• Progress in Medical Physics
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• v.9 no.3
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• pp.185-192
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• 1998

It is necessarily to evaluate the energy of X-ray emitted from linear accelerator in order to determine the accurate absorbed dose. The method of direct measurement for x-ray energy is very difficult and impractical. Therefore the method of using beam quality index is generally used. Several dosimetry protocols recommend the use of quality indices such as depth of dose maximum at radiation central axis, dose gradient, and dose level. The linear accelerator manufactures follow the recommendation as dosimetry protocols. The study was performed for us to select the most suitable parameter among the Quality indices as described above. For photon beams of 4, 6, 10, 15, and 21 MV nominal energies produced by four kinds of accelerators(Mitsubishi, Scanditronix, Siemens, Varian) in eleven institutions, We evaluated the x-ray energies obtained by the Quality indices as recommended by several dosimetry protocols and manufactures. Results showed that there were energy spreads according to the same accelerators and Quality indices even though nominal energies were same. It appeared that the percent depth dose at 10 cm (D$_{10}$(%)) gave the smallest deviation and spread of energies. As energies increased, the energy deviation increased for all the quality indices. It is desirable for the use of unified quality index to compare the evaluation of beam quality at different institutions.

• The Journal of the Korea Contents Association
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• v.16 no.7
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• pp.681-688
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• 2016

This study assess their quality of radiation on analysis of the spectrum of resolution suggesting IEC 61267 in radiation quality that RQA3, RQA5, RQA7, RQA9 and combination of clinical condition using several quality of radiation. In experiments edge method first, the spatial resolution assessment used image of the additional filter and SID is obtained the IEC 62220-1, spatial resolution and sharpness of the obtained image was evaluated in the MTF value 10%(0.1), MTF value 50%(0.5) using a Matlab program. Second, MCNPX simulation used spatial resolution analysis was radiation quality particle fluence and spectrum analysis in energy. As a result, make use of additional filter, image quality evaluation of SID that RQA3 radiation quality combination qualification is higher spatial resolution and sharpness make unused of additional filter and SID 100cm. RQA7 radiation quality combination qualification is higher that spatial resolution make unused of additional filter and SID 150cm. RQA9 radiation quality combination qualification is higher that spatial resolution and sharpness make used of additional filter and SID 180cm. spectrum analysis of radiation quality by reducing consequent errors occurring in the experiment that error due to the reproducibility of the X-ray tube, occur in an error of correction the detector suggest ideal conditions from spectrum analysis through MCNPX simulation. In conclusion, by suggesting spatial resolution and sharpness of result for various radiation quality, It provide basic data that radiation quality condition and quantitative assessment method for laboratory in clinical using detector evaluation.

• Journal of radiological science and technology
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• v.31 no.1
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• pp.89-95
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• 2008

The quality correction factor for used beam and qualities is strongly required for clinical dosimetry by TRS-398 protocol of IAEA. In this study the quality correction factors for a commercial plane-parallel ionization chamber in high energy electron beams were calculated by Monte Carlo code(DOSRZnrc/EGSnrc). In comparison of quality correction factor, the difference between this study and TRS-398 were within 1% in 5-20 MeV. In case of 4MeV the difference was 1.9%. As an independent method of determination of quality correction factor this study can be applied to evaluate values in the protocol or calculate the factor for a new chamber.

• 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.

• Progress in Medical Physics
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• v.17 no.1
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• pp.54-60
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• 2006

In order to apply the TRS-398 dosimetry protocol developed by IAEA we directly calculated the quality correction factors for high energy photons. The calculations were peformed for seven commercial cylindrical chambers (A12, IC70, N23333, N30001, N30006, NE2571, PR06C/G). In comparison with quality correction factors given by TRS-398 our results were in good agreement within ${\pm}0.3%$ (maximum ${\pm}0.3%$) for all chambers and photon qualities.

• Progress in Medical Physics
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• v.25 no.3
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• pp.123-127
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• 2014

The Cs-137 irradiator is widely used to irradiate biological samples for radiobiological research. To obtain the accurate outcomes, correct measurements of the delivered absorbed dose to a sample is important. The IAEA protocols such as TRS-277 and TRS-398 were recommended for the Cs-137 reference dosimetry. However in TRS-398 protocol, currently known as the most practical dosimetry protocol, the quality factor ($k_{Q,Q_0}$) for Cs-137 gamma rays is not suggested. Therefore, the use of TRS-398 protocol is currently unavailable for the Cs-137 dosimetry directly. The calculation method previously introduced for high energy photon beams in radiotherapy was used for deriving the Cs-137 beam qualities ($k_{Q,Q_0}$) for the 15 commercially available farmer type ionization chambers in this study. In conclusion, $k_{Q,Q_0}$ values were ranged from 0.998 to 1.002 for Cs-137 gamma rays. These results can be used as the reference and dosimeter calibrations for Cs-137 gamma rays in the future radiobiological researches.

• Progress in Medical Physics
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• v.22 no.3
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• pp.148-154
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• 2011

The quality factors ($k_{Q,Q_0}$) were evaluated by appling the results recently studied for the effect of central electrode in TRS-398 protocol. The PTW-31010 and IBA-CC13 chambers were used in this study. The quality factors were calculated as a function of beam quality for high energy electron and photon beams and compared with data currently used in TRS-398 protocol. In the PTW-31010 chamber using aluminium electrode, appling the new central electrode collections, the quality factors were 0.4% and 0.9% higher than current TRS-398 data for high energy photon and electron beams respectively. In the IBA-CC13 chamber using C-552 electrode, there are no variations in quality factors compared to TRS-398 data currently used.

• 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.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.149-152
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• 2004

물 흡수선량 표준에 토대를 두고 있는 프로토콜에서는 저에너지 전자선의 경우 평행평판형이온함의 사용과 기준 선질 $^{60}$CO 감마선의 물 흡수선량 교정정수를 받은 원통형이온함을 사용하여 고에너지 전자선에서 평행평판형이온함을 교차교정하도록 권고하고 있다. 따라서 본 연구에서는 국제원자력기구의 프로토콜(IAEA TRS-398)에서 권고하고 있는 절차에 따라 저에너지 전자선에 대한 원통형이온함의 선질보정정수를 계산하고, 원통형이온함과 평행평판형이온함의 교정방법에 따른 흡수선량을 상호 비교하였다. 그 결과 전자선에너지 10 MeV 이상에서는 두 이온함간의 선량이 잘 일치하였으나 전자선에너지 6, 9 MeV에서 최대 3.3%까지 선량 차이를 보여 저에너지 전자선에서는 반드시 평형판판형이온함의 사용하여 선량측정 할 것을 권고한다. 교정방법 차이에 의한 평행평판형이온함의 선량은 서로 잘 일치하는 것으로 나타나 표준기관에서 직접 교정받은 $^{60}$Co 감마선의 물 흡수선량교정정수를 사용하여 전자선 물 흡수선량을 결정해도 큰 영향은 없을 듯하다. 또한 평행평판형이온함을 교차 교정하기 위한 전자선 에너지에 따른 흡수선량을 상호 비교한 결과 20MeV이외 12, 16 MeV의 전자선 에너지에서도 잘 일치하여 교차교정을 위한 전자선의 기준 선질에 대한 연구가 더 진행되어야 한다고 사료된다.

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.177-178
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• 2015

디지털방사선영상시스템의 영상 품질을 비교하기 위해 영상의 정량적인 분해능을 나타내는 변조전달함수(MTF), 노이즈 특성을 나타내는 잡음력 스펙트럼(NPS)을 이용하여 영상 품질평가를 하였다. IEC61267 선질을 사용하여 IEC62220-1에서 제시하는 기하학적인 조건과 실제 임상에서 사용되어지는 기하학적인 조건을 사용하여 그리드 및 부가필터, 임상선량을 이용하여 edge 팬텀을 사용하여 MTF, NPS값을 측정하였다. 그리드사용 유 무, 부가필터사용 유 무, kV, 임상선량(mAs), 영상검출기까지의 거리에 따른 MTF 결과는 임상조건 100cm, 180cm과 IEC62220-1 기하학적인 조건 150cm에서 MTF 공간주파수 측정값은 비슷하게 나타났으며, 오히려 임상조건 100cm에서 공간주파수가 높게 나타나는 경우도 있었다. NPS 결과는 선량(mAs)이 증가함에 따라 감소함을 나타내었다. IEC61267 선질을 이용한 영상품질평가에서는 IEC62220-1기하학적인 조건을 이용한 품질평가보다 임상조건 기하학적인 조건을 사용한 영상의 품질이 좋았다. 본 논문의 영상특성 평가 연구 결과들을 바탕으로 향후 IEC 표준의 영상평가에서 제시하는 평가방법보다는 임상 조건을 적용한 영상특성 평가방법을 적용한다면 실제 임상의 디지털방사선영상시스템의 영상품질을 적절하게 유지할 수 있을 것으로 사료된다.