• Nuclear Engineering and Technology
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• 제53권8호
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• pp.2646-2651
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• 2021

A rectangular-shaped PET system with an adjustable gantry (AGPET) has been developed for imaging small animals. The AGPET system employs a new depth of interaction (DOI) method using a depth dependent reflector patterns and a new digital time pickoff method based on the pulse reconstruction method. To evaluate the performance of the AGPET, timing resolution, intrinsic spatial resolution and point source images were acquired. The timing resolution and intrinsic spatial resolution were measured using two detector modules and Na-22 gamma source. The PET images were acquired in two field of view (FOV) sizes, 30 mm and 90 mm, to demonstrate the characteristic of the AGPET. As a result of in the experiment results, the timing resolution was 0.9 ns using the pulse reconstruction method based on the bi-exponential model. The intrinsic spatial resolution was an average of 1.7 mm and the spatial resolution of PET images after DOI correction was 2.08 mm and 2.25 mm at the centers of 30 mm and 90 mm FOV, respectively. The results show that the proposed AGPET system provided higher sensitivity and resolution for small animal imaging.

• 대한방사선기술학회지:방사선기술과학
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• 제39권2호
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• pp.209-225
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• 2016

본 연구는 핵의학 분야의 방사선종사자에 대해 방사선 피폭선량을 지식, 인식, 행태 및 이와 관련된 요인으로 분석하고, 특히 여성 핵의학 방사선종사자를 중심으로 피폭선량과 관련요인을 분석하고자 하였다. 핵의학과에 근무하는 방사선종사자 106명(여성 : 42명, 남성 : 64명)을 대상으로 방사선 피폭선량과 일반적 특성, 지식, 인식, 행태에 대한 설문조사를 시행하고, 분석하였다. 성별에 따른 핵의학 방사선종사자의 피폭선량을 지식, 인식, 행태 요인으로 분석한 결과, 여성 핵의학 방사선종사자에서 피폭선량과 지식 점수는 -0.221, 피폭선량과 행태 점수는 -0.512로 음의 상관관계가 있었다. 남성 핵 의학 방사선종사자는 피폭선량과 행태 점수는 -0.248로 음의 상관관계가 있었다. 임신 경험 유무에 따른 여성 핵 의학 방사선종사자의 피폭선량을 지식, 인식, 행태 요인으로 분석한 결과, 임신 경험이 없는 방사선종사자의 피폭선량과 지식 점수는 -0.238, 피폭선량과 행태 점수는 -0.511이었으며, 임신 경험이 있는 방사선종사자의 피폭선량과 인식 점수는 -0.540, 피폭선량과 행태 점수는 -0.643으로 음의 상관관계가 있었다. 핵의학 방사선종사자의 피폭선량의 관련요인에 대한 회귀분석에서 성별 요인이 가장 영향력이 있었으며, 남성에 비해 여성의 피폭선량이 3.272 mSv 낮았다. 여성 핵의학 방사선종사자의 피폭선량의 관련요인에 대한 회귀분석에서 행태 요인이 가장 영향력이 있었으며, 임신 경험이 없는 방사선종사자에 비해 임신 경험이 있는 방사선종사자의 피폭선량이 0.332 mSv 낮았다. 핵의학 방사선종사자 중 여성은 방사선 지식정도에 비례하여 행태에 반영하고 방사선 방어에 대해 실질적으로 노력하는 반면 남성은 방사선 지식을 행태적으로 거의 활용하지 않는 것으로 여겨진다. 이에 남성은 보다 적극적인 방사선 방어에 대한 교육을 통해 피폭선량 저감을 위한 활동이 요구된다. 또한 여성 핵의학 방사선종사자 중 임신 경험이 없는 방사선종사자는 방사선 방호와 관련하여 지식 정도에 비례하여 행태에 반영하지만, 임신 경험이 있는 방사선종사자는 지식 정도와는 관계없이 인식 정도가 행태에 반영되고 있으므로 이에 대해 임신 경험이 없는 방사선종사자는 방사선 방어에 대한 인식을 강화할 수 있는 방법을 모색하고, 임신 경험이 있는 방사선종사자는 지식을 강화할 수 있는 교육의 적용이 요구될 것으로 사료된다.

• 조명전기설비학회논문지
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• 제16권6호
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• pp.7-12
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• 2002

본 논문은 공동평가업체인 알파사에서 개발된 건축마감재인 바이오 액상세라믹의 물리, 화학적 특성 원적외 방사특성과 생체에의 효능을 실험을 통하여 평가한 것이다.

• 대한방사선기술학회지:방사선기술과학
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• 제37권2호
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• pp.85-91
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• 2014

본 연구는 휘진성 형광체를 이용하여 디지털 의료영상시스템의 환경에서 산란선에 의한 영상 특성을 연구하였다. 아크릴 팬텀을 사용하여 관전압 (50 kVp부터 120 kVp까지), 조사야($4{\times}4cm^2$부터 $26{\times}26cm^2$까지), 팬텀의 두께 (1 cm부터 25 cm까지)를 각각 변화시켜 실험을 실시하였다. 실험 방법은 영상을 ImageJ와 특성곡선을 사용하여 분석하였다. 관전압은 50 kVp ~ 70 kVp에서는 관전압이 증가하면서 일차선에 대한 산란선의 비율도 증가하지만, 80 kVp부터는 일정한 비율을 나타내었다. 조사야가 증가함에 따라 일차선에 대한 산란선의 비율은 증가한다. 팬텀 두께가 증가함에 따라 산란선이 증가한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.306-309
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• 2004

Recently, the environmental problem has received considerable attention. so, many lamps have been developing for environmental requirement and energy efficiency. also, at glow discharge lamp researchers try to reduce energy spending that is power saving lamp. this kind requirement agree with strong points of electrodeless fluorescent lamp has received to now lighting sauce. At low pressure as mTorr I.C.P make high density plasma easily, is good to maintain discharge, has high ionization and does not have failing lighting and losing ability of electron radiation by oxidation and volatilization of electrodes, because this tape does not have electrodes. This point of I.C.P can use at electrodeless fluorescent lamp in this study ICP display elements and Ar, Ne, Kr are researched for optical characteristic. each gas is looked into optical characteristic, also mixed gases is experiment for optical characteristic.

• 대한임상독성학회지
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• 제9권2호
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• pp.39-48
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• 2011

In mass casualty situation due to radiological accidents, it is important to start aggressive management with rapid triage decisions. External contamination needs immediate decontamination and internal contamination should be treated with special expertise and equipment to prevent the rapid uptake of radionuclides by target organs. Acute radiation syndrome shows a sequence of events that varies with the severity of the exposure. More severe exposures generally lead to more rapid onset of symptoms and severe clinical findings. After the massive exposure, various systems of the body reflect their severe damages that can lead to death within hours or up to several months. The disease progression has classically been divided into four stages: prodromal, latent, manifest illness, and recovery or death. Three characteristic clusters of symptoms including the hematopoietic syndrome, the gastrointestinal syndrome and the cerebrovascular syndrome are all associated with the acute radiation syndrome. The standard medical management of the patients with a potentially survivable radiation exposure includes good medical, surgical and supportive measures. Specific treatment with cytokines and bone marrow transplantation should be considered. The management of internal contamination is much the same as the treatment of poisoning. The standard decontamination should be applied to reduce uptake, and the chelating agents can be administered to enhance the clearance of radioisotopes. Radioactive iodine ($^{131}I$) as one of the nuclear fission products can increase the incidence of thyroid cancer in children. Potential benefit of potassium iodide prophylaxis is greater especially in neonates, infants and small children.

• Toxicological Research
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• 제20권2호
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• pp.117-122
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• 2004

The present study was carried out to establish a short-term teratogenicity study for detecting developmental toxic potential induced by gamma radiation in ICR mice. Pregnant mice were exposed at dose levels of 0, 0.5, 1, 2, or 4 Gy on gestational day 8.5. All dams were subjected to caesarean section on gestational day 10.5 and their embryos were examined for growth, differentiation, and morphological abnormalities. An increase in the number of resorption was found at 4 Gy in a dose-dependent manner. Dose-dependent decreases in the developmental score of yolk sac circulation and olfactory system at above 1 Gy, in the number of somite pairs and developmental score of allantois, optic system, and maxillary process at above 2 Gy, and in the all growth and developmental parameters examined at 4 Gy were found. Various types of morphological abnormalities were seen at dose levels of 0.5 Gy or greater. Characteristic malformations induced by gamma radiation were abnormal axial rotation, hematoma, craniofacial hypoplasia, open neuropore, shortened prosencephalon, kinked somites, irregular somites, swelling, hydropericardium, absent branchial bar, and absent limb bud. Morphological alterations such as hematoma, craniofacial hypoplasia, open neuropore, and kinked somites were noted even in the lowest dose (0.5 Gy). These results indicated that the short-term teratogenicity study established in this study can be a useful tool for not only detecting the developmental toxic potential induced by gamma radiation, but also screening radio-protective agents in ICR mice.

• 한국전자파학회논문지
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• 제11권4호
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• pp.627-633
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• 2000

본 논문에서는 후방 전방향 특성이 요구되는 비행체 탑재 안테나의 이상적인 방사패턴을 얻기 위해. 새 롭게 고안된 프린트형 역F안테나를 로케트 또는 미사일의 몸체 하단부에 있는 Fin측면상에 표연 장착하여 방사 패턴을 측정(중심주파수 : 1.81 GHz)하였으며, 그 결과 기존의 비행체 원통 몸체상에 장착된 역F안테나보다 비 행체의 후미 축상을 기준으로 대칭적인 방사패턴 특성을 얻었다. 또한 후미 방향으로 지향성을 높이기 위해 반 사기 역할을 하는 무급전 소자를 프린트형 역F안테나의 전방 방향 $\lambda$/8( $\lambda$ :파장, 10.5 em) 지점에 위치시켜 방 사패턴을 측정한 결과 전후비가 8dB 개선된 지향 특성을 얻었다.

• Journal of electromagnetic engineering and science
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• 제14권3호
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• pp.299-305
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• 2014

A wideband circularly polarized (CP) antenna with a single feed is proposed for use in global navigation satellite systems. Its primary radiation elements are composed of two orthogonal bowtie dipoles, which are equipped with double-printed vacant-quarter rings to allow direct matching of the antenna to a single $50-{\Omega}$ coaxial line and to produce CP radiation. The crossed bowtie dipole is appropriately incorporated with a planar metallic reflector to produce the desired unidirectional radiation pattern as well as to achieve a wideband characteristic in terms of impedance matching and axial ratio (AR) bandwidths. The designed antenna was fabricated and measured. The prototype antenna with an overall 1.2-GHz frequency size of $0.48{\lambda}_o{\times}0.48{\lambda}_o{\times}0.25{\lambda}_o$ produced a measured ${\mid}S_{11}{\mid}$<-10 dB bandwidth of 1.05-1.79 GHz and a measured 3-dB AR bandwidth of 1.12-1.64 GHz. It also showed right-hand CP radiation with a small gain variation (${\pm}0.3dB$) and high radiation efficiency (>93%) over the operational bandwidth.

• 대한방사선기술학회지:방사선기술과학
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• 제7권1호
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• pp.23-33
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• 1984

In the present study, we determined reduction value of radiation on chest film by film method and made a reduction curves. The reduction radio in exposure to radiation was induced by comparative investigation of characteristic curves and reduction one. Basing on these result, we could reduce a radiation dose on body surface in 50% at the time of chest radiography, if 17.8mm aluminium or 0.87mm copper filter were used in addition to conventional filter at 140KV tube voltage. The present study further revealed that the additional use of the aluminium or copper filter at the time of high voltage radiography in chest facilitates to identify an image of some pathologic focus overlapping wist clavicle and ribs.