• Journal of the Korean Society of Radiology
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• v.10 no.2
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• pp.125-131
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• 2016

Radiation therapy is usually using linear accelerator and used X-ray energy is also getting higher. Recently linear accelerators has been developed 3F mode and tracking jaw technology and that was applied for patient therapy. This study aims at measuring photoneutrons depending on the use of 3F and tracking jaw system when radiation is irradiated using a linear accelerator. The generation of photoneutrons of 3F system was 70% smaller than 2F system and that of tracking jaw system was 83% higher than static jaw system. Photoneutron value is relatively low. However, it must be minimized for Photoneutron exposure during radiation therapy.

• Journal of radiological science and technology
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• v.39 no.1
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• pp.89-97
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• 2016

As previous studies to proceed with the evaluation of the radioactive at linear accelerator's shielding concrete wall. And the shielding wall was evaluated the characteristics for the incoming neutron. As a result, the shielding wall is the average amount of incoming neutrons 10 MV 4.63E-7%, 15 MV 9.69E-6%, showed the occurrence of 20 MV 2.18E-5%. The proportion of thermal neutrons of which are found to be approximately 18-33%. The neutron generation rate can be seen as a slight numerical order. However, in consideration of the linear accelerator operating time we can not ignore the effects of neutrons. Accordingly radioactive problem of the radiation shield wall of the treatment room will be this should be considered.

• 전기의세계
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• v.13 no.4
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• pp.49-55
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• 1964

고 energy영역의 소립자 연구는 기존 선진제국의 대연구소에 의존할 수 밖에 없어도 저 energy의 물성론이나 공업적면 및 의료용의 이용을 목표로 한 Linac는 radar의 micro파 기술이 있는 우리나라에서도 제작이 쉽게 가능하다. 그것은 기계적으로 micron범위의 정도를 요하는 가속관 부분만 도입해서 15MeV의 Linac를 첫 단계로 완성하면 원자로와 아울러 연구 및 생산기술면에 있어서 커다란 무기로서 활용할 수 있는 기구가 될것이다. 또 한걸음 나아가서는 우리나라의 군사과학기술을 민간공업부문에 전용할 수 있는 좋은 계기가 될것이다.

• Progress in Medical Physics
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• v.8 no.2
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• pp.59-65
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• 1997

We have designed the software for geometrical QC/QA for medical linear accelerator using electronic portal imaging devices (EPID). The radiation-light field congruence, the collimator rotation axis, and the gantry rotation axis could be estimated with this software. Precision of the system is within 1mm. The collimator and the gantry rotation axis could be measured by superpositioning the images from 4 different collimator (or gantry) angles. The EPID system and the analysis software which was developed in this study make it possible that the quantitative and the objective geometrical QC/QA of the linear accelerator.

• 전기의세계
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• v.13 no.3
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• pp.63-69
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• 1964

한나라의 과학수준이 rocket기술이나 가속기의 출력 energy로서 운운 되었을 때가 있었는데 그때의 기속기는 원자핵 반응을 인공적으로 실험해 보는데 없어서는 안되는 것이기 때문이었다. 2차대전중 원자폭전의 출현을 보게 한 원자로의 발전은 대전후에는 평화적인 이용면에 따르는 응용 분야가 없는 고 energy의 소립자 연구라든지 isotope생산, 고분자화학 및 의료용등에는 대전중에 발전된 잔자기술의 이용으로 더 큰 가속기의 출현이 필요하였다. 특히 이 Electron Accelerator(이하 Linac라고 함)는 높은 고압과 큰 자석을 쓰지 않는 면에서 손쉽게 우리 신변에서 초고압 X선 이상의 효과로 쓸수있게해 주어서 그 이용면은 매우 다급해졌다. 여기서 우리나라의 입장에서 이러한 것을 살펴볼 때 첫째의 radar기술이 충분히 있으면서 이러한 것을 평화적 생산면에서 아직 활용하지 못하고 있으며 한편에서는 외국으로 부터 강력 동위원소를 도입하여 오고 있는데 Linac를 제작하여 여기서 이용하면 이러한 동위원소의 강도 이상의 것을 우리나라 기술로서 제작할 수 있다. 여기서 그 원리와 제작면에 있어서의 문제점 및 국제적인 이용 현황을 소개해 보겠다.

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.541-542
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• 2006

• Journal of radiological science and technology
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• v.39 no.4
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• pp.571-575
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• 2016

Monte Carlo simulations are widely used as the most accurate technique for dose calculation in radiation therapy. In this paper, the GATE6(Geant4 Application for Tomographic Emission ver.6) code was employed to calculate the dosimetric performance of the photon beams from a linear accelerator(LINAC). The treatment head of a Varian 21EX Clinac was modeled including the major geometric structures within the beam path such as a target, a primary collimator, a flattening filter, a ion chamber, and jaws. The 6 MV photon spectra were characterized in a standard $10{\times}10cm^2$ field at 100 cm source-to-surface distance(SSD) and subsequent dose estimations were made in a water phantom. The measurements of percentage depth dose and dose profiles were performed with 3D water phantom and the simulated data was compared to measured reference data. The simulated results agreed very well with the measured data. It has been found that the GATE6 code is an effective tool for dose optimization in radiotherapy applications.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.638-641
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• 2018

현재 선진국에서는 고출력 양성자 선형 가속기를 기반으로 한 의료용 암치료기인 BNCT(Boron Neutron Capture Therapy)에 대해 활발히 연구 중이며 다원시스도 2016년부터 A-BNCT 사업을 진행 중이다. A-BNCT에 적용된 양성자 선형 가속기의 RF(Radio Frequency)전원을 공급하기 위해 352 MHz, 1.5 MW의 고출력을 가지는 클라이스트론을 사용하였다. 클라이스트론의 출력인 RF의 크기와 위상을 안정적으로 제어하기 위해 90 kV, 30 A, 120 Hz, 1.7 ms의 구형파 출력을 가지는 고전압 전원장치를 적용하였다. 또한 고전압 전원장치의 출력전압 변동률을 0.5% 이내로 유지시키기 위해 전압보상회로를 적용하여 회로 시뮬레이션과 실부하 실험을 통해 펄스전원장치의 성능을 검증하였다.

• Journal of Radiation Protection and Research
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• v.11 no.1
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• pp.51-56
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• 1986

It is important to measure and protect from the radiation space dose and induced activity at the high energy medical linear accelerator facilities. These are to consider the additional risk to patients undergoing treatment, machine operators and staff members. Measurements of the space dose distribution and induced radioactivity at the 18 MeV medical linear accelerator facility in the Yonsei Cancer Center. 1. Exposure space dose for 300 rads monitor doses of 18 MeV electron are measured as 50 mR at 1 meter from patients. 2. Exposure space dose for 300 rads monitor doses of 10 MV X-ray are detected as 350 mR at 1 meter from phantom. 3. Induced radioactivity by photonuclear reaction was measured as 0.65 mR/hr from collimater after 30 Gy(3,000 rads) irradiated. 4. Analyzing the decay curves and energy spectrum of induced radioactivity, detected a few materials to be activated by photoneutron reaction, $^{65}Cu({\gamma}{\cdot}n)\;^{64}Cu,\;^{186}W({\gamma}{\cdot}n)\;^{185}W,\;^{181}Ta({\gamma}{\cdot}n)\;^{180}Ta,\;^{199}Au({\gamma}{\cdot}n)\;^{198}Au$.

• Journal of Radiation Protection and Research
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• v.6 no.1
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• pp.34-40
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• 1981

The logical development of an optimum structural shielding design and the computation of protective barriers for high energy radiation therapy room, Toshiba 13 MeV. are presented. We obtained following results by comparison in between the precalculating values and actual survey after complete installation of radiogenerating units. 1. The calculating formula for the protective barrier written in NCRP report #34(1970) was the most ideal and economic calculating methods for the construction of barrier and to determine thickness for the meeting requirements of the number of patients of 80-100 in daily treatment. 2. The precalculating values of protective barrier are 5 times more protective than that of actual measurement. It is depending on radiation workload and utilization the datas most sequrely. 3. The dose rate during exposure are 2-10 mR/hr at out of the door and the controll room. 4. The foul smelling and ozone gas production from long exposure of cancer patients cannot be eliminated when the room is ill ventilated.