摘要
目的:探讨CT扫描中Z轴自动管电流调制技术对图像质量、辐射剂量的影响,以及如何应用自动管电流调制技术。方法:对照组(25例)用固定管电流100～220mA扫描。自动管电流组分别选择噪声指数NI10和NI12.5扫描,管电流分别为80～480mA和80～369mA,测定并记录特定兴趣平面噪声,记录管电流平均值。由2位有经验的影像专业人员分别评价图像。结果:所有图像都能满足诊断要求。与固定管电流比较,头颈平面噪声无明显差异,颈肩平面不存在显著差异(P<0.05)。辐射剂量NI10组(94.8±17.9)和NI12.5组(74.8±18.3)明显低于固定管电流组(130.4±43.1)。结论:在多层CT颈部扫描中,Z轴自动mA技术与固定mA相比,其图像质量没有明显的差异,但自动管电流组辐射剂量却分别降低了27%(NI10)和43%(NI12.5)。噪声指数应根据所要显示的组织结构、病灶大小及性质等选择。
Objective To study the effect of image quality and radiation dose by using Z-axis automatic tube current modulation （ATCM）, as well as the application of automatic tube current modulation technology. Methods A control group consisting of 25 patients underwent cervical MDCT with fixed-current technique （100-220mA）. Of two study groups of 25 patients, one underwent cervical MDCT using z-axis ATCM with the noise index of NI10 and tube current intensity of 80- 480 mA,and the other with the noise index of NI12.5 and tube current intensity of 80-369 mA. The noise and mean tube current-time products （mAs） were recorded. Two radiologists evaluated images for diagnostic acceptability. Results All CT examinations of study and control groups were diagnostically acceptable, though objective noise was different with z-axis ATCM than with fixed current. ATCM resulted in significant radiation dose reduction （NI10, 94.8±17.9 mAs; NI12.5, 74.8±18.3 mAs）, when compared with the fixed current （130.4±43.1 mAs）. Conclusion Z-axis Automatic mA technique has no significant change in image quality when compared with the fixed mA technique, but the radiation dose is decreased by 27% （NI10） and 43% （NI12.5）, for MDCT evaluation of neck. NI has to be selected on the basis of the tissue, lesion size and nature.
出处
《医疗卫生装备》
CAS
2010年第1期8-9,共2页
Chinese Medical Equipment Journal
关键词
CT
自动管电流调制
辐射剂量
computed tomography
automatic tube current modulation
radiation dose
