• Title/Summary/Keyword: 안구차폐

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Radiation Exposure Evaluation of Visual Organs using Bismuth Shielding Material on Head CT Scan (두부 CT촬영 시 비스무스 차폐체를 활용한 시각 기관의 방사선피폭평가)

  • Kang, Se-Sik;Kim, Changsoo;Kim, Jung-Hoon
    • The Journal of the Korea Contents Association
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    • v.16 no.7
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    • pp.451-456
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    • 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%.

Reduction of Radiation Exposure Dose of Eyeball and Thyroid for Chest and Abdomen CT Scan (흉부 및 복부 CT 검사 시 안구와 갑상선의 방사선 피폭선량 저감)

  • Lee, Jun Seok;Chon, Kwon Su
    • Journal of the Korean Society of Radiology
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    • v.13 no.2
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    • pp.147-151
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    • 2019
  • In chest and abdomen CT scans, the radiation exposure doses by scattering lines were measured at the eyeball and thyroid. Radiation exposure was investigated by using shielding devices. The chest and abdomen CT scan protocols used in the real examination were applied to measure and compare radiation doses before and after the use of shielding devices at the eyeball and the thyroid. The radiaton doses were measured with OSLD dosimeters. Barium, tungsten sheets, goggles and neck shields were used to protect the scattered X-ray. The chest CT scans showed respectively 3.01 mSv and 6.21 mSv at the eyeball and the thyroid by the scattered X-ray. The abdomen CT scans showed 0.55 mSv and 3.22 mSv for the eyeball and the thyroid respectively. Barium and tungsten sheets had 11% to 13% protection rates at the eyeball and the thyroid for chest CT scan, and 34% to 49% reduction in radiation dose for the abdomen CT scan. Because of the significant radiation dose, which causes cataracts and thyroid cancer by the repeated and continuous radiation exposure, for the chest and the abdomen CT scans, it is required to use shielding devices to reduce radiation dose for examinations.

Dose Assessment of Orbital Adnexa in Electron Beam Therapy for Orbital Lymphoma (안와림프종의 전자선 치료 시 안구 부속기관에 대한 선량평가)

  • Dong Hwan Kim;Yong In Cho
    • Journal of the Korean Society of Radiology
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    • v.18 no.3
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    • pp.283-292
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    • 2024
  • Radiation side effects and complications on the ocular adnexa during electron beam therapy for orbital lymphoma can increase the incidence of posterior subcapsular cataracts. This study simulated a medical linear accelerator and a mathematical model of the eye using monte carlo simulations to evaluate the dose to the ocular adnexa and compare the shielding effectiveness on different parts of the ocular adnexa based on lens shield thickness. The dose assessment results of the ocular adnexa showed that the lens's sensitive area had the highest absorbed dose distribution when no shield was used, followed by the lens's non-sensitive area, the anterior chamber, vitreous humor, cornea, and eyelid in descending order. With the use of a shield, a 2 mm thick shield demonstrated a dose reduction effect of over 90% in the lens's sensitive area, over 83% in the non-sensitive area and anterior chamber, and a dose reduction effect of 30 to 62% in the vitreous body, cornea, and eyelid. For dose reduction in the lens's sensitive area during electron beam therapy for orbital lymphoma, it is necessary to use a shield of at least 2 mm thickness. Additionally, shielding strategies considering the thickness and area of the shield for other ocular adnexa besides the lens are required.

Assessment of the Eye Lens Dose Reduction by Bismuth Shields in Rando Phantom Undergoing CT of the Head (Head CT 검사 시 안구 차폐용 Bismuth사용에 의한 수정체 선량 감소에 대한 평가)

  • Cho, Pyong-Kon;Kim, You-Hyun;Choi, In-Ja;Chang, Sang-Gyu;Chung, Jung-Pyo;Lee, Hyun;Kim, Jang-Seob;Shin, Dong-Cheol;Choi, Jong-Hak;Lee, Ki-Sung;Lee, Won-Ho
    • Journal of radiological science and technology
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    • v.31 no.2
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    • pp.171-175
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    • 2008
  • The aim of this study is to assess the dose reduction of eye lens and availability of bismuth garments resulting from the use of radioprotective bismuth garments to shield the eyes of patients undergoing head CT. Rando phantom and TLDs were used to determine the amount of dose reduction by bismuth shielding of the eye in the following simulated CT scans : (a) scanning of the head including orbits, (b) scanning of the whole head, and (c) $20^{\circ}$ angled scanning of the head excluding orbits. The average dose reduction of eye lens was 43.2%, 36.0% and 1.4% for the three CT scans listed above. Significant reduction in the eye lens dose was achieved by using superficial orbital bismuth shielding during head CT scans. However, bismuth shields should not be used for the patients when their eyes are excluded from the primarily exposed region.

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Dose Distribution for Eye Shielding Block In 6 MV Photon Beam Therapy (6 MV 광자선치료에서 안구차폐기구의 제작과 선량분포 측정)

  • Lee, Kyung-Ja
    • Radiation Oncology Journal
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    • v.10 no.2
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    • pp.155-161
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    • 1992
  • The eye lens is known to be radiosensitive organ and catarat can be induced by relatively low dose of radiation. In the treatment of head and neck tumors, shielding blocks are frequently used to minimize dose on sensitive organs. The shielding block, which is made of high atomic number materials (cerrobend), produce significant dose perturbations in megavoltage photon beams. The effects of these perturbations of eye shielding blocks are measured with film and ion chambers for the treatment of head and neck malignancies. Optimum parameters for the treatment are suggested.

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Effectiveness of Bismuth Shield to Reduce Eye Lens Radiation Dose Using the Photoluminescence Dosimetry in Computed Tomography (CT 검사에서 유리선량계를 이용한 수정체의 비스무트 차폐 효과)

  • Jung, Mi-Young;Kweon, Dae-Cheol;Kwon, Soo-Il
    • Journal of radiological science and technology
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    • v.32 no.3
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    • pp.307-312
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    • 2009
  • The purpose of our study was to determine the eyeradiation dose when performing routine multi-detector computed tomography (MDCT). We also evaluated dose reduction and the effect on image quality of using a bismuth eye shield when performing head MDCT. Examinations were performed with a 64MDCT scanner. To compare the shielded/unshielded lens dose, the examination was performed with and without bismuth shielding in anthropomorphic phantom. To determine the average lens radiation dose, we imaged an anthropomorphic phantom into which calibrated photoluminescence glass dosimeter (PLD) were placed to measure the dose to lens. The phantom was imaged using the same protocol. Radiation doses to the lens with and without the lensshielding were measured and compared using the Student t test. In the qualitative evaluation of the MDCT scans, all were considered to be of diagnostic quality. We did not see any differences in quality between the shielded and unshielded brain. The mean radiation doses to the eyewith the shield and to those without the shield were 21.54 versus 10.46 mGy, respectively. The lens shield enabled a 51.3% decrease in radiation dose to the lens. Bismuth in-plane shielding for routine eye and head MDCT decreased radiation dose to the lenswithout qualitative changes in image quality. The other radiosensitive superficial organs specifically must be protected with shielding.

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Preliminary Research on the Implementation of Information of Human Facial Part Required for the 3D Printing of Eye Shield (안구차폐체 제작에 필요한 안면부 3차원 정보 구현의 기초연구)

  • Choi, Seokyoon
    • Journal of the Korean Society of Radiology
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    • v.13 no.7
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    • pp.955-960
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    • 2019
  • The Computed tomography (CT) scan can have high radiation in a few tests, and this risk is significant given that it is often repeated in one patient. In children, the incidence of radiation-induced cancer is reported because organs are growing, are more sensitive to radiation. 3D printing has recently been studied to be applied to various applications as a research field for 3D printing applications, research on fabrication of radiation shields and materials has been conducted. The purpose of the 3D printer is to replace the existing panel-type shields and to make customized designs according to the shape of the human body. Therefore, research on 3D information processing to be input to the 3D printer is also necessary. In this study, 3D data of the human body surface, which is the preliminary step of the manufacture of patient-specific eye shield using stereo vision depth map technology, was studied. This study aims to increase the possibility of three-dimensional output. As a result of experimenting with this method, which is relatively simple compared with other methods of 3D information processing, the minimum coordinates for 3D information are extracted. The results of this study provided the advantages and limitations of stereo images using natural light and will be the basic data for the manufacture of eye shields in the future.