• Title, Summary, Keyword: 잠상퇴행

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A Study on the Measurement of the Personal Exposure Dose by Film Badge Dosimeter (필름배지선량계에 의한 개인피폭선량 측정에 관한 연구)

  • Chung, Woon-Kwan
    • Journal of Radiation Protection and Research
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    • v.19 no.1
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    • pp.37-50
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    • 1994
  • The experimental evaluation of exposure conversion formula using the relationship between optical photo-density, exposure dose and the quality of radiation characteristics of radiation energy to X-ray and ${\gamma}-rays$. The film badge dosimeter is analysed by exposure conversion formula which evaluate image fading characteristics for development time and directional characteristics for incident beam angle. In conclusion, exposure conversion formula evaluated of this study is satisfied with quality decision criterion of the film badge dosimeter.

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Characteristics of $CaSO_4$:Dy TL Dosimeters by Determining LLDs, Fadings and Sensitivity Changes in Repeat Uses (최소검출한계, 잠상퇴행 및 반복사용으로 인한 감도면화 결정에 의한 $CaSO_4$:Dy 열형광선량계 특성)

  • Kim, Jang-Lyul;Kim, Bong-Hwan;Chang, Si-Young;Lee, Hyung-Sub;Lee, Jae-Ki
    • Journal of Radiation Protection and Research
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    • v.22 no.3
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    • pp.161-170
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    • 1997
  • Theoretical and experimental determination of the lower limits of detection (LLD) of C-300-A $CaSO_4$:Dy TL dosimeters which are currently used for the personnel monitoring in Korea Atomic Energy Research Institute(KAERI) are described with a critical level which is defined as the signal level above which a result has a probability of being due to a fluctuation of the background. The personnel monitoring processors can derived easily the LLD of their system using this method with the background readings of their service interval and the irradiation readings of the known doses. Experimental studies were also conducted for the fading rates of the dosimeters with the temperatures and humidities for 3 months. Finally sensitivity changes in repeat uses were measured for 40 times consecutive uses of the dosimeters. The applications of the experimental results of fading rates and sensitivity changes in real personnel monitoring services are discussed briefly.

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Thermal Annealing and Fading Characteristics of LiF:Mg,Cu,P TLD (LiF:Mg,Cu,P TLD의 잠상퇴행과 열처리 특성)

  • Doh, Sih-Hong;Lee, Woo-Gyo;Yoo, Myung-Jin;Kang, Hee-Dong;Kim, Do-Sung
    • Journal of Sensor Science and Technology
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    • v.7 no.5
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    • pp.313-318
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    • 1998
  • The thermal annealing, reusability and fading characteristics of the highly sensitive LiF:Mg,Cu,P TLDs are investigated. Thermoluminescent sensitivity of the fabricated LiF:Mg,Cu,P TLD is 25.3 times higher than the commercial dosimeter TLD-700(Harshaw Chemical Co.). The main dosimetric peak shows no fading for 1 month at room temperature and 50% for 7 days at $100^{\circ}C$. The thermal annealing characteristics is examined in the temperature range from $260^{\circ}C$ to $320^{\circ}C$. For annealing the TLD at $280^{\circ}C$ for 10 minutes, TLDs can be reusable by recovering the initial sensitivity.

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Cause and Solution of an Artifact Generation by Parameter in Computed Radiography System (Computed Radiography 영상에서 Parameter에 의한 Artifact 원인과 해결방안)

  • Dong, Kyung-Rae;Choi, Jun-Gu;Hong, Seong-Il
    • The Journal of the Korea Contents Association
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    • v.9 no.5
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    • pp.145-155
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    • 2009
  • There is a great deal of merit in CR system but artifact not produced in old system of film or screen newly is created. we studied 3 cases of artifact with CR system in one hospital, Gwangju. In the first case of the delay time and density, As the time was delayed, the density of the artifact was increased up to 67 percent in the natural radiation. The Second, Fading of the artifact decreased 33 percent in the rate of the emission after 10 hours, and the more the time was delayed, the less the quality of image was deteriorated. Third, Artifact was produced by the collimation when the radiologic technologist was performed, and by the Guiding plate and Suction cup when the radiation equipment was done. Therefore, when health care provider have to understand the artifact exactly and check regularly, the quality of the picture and the satisfaction of the medical examination is increased.

Noise Changes in Image Plate (시간변화에 따른 영상판의 노이즈 변화)

  • Choi, Seokyoon;Im, In-Chul
    • Journal of the Korean Society of Radiology
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    • v.12 no.2
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    • pp.271-275
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    • 2018
  • It is possible to do not use the Image Plate for a long time in the clinic. for the acquisition of reliable images the decommissioning process is very important. In this study, we would like to look at complex noises that may occur during Image Plate use depending on the frequency and time of day. first, we got the image from computer radiography. second, We calculate the noise changes using Peak Signal to Noise Ratio(PSNR) and Noise Power Spectrum(NPS). finally, we suggest that remove the noise from the IP for more than 4 hours. and It turned out to be better to remove the noise more than once. this study will be a quantitative reference for Image Plate management and use in the clinical trial.