• Title/Summary/Keyword: Lens shield

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Dosimetric characteristics of an independent collimator system using measurements performed quarter fields. (Tungsten eyeball shield block의 임상적용에 관한 고찰)

  • Jeong, Deok-Yang;Lee, Byoung-Koo;Hwang, Woong-Koo
    • The Journal of Korean Society for Radiation Therapy
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    • v.14 no.1
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    • pp.89-94
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    • 2002
  • During radiation therapy with electron beam to eyelid, we must keep the minimal dose on eyeball as possible. especially in the treatment of Sebaceous gland carcinoma, Squamouse cell ca., and basal cell ca. of eyelid and low grade MALToma etc. But if radiation field covered the upper & lower eyelid, it makes a cataract on lens of treated eye, in late complications. Now we reports the advantages of Tungsten eyeball shielding block compare to previously used lead block. with BOLX-I material, we made a eyeball model and measured the absorbed dose of 6MeV & 9MeV electron hem at 6 point of eyeball model with TLD chip. And compare the absorbed dose to previously lead block and other types of Tungsten eyeball shielding block.

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The Evaluation of Eye Dose and Image Quality According to The New Tube Current Modulation and Shielding Techniques in Brain CT (두부 CT에서 차폐기법과 새로운 관전류변조기법에 따른 눈의 선량과 화질평가)

  • Kwon, Soonmu;Kim, Jungsu
    • Journal of the Korean Society of Radiology
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    • v.9 no.5
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    • pp.279-285
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    • 2015
  • The eye of human is a radiation sensitive organ and this organ should be shielded from radiation exposure during brain CT procedures. In the brain CT procedures, bismuth protector using to reduce the radiation exposure dose for eye. But protecting the bismuth always accompanies problem of the image quality reduction including artifact. This study aim is the eye radiation exposure dose and image quality evaluation of the new tube current modulation such as new organ based-tube current modulation, longitudinal-TCM, angular-TCM between shielding scan technique using bismuth and lead glasses. As a result, radiation dose of eye is reduced 25.88% in new OB TCM technique then reference scan technique and SNR new OB TCM is 6.05 higher than bismuth shielding scan technique and lower than reference scan technique. In clinical brain CT, new OB TCM technique will contribute to reduction of radiation dose for eye without decrease of image quality.

Effect of Reducing Scattering Radiation Exposure of Medical Staffs When Additional Shielding is Used in Interventional Radiology (중재적 방사선시술에서 부가 차폐체 사용 시 종사자의 산란선 피폭 감소효과)

  • Kim, Min-Jun;Baek, Kang-Nam;Kim, Sungchul
    • Journal of radiological science and technology
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    • v.44 no.6
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    • pp.629-633
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    • 2021
  • This article is designed to look into the radiation exposure dose to each body part and the shielding effect for workers using an additional shielding to reduce their radiation exposured by scattering radiation which is generated in a space between the operating table and lead curtain during interventional radiology(IR) procedures. After placing a human phantom on the table of SIEMENS' angiography machine, the following measurements were taken, depending on the presence of an additional shield of lead equivalent of 0.25 mmPb, manufactured for this purpose: dose to gonad, dose to an area where the personal dosimeter is placed, and dose to an area of eye lens is located. An ion chamber(chamber volume 1,800 cc) was utilized to measure scattering radiation. The two imaging tests were carried out as follows: fluoroscopy of the abdomen (66 kV, 100 mA, 60 seconds) and of the head (70 kV, 65 mA, 60 seconds); and digital subtraction angiography(DSA) of the abdomen (67 kV, 264 mA, 20 seconds) and of the head (79 kV, 300 mA, 20 seconds). In all the experiments, the shielding efficiency of the gonad position was the largest at 59.8%. In case an additional shielding was used as protection against scattering radiation that came through the operating table and the lead curtain during an IR, the radiation shielding efficiency was estimated to be up to 59.8%, leading to a conclusion that its presence may effectively reduce the radiation exposure dose of medical staffs.

Analysis of CT Image Quality Change according to Clinical Application Shielding Materials (임상 적용 차폐물질에 따른 선량 및 CT 화질 변화 분석)

  • Hyeon-Ju Kim
    • 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.