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RISS 인기검색어
- 검색키워드
- 저자 : 신설경(Sul Kyung Shin) (검색결과 1 건)
- 무료
- 기관 내 무료
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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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