• Title, Summary, Keyword: 공기커마

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Evaluation of Energy Dependency for Air Kerma Area Product by RQR Beam Quality and Indirect Calibration (RQR 선질에 따른 공기커마 면적선량계의 에너지 의존성 평가와 간접 교정)

  • Kim, Jung-Su;Kim, Sung-Hwan;Kim, Mi-Jeong;Lee, Seung-Youl;Lee, Tae-Hee;Seoung, Youl-Hun
    • Journal of the Korean Society of Radiology
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    • v.12 no.6
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    • pp.769-776
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    • 2018
  • According IEC 60601-1 ed3.1 and IEC 60601-2-45 regulation, diagnostic X-ray equipment should be display to measured and calculated air kerma area product. On the clinical X ray equipment, air kerma area product dosimeter would like to have an evidence for dosimeter accuracy and energy dependency. This study was performed to indirect calibration and energy dependency test for attached type air kerma area product (KAP) dosimeter by RQR standards beam quality. On the RQR5 beam quality, attached KAP dosimeter error showed -7.5%, respectably. On the RQR9 beam quality, attached KAP dosimeter error showed -10.4%, respectably. All RQR beam quality, average absolute error was $8.30%{\pm}2.85%$, respectably. On this study, attached KAP dosimeter was satisfied to IEC 60580 and AAPM TG 190. This calibration method of KAP dosimeter will help to performance maintain for clinical KAP dosimeter.

Quality Assurance of Air Kerma Strength for Ir-192 High Dose Rate Source (Ir-192 고선량률 선원에 대한 공기커마강도의 품질보증)

  • Kim, Jong-Eon;Yoon, Chun-Sil;Kim, Sung-Hyun
    • Journal of radiological science and technology
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    • v.30 no.2
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    • pp.147-151
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    • 2007
  • AAPM TG43 report has recommended to measure air kerma strength with the strength of source. Main purpose of this study is to verify the accuracy of air kerma strength provided by manufacturer. Materials for this study were MAX-4001 Electrometer, HDR 1000 Plus of the corporation of standard imaging, and 6 french bronchial Applicator with 1000 mm. we measured ionization current in 10-90 mm range from the bottom of the central axis of chamber. The reference point of calibration displayed by the maximum ionization current in the ionization current curve was measured, and air kerma strength was computed from the maximum ionization current. we acquired 50 mm distance to correspond with the maximum ionization current in the ionization current curve. Its distance has perfectly fitted to the source reference point of calibration certificate of UW-ADCL. Air kerma strength computed value has measured about 0.5% more than calibration value provided by manufacturer. Air kerma strength of calibration certificate provided by manufacturer has acquired reliable results. This study shows that considering the move error of dwell position of source and the dead space length in well-type chamber is a good way to get an accurate result.

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Consistent Comparison for The Linearity Air Kerma of IEC Standards and Commercial Load in Diagnosing DR Generators (진단용 DR 발생장치에서 IEC 표준규격과 상용부하의 공기커마 직선성에 대한 일관성 비교)

  • Han, Beom-Hui;Kim, Chong-Yeal;Lee, Sang-Ho;Han, Sang-Hyun;You, In-Gyu
    • Journal of the Korean Society of Radiology
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    • v.6 no.5
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    • pp.389-394
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    • 2012
  • In this study, based on IEC 60601-2-54 standard load conditions presented in the limited interval over the air kerma at the absolute linearity closely evaluated by measuring the X-ray results were as follows: 10 units targeted all Diagnostic X-ray generating device (DR) presented in the IEC 60601-2-54 standard linearity of air kerma emerged as inappropriate, the general evaluation of the dose linearity from four in the top 50% and 80 kVp % of the two measurement series were as irrelevant all the rest from six of the top tube voltage of 50% and 80% of the two measurement series, appeared in all suitable. Presented in IEC 60601-2-54 standard dose linearity testing and conventional linearity tests showed many differences. IEC 60601-2-54 standard linearity in the proposed international standards of air kerma is the recommendation of the existing dose linearity considerably more feasible, and to quantify the amount of radiation as the standard suggested by the standard IEC 60601-2-54 air kerma of a diagnostic X-ray imaging device linearity performance management is considered key elements in the critical appraisal.

Comparison of Air Kerma­based and Absorbed Dose to Water­based Protocols in the Dosimetry of High Energy Electron Beams (고 에너지 전자선에 대한 공기커마와 물 흡수선량에 기반한 프로토콜간의 비교)

  • 박창현;신동오;박성용
    • Progress in Medical Physics
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    • v.14 no.4
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    • pp.249-258
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    • 2003
  • A few years ago, a proposal was made to change the dosimetry from the air kerma-based reference dosimetry to the absorbed dose-based reference dosimetry for all radiotherapy beams of ionizing radiation to improve the accuracy of dosimetry. Here, we present a dosimetry study in which the two most widespread absorbed dose­based protocols (IAEA TRS­398 and AAPM TG­51) were compared with an air kerma­based protocol (IAEA TRS-277) by measuring the absorbed dose in the same reference depth. Measurements were performed in three clinical electron beam energies using a PTW 30002 cylindrical chamber, and Markus and Roos plane­parallel chambers. $^{60}$ Co calibration factors were obtained from the KFDA. The absorbed dose differences between the air kerma­based and absorbed dose­based protocols were within 2.0% for all chambers in all beams. The results thus show that the obtained absolute dose values will be not significantly altered by changing from the air kerma­based dosimetry to the absorbed dose­based dosimetry. It was also shown that absorbed dose values between the absorbed dose­based protocols agreed by deviations of less than 0.5% for a cylindrical chamber and less than 0.7% for plane­parallel chambers using cross­calibration factors. Although the use of a cylindrical chamber and plane­parallel chambers resulted in a difference of less than 2% for all situations investigated here, to reduce errors, the plane­parallel chambers are recommended for electron energies in which the use of cylindrical chamber is not permitted in each protocol.

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The Development of Air-kerma Strength Calculation Algorithm in Terms of the Absorbed Dose to Water for HDR Ir-192 Source (기준점에서의 물 흡수선량을 이용한 Ir-192 선원의 공기커마 세기 계산을 위한 알고리즘 개발)

  • Huh, Hyun-Do;Kim, Woo-Chul;Loh, John-Jk;Lee, Suk;Lee, Sang-Hoon;Cho, Sam-Ju;Shin, Dong-Oh;Choi, Jin-Ho;Kwon, Soo-Il;Kim, Seong-Hoon
    • Progress in Medical Physics
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    • v.17 no.4
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    • pp.232-237
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    • 2006
  • The aim of this study was to develop the calculation algorithm of source strength of Ir-192 source In terms of the absorbed dose to water instead of an apparent activity (Ci). For this work the Multi Purpose Brachytherapy Phantom(MPBP) was developed, which was designed to locate the source and the chamber precisely at a specific position Inside the water phantom. The reference point of measurement was set at the 5 cm distance along the transverse axis of the source. For a brachytherapy source calibration, the absorbed dose to water calibration factor ($N_{D.W.Q}$) of an lonization chamber were determined and then apply standard protocols of absorbed dose to water. The calibration factor ($N_{D.W.Q}$) of the ion chamber (TM30013, PTW, Germany) was determined using the EGSnrcCPP Monte Carlo Code. The calculated calibration factor ($N_{D.W.Q}$) was 5.28 cGy/nC. The calculated factor was then used to determine the absorbed dose to water from which the air kerma strength for an Ir-192 source can be easily derived at the reference point (5 cm). The calculated air kerma strength showed discrepancies of -0.6% to +1.8% relative to the air kerma strength provided by the vendor, In this work we demonstrated that the air kerma strength ($S_k$) could be determined from the absorbed dose to water calibration factor for Ir-192 source. In audition, this source calibration method could be applied directly to the dose Calculation formalism of AAPM report TG-43.

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A Model for Radiological Dose Assessment in an Urban Environment (도시환경에서 방사성물질 오염에 따른 선량평가모델)

  • Hwang, Won-Tae;Kim, Eun-Han;Jeong, Hyo-Joon;Suh, Kyung-Suk;Han, Moon-Hee
    • Journal of Radiation Protection and Research
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    • v.32 no.1
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    • pp.1-8
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    • 2007
  • A model for radiological dose assessment in an urban environment, METRO-K has been developed. Characteristics of the model are as follows ; 1) mathematical structures are simple (i.e. simplified input parameters) and easy to understand due to get the results by analytical methods using experimental and empirical data, 2) complex urban environment can easily be made up using only 5 types of basic surfaces, 3) various remediation measures can be applied to different surfaces by evaluating the exposure doses contributing from each contamination surface. Exposure doses contributing from each contamination surface at a particular location of a receptor were evaluated using the data library of kerma values as a function of gamma energy and contamination surface. A kerma data library was prepared fur 7 representative types of Korean urban buildings by extending those data given for 4 representative types of European urban buildings. Initial input data are daily radionuclide concentration in air and precipitation, and fraction of chemical type. Final outputs are absorbed dose rate in air contributing from the basic surfaces as a function of time following a radionuclide deposition, and exposure dose rate contributing from various surfaces constituting the urban environment at a particular location of a receptor. As the result of a contaminative scenario for an apartment built-up area, exposure dose rates show a distinct difference for surrounding environment as well as locations of a receptor.

Quality Correction for Ir-192 Gamma Rays in Air Kerma Strength Dosimetry Using Cylindrical Ionization Chambers (원통형 전리함을 이용한 Ir-192 선원에 대한 공기커마세기 측정 시 선질보정에 관한 연구)

  • Jeong, Dong-Hyeok;Kim, Jhin-Kee;Kim, Ki-Hwan;Oh, Young-Kee;Kim, Soo-Kon;Lee, Kang-Kyoo;Moon, Sun-Rock
    • Progress in Medical Physics
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    • v.20 no.1
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    • pp.30-36
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    • 2009
  • The quality correction in the air kerma dosimetry for Ir-192 using farmer type ionization chambers calibrated by Co-60 quality is required. In this study we determined quality factor ($k_u$) of two ionization chambers of PTW-N30001 and N23333 for Ir-192 source using dosimetric method. The quality factors for energy spectrum of microSelectron were determined as $k_u$=1.016 and 1.017 for PTW-N30001 and N23333 ionization chambers respectively. We applied quality factors in air kerma dosimetry for microSelectron source and compared with reference values. As a results we found that the differences between reference air kerma rate and measured it with and without quality correction were about -0.5% and -2.0% respectively.

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Intercomparison of the KAERI Reference Photon and Beta Radiation Measurements (한국원자력연구소 기준 광자 및 베타선장 측정의 국제상호비교)

  • Chang, Si-Yeong;Kim, Bong-Hwan;Kim, Jang-Lyul;McDonald, J.C.;Murphy, M.K.
    • Journal of Radiation Protection and Research
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    • v.21 no.4
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    • pp.255-262
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    • 1996
  • This paper describes the results of intercomparison measurements of KAERI reference photon and beta radiation fields between the KAERI and the PNNL(Pacific Northwest National Laboratory), recently performed at KAERI radiation calibration and dosimetry laboratory on the basis of the ANSI N13.11 criteria for personal dosimeter performance test. Each laboratory used her own radiation detectors or measurement devices traceable to her national primary standard in measuring the exposure rates for photon fields, the absorbed dose rates for beta radiation fields. The agreements in reference radiation measurements between two laboratories were found to be less than ${\pm}2.0%$ for photon fields, ${\pm}1.0%$ for beta radiation fields. Therefore, it could be concluded that KAERI reference radiation fields comply well with the international standard and thus can further serve as a national basis for the researches and developments in radiation protection dosimetry in Korea.

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