【摘要】 目的优化患者CT扫描参数,减少其辐射危害。方法以成人头部,胸部和腹部CT扫描为考察对象,应用CT专用16cm直径CTDI测量模体,改变kVp和mAs组合,测量所扫描图像的噪声,高对比分辨率,低对比分辨率等,以此为依据决定图像是否合格,并从合格影像中选出辐射剂量最小的一组kVp/mAs做为最优化结果。结果在噪声,高对比分辨率,低对比分辨率等都合格的情况下,各部位辐射剂量最小的一组kVp/mAs分别是:130/90(成人头部),110/70(成人胸部),130/65(成人腹部)。其辐射剂量相对设备预设条件下的辐射剂量下降百分比分别是:25.0%,12.0%和34.3%。结论体模实验证明,合理组合kVp和mAs设置可以在保证图像质量的情况下降低CT辐射剂量,从而为临床实际的CT剂量最优化提供借鉴。更多还原

【Abstract】 Objective To optimize CT scanning parameters in routine examination and to reduce its radiation hazards.Methods A survey of radiation doses in computed tomography protocols was performed with phantoms and ionization chamber.Changes in kVp and mAs were proposed and the average noise,contrast and spatial resolution were determined.Qualifying images were submitted to assessment of dose reduction.Results The reduction in dose achieved ranged between 3.8%and 25%for adult skull,9.6%and 34.3%for abdomen,6.4%and 12%for chest.Keeping the image quality at acceptable levels,the scanning protocols(kVp/mAs)for the minimum radiation dose were 130/90(adult head)110/70(adult chest),130/65(adult abdomen).Conclusion Radiation dose levels can be reduced by optimizing CT scanning parameters,keeping the noise at acceptable levels.更多还原