• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.187-188
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• 2011

저 에너지 방사선검사 시 부득이하게 방사선 노출을 받게 되는 방사선 작업종사자나 환자의 보호자가 위치와 거리에 따른 방사선 피폭 선량의 감소 방안을 알아보고자 한다. Ion chamber mode 2026c, Reader기 20X6-1800을 사용하여 구강내 검사와 구강외 검사의 각각 검사실과 조정실에서의 관전압의 변화, 관전류와 조사시간의 변화, 조사방향의 변화에 따라 선량을 측정하였다. 그 결과 검사실 안에서는 최고선량이 평균 $702.8{\mu}R$으로 측정 되었으며, 조정실 안에서 측정하였을 경우 $20{\mu}R$이하의 낮은 선량을 보였으며, 후방검사보다 측방검사가 낮은 선량으로 나타났다. 방사선검사 시 위치와 거리에 따른 조사선량을 비교 분석하여, 적절한 거리 확보와 조사되는 중심방사선을 기준으로 측방($90{\sim}135^{\circ}$)에 위치함으로써 방사선 방어에 도움을 줄 것이며, 차폐문을 이용하여 방사선 피폭으로부터 감소 효과를 볼 수 있을 것이다.

• Journal of the Korean Society of Radiology
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• v.7 no.6
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• pp.415-418
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• 2013

Thermoluminescent dosimeter utilizes the fact that when irradiated specimen is heated up, some part of the absorbed energy is emitted from the specimen as light with longer wavelength. This research aims at analyzing the glow curves of four TLD-100 exposed to a magnetic field and those of other four TLD-100 not exposed to one by treating them with heat and irradiating them, which are commonly used as thermoluminescent dosimeter, in the same condition. As the result of the experiment, regarding the electrons captured by irradiation, some of the electrons of lower traps were combined with positive holes of valence band through the exposure to a magnetic field, and the peak size decreased by 48%. The reduction in the size of the lower traps caused the TLD-100 exposed to a magnetic field to display a low level of dose. In addition, low traps estimated activation energies are 1.6 eV and 1.5 eV.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.807-812
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• 2018

In this study, we investigated the conditions used in setting the recommendation level of general radiography diagnostic reference and tried to evaluate the effective dose and biological evaluation using PCXMC v2.0 program. As a result based on the effective dose of male in ICRP 60, the highest Pelvis AP was 0.794 mSv. The lowest Chest PA was 0.050 mSv. In the case of ICRP 103, the highest T-Spine AP was 0.906 mSv The lowest Chest PA was 0.052 mSv. For 40 years old male and female adults, effective doses of general radiography were evaluated and even if the medical exposures are not subject to the limit of dose, efforts should be made to reduce the medical exposures of the people by keeping the dose below the recommended amount in order to minimize the probable effect of radiation hazard.

• The Journal of the Korea Contents Association
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• v.15 no.6
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• pp.283-289
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• 2015

Recently, high energy photon radiotherapy is a growing trend for increasing therapy results. Commonly, if you use high energy photons above 6~8 MeV nominal accelerator voltage, It lead the photo-nuclear reaction and the generation of photo-neutron are accompanied and these problematic factors are issued in the view of radiation protection. Therefore, in this study analyzed for dose distribution of photo-neutron in radiotherapy room based on MCNPX. As a result, absorbed dose is increased sharply from 10 MV to 12 MV. It was founded that the rapid increasement of photoneutron fluence was related to the absorbed dose at above 10 MV. Also, in case of the recommendation of ICRP 103, the outcome of an exchanged equivalent dose which based on calculated an absorbed dose, showed lower equivalent dose than ICRP 60 by reflecting the contribution of secondary photon for absorbed dose of human body in the low energy band.

• Journal of Radiation Protection and Research
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• v.37 no.2
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• pp.84-89
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• 2012

The purpose of this study was to compare radiation dose and image quality between low-dose (LDP) and standard-dose protocol (SDP). LDP (120 kVp, 30 mAs, 2-mm thickness) and SDP (120 kVp, 180 mAs, 1.2-mm thickness) images obtained from 61 subjects were retrospectively evaluated at level of carina bifurcation, using multi-detector CT (Brilliance 16, Philips Medical Systems). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated at ascending aorta and infraspinatus muscle, from CT number and back-ground noise. Radiation dose from two protocols measured at 5-point using acrylic-phantom, and CT number and noise measured at 4-point using water-phantom. All statistical analysis were performed using SPSS 19.0 program. LDP images showed significantly more noise and a significantly lower SNR and CNR than did SDP images at ascending aorta and infraspinatus muscle. Noise, SNR and CNR were significantly correlated with body mass index (p<0.001). Radiation dose, SNR and CNR from phantom were significant differences between two protocols. LDP showed a significant reduction of radiation dose with a significant change in SNR and CNR compared with SDP. Therefore, exposure dose on LDP in clinical applications needs resetting highly more considering image quality.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.157-157
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• 2004

• Nuclear Engineering and Technology
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• v.13 no.3
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• pp.161-167
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• 1981

For determination of mutation frequency induced by chronic irradiation of low dose gamma rays, Tradescarrfia clone 4430 was exposed to Co-60 ${\gamma}$ rays with different exposure rates from 3.6mR/day to 182R/day in or out of the Gamma Field at Kumkok Experiment Farm of KAERI. Somatic mutations based on pink mutant events of the stamen hair cells were clearly observed by the treatment. The pink mutant events were increased proportionally with increasing exposure rates of gamma ray except for relatively high dose rates of 105 R/day and 182 R/day, indicating saturation effect of mutation. The somatic pink mutations could be fairly detectable even in the low dose rate of 3.6mR/day. Therefore, this stamen hair system of Tradescantia clone 4430 seemed to be an reasonable test system for detecting mutability of low level irradiation. These results imply that artificial mutation induction in the fruit and ornamental trees could be expected in the ${\gamma}$-field.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.720-724
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• 1998

감마선이 Artemia 알의 부화에 미치는 영향을 알아보고자, 10Gy, 100Gy, 3kGy, 6kGy과 9kGy의 선량으로 건조 상태의 알을 조사한 후 부화율과 nauplius기의 출현률을 조사하였다. 1kGy 이하의 방사선 조사군에서는 부화율과 nauplius기의 출현률이 대조군에 비하여 높게 나타났다. 3kGy 방사선조사군의 경우 대조군과 유사한 부화율을 보였으나 nauplius기의 출현률은 감소하였다. 6kGy의 방사선조사군에서는 알들의 부화 지연과 부화율의 감소가 뚜렷하였다. 50％의 부화율을 나타내는 선량은 약 5.5kGy였으며, 9kGy에서는 100％ 치사선량을 나타내었다. 본 실험에서 조사한 선량증에서 비교적 낮은 선량의 범위에서는 이온화방사선에 의하여 Artemia 알의 부화시간 단축 및 부화율이 다소 증가하는 결과를 보였다. 따라서 이온화방서선을 이용한 Artemia 알의 부화률을 촉진지킬 수 있는 적정 선량에 대한 연구는 상업적으로도 가치가 있다고 생각되며, 향후 이에 대한 추가적인 연구를 통한 상업적인 활용이 기대된다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.57-62
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• 1996

ANSI N13.32는 손목팬텀과 손가락팬텀에서 말단선량계의 특성조사를 위하여 방향의존성인자를 선량계의 성능평가에 적용하도록 권고하고 있다. 본 연구에서는 말단선량의 정확한 선량평가를 위하여 ANSI N13.32에 제안된 팬텀과 동일하게 모사하고 그 팬텀내의 7mg/$\textrm{cm}^2$ 깊이에서 단일에너지를 가진 광자의 선량당량환산인자 및 방향의존성인자를 MCNP 전산코드를 사용함으로써 계산하였다. 또한 본 연구의 최종목적인 ISO Narrow X-선 빔에 의해 조사된 손가락팬텀에서 선량당량환산인자 및 방향의존성인자를 도출하였다. 전산 수행한 결과 낮은 전압에서 발생된 X-선 빔인 경우, 팬텀의 주축을 따라 수평회전각이 증가할수록 방향의존성인자가 크게 감소하며, 한편 높은 전압에서 생성된 X-선 빔인 경우, 수평회전각이 증가할수록 방향의존성인자간 처음에는 근소하게 감소하지만 90。까지는 증가하고 있음을 알 수 있었다.

• Food Industry
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• s.168
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• pp.28-31
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• 2002

한국산 콩 발효식품인 청국장과 된장의 생리활성효과에 대한 감마선의 영향을 살펴보았다. 청국장과 된장은 시중에서 구입하였으며 5,10,20 kGy의 선량으로 조사하였다. 생리활성효과로 angiotensin converting enzyme inhibition, xanthine oxidase inhibition, tyrosinase inhibition과 전자공여능을 살펴본 결과 10 kGy 보다 낮은 조사선량에서는 어떠한 영향도 끼치지 않는 것으로 나타났다.