• Nuclear Engineering and Technology
• /
• v.52 no.11
• /
• pp.2613-2619
• /
• 2020

This work investigated the gamma-ray shielding performance, and the physical and mechanical properties of poly (methyl methacrylate) (PMMA) composites embedded with 0-44.0 wt% bismuth trioxide (Bi₂O₃) fabricated by the fast ultraviolet (UV) curing method. The results showed that the addition of Bi₂O₃ had significantly improved the gamma shielding ability of PMMA composites. Mass attenuation coefficient and half-value layer were examined using five gamma sources (Cs-137, Ba-133, Cd-109, Co-57, and Co-60). The high loading of Bi₂O₃ in the PMMA samples improved the micro-hardness to nearly seven times that of the pure PMMA. With these enhancements, it was demonstrated that PMMA/Bi₂O₃ composites are promising gamma shielding materials. Furthermore, the fast UV curing exerts its great potential in significantly shortening the production cycle of shielding material to enable rapid manufacturing.

• The Journal of the Korea Contents Association
• /
• v.14 no.8
• /
• pp.233-242
• /
• 2014

The purpose of this study is to compare the reduction of the dose radioactivity by CARE kV with that of the Bismuth shielding. First, CT was performed with transparent materials, including a Bismuth shielder which is a well-known material for decreasing the dose of radiation. Moreover, we have estimated and compared the affects of the reduction of dose on eye lens, thyroid, breast and genitals. These steps aim to compare reactions with and without the application of the Rando phantom with PLD as well as with CARE kV or not. As a result, during the Brain angio scan, the dose of CARE kV set inspection test methods showed the least dose. Depending on whether we use CARE kV, which showed the effect of dose reduction by 63%. During the Carotid angio scan, the dose was increased by 13% by how to set CARE kV+Bismuth. During the Cardiac angio scan, which showed the effect of dose reduction by 31% by how to set CARE kV+Bismuth. During the Lower extremity angio scan, the dose was measured least by how to set up the whole Bismuth. Compared with CARE kV set of test methods, which showed the effect of dose reduction by 9%.

• Journal of the Korean Society of Radiology
• /
• v.12 no.4
• /
• pp.467-474
• /
• 2018

CBCT is useful for improving the accuracy of the treatment site, but Repeated use increases the exposure dose. In this study, we aimed to provide basic data for dose reduction in CBCT implementation by dataization the simulating and dose reduction effect using shielding substance. Material in this study, Analyzation the photon beam by simulate the CBCT Through MCNPX and then calculate the absorption dose of body organ at shooting moment of thoracic abdominal position as target UF-Revise simulated body. At this time. Dose reduction effects at this time were evaluated according to the texture of materials and presence of shielding materials( lead, antimony, barium, sulfate, tungsten, bismuth). When CBCT was taken without shielding, the dose was calculated to be high in the breast and spine, and the dose in the esophagus and lung was calculated to be low. The doses according to the shield material were calculated as barium sulfate, antimony, bismuth, lead, and tungsten. The shielding rate was the highest in the thymus (73.6%) and the breast (59.9%) compared with the dose reduction according to presence or absence of the shield. However, it showed the lowest shielding rate in lung (2.1%) and spine (12.6%).

• Journal of the Korea Convergence Society
• /
• v.12 no.11
• /
• pp.119-126
• /
• 2021

Radiation shielding clothing for medical institutions is used based on lead equivalent of 0.25 mmPb. However, this study intends to study the shielding suit that can guarantee the user's activity while considering the sensitivity of each part of the body. By manufacturing based on eco-friendly shielding material, it was attempted to solve the weight problem and environmental problem of existing lead aprons, and to present the same shielding performance as lead equivalent in thickness. The fabric of the produced shielding sheet was manufactured through a calendar process that adjusts the thickness of the shielding sheet from lead equivalent 0.12 mmPb to 0.32 mmPb. In addition, the usability evaluation of the manufactured shielding clothes was conducted for the subjects who were workers in medical institutions. As a result, the activity became easier and the weight was reduced by 0.26 kg. In the future, it is thought that it is necessary to improve the shielding suit design considering the activity.

• Journal of radiological science and technology
• /
• v.37 no.1
• /
• pp.49-56
• /
• 2014

Recently with CT developed, various studies for reduction of exposure dose is underway. Study of bismuth shields in these studies is actively underway, and has already been applied in the clinical. However, the application of the PET/CT examination was not activated. Therefore, through this study, depending on the application of bismuth shields in the PET/CT examination, we identify the quality of the image and the impact on the Standard Uptake Value (SUV). In this study, to apply to the shielding of the breast, by using the bismuth shields that contains 0.06 mm Pb ingredients, was applied to the PET/CT GEMINI TF 64 (Philips Healthcare, Cleveland, USA). Phantom experiments using the NEMA IEC Body Phantom, images were acquired according to the presence or absence of bismuth shields apply. Also, When applying, images were obtained by varying the spacing 0, 1, 2 cm each image set to the interest range in the depth of the phantom by using EBW-NM ver.1.0. When image of the PET Emission acquires, the SUV was in increased depending on the use of bismuth shields, difference in the depth to the surface from deep in the phantom increasingly SUV increased (P<0.005). Also, when using shields, as the more gab decreased, SUV is more increased (P<0.005). Through this study, PET/CT examination by using of bismuth shields which is used as purpose of reduction dose. When using shields, the difference of SUV resulting from the application of bismuth shields exist and that difference when gab is decrease and surface is wider. Therefore, setting spacing of shield should be considered, if considering the reduction of the variation of SUV and image quality, disease of deep organs should be a priority rather than superficial organ disease. Use of bismuth shielding factor considering the standard clinical examination, decrease unnecessary exposure can be expected to be considered.

• Journal of radiological science and technology
• /
• v.47 no.3
• /
• pp.205-211
• /
• 2024

Currently, with the development of technologies, X-ray examinations for medical examinations at hospital is increasing. This study was conducted to help reduce radiation exposure by measuring the exposure dose received by pediatric patients and the spatial dose of the X-ray room. Dosimeters were installed in the eyeball, thyroid gland, breast, gonads and 4 directions at a distance of 30 cm, 40 cm, 50 cm from the phantom. The dose was measured ten times each, before, and after the application of the bismuth shield under the examination conditions of the head, chest, and abdomen of pediatric patients. Under the condition of head examination, when a shielding was applied, the dose reduction rate was 68.58% for the eyeball, 72.88% for the thyroid, 84.2% for the breast, and 72.36% for the gonad. The chest examination showed reductions of 19.56% eyeball, 56.98% thyroid, 1.21% breast, and 0.68% gonad. The abdominal examination showed reduction rates of 2.6% eyeball, 10.67% thyroid, 19.85% breast, and 82.02% gonad. Spatial dose decreased by 62.25% at 30 cm, 61.16% at 40 cm, and 68.68% at 50 cm. When the bismuth shield was applied, there was a decrease in dose across all examinations, as well as a reduction in spatial dose. Continued research on the use of bismuth shields will help radiological technologists achieve their goal of dose reduction.

• The Journal of the Korea Contents Association
• /
• v.16 no.7
• /
• pp.451-456
• /
• 2016

To analyse the absorbed radiation dose of the visual organs (eyes, corneas, lenses) during a head CT scan, a with the purpose of radiation protection was designed. Afterwards, the reduction rate of radiation dose when using an eye-shielding was analyzed. The results showed that the higher the energy, the higher the absorbed dose of the eyes. Excluding the head, the organs with high dose were the eyes, corneas, and lenses, respectively. Furthermore, the dose reduction rate before and after shielding was between 38% and 55% for the eyes, and between 35% and 52% for the corneas. In the case of the lenses, when the front was shielded, the reduction rate was 51%, and when the front and the side were shielded simultaneously, the reduction rate was 67%.

• Journal of the Korean Society of Radiology
• /
• v.17 no.3
• /
• pp.441-447
• /
• 2023

Lead(Pb), which is currently mainly used for shielding purposes in the medical radiation, has excellent radiation shielding functions, but is continuously exposed to radiation directly or indirectly due to the harmfulness of lead itself to the human body and the inconvenience caused by its heavy weight. Research on shielding materials that are human-friendly, lightweight, and convenient to use that can block risks and replace lead is continuously being conducted. In this study, based on the commonly used polyethylene terephthalate (PET) film and the fabric material used in actual radiation protective clothing, a multi-layer thin film was realized through sputtering and vacuum deposition of bismuth, tungsten, and tin, which are metal materials that can shield radiation. Thus, a shielding film was produced and its applicability as a radiation shielding material was evaluated. The radiation shielding film was manufactured by establishing the optimized conditions for each shielding material while controlling the applied voltage, roll driving speed, and gas supply amount to manufacture the shielding film. The adhesion between the parent material and the shielding metal thin film was confirmed by Cross-cut 100/100, and the stability of the thin film was confirmed through a hot water test for 1 hour to measure the change of the thin film over time. The shielding performance of the finally realized shielding film was measured by the Korea association for radiation application (KARA), and the test conditions (inverse wide beam, tube voltage 50 kV, half layer 1.828 mmAl) were set to obtain an attenuation ratio of 16.4 (initial value 0.300 mGy/s, measured value 0.018 mGy/s) and damping ratio 4.31 (initial value 0.300 mGy/s, measured value 0.069 mGy/s) were obtained. by securing process efficiency for future commercialization, light and shielding films and fabrics were used to lay the foundation for the application of films to radiation protective clothing or construction materials with shielding functions.

• Journal of the Korean Society of Radiology
• /
• v.13 no.7
• /
• pp.969-977
• /
• 2019

Applying the bismuth shield used to reduce the radiation exposure, image quality may be reduced due to beam hardening caused by the shield during CT scan. Therefore, we tried to find out the energy range that can reduce image degradation by applying GSI mode of G company's dual energy CT and examine the possibility through experiment. As a result, after bismuth shielding, 118 ± 10.6 HU and 50.1 ± 14.6 HU at 50 keV after dual-energy CT scan were the most similar to the CT value before image deterioration(p> 0.05). It was measured 176.6 ± 7.1 and 138.3 ± 1.1 at 50 keV(p> 0.05). Experiments showed that the use of the shield during CT inspection inevitably degrades the image quality, but experiments show that the GSI function of the dual energy CT can maintain the image quality even when the shield is used. If the various shields are secured after the evaluation using the dual energy CT, it is expected to overcome the disadvantages of poor image quality caused by the use of the radiation shield for reducing the exposure, which is the biggest disadvantage of the CT scan.

• The Journal of the Korea Contents Association
• /
• v.15 no.7
• /
• pp.282-288
• /
• 2015

A monte carlo simulation about shielding material and thickness of the syringe shield for radiation shield was performed. As a result of analysis, high atomic number materials such as tungsten, lead and bismuth have the highest shielding effect. However, $^{18}F$, $^{67}Ga$ and $^{111}In$ show high energy distribution in the region with thin shielding thickness. As the thickness of shielding materials increased, the energy distribution decreased due to reduction of ${\gamma}$-ray. In the case of low atomic number materials, they, showed energy distribution from highest to lowest, were barium sulfate, steel, stainless, iron and copper. Aluminum, plastic, concrete and water showed diverse aspect. they showed relatively high energy distribution because of increased ${\gamma}$-ray that penetrate the shield.