• Title/Summary/Keyword: Shielding Device

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Development and Efficiency Evaluation of Auxiliary Shielding using Elbow Support (팔꿈치 지지대를 사용한 보조 차폐 기구의 개발 및 효용성 평가)

  • Hyun-Woo Im;Jae-Suk Kim;Dong-Gu Kang
    • Journal of the Korean Society of Radiology
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    • v.18 no.1
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    • pp.11-20
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    • 2024
  • As the importance of intervention has recently increased, interest in the health of medical staff performing the procedure is increasing. Existing radiation shielding devices have limited the operator's movement and have not been properly used due to the risk of infection, and adequate radiation shielding of the operator's gonads and furthermore, the entire area of the procedure room has not been achieved. An auxiliary shielding device was manufactured by attaching a Bismuth to the elbow support used in the procedure, and the radiation shielding effect was measured. As a result of the measurement, the average spatial dose rate decreased by about 64.8%, and the independent sample t-test analysis showed statistically significant below the significance probability (p<0.05). The use of an auxiliary shielding device is considered to be an effective shielding method that can shield the operator's gonads and reduce the radiation spatial dose rate of the entire area of the procedure room.

Evaluations of the Space Dose and Dose Reductions in Patients and Practitioners by Using the C-arm X-ray Tube Shielding Devices Developed in Our Laboratory

  • Kim, Jae Seok;Kim, Sung Ho;Lee, Bu Hyung;Kwon, Soo Il;Jung, Hai Jo;Hoe, Seong Wook;Son, Jin Hyun;Kang, Byeong Sam
    • Progress in Medical Physics
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    • v.27 no.4
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    • pp.241-249
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    • 2016
  • The present study used a digital angiography x-ray device to measure the space dose and exposure dose of patients and practitioners using x-ray tube shielding devices developed in our laboratory. The intent of the study was to reduce the space dose within the test room, and to reduce the exposure dose of patients and practitioners. The patient and practitioner exposure doses were measured in five configurations in a human body model. The glass dosimeter was placed on the eye lenses, thyroid glands, left shoulder, right shoulder, and gonads. The beam was collimated at full size and at a 48% reduction for a comparative analysis of the measurements. The space dose was measured with an ion chamber at distances of 50 cm, 100 cm, and 150 cm from the x-ray tube under the following conditions: no shielding device; a shielding device made of 3-mm-thick lead (Pb) [Pb 3 mm shield], and a shielding device made of 3-mm-thick Pb (outside) and 3-mm-thick aluminum (Al) (inside) [Pb 3 mm+Al 3 mm shield]. The absorbed dose was the lowest when the 3-mm-thick Pb+3-mm-thick Al shield was used. For measurements made with collimated beams with a 48% reduction, the dose was the lowest at $154{\mu}Gy$ when the 3-mm-thick Pb+3-mm-thick Al shield was used, and was $9{\mu}Gy$ lower than the measurements made with no shielding device. If the space dose can be reduced by 20% in all situations where the C-arm is employed by using the x-ray tube shielding devices developed in our laboratory, this is expected to play an important role in reducing the annual exposure dose for patients, practitioners, and assistants.

Optimization of shielding to reduce cosmic radiation damage to packaged semiconductors during air transport using Monte Carlo simulation

  • Lee, Ju Hyuk;Kim, Hyun Nam;Jeong, Heon Yong;Cho, Sung Oh
    • Nuclear Engineering and Technology
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    • v.52 no.8
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    • pp.1817-1825
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    • 2020
  • Background: Cosmic ray-induced particles can lead to failure of semiconductors packaged for export during air transport. This work performed MCNP 6.2 simulations to optimize shielding against neutrons and protons induced by cosmic radiation Methods and materials: The energy spectra of protons and neutrons by incident angle at the flight altitude were determined using atmospheric cuboid model. Various candidates for the shielding materials and the geometry of the Unit Load Device Container were evaluated to determine the conditions that allow optimal shielding at all sides of the container. Results: It was found that neutrons and protons, at the flight altitude, generally travel with a downward trajectory especially for the particles with high energy. This indicated that the largest number of particles struck the top of the container. Furthermore, the simulation results showed that, among the materials tested, borated polyethylene and stainless steel were the most optimal shielding materials. The optimal shielding structure was also determined with the weight limit of the container in consideration. Conclusions: Under the determined optimal shielding conditions, a significantly reduced number of neutrons and protons reach the contents inside the container, which ultimately reduces the possibility of semiconductor failure during air transport.

Low Resistance SC-SJ(Shielding Connected-Super Junction) 4H-SiC UMOSFET with 3.3kV Breakdown Voltage (3.3kV 항복 전압을 갖는 저저항 SC-SJ(Shielding Connected-Super Junction) 4H-SiC UMOSFET)

  • Kim, Jung-hun;Kim, Kwang-Soo
    • Journal of IKEEE
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    • v.23 no.3
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    • pp.756-761
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    • 2019
  • In this paper, we propose SC-SJ(Shielding Connected-Super Junction) UMOSFET structure in which p-pillars of conventional 4H-SiC Super Junction UMOSFET structures are placed under the shielding region of UMOSFET. In the case of the proposed SC-SJ UMOSFET, the p-pillar and the shielding region are coexisted so that no breakdown by the electric field occurs in the oxide film, which enables the doping concentration of the pillar to be increased. As a result, the on-resistance is lowered to improve the static characteristics of the device. Through the Sentaurus TCAD simulation, the static characteristics of proposed structure and conventional structure were compared and analyzed. The SC-SJ UMOSFET achieves a 50% reduction in on-resistance compared to the conventional structure without any change in the breakdown voltage.

Evaluation of the Effectiveness of the Shielding Device and the Organ Dose of Subject During Bone Mineral Density (골밀도검사에서 피검자의 장기선량 측정 및 차폐기구의 효용성 평가)

  • Cho, Yong-In;Kim, Jung-Hoon
    • Journal of radiological science and technology
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    • v.43 no.3
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    • pp.187-194
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    • 2020
  • Bone mineral density is a examination to measure the amount of bone in patients with metabolic bone disease. It is a low dose, but may cause unnecessary exposure to the gonads and other organs located in the periphery when examining the lumbar and proximal femurs. Therefore, the purpose of this study was to evaluated the exposure dose for each organ exposed during the bone mineral density through simulation, and analyzed the applicability of the subject to radiation shielding devices using 3D printing materials. As a result, the highest dose was shown at 11.47 uSv in the breast during lumbar examination and 8.98 uSv in the testis during proximal femur examination. Also, the farther away from the examination site, the lower the effect of the scattering-ray. The shielding effect of using 3D printing shielding device showed high results in proportion to the effective atomic number and specific gravity of the printing material. Among the printing materials, ABS + W showed an effect of at least 78.72 to 96.3 9% compared to the existing lead material.

An analysis of new IGBT(Insulator Gate Bipolar Transistor) structure having a additional recessedwith E-field shielding layer

  • Yu, Seung-Woo;Lee, Han-Shin;Kang, Ey-Goo;Sung, Man-Young
    • Journal of IKEEE
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    • v.11 no.4
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    • pp.247-251
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    • 2007
  • The recessed gate IGBT has a lower on-state voltage drop compared with the DMOS IGBT, because there is no JFET resistance. But because of the electric field concentration in the corner of the gate edge, the breakdown voltage decreases. This paper is about the new structure to effectively improve the Vce(sat) voltage without breakdown voltage drop in 1700V NPT type recessed gate IGBT with p floating shielding layer. For the fabrication of the recessed gate IGBT with p floating shielding layer, it is necessary to perform the only one implant step for the shielding layer. Analysis on the Breakdown voltage shows the improved values compared to the conventional recessed gate IGBT structures. The result shows the improvement on Breakdown voltage without worsening other characteristics of the device. The electrical characteristics were studied by MEDICI simulation results.

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Evaluating the Efficiency of the Device in Shielding Scattered Radiation during Treatment of Carcinoma of the Penis (음경암의 방사선치료 시 자체 제작한 Device의 산란선 차폐 효과에 대한 유용성 평가)

  • Gim, Yang-Soo;Lee, Sun-Young;Lim, Suk-Gun;Gwak, Geun-Tak;Pak, Ju-Gyeong;Lee, Seung-Hoon;Hwang, Ho-In;Cha, Seok-Yong
    • The Journal of Korean Society for Radiation Therapy
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    • v.21 no.1
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    • pp.9-15
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    • 2009
  • Purpose: We evaluated the device that was created for maintaining the patient's setup and protecting the testicles from scattered radiation during treatment of carcinoma of the penis. Materials and Methods: The phantom testicles were made of vaseline cotton gauze and the device consisted of 5 mm of acryl box and 4 mm of lead shielding. $3{\times}3\;cm^2$, $4{\times}4\;cm^2$, $5{\times}5\;cm^2$, $6{\times}6\;cm^2$, $7{\times}7\;cm^2$ field sizes were used for this study and measurement was made at 4, 5, 6, 7, 8, 10 cm from the lower edge of the field for 10 times with lead shielding and without the shielding respectively. 200 cGy was delivered using 6 MV photons. Results: The scatted radiation without lead shielding at 4, 5, 6, 7, 8, 10 cm from the lower edge of the field were 14.8-4.7 cGy with $3{\times}3\;cm^2$, 15.7-5.2 cGy with $4{\times}4\;cm^2$, 17.6-5.5 cGy with $5{\times}5\;cm^2$, 19.9-6.6 cGy with $6{\times}6\;cm^2$, 22.2-7.6 cGy with $7{\times}7\;cm^2$ and the measured dose without lead shielding were 7.1-2.6 cGy with $3{\times}3\;cm^2$, 8.9-3.6 cGy with $4{\times}4\;cm^2$, 12.3-4.8 cGy with $5{\times}5\;cm^2$, 14.6-5.0 cGy with $6{\times}6\;cm^2$ and 21.1~6.4 cGy with $7{\times}7\;cm^2$. As shown above, the scatted radiation decreased after using lead shielding. Depending of the range of field sizes, the resulting difference between without shielding values and with shielding values were: 7.8-1.1 cGy at 4 cm, 5.1-1.2 cGy at 5 cm, 3.8-1.1 cGy at 6 cm, 3.4-1.7 cGy at 7 cm, 2.8-1.7 cGy at 8 cm, 2.4-2.5 cGy at 9 cm and 2.1-1.8 cGy at 10 cm. In the situation as described above, the range in values depending on the distance was 7.8-1.1 cGy with $3{\times}3\;cm^2$, 6.9-1.6 cGy with $4{\times}4\;cm^2$, 5.3-0.8 cGy with $5{\times}5\;cm^2$, 5.3-1.5 cGy with $6{\times}6\;cm^2$ and 1.1-1.8 cGy with $7{\times}7\;cm^2$. Conclusion: Using the device we created to shield the testicles from scattered radiation during treatment of carcinoma of the penis, we have found that scattered radiation to the testicles is decreased by the phantom testicles, and by increasing the distance between the testicles and penis.

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The Use of Lens Shielding Device(L.S.D.) for a Conjunctival Lymphoma

  • Cho Hyun Sang;Ju Sang Gyu;Song Ki Won;Park Young Hwan
    • The Journal of Korean Society for Radiation Therapy
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    • v.9 no.1
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    • pp.40-45
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    • 1997
  • When therapeutic irradiation is indicated for the orbital tumors, the greatest concern is the risk of radiation-induced cataract. Conjunctival lymphoma is one of the good examples. We would like to report the procedure of the lens shielding device(L.S.D) and the result of irradiated dose to the lens. L.S.D. consistes of two parts : load alloy to attenuate electron beam, and dental acryl which completely covers the lead alloy to avoid discomfort of cornea from contacting directly with cerrobend and side scattering by cerrobend. And for easy location and removal, side bars were made on each side. Radiation doses were meaured with TLD(TLD 3500 Hawshaw). Markus chamber in a polystyrene phantom. The phantom was irradiated with 9MeV electron beams from Clinac 2100C with $6{\times}6cm$ electron cone. The relative dose at 6mm depth where the lens is located was $4.2\%$ with TLD and $5.1\%$ with Markus chamber clinically when 2600 cGy are irradiated to the eyeball, the mapinary dose to the lens will be 109 cGy or 132 cGy, which will significently reduce the cataract.

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Electromagnetic Interference Shielding Effectiveness of Hybrid Conductive Fabrics (하이브리드 전도성 직조섬유의 전자파 차폐효과)

  • Han, Gil-Young;Kim, Ki-Yeol;Yun, Tae-Soon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.14 no.2
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    • pp.81-86
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    • 2015
  • This study investigated electromagnetic interference (EMI) shielding effectiveness (SE) of hybrid conductive fabrics. The coaxial transmission line method was used to measure the EMI Shielding effectiveness of the conductive fabrics. We designed and constructed a measuring system, consisting of a network analyzer and a device that serves as a sample holder and at the same time as a transmission medium of incident electromagnetic waves. The measurements of SE were carried out in a frequency range from 100 MHz to 2 GHz. The results of the EMI shielding experiments showed that the maximum electromagnetic shielding effectiveness (EMSE) values of sandwich type C/A/C (carbon fiber sheet/aluminum foil tape/carbon fiber sheet) and C/Ni/C (carbon fiber sheet/magnetic shielding foil/carbon fiber sheet) samples were 55 dB and 113 dB, respectively, at a frequency of 1.9 GHz.

The Manufacturing of Electromagnetic Shielding Sheet Using the Carbon and Wood Fiber Mixture (탄소와 목재섬유 혼합물을 이용한 전자기파 차폐용 시트의 제조)

  • Kim, Hyoung-Jin;Um, Gi-Jeung
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.38 no.4 s.117
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    • pp.68-75
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    • 2006
  • Electromagnetic shielding sheet using the carbon and wood fiber mixture was manufactured in an effort to develop an electromagnetic shielding packaging material. Carbon fibers were cut into 5, 10, and 15 mm using the automatic cutting device and blown and dispersed using compression air passed through the fine nozzle. Then carbon fibers were slurried with water (0.1% consistency), and softwood kraft pulp along with cone starch were added. The wet mats were manufactured by dewatering in modified hand-sheet machine. The wet mats were pressed upto $4kgf/cm^2$ in the carbon and wood fiber mixture mat press. The wet mats were dried in the automatic controlled plate dryer. Investigation on the formation and surface structure of the newly developed carbon and wood fiber mixture electromagnetic shielding sheet were carried out using the scanning electron microscopy and the image analyzer. Finally electromagnetic shielding characteristics of the newly developed carbon and wood mixture sheet were measured using net-work analyser. The result was promising in the light of the fact that this method could open a new way to substitute the expensive imported electromagnetic shielding sheet.