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RISS 인기검색어
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- 저자 : 이대규(Dae Kyoo Lee) (검색결과 3 건)
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흉부 CT검사시 AEC Program 적용에 의한 선량감소효과에 관한 연구
이대규(Dae kyoo Lee),남윤철(Yoon Chul Nam),김문찬(Moon Chan Kim) 대한CT영상기술학회 2006 대한CT영상기술학회지 Vol.8 No.1
Purpose The purpose of this study is to check how much a radiation dose of the thoraxis reduced when using AEC technique in CT examination, and to apply the program properly to clinical cases. Materials and Methods We measured organ doses of thyroid, upper chest, mid chest, lower chest, breast, liver when conducting a test by using Brilliance CT made by Philips, instead of AEC program, and compared the radiation dose reduction effect of each organ by measuring the effect shown when using D-DOM (a method of controlling a tube current according to the thickness of a subject for photography toward X-Y axis of a revolving angle of a tube) among AEC programs, and Z-DOM(a method of controlling a tube current according to the thickness of Z-axis position). Results The comparison between dose with AEC program and dose without AEC program in chest routine CT were as follows, 1. The thyroid dose using D-DOM and Z-DOM wasreduced 23.9% and 49.5% respectively rather than dose of non-AEC program. 2. The upper chest dose using D-DOM and Z-DOM was reduced 18.3% and 17.8% respectively rather than dose of non-AEC program. and The mid. chestdose using D-DOM and Z-DOM was reduced 15.2% and 12.7% respectively rather than dose of non-AEC program. and The lower chest dose using D-DOM and Z-DOM was reduced 5.8% and 22.4% respectively rather than dose of non-AEC program. 3. The breast dose using D-DOM and Z-DOM was reduced 10.7% and 7.5% respectively rather than dose of non-AEC program. 4. The liver dose using D-DOM and Z-DOM was reduced 20.3% and 26.4% respectively rather than dose of non-AEC program. 5. It was proven that as for the radiation dose reduction effect by D-DOM, the control of a tube current was mostly performed in the asymmetrical part such as shoulder when comparing upper chest (18.3%), mid. Chest(15.2%), and lower chest(5.8%). 6. Thyroid, Lower chest showed a greater radiation dose reduction effect when using Z-DOM rather than D-DOM. Conclusion The radiation dose reduction effect in each organ was proven higher by far when using AEC program. In particular, D-DOM demonstrated an excellent radiation dose reduction effect in the part that showed a great difference of thickness between AP and Lateral(ex. shoulder). Z-DOM displayed an outstanding effect in the neck part.
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Spiral CT에서 Interpolation이 선량증가에 미치는 영향에 관한 연구
이대규(Dae kyoo Lee),남윤철(Yoon Chul Nam),김문찬(Moon Chan Kim),한동균(Dong Kyoon Han) 대한CT영상기술학회 2008 대한CT영상기술학회지 Vol.10 No.1
The purpose of this study is to recognize how much dose and scan length increased by interpolation in spiral scan and to understand about correlation with factors such as beam collimation and pitch. We measured dose and scan length changing pitch and beam collimation using the GE company equipments.
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신상보(Sang Bo Shin),신설경(Sul Kyung Shin),이대규(Dae Kyoo Lee),김문찬(Moon Chan Kim) 대한CT영상기술학회 2007 대한CT영상기술학회지 Vol.9 No.1
Purpose The increased radiation sensitivity of children causes them to have an age-dependent radiation risk that is 2-3 times larger than that of the general population. For this reason, the purpose of this study is selection of optimal x-ray exposure factors in pediatric CT. The absolute values for radiation exposure in CT depend strongly on the scan parameters, scanner characteristics, and the patients. Materials and Methods There are separate data provided for body applications(measured in a 32cm PMMA phantom) or head scans(16cm PMMA phantom). CTDI measurements are made at various positions within a body or head PMMA phantom. Measurements of the CTDI are performed in the center and 1cm below the surface of a cylindrical plexiglas phantom of 32cm diameter for the bodyand 16cm for the head. In a larger patient more is absorbed in the periphery so that the local dose in the center is less than it would be for a slimmer patient. Dose to the periphery also decreases for larger patients. Results CTDIw decreases with larger phantom diameters, which implies that the real average dose is underestimated for children and slim patients. Radiation induced risk in children can be substantially higher than the risk in the adult population. For this reason, the radiologist should double-check the indication for CT, and should adapt the radiation dose to the body cross-section. Longitudinal and adaptive dose modulation would be ideal technique, but presently only rough suggestion based on the body weight are available. One have to keep in mind, however, that the body weight may underestimate the dose requirements in obese children because their body cress-section can be larger than that of a taller child of identical weight. Tube current modulation takes advantage of the fact that there is a substantial difference in radiation attenuation of a body. Conclusion The best choice is adapts dose modulation at pediatric CT. This will be important step towards more constant image quality and dose reduction in CT.
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