• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.78-80
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• 2004

본 연구에서는 쐐기형태의 선량분포를 구현할 수 있도록 고안된 미국 Varian사 동적쐐기(EDW ; Enhanced Dynamic Wedge)의 표면선량(surface dose)과 주변선량(peripheral dose) 특성을 분석하였다. 쐐기각도 15${\circ}$, 30${\circ}$, 45${\circ}$, 50${\circ}$를 대상으로 금속쐐기를 사용했을 경우와 동적쐐기를 사용했을 경우에 대해 해당 선량특성을 비교, 분석하였다. 표면선량 측정 결과, 동적쐐기가 금속쐐기보다 더 높은 선량 분포를 보였으며, 주변선량의 경우, 금속쐐기가 동적쐐기보다 더 높은 선량분포를 보였다. 이는 금속쐐기의 빔 필터링에 의한 빔 경화(hardening) 현상과 광자선과의 산란 현상에 기인한 결과로 방사선치료 계획 시 동적쐐기의 적용에 있어 고려해야 할 주요 특성이라 사료된다.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2616-2618
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• 2004

본 논문에서는 휴대용 선량계 시스템에 대해 논하였다. 휴대용 선량계는 감마선과 속중성자 및 열중성자를 현장에서 실시간으로 측정 할 수 있는 휴대용 선량계이다. 선량계는 선량계의 소형화를 위해 모듈별로 구성하여 공간의 최적화를 취하였다. 모듈의 구성은 시스템의 전반적인 제어를 하는 CPU부 센서로부터 측정한 데이터를 처리하는 신호처리부 방사선량을 측정하는 센서부로 구성되어졌다. 센서 모듈의 PIN 다이오드와 MODFET 센서를 이용하여 감마선, 속중성자, 열중성자를 측정한다. 휴대용 선량계를 관리하고 측정한 데이터의 백업 및 분석을 위하여 PC용 관리프로그램과 블루투스 통신을 사용하여 통신하도록 만들어 사용하였다. 측정 지역의 방사선량을 휴대용 선량계로 측정하여 PC용 관리프로그램에서 방사선량을 확인 할 수 있다.

• Journal of The Korean Radiological Technologist Association
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• v.29 no.1
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• pp.6-11
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• 2003

목적 : 전신방사선조사(TBI)시 균등한 선량을 조사할 목적으로 사용되는 각 신체부위별 보상체(compensator) 두께의 결정은 열형광선량계(TLD)를 이용하여 표면선량(surface dose)을 측정하고, 심부선량(depth dose)으로 환산하는 방법을 주로 이용한다. 그러나 이와 같은 방법은 골(bone) 조직에 대한 선량감쇠(dose attenuation)의 영향이 고려되지 않아 신체중심부에서의 정확한 심부선량을 알 수가 없다. 이에 본 연구

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3412-3418
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• 2013

The Purpose of this study was to evaluate by comparing the dose change and build up characteristic according to delay time in 30 days of glass dosimeter processed preheat and non preheat when measuring accumulation dose of radiation by using glass dosimeter over the long haul. For obtaining low dose with 0.1 mGy, 1 mGy and 5 mGy, we employed diagnostic generator AccuRay-650R. We compared the build up characteristic over the long haul by exposuring radiation to 30 glass dosimeters sorted into 10 glass dosimeters per tube voltage and current. In Non preheat glass dosimeter, initial measured dose was inferior to exposed dose but as time goes on, was close to exposed dose steadily. In 72 hour after experiment end, non preheat glass dosimeters were not indicated the difference from preheat glass dosimeters and statistical analysis were meaningful (p>0.05). Initial measured dose for low glass dosimeter processed preheat was close to exposed dose and stable. After 15 days dose was gradually increased. Previous study characteristics of glass dosimeter were with respect to characteristic of glass dosimeter in high dose of high energy area. However, in this study, we make a judgment to measure the dose of glass dosimeter without preheat processing when measuring the accumulation dose of low dose in conclusion.

• Journal of Radiation Protection and Research
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• v.31 no.2
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• pp.97-104
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• 2006

In recent years, the MOSFET dosimeter has been widely used in various medical applications such as dose verification in radiation therapeutic and diagnostic applications. The MOSFET dosimeter is, however, mainly made of silicon and shows some energy dependence for low energy Photons. Therefore, the MOSFET dosimeter tends to overestimate the dose for low energy scattered photons in a phantom. This study determines the correction factors to compensate these dependences of the MOSFET dosimeter in ATOM phantom. For this, we first constructed a computational model of the ATOM phantom based on the 3D CT image data of the phantom. The voxel phantom was then implemented in a Monte Carlo simulation code and used to calculate the energy spectrum of the photon field at each of the MOSFET dosimeter locations in the phantom. Finally, the correction factors were calculated based on the energy spectrum of the photon field at the dosimeter locations and the pre-determined energy and directional dependence of the MOSFET dosimeter. Our result for $^{60}Co$ and $^{137}Cs$ photon fields shows that the correction factors are distributed within the range of 0.89 and 0.97 considering all the MOSFET dosimeter locations in the phantom.

• Journal of Radiation Protection and Research
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• v.36 no.2
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• pp.86-92
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• 2011

This study used the optically stimulated luminescence dosimeters (OSLDs), recently, received the revaluation of usefulness in vivo dosimetry, and the diode detecters to measure the skin dose of patient with the rectal cancer. The measurements of dose delivered were compared with the planned dose from the treatment planning system (TPS). We evaluated the clinical application of OSDs in radiotherapy. We measured the calibration factor of OSLDs and used the percent depth dose to verified, also, we created the three point of surface by ten patients of rectal cancer to measured. The calibration factors of OSLD was 1.17 for 6 MV X-ray and 1.28 for 10 MV X-ray, demonstrating the energy dependency of X-ray beams. Comparison of surface dose measurement using the OSLDs and diode detectors with the planned dose from the TPS, The skin dose of patient was increased 1.16 ~ 2.83% for diode detectors, 1.36 ~ 2.17% for OSLDs. Especially, the difference between planned dose and the delivery dose was increased in the perineum, a skin of intense flexure region, and the OSLDs as a result of close spacing of measuring a variate showed a steady dose verification than the diode detecters. Therefore, on behalf of the ionization chamber and diode detecters, OSLDs could be applied clinically in the verification of radiation dose error and in vivo dosimety. The research on the dose verification of the rectal cancer in the around perineal, a surface of intense flexure region, suggest continue to be.

• The Journal of the Korea Contents Association
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• v.17 no.9
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• pp.292-299
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• 2017

Radiation protection aims to prevent a deterministic effect and minimize a stochastic effect. Overestimating a deterministic effect and a stochastic effect can result in an inaccurate assessment of the risks that will occur in the future, and thus accurate evaluation of the absorbed dose of these fundamental amounts is especially important. This study was intended to measure Kerma using PCXMC 2.0 based on Monte Carlo simulations and to assess the exact absorbed dose by comparing doses produced using multipurpose dosimeter and glass dosimeter. It has been decided to conduct experiments for skull, abdomen and pelvis, and Kerma measured PCXMC 2.0 based on Monte Carlo simulations. The absorbed dose was measured using muli purpose dosimeter and glass dosimeter. The results for the experiments conducted in skull, abdomen, pelvis show that the difference in dose appears great in the order of PCXMC 2.0, muli purpose dosimeter, and the glass dosimeter, and muli purpose dosimeter showed a value closer to that of Kerma. As a result, it has been found that the glass dosimeter was the most advantageous in measuring the actual absorbed dose.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.305-312
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• 2016

This study were compared with the direct measurement and indirect dose methods through various dose calculation in head and wrist. And, the modified equation was proposed considering equipment type, setting conditions, tube voltage, inherent filter, added filter and its accompanied back scatter factor. As a result, it decreased the error of the direct measurement than the existing dose calculation. Accordingly, diagnostic radiography patient dose comparison would become easier and radiogrphic exposure control and evaluation will become more efficient. The study findings are expected to be useful in patients' effective dose rate evaluation and dose reduction.

• Progress in Medical Physics
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• v.19 no.1
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• pp.9-13
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• 2008

The purpose of this study was to measure the skin dose using the glass dosimeter and diode and to compare those measurements to the planned skin dose from the treatment planning system. For the reproducibility of the glass dosimeter (ASAHI TECHNO GLASS CIRPORATION, Japan), the same dose was irradiated to 40 glass dosimeters three times, among which 28 with the reproducibility within 3% were selected for the use of this study. For each of 27 breast cancer patients, the glass dosimeters and diodes were attached to 4 different locations on the skin to measure the dose during treatment. All the patients received one fraction of 180 cGy each. The maximum difference of measurements between the glass dosimeter and diode at the same location was 3.2%. Comparing with the planned skin dose from the treatment planning system (Eclipse v6.5, Varian, USA), the dose measured by the glass dosimeter and the diodeshowed on an average 3.4% and 2.3% difference, respectively. The measured doses were always less than the planned skin dose. This may be due to the specific errors of both detectors. Also, the difference may be caused by the fact that since the skin where the detectors were attached is pretty moveable, it was not fix the detectors on the skin.

• 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.