clothing made of lightweight, shielding material with good shielding efficiency, circulation task, task sharing, and substitution equipment such as auto dispenser.

• Journal of radiological science and technology
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• v.33 no.2
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• pp.121-126
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• 2010

Traditionally, lead has been primarily used to shield the radiation in the hospital, because of its soft texture, durability and cost effectiveness. However, lead can be dangerous because of its toxicity when exposed to the human body, and it is classified as a heavy metal like cadmium, mercury, and arsenic etc. In order to compensate its noxious properties on the human body, researchers are trying to develop a radiation shield which has similar shielding efficiency and can also be manufactured in any form. In this study, sulfuric acid barium was mixed with fiber, rubber, and silicon all of which are harmless to the human body, tested, and evaluated for its ability of medical radiation shield. The result of this study showed that the sheet containing silicon and barium has the strongest shielding abilities.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.1
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• pp.35-41
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• 2007

Purpose: To evaluate the effectiveness of a simple and practical shielding device to reduce the fetal dose for a pregnant patient undergoing radiation therapy of brain metastasis. Materials and Methods: The dose to the fetus was evaluated by simulating the treatments using the anthropomorphic phantom. The prescription dose at mid-brain is $300cGy{\times}10$ fractions with 6 MV photon with $18{\times}22cm^2$ field size. The additional shielding devices to reduce the fetal dose are a shielding wall, cerrobend plates and lead (Pb) sheets over acrylic bridge. Various points of measurement with off-field distance were detected by using ion-chamber (30, 40, 50, and 60 cm) with and without the shielding devices and TLD (30, 40, 50, 60, and 70 cm) only with the shielding devices. Results: The doses to the fetus without shielding were 3.20, 3.21, 1.44, 0.90 cGy at the distances of 30, 40, 50, and 60 cm from the treatment field edge. With shielding, the doses were reduced to 0.88, 0.60, 0.35, 0.25 cGy, and the ratio of the shielding effect varied from 70% to 80%. TLD results were 1.8, 1.2, 0.8, 1.2, and 0.8 cGy (70 cm). The total dose to the fetus was expected to be under 1 cGy during the entire treatment. Conclusion: The essential point during radiation therapy of pregnant patient would be minimizing the fetal dose. 10 cGy to 20 cGy is the threshold dose for fetal radiation effects. Our newly developed device reduced the fetal dose far below the safe level. Therefore, our additional shielding devices are useful and effective to reduce the fetal dose.

• Journal of Radiation Protection and Research
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• v.42 no.1
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• pp.26-32
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• 2017

Background: Ionizing radiation is known to be harmful to human health. The shielding of ionizing radiation depends on the attenuation which can be achieved by three main rules, i.e. time, distance and absorbing material. Materials and Methods: The mass attenuation coefficient, linear attenuation coefficient, Half Value Layer (HVL) and Tenth Value Layer (TVL) of X-rays (32 keV, 74 keV) and gamma rays (662 keV) are measured in Barium compounds. Results and Discussion: The measured values agree well with the theory. The effective atomic numbers ($Z_{eff}$) and electron density (Ne) of Barium compounds have been computed in the wide energy region 1 keV to 100 GeV using an accurate database of photon-interaction cross sections and the WinXCom program. Conclusion: The mass attenuation coefficient and linear attenuation coefficient for $BaCO_3$ is higher than the $BaCl_2$, $Ba(No_3)_2$ and BaSO4. HVL, TVL and mean free path are lower for $BaCO_3$ than the $BaCl_2$, $Ba(No_3)_2$ and $BaSO_4$. Among the studied barium compounds, $BaCO_3$ is best material for x-ray and gamma shielding.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.215-221
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• 2023

Among brain CT scan conditions including the lens, the tube voltage was changed to 80, 100, and 120 kVp and applied. The change in dose was analyzed using lead, lead goggles and barium sulfate silicon shielding materials, and the degree of influence of the shielding materials on image quality was compared and analyzed by applying the SNR, CNR, and SSIM index analysis methods. As a result, it was analyzed that although the dose was reduced by applying all shielding materials, the difference in dose reduction was not large (P > 0.05). In addition, as for the change in image quality due to the application of the shielding material, SNR and CNR were the highest when lead goggles were applied, and the structural similarity was measured to be the best as it was closest to the reference value of 1 in SSIM analysis. Therefore, based on the results of this study, it is thought that if more diverse shielding materials and clinical test results are derived and applied, it will be helpful for the clinical application criteria in the case of shielding utilization inspection.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.547-553
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• 2017

In the current medical field, lead is widely used as a radiation shield. However, the lead weight is very heavy, so wearing protective clothing such as apron is difficult to wear for long periods of time and there is a problem with the danger of lethal toxicity in humans. Recently, many studies have been conducted to develop substitute materials of lead to resolve these problems. As a substitute materials for lead, barium(Ba) and iodine(I) have excellent shielding ability. But, It has characteristics emitting characteristic X-rays from the energy area near 30 keV. For patients or radiation workers, shielding materials is often made into contact with the human body. Therefore, the characteristic X-rays generated by the shielding material are directly exposured in the human body, which increases the risk of increasing radiation absorbed dose. In this study, we have developed the FLUKA transport code, one of the most suitable elements of radiation transport codes, to remove the characteristic X-rays generated by barium or iodine. We have verified the reliability of the shielding fraction of the structure of the structure shielding by comparing with the MCPDX simulations conducted as a prior study. Using the MCNPX and FLUKA, the double layer shielding structures with the various thickness combination consisting of barium sulphate ($BaSO_4$) and bismuth oxide($Bi_2O_3$) are designed. The accuracy of the type shown in IEC 61331-1 was geometrically identical to the simulation. In addition, the transmission spectrum and absorbed dose of the shielding material for the successive x-rays of 120 kVp spectra were compared with lead. In results, $0.3mm-BaSO_4/0.3mm-Bi_2O_3$ and $0.1mm-BaSO_4/0.5mm-Bi_2O_3$ structures have been absorbed in both 33 keV and 37 keV characteristic X-rays. In addition, for high-energy X-rays greater than 90 keV, the shielding efficiency was shown close to lead. Also, the transport code of the FLUKA's photon transport code was showed cut-off on low-energy X-rays(below 33keV) and is limited to computerized X-rays of the low-energy X-rays. But, In high-energy areas above 40 keV, the relative error with MCNPX was found to be highly reliable within 6 %.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1822-1829
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• 2024

The search for materials that serve as good shields for radiation has become very important in light of the increasing exposure to ionizing radiation in various vital sectors. The aim is to search for novel materials with better radiation shielding properties that are stable, nontoxic, and abundant and environment friendly. The solidstate reaction approach has been used to synthesize a few ceramics, including BaZr_XTi_1-XO₃, Ba_1-XLa_XTiO₃ and Ba_1-XLa_XZr_XTi_1-XO₃ (with x = 0.10) i.eBaZr_0.10Ti_0.90O₃ (BZT), Ba_0.90La_0.10TiO₃ (BLT), and Ba_0.90La_0.10Zr_0.10Ti_0.90O₃ (BLZT). The density of the prepared samples varies from 6.3471 to 11.6003 g/cm³. The X-ray diffraction technique, shows strong peaks to confirm the crystalline structure of prepared ceramic samples. Using the G-P fitting approach, the advanced radiation shielding parameters (build-up factor) have been evaluated in the photon energy region of 1.5 keV-15 MeV. It is observed from the results that exposure buildup factor (EBF) and energy absorption buildup factor (EABF) are maximum for BLZT and has the minimum value for BZT in the entire photon energy regime. The results of this work should be useful in radiation shielding applications such as in industry, medicine, and nuclear engineering.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.565-572
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• 2019

In this study, shielding analysis of material and thickness of 3D printer filaments was performed for the manufacture of custom shielding by radiation workers during outdoor radiographic test. The shielding was attached to the ICRU Slab Phantom after selecting the voxel source $^{192}Ir$ and $^{75}Se$ through simulation using MCNPX, and the distance between the source and the slab Phantom was set at 100 cm. The 12 shielding materials were divided into 5 mm units up to 200 mm from the absence of shielding materials to evaluate the energy absorbed per unit mass of each shielding material. The results showed that the shielding effect was high in the order of ABS + Tungsten, ABS + Bismuth, PLA + Copper, PLA + Iron from all sources of radiographic test. However, compared to lead, the shielding effect was somewhat lower. Based on this study in the future, further study of the atomic number and the high density filament material is necessary.

• Korean Journal of Materials Research
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• v.8 no.5
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• pp.457-463
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• 1998

New neutron shielding materials, KNS-201, KNS-301 and KNS-601 have been fabricated to be used for radioactive material shipping and storage cask. The base materials are a modified and a hydrogenated bisphenol- A type and novolac type epoxy resin, and aluminium hydroxide and boron carbide are added. These shielding materials offer good fluidity at processing, which makes it possible to form this resin shield into complicated geometric shapes such as radioactive material shipping and storage cask. Several measurements were made for the shielding materials to evaluate the thermal and mechanical properties and radiation resistance. The properties of the shielding materials are as follows: onset temperatures 2S7~28$0^{\circ}C$, thermal conductivities 0.9S~1.14W/m. K, thermal expansion coefficients 0.77~1.26x$10_{-6}{\circ}C_{-1}$, combustion characteristics < 80$0^{\circ}C$, ATB(average time of burning) < 5sec, AEB(average extent of burning) < 5mm, tensile strengths 2.5~3.2kg/$\textrm{mm}^2$, compressive strengths 13.2~1S.2kg/$\textrm{mm}^2$, flexural strengths 5.2 -6.4kg/$\textrm{mm}^2$. In general, the concerned properties of KNS-201, KNS-301 and KNS-601 were revealed to be better than those of NS-4- FR. foreign neutron shielding material. It is also observed that the radiation resistance of KNS- 601 was better than those of KNS-201 and KNS-301.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2842-2849
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• 2024

The amorphous glasses containing PbO, ZnO, MgO, and B₂O₃ have been fabricated using the melt quenching technique. The structural properties have been analysed using the Fourier-transform infrared (FTIR) and Raman spectroscopy. Derivative of Absorption Spectra Fitting (DASF) method have been used to estimate the band gap energy from the UV-Vis absorption data which decreases from 3.02 eV to 2.66 eV with increasing the concentration of the PbO.The four glass samples 0.284 and 0.826 MeV showed unique variations in terms of gamma attenuation ability. LZMB4 glass sample proved to be the mist effective in terms of shielding of gamma radiation as it requires little distance compared to LZMB3, LZMB2 and LZMB1 to attenuate. RPE revealed a raise with increase in the thickness of the material and reduces as the energy raises. TF is superior in LZMB1 compared to LZMB2, LZMB3 and LZMB4, confirming that, LZMB4 will attenuate better. The Z_Eff of the materials was seen falling as the energy increases, confirming that the linear attenuation coefficient of the glass materials decreases when the energy is increased. The results confirmed that, glass material LZMB4 is the best option especially for gamma radiation shielding applications compared to LZMB3, followed by LZMB2, then LZMB1.