• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.66-66
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• 2003

목적 : 선량측정의 정확성을 향상시키기 위하여 물 흡수선량 표준에 토대를 두고 있는 표준측정법, AAPM TG-51과 IAEA TRS-398, 이 발표되어 선량측정의 파라다임이 변화하고 있다. 본 연구에서는 이들 대표적인 표준측정법에 대하여 사용자 편의성을 고려하여 웹에 기반한 선량교정 프로그램을 개발하고자 한다. 대상 및 방법 : 미국의학물리학회 AAPM TG-51과 국제원자력기구 IAEA TRS-398 표준측정법에 선량교정 프로그램은 Microsoft IIS 6.0 웹서버와 .NET 플렛폼상에서 Visual Studio. NET 도구를 사용하여 개발하였다. 개발언어로는 C# 언어를 사용하였고 각 표준측정법에 대한 선량교정 작업서는 ASP. NET 페이지로 작성하였다. 웹페이지와 산량 교정 모듈을 분리하여서 개발 후 유지보수가 쉽게 설계하였다. 또한 기준점에서의 선량 계상에 사용하는 모든 물리적인 파라미터와 데이터는 데이터베이스에 저장하였다. 이로써 향후 수식체계의 변화 또는 물리적인 데이터의 변화로 인한 프로그램 수정이 최소화하도록 하였다. 결과 : 이들 표준측정법은 모두 물 흡수선량 교정인수에 토대를 두고 있으나 측정 조건 및 물리적인 자료 에 있어 약간의 차이를 보이고 있다. 그러므로 각 표준측정법간의 유사점 및 차이점을 비교 분석하기가 용이하였다. 그리고 개발된 프로그램을 이용하여 표준측정법에서 제시된 선량교정 작업서에 따라 선량 교정을 수행한 교정 결과 데이터를 XML 파일 형식으로 저장하여 이전의 측정 자료를 관리할 수 있게 하였다. 이 과거 측정 자료를 사용하여 출력 선량 교정의 변화 및 기타 중요한 물리적인 데이터 값의 변화를 분석할 수 있다. 결론 : 두 표준측정법에 대한 선량교정 프로그램은 사용자가 선호하는 표준측정법을 선택할 수 있고, 웹에 토대를 두고 있어 프로그램으로 전국 방사선종양학과의 방사선치료기기의 출력 및 물리적인 변화에 대한 자료를 비교 분석하기 용이하고 수작업으로 인해 발생할 수 있는 실수 및 오차를 줄일 수 있다. 또한 개발된 프로그램의 활용을 통하여 국내 실정에 적합한 물 흡수선량 표준에 기반한 표준측정법 개발에 토대를 마련하는데 있어 기여할 것으로 사료된다.

• Journal of the Korean Society of Radiology
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• v.11 no.1
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• pp.37-42
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• 2017

We measured the absorbed dose and the area dose using an ionization chamber type of area dose product (DAP) meter and measured the calibration factor in the X-ray examination. In the indirect dose measurement method, the detector was installed in the radiation part of the X-ray equipment, and the measured value was calculated as the dose at the exposure part. The instrument used to calculate the calibration factor was an X-ray equipment (DK-550R / F, DongKang Medical Co., Ltd., Seoul, Korea). The calibration method for the calibration factor was to connect the DAP meter (PD-8100, Toreck Co. Ltd., Japan) to the calibration dosimeter tube voltage of 70 kV, tube current of 500 mA, 0.158 sec. The reference dosimeter used a semiconductor (DOSIMAX plus A, Scanditronix, $Wellh{\ddot{o}}fer$, Germany). After installing the DAP meter on the front of the multi-collimator of the ionization chamber, the calibration factor of the dosimeter was obtained using the reference dosimeter for accurate dose measurement. Experimental exposure values and values from the calibration dosimeter were calculated by multiplying each calibration factor. The calibration factor was calculated as 1.045. In order to calculate the calibration coefficient according to the tube voltage in the ionization type DAP dosimeter, the absorbed dose and the area dose were calculated and the calibration factor was calculated. The corrective area dose was calculated by calculating the calibration factor of the DAP meter.

• 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.

• Journal of the Korean Society of Radiology
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• v.7 no.1
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• pp.93-98
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• 2013

The purpose of this study is to investigate the calibration of an optically stimulated luminescent nanoDot dosimeter(OSLnD) to 6 MV photon beam. Dose ranges of the calibration of linear and non-linear from the analysis of dose response of the OSLnD were decided. To evaluate the accuracy of calibration equation and the calibration, the sets of the calibration and quality control dosimeter were used to make. The calibrations were performed by the linear and the non-linear in the dose range of 0~300 cGy and 20~1300 cGy, respectively. The errors of the calibration were acquired less than 0.1% respectively from the measurement of the quality control dosimeters for the calibration of linear and the non-linear. This study provides the calibration equation of the OSLnD to the 6 MV photon beam.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2005.04a
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• pp.96-99
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• 2005

본 연구에서는 식품의약품안전청의 도움을 받아 1998년부터 2003년까지 장기간에 걸친 교정정수의 분석을 통한 원통형이온함의 모델별 안정성을 확인하여 보다 효율적인 이온함의 선택으로 방사선치료기관의 선량측정체계의 정확도 향상에 기여하고자 한다. 방사선치료기관에서 사용하고 있는 Farmer형의 원통형이온함에 대한 에어커마 교정정수(NK)를 분석한 결과 Wellhofer FC65G (IC70)와 PTW 30001, 30013 (30006) 그리고 NE 2571 이온함 모델에 대한 교정정수는 모두 0.3%이내에서 잘 일치하였다. 또한 에어커마 교정정수를 이용하여 계산된 물 흡수선량 교정정수(Cal. ND,W)와 실제 측정에 의해 결정된 물 흡수선량 교정정수(Mea. ND,W)를 비교한 결과는 약 1.0% 정도 측정에 의한 교정정수가 높게 나타났으며 에어커마 교정정수를 분석한 결과와 마찬가지로 위 동일한 모델의 이온함에 대해서 측정의 표준편차가 0.14～0.17%로 나타나 장기적인 안정성이 입증되었다.

• Radiation Oncology Journal
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• v.20 no.4
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• pp.381-390
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• 2002

Purpose : To develop a dose calibration program for the IAEA TRS-277 and AAPM TG-21, based on the air kerma calibration factor (or the cavity-gas calibration factor), as well as for the IAEA TRS-398 and the AAPM TG-51, based on the absorbed dose to water calibration factor, so as to avoid the unwanted error associated with these calculation procedures. Materials and Methods : Currently, the most widely used dosimetry Protocols of high energy photon beams are the air kerma calibration factor based on the IAEA TRS-277 and the AAPM TG-21. However, this has somewhat complex formalism and limitations for the improvement of the accuracy due to uncertainties of the physical quantities. Recently, the IAEA and the AAPM published the absorbed dose to water calibration factor based, on the IAEA TRS-398 and the AAPM TG-51. The formalism and physical parameters were strictly applied to these four dose calibration programs. The tables and graphs of physical data and the information for ion chambers were numericalized for their incorporation into a database. These programs were developed user to be friendly, with the Visual $C^{++}$ language for their ease of use in a Windows environment according to the recommendation of each protocols. Results : The dose calibration programs for the high energy photon beams, developed for the four protocols, allow the input of informations about a dosimetry system, the characteristics of the beam quality, the measurement conditions and dosimetry results, to enable the minimization of any inter-user variations and errors, during the calculation procedure. Also, it was possible to compare the absorbed dose to water data of the four different protocols at a single reference points. Conclusion : Since this program expressed information in numerical and data-based forms for the physical parameter tables, graphs and of the ion chambers, the error associated with the procedures and different user could be solved. It was possible to analyze and compare the major difference for each dosimetry protocol, since the program was designed to be user friendly and to accurately calculate the correction factors and absorbed dose. It is expected that accurate dose calculations in high energy photon beams can be made by the users for selecting and performing the appropriate dosimetry protocol.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.508-515
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• 2018

The purpose of this study was to analyze the errors of the built - in dose area product and the calibrated moving dose area product when using automatic exposure controller of the interventional equipment. And then, the importance of the dosimeter calibration and the necessity of the calibration guideline were investigated. The experimental method was to assemble the phantom into Thin, Normal, and Heavy Adult according to the NEMA Phantom manual and to measure the dose area with the built-in dose area product and the moving dose area product. As a result, in all thicknesses, the built-in dose area product showed higher doses than the moving dose area product, and the thicker the thickness, the larger the difference. In addition, paired t-test was performed for each item and there was a significant difference in each item between p<0.05. In conclusion, considering the intervention which is highly exposed to the radiation exposure, it is that we have to know the accurate dose when using the AEC of the equipment. And there is no calibration guide for the built-in dose area meter, thus calibration guidelines should be prepared.

• Progress in Medical Physics
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• v.6 no.1
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• pp.13-18
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• 1995

Dose distribution of HDR-RALS source represents an inverse square law as the distance. Difference of measurement value and calculation value according of brachytherapy. Therefore, in HDR-RALS dose calibration and calculation have an important effect in treatment of uterine cervical cancer and absorbed dose of interesting points. In intracavitary therapy, particula attention is paid for precise determination of the doses to be applied. In this report, we have discussed that the calibration of a HDR-RALS, differences between calculation dose use of isodose chart and measurement in rectum. Dose rate calibration of radiation sources are obtained from air kerma and Г factor with calibraed ion chamber for cobalt source. and used semiconductor detector for compared with measurement in phantom. Eighteen patients were treated with a HDR-RALS for intrcavitarty irradiation (ICR) using a cobalt-cesium source. Repoductivity of dose measurements were 0.3 -1.1％ in phantom. The means of dose distribution was -6- ＋21％ between calculation of isodose chart and measurement of recyum, and was same mean value upper 6.3％ in measurement value than calculation does.

• Progress in Medical Physics
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• v.14 no.3
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• pp.175-183
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• 2003

Absorbed dose dosimetry protocols of high energy photon and electron beams, which are widely used and based on an air kerma (or exposure) calibration factors, have somewhat complex formalism and limitations for improving dosimetric accuracy due to the uncertainty of the physical parameters used. Recently, the IAEA and the AAPM published the absorbed dose to water-based dosimetry protocols(IAEA TRS-398 and AAPM TG-51). The dose calibration programs for these two protocols were developed. This program for high energy photon and electron beams was also developed for users to use in a window environment using the Visual C++ language. The formalism and physical parameters of these two protocols were strictly applied to the program. The tables and graphs of the physical data, and the information of ion chambers were numericalized for their incorporation into a database. This program can be useful in developing new dosimetry protocols in Korea.

• Progress in Medical Physics
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• v.23 no.2
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• pp.114-122
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• 2012

For the determination of absorbed dose to water from a linear accelerator photon beams, it needs a exposure calibration factor $N_x$ or air kerma calibration factor $N_k$ of air ionization chamber. We used the exposure calibration factor $N_x$ to find the absorbed dose calibration factors of water in a reference source through the TG-21 and TRS-277 protocol. TG-21 used for determine the absorbed dose in accuracy, but it required complex calculations including the chamber dependent factors. The authors obtained the absorbed dose calibration factor $N_{dw}{^{Co-60}}$ for reduce the complex calculations with unknown $N_{dw}$ only with $N_x$ or $N_k$ calibration factor in a TM31010 (S/N 1055, 1057) ionization chambers. The results showed the uncertainty of calculated $N_{dw}$ of IC-15 which was known the $N_x$ and $N_{dw}$ is within -0.6% in TG-21, but 1.0% in TRS-277. and TM31010 was compared the $N_{dw}$ of SSDL to that of PSDL as shown the 0.4%, -2.8% uncertainty, respectively. The authors experimented with good agreement the calculated $N_{dw}$ is reliable for cross check the discrepancy of the calibration factor with unknown that of TM31010 and IC-15 chamber.