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RISS 인기검색어
- 검색키워드
- 저자 : 정희일(Hee-Il Jung) (검색결과 3 건)
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PET/CT 장치의 uniformitly측정에 관한 연구
김수근(Su-Keun Kim),정희일(Hee-Il Jung),박성옥(Soung-Ock Park) 대한방사선과학회(구 대한방사선기술학회) 2006 방사선기술과학 Vol.29 No.1
PET scanner는 양전자의 소멸복사에 의한 511Kev의 감마선을 검출한다. multi ring detector에서 선원과 검출기사이의 기하학적 위치에 따른 감마선 검출에 대한 균등성(uniformity)을 검토 분석하였다. 감마선원과 검출기의 배열위치에 따른 이론적 검토와 일정한 크기의 phantom 내에서 방출되는 감마선을 2차원적으로 preset count하고, 검출기의 위치에 따라 평균계수치에 대한 편차율의 분포를 통하여 그 균등성을 비교 분석하였다. 1bed data를 얻을 수 있는 47개의 검출기군으로 분류하고, 각 검출기군의 위치에 따른 편차율을 비교분석한 결과, 산란선과 산란되지 않은 모든 방사선량의 분포가 많은 중심군인 3번째부터 45번째까지에서는 평균편차의 비율이 0.1~0.7%로 비교적 균등도가 높게 나타났으나, 주변부에서는 편차율의 분포가 1.1~5.2%의 차이를 나타내고 있어, 주변부에서의 균등성이 중심부보다 감소되었다. 이것은 검출기 위치에 따른 계수율의 차이에 대한 이론적 근거와 일치하고 있으며, 감도를 알기위한 계수측정 부분에서도 중심부와 주변부와의 차이가 크게 다르게 나타났다. 이와같은 불균등성을 감소시키기 위하여 선원으로부터 모든 검출기 유효시야(UFOV) 내에서 충분한 방사능이 검출될 수 있도록 하는 우선적 조치가 필요하다고 판단된다. The PETscanner can detect the photon pair arriving from the source in phantom. The number of light photons released by the crystal(scintillator - BGO or LSO). In recent scintillation crystals in block structures were incorporated into full ring systems, and their resulted marked improvement in spatial resolution and increase in a sensitivity to annihilations. The uniformity of the crystal sensitivty is very important to makes correct imformation of abnormal states in organs. These factors influenced by the dection efficiency of the scintillators. We have study about the uniformity of crystals to the annihilation, And study about the standard deviaion to average counts. The relative standard deviation in central detector groups more uniformed than circumferenced detector groups. It is caused detected quanta of gamma ray by the geometrical factors of PET detector. PET cameras are available with different geometric arrangement and several parallel rings oriented in the axial direction. The center groups from 7th to 40th groups are comparatively uniform and sensitive. But at the circumferenced detectors decreased the sensitivity and uniformity.
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감염 근관에서 분리된 연쇄구균의 16S Ribosomal DNA 중합효소 연쇄반응과 제한효소 절단길이 다형성에 관한 연구
정희일,임미경 원광대학교 치의학연구소 1995 圓光齒醫學 Vol.5 No.2
Bacteria have been regarded as one of the most important factors in pulpal and periapical diseases. Streptococci are most frequently isolated facultative anaerobes in infected root canals. Recently molecular biological techniques have been rapidly progressed. This study was designed to apply the molecular biological tools to the identification and classification of streptococci in the endodontic microbiology. Streptococci isolated from infected root canals were identified with both Vitek Systems and API 20 STREP. Identification results were somewhat different in several strains of streptococci. Eighteen streptococci and enterococcal chromosomal DNA were extracted and they had two or three plasmid DNA. It was difficult to digest plasmid DNA using HindⅢ and EcoRI and to differentiate strains by restriction enzyme analysis of plasmid DNA. 16S rDNA of chromosome was amplified by polymerase chain reaction (PCR) and then restriction fragment length polymorphism (RFLP) after using several kinds of restriction enzymes was observed. The molecular mass of 16S rDNA of chromosomal DNA was approximately 1.4kb. There were three to five RFLP patterns using eight restriction enzymes. RFLP patterns digested with Cfol which recognizes four base sequences were identical in all stains. HindⅢ which recognizes six base sequences could not digest the 16S rDNA. Restriction enzymes which recognize five base sequences were suitable for RFLP pattern analysis. At least three different kinds of restriction enzymes were needed to compare each strains. It was suggested that 16S rDNA PCR-RFLP methodology was relatively simple and rapid to differentiate and classify strains and could be used in the epidemiological study of root canal infections.
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