• Title, Summary, Keyword: ANSI X-Ray

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Calculations of ISO Narrow and ANSI X-Ray Spectra, Their Average Energies and Conversion Coefficients (ISO Narrow Series및 ANSI의 X선 스펙트럼, 평균에너지 및 선량환산인자의 이론적 계산)

  • Kim, Jang-Lyul;Kim, Bong-Whan;Chang, Si-Young;Lee, Jai-Ki
    • Journal of Radiation Protection and Research
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    • v.20 no.2
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    • pp.129-136
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    • 1995
  • In spite of the prescriptions on the reference X-ray fields given by the International Organization of Strandard(ISO) and American National Standard Institute(ANSI), the measurement of X-ray spectrum is not only time consuming but very difficult, paticularly when significant corrections have to be applied to the measured pulse-height distributions of the observed spectra. This paper describes the calculation method of ISO Narrow Series and ANSI X-ray filtered radiations by theoretical model which is modified framer's theory by target attenuation and backscatter correction. The X-ray spectra, average energies and conversion coefficients are calculated and compared with those obtained using the spectra prescribed by ISO and AMSI to assure good agreement.

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Development of TLD Algorithms by Monochromatic Fluorescence Radiations and Continuous Spectrum X-rays (단일에너지 형광 X선 및 연속 스펙트럼 X선장에 의한 TLD 알고리즘 개발)

  • Kim, Jang-Lyul;Kim, Bong-Hwan;Chang, Si-Young;Lee, Jai-Ki
    • Journal of Radiation Protection and Research
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    • v.23 no.3
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    • pp.159-174
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    • 1998
  • Personal dosimetry system is required to measure the personal dose equivalent accurately in a wide range of radiation fields, but the dose evaluation algorithms have been developed with the X-ray fields described in MOST Ordinance (equivalent to the ANSI N13.11) from which the actual fields to be monitored may be significantly different. To evaluate the dose more accurately when workers are exposed to the non-ANSI N13.11 radiation fields, two algorithms for monochromatic radiations (one algorithm was used for various ratios of TL dosimeter and the other for matrix approximation) were developed with the experimental data of the energy responses of the $CaSO_4:Dy$ TL materials irradiated by monochromatic X-ray fields recently established in KAERI, and compared with the another algorithm developed on the basis of the ANSI N13.11 continuous spectrum X-ray fields. Then it follows the discussions for some results of the algorithm testing including mixed fields irradiations and angular response conducted in IAEA/RCA intercomparison as well as ANSI and ISO continuous spectrum X-ray and monochromatic radiation fields. The developed algorithms were successfully performed the test not only in the continuous spectrum X-ray fields given by MOST Ordinance but also in the several non-MOST Ordinance radiation fields which could be encountered in the practical working environments.

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A Theoretical Calculation for Angular Dependence of X-ray Beams on Extremity Phantom (말단팬텀에서 X-선 빔의 방향의존성에 관한 이론적 계산)

  • Kim, Jong-Soo;Yoon, Suk-Chul;Kim, Jang-Lyul;Kim, Kwang-Pyo
    • Journal of Radiation Protection and Research
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    • v.21 no.4
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    • pp.263-271
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    • 1996
  • The ANSI N13.32 recommends that a study of the angular response of a dosimeter be carried out once, although no pass/fail criterion is given for angular response. Gamma dose equivalent conversion and angular dependence factors were calculated by using MCNP code for the case of ANSI N13.32 extremity phantoms(finger and arm) at the depth of $7mg/cm^2$. Those extremity dosimeters were assumed to be irradiated from both monoenergitic photons and ISO X-ray narrow beams. These calculated gamma dose equivalent conversion and angular dependence factors were compared to B. Grosswendt's result calculated by using X-ray beams. The result showed that the dose equivalent conversion factors of this study agreed well with that of B. Grosswendt for all energies within 2% except 7% in the case of the low energies. In the case of angular dependence factors comparison, they agreed within 3%. It was shown that angular dependence factors of the finger phantom decreased as the horizontal angle of the phantom increased for the ISO X-ray beams less than 60keV. For the higher energy X-ray beams range they decreased slightly around 40 degree, but then increased from this energy to 90 degree.

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Reference X-ray Irradiation System for Personal Dosimeter Testing and Calibration of Radiation Detector

  • Lee, Seung Kyu;Chang, Insu;Kim, Sang In;Lee, Jungil;Kim, Hyoungtaek;Kim, Jang-Lyul;Kim, Min Chae
    • Journal of Radiation Protection and Research
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    • v.44 no.2
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    • pp.72-78
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    • 2019
  • Background: In the calibration and testing laboratory of Korea Atomic Energy Research Institute, the old X-ray generator used for the production of reference X-ray fields was replaced with a new one. For this newly installed X-ray irradiation system, beam alignment as well as the verification of beam qualities was conducted. Materials and Methods: The existing X-ray generator, Phillips MG325, was replaced with YXLON Y.TU 320-D03 in order to generate reference X-ray fields. Theoretical calculations and Monte Carlo simulations were used to determine initial filter thickness. Beam alignment was performed in three steps to deliver a homogeneous radiation dosage to the target at different distances. Finally, the half-value layers were measured for different X-ray fields to verify beam qualities by using an ion chamber. Results and Discussion: Beam alignment was performed in three steps, and collimators and other components were arranged to maintain the uniformity of the mean air kerma rate within ${\pm}2.5%$ at the effective beam diameter of 28 cm. The beam quality was verified by using half-value layer measurement methods specified by American National Standard Institute (ANSI) N13.11-2009 and International Organization for Standardization (ISO)-4037. For each of the nine beams than can be generated by the new X-ray irradiation system, air kerma rates for X-ray fields of different beam qualifies were measured. The results showed that each air kerma rate and homogeneity coefficient of the first and second half-value layers were within ${\pm}5%$ of the recommended values in the standard documents. Conclusion: The results showed that the new X-ray irradiation system provides beam qualities that are as high as moderate beam qualities offered by National Institute of Standards and Technology in ANSI N13.11-2009 and those for narrow-spectrum series of ISO-4037.

A Study on the Angular Dependence of the PB-3 Dosimeter Using Teledyne 9150 TLD Reader System (열형광선량계(도시메터타입 : PB-3)의 방향의존성에 관한 연구)

  • Son, Jung-Kwon;Kim, Jong-Kyung;Yoon, Suk-Chul
    • Journal of Radiation Protection and Research
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    • v.19 no.3
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    • pp.189-198
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    • 1994
  • An angular dependence experiment was made and a performance test of the Teledyne dosimetry system was done in accordance with the ANSI N13.11-1992. The angular dependence experiment was performed with $^{137}Cs$ and low energy X-ray beam. Teledyne dosimetry system performed well at the $0^{\circ}$ angle of incidence for all dosimeters in both vertical and horizontal irradiations. It would have easily passed the 0.5 tolerance limit. But the dosimetry system was not performed well at the ${\pm}60^{\circ}$ angle of incidence for low energy X-ray beam. The accuracy for $^{137}Cs$ beam at all angles of incidence was within the 0.5 tolerance limit. Therefore performance of the dosimetry system could be considered acceptable in case that the dosimeter is irradiated to $^{137}Cs$ beam. However, it could not be acceptable for the dosimeter irradiated to low energy X-ray, especially at more than ${\pm}40^{\circ}$

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A Study for Effects of Image Quality due to Scatter Ray produced by Increasing of Tube Voltage (관전압 증가에 기인한 산란선 발생의 화질 영향 연구)

  • Park, Ji-Koon;Jun, Je-Hoon;Yang, Sung-Woo;Kim, Kyo-Tae;Choi, Il-Hong;Kang, Sang-Sik
    • Journal of the Korean Society of Radiology
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    • v.11 no.7
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    • pp.663-669
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    • 2017
  • In diagnostic medical imaging, it is essential to reduce the scattered radiation for the high medical image quality and low patient dose. Therefore, in this study, the influence of the scattered radiation on medical images was analyzed as the tube voltage increases. For this purpose, ANSI chest phantom was used to measure the scattering ratio, and the scattering effect on the image quality was investigated by RMS evaluation, RSD and NPS analysis. It was found that the scattering ratio with increasing x-ray tube voltage gradually increased to 48.8% at 73 kV tube voltage and to 80.1% at 93 kV tube voltage. As a result of RMS analysis for evaluating the image quality, RMS value according to increase of tube voltage was increased, resulting in low image quality. Also, the NPS value at 2.5 lp/mm spatial frequency was increased by 20% when the tube voltage was increased by 93 kV compared to the tube voltage of 73 kV. From this study, it can be seen that the scattering radiation have a significant effect on the image quality according to the increase of x-ray tube voltage. The results of this study can be used as basic data for the improvement of medical imaging quality.

A Theoretical Calculation of Photon Dose Equivalent Conversion Factor For Extremity Dosimeter (말단선량계의 광자선량당량환산인자에 대한 이론적 계산)

  • Kim, Kwang-Pyo;Lee, Won-Keun;Kim, Jong-Su;Yoon, Yeo-Chang;Yoon, Suk-Chul
    • Journal of Radiation Protection and Research
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    • v.21 no.1
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    • pp.41-50
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    • 1996
  • In this study, the theoretical calculation of the air kerma-to-dose equivalent conversion factors was performed with a Monte Carlo N-Particle transport code for the two types of extremity phantom of the ANSI and the KAERI, respectively. Considering the distribution of absorbed dose due to the interaction of homogeneous Parallel broad beam of monoenergetic primary photons in the range between 15keV and 1.5MeV, the air kerma-to-dose equivalent conversion factors based on the kerma approximation were calculated. It is showed that all the theoretical conversion factors of the two types of the extremity phantom for the ANSI and the KAERI agree well with the experimental values of the ANSI N13.32 draft(1995) for each energy within 5.7%, maximum difference ratio, except for 13.6%, difference ratio in the case for the energy of less than 40keV. It is due to uncertainties of experiment occurred in the low X-ray energy range and geometry considered in the MCNP code.

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The Relative and Absolute Speed of Radiographic Screen-Film Systems (증감지(增感紙)-필름계(系)의 상대감도(相對感度)와 절대감도(絶對感度)에 관한 실험(實驗))

  • Huh, Joon;Lee, In-Ja
    • Journal of radiological science and technology
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    • v.16 no.1
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    • pp.67-80
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    • 1993
  • Recently, a large number of new screen-film systems have become available for use in diagnostic radiology. These new screens are made of materials generally known as rare-earth phosphors which have high x-ray absorption and high x-ray to light conversion efficiency compared to calcium tungstate phosphors. The major advantage of these new systesms is reduction of patient exposure due to their high speed or high sensitivity. However, a system with excessively high speed can result in a significant degradation of radiographic image quality. Therefore, th speed is important parameters for users of these system. Our aim of in this was to determine accurately and precisely the absolute speed and relative speeds of both new and conventional screen-film system. We determined the absolute speed in condition of BRH phantom beam qulity and the relative speed were measured by a split-screen technique in condition of BRH and ANSI phantom beam qulity. The absolute and the relative speed were determined for 8 kinds of screen-4 kinds of film in regular system and 7 kinds of screen-7 kinds of film in ortho system. In this study we could know the New Rx, T-MAT G has the highest film speed, also know Green system's stndard deviation of relative speed larger than blue system. It was realized that there were no relationship between the absolute speed and the blue system. It was realized that there were no relationship between the absolute speed and the relative speed in ortho or regular system.

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Domestic Intercomparison Study for the Performance of Personnel Dosimeters (개인선량계 성능의 국내 상호비교)

  • Kim, Jang-Lyul;Chang, Si-Young;Kim, Bong-Hwan
    • Journal of Radiation Protection and Research
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    • v.21 no.3
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    • pp.147-153
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    • 1996
  • The Korea Atomic Energy Research Institute(KAERI) conducted a intercomparison study for personnel dosimetry services in Korea to enhance the accuracy and precision of the dosimetry system. Nine types of dosimeters(6 TLD, 3 film badge) from 7 institutions took part in this intercomparison study. Each participant submitted 30 dosimeters including transit control for irradiations. Both TLDs and film badges were irradiated with Cs-137 gamma, Sr/Y-90 beta and 4 X-ray beams in ISO wide series. Four dosimeters were irradiated on phantom with same dose equivalent for each field category. The delivered dose equivalent was in the range of $0.1{\sim}10mSv$. The participants assessed the results of their dosimeter readings in terms of the ICRU operational quantities for personal monitoring, Hp(10) and Hp(0.07). Most participants except 1 dosimeter estimated the delivered dose equivalent with biases less than ${\pm}25%$ for Cs-137 and Sr/Y-90. But for X-rays, the biases exceeded ${\pm}35%$ in some cases bacause the dose evaluation algorithm was based on the ANSI N13.11 X-ray fields which are different from those given by ISO.

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The Study on Scattered Radiation Effects According to Acquisition of X-ray Imaging using Monte Carlo Simulation (몬테카를로 시뮬레이션을 이용한 X선 의료영상 획득 시 산란선 발생 영향 연구)

  • Park, Ji-Koon;Kang, Sang-Sik;Yang, Seung-Woo;Heo, Ye-Ji;Kim, Kyo-Tae
    • Journal of the Korean Society of Radiology
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    • v.12 no.5
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    • pp.549-555
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    • 2018
  • The medical imaging technique images the contrast formed based on the difference in absorption coefficient of X-rays which changes according to the composition and thickness of the object. At this time, not only primary rays entering the image detector but also scattered rays greatly affect the image quality. Therefore, in this paper, Forward scattering rate and Scattered to primary ratio analysis were performed through Monte Carlo simulation in order to consider influence of scattered ray generated according to object thickness and radiation exposure area change on image quality. In the study, the Forward scattering rate corresponding to the thickness of the object was analyzed at a maximum of 15.3%p and the Scattered to primary ratio was analyzed at 2.00 to 4.54, but it was analyzed as maintaining a constant value for radiation exposure area change. Based on these results, the thickness of the object should be considered as a factor influencing the quality of the image, but radiation exposure area verified that it is a factor that does not affect the image quality. We believe that the results of this research can be utilized as basic information of scattered radiation to improve image quality.