• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.33-35
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• 2004

방사선치료를 위한 고에너지 광자선의 품질관리를 위해 사용하는 TLD의 광자선 선질에 대한 에너지 의존도를 몬테카를로 모사법을 사용하여 평가하였다. IAEA 선량보증사업에 이용되는 LiF TLD 및 홀더를 EGS4기반의 사용자 코드인 DOSIMETER 와 MCNP4C 몬테카를로 코드를 사용하여 기하학구조를 구성하고, Co, 4, 6,10 밑 15 MV 광자선을 시뮬레이션하였다. DOSIMETER계산 결과를 통해 TLD의 에너지 보정인자가 실험 데이터와 일치함을 확인할 수 있었으며, 이와 별도로 캡슐에 의한 교란량도 무시할 수 없음을 발견하였다.

• Journal of the Korean Society of Radiology
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• v.10 no.6
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• pp.427-433
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• 2016

Recently increased use of high energy x-ray in radiation therapy, so therapeutic efficiency of tumors that located deep part also increased. However, photoneutron is problem which is generated caused by photoneuclear reaction. Photoneutron is continually required management because of that is more harmful than photon. In this regard, the study utilizing simulation of the Monte Carlo method is actively progress about photoneutron but measure is deficient. So this study was analyzed the correlation between the measured photon and photoneutron by radiation measurement device. As a result, photons were reduced when distance is farther and field size is smaller. But photoneutron were increased when field size is smaller and increased to a certain distance then reduced.

• Journal of Radiation Protection and Research
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• v.21 no.2
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• pp.125-129
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• 1996

The energy response of HPGe detector for low energy Photons was determined by using three Monte Carlo codes. MCNP4A. EGS4, and CYLTRAN in ITS3. In this study. bare HPGe detector$(100 mm^2{\times}10mm)$ was used and a pencil beam was incident perpendicularly on the center of the detector surface. The photopeak efficiency, $K_{\alpha}$ and $K_{\beta}$ escape fractions were calculated as a function of incident X-ray energies ranging from 12 to 60 keV in 2-keV increments. Since the Compton. elastic. ana penetration fraction were negligible in this energy range. they were ignored in the calculation. Although MCNP. EGS, and CYLTRAN codes calculated slightly different energy response of HPGe detector for low energy Photons, it appears that the three Monte Carlo codes can Predict the low energy Photon scattering Processes accurately. The MCNP results, which are generally known as to be less accurate at low energy ranges than the EGS and ITS results. are comparable to the results of EGS and ITS and are applicable to the calculation of the low energy response data of a detector.

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.167-168
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• 2015

고에너지 의료용 선형가속기를 이용한 폐암 방사선치료 시 갑상선에 미치는 선량을 평가하였다. 산란광자의 영향은 3DCRT 시 평균 27.9mSv, IMRT에 있어서는 43.6mSv로 평가 되었다. 광중성자의 영향은 3DCRT 시 평균 3.2mSv, IMRT에 있어서는 평균 4.7mSv로 평가 되었다. 산란광자와 광중성자 모두 3DCRT 보다 IMRT가 높은 것으로 평가 되었다. 본 연구를 통하여 고에너지를 이용한 방사선치료 시 인접한 정상조직에 상당한 양의 산란선량이 영향을 주는 것으로 평가된 바와 같이 방사선을 이용한 암 치료 종사자는 이러한 내용을 충분히 인지하여 피폭 저감화를 위한 노력이 필요할 것으로 사료된다.

• Proceedings of the Korea Contents Association Conference
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• 2014.11a
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• pp.181-182
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• 2014

고에너지 의료용 선형가속기를 이용한 폐암 방사선치료 시 갑상선에 미치는 선량을 평가하였다. 산란광자의 영향은 3DCRT 시평균 27.9mSv, IMRT에 있어서는 43.6mSv로 평가 되었다. 광중성자의 영향은 3DCRT 시 평균 3.2mSv, IMRT에 있어서는 평균 4.7mSv로 평가 되었다. 산란광자와 광중성자 모두 3DCRT 보다 IMRT가 높은 것으로 평가 되었다. 본 연구를 통하여 고에너지를 이용한 방사선치료 시 인접한 정상조직에 상당한 양의 산란선량이 영향을 주는 것으로 평가된 바와 같이 방사선을 이용한 암치료 종사자는 이러한 내용을 충분히 인지하여 피폭 저감화를 위한 노력이 필요할 것으로 사료된다.

• 대한방사선치료학회:학술대회논문집
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• 1999.05a
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• pp.14-14
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• 1999

• Progress in Medical Physics
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• v.6 no.2
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• pp.51-60
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• 1995

Lithium Fluoride (LiF; TLD-100) crystal chips are normally used as thermolu minescence dosimeters (abbreviated as NC-100) for estimating the absorbed dose to the skin of a patient or in a solid water phantom undergoing radiotherapy with megavoltage photon (6 and 15MV) beams. In general, investigation has revealed a reduction in the sensitivity of NC-100 chips after many runs through heating cycles. A TLD-100 chip laminated with gold plate (140${\mu}{\textrm}{m}$) on the upper surface layer of its face toward the photon beam (abbreviated as GC-100) has properties different from that of a NC-100 chip activated by incident photons and contaminant electrons with various lower energies coming from the gantry head and air. Activation of the valence band electrons of GC-100 chips by incident photons, positrons and electrons-which come from the gold plate by mainly pair production process and partly from Compton scattering-results in more enhanced signal intensity, higher response per monitor unit, as well as a good linearity with monitor units and independence of dose rate. Since the electron beams (6 and 15 MeV) do not have the probability of pair production process with gold plate, there is only a small difference (about a 3.3％ increase for 15 MeV) in the signal gaps in the TL readout for electron beams between GC- and NC-100 chips. The 3.3％ increase is entirely due to the buildup caused by the 140 m gold plate. The sensitivity of GC-100 chips is much more susceptible to high energy photon beams than electron one because of pair production. The interaction of high energy photon with a material of high atomic number, such as the good plate in this case, results in a considerably significant probability of pair production. The gold plate on the NC-100 chips acts as not only an intensifier of their signals but also acts as a filter of contaminant electrons in therapeutic high energy X-ray beams.

• 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.

• Journal of radiological science and technology
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• v.31 no.4
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• pp.415-417
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• 2008

This study is to measure the radiation dose of neutrons generated by the particle accelerator during X-ray (photon) treatment with a neutron detection method by using CR-39, and to research how the generation of neutrons may incur problems associated with radiation doses for patient treatment when using high energy photons for cancer treatment as a clinical application. The findings are summarized as follows : The results showed that average 0.35mSv was measured with exposure of 1Gy photon in case of fast neutron, 0.65mSv with exposure of 2Gy photon, 1.82mSv exposure of 5Gy, 0.26mSv with exposure of 1Gy photon in case of thermal neutron, 0.56mSv with exposure of 2Gy photon, and 1.23mSv with exposure of 5Gy of photon. By measuring the occurrence of neutron by using Wedge Filter, it has been confirmed that the occurrence of neutrons increased when using Wedge Filter. The results also showed that more neutrons were detected over the existing experiments when using an SRS Cone requiring high doses of radiation. Total 2.85mSv neutrons were found on the average with exposure of 5Gy photon in case of fast neutron and 1.37mSv neutrons were found on the average with exposure of 5Gy photon in case of thermal neutron. During the general treatment, about 1.6 times more neutrons over 5Gy photon were found in case of fast neutron and about 1.12 time more neutrons over 5Gy photon were found in case of thermal neutron.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.199-204
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• 1998

고에너지 전자가 매질 내에서 수송될 때, 매질 내에서 Photoneutron 생성률과 생성된 중성자 에너지 분포를 EGS4 코드를 사용하여 계산하였다. EGS4 코드는 광자-전자 연계 수송코드로 Photoneutron 반응단면적을 제공하지 않기 때문에, Photoneutron 반응단면적 계산루틴과 생성된 중성자 에너지분포 계산루틴을 작성하여 Ta와 Pb의 표적 매질에 100 MeV의 전자가 입사하였을 때 표적의 두께변화에 따른 Photoneutron 생성률과 생성된 중성자 에너지분포를 계산하였다.