【摘要】 目的　探讨多层螺旋CT肺部低剂量扫描的最佳参数。方法　对 60名健康志愿者和 47例病例进行胸部多层螺旋CT扫描 ,分别采用 6种不同参数重复扫描 ,即低剂量 :10mA、2 0mA、3 0mA、40mA、5 0mA。常规剂量 :3 0 0mA。管电压、扫描周期、床速及层厚均相同 ,分别为 12 0kV、0 .8s/Rot、17.5mm /Rot和 2 .5～ 3 .75mm。在不同条件下分别对肺尖部、肺中部及肺底部所检出病灶进行统计分析。结果　 2 0mA条件扫描能清晰显示肺中部和肺底部正常结构与支气管Ⅲ级以上分支 ,并能准确检出肺内病灶 ,与常规剂量相比均无显著性差异 ( χ2 =0 .3 ,Ρ >0 .0 5 ;χ2 =1.0 6,Ρ >0 .0 5 ) ;而肺尖部则需要 3 0～ 5 0mA的条件才能达到准确检出病灶的目的。结论　 2 0mA的管电流可作为MSCT低剂量扫描筛查早期肺癌的参考条件 ,而肺尖部扫描时应将管电流增加到 3 0～ 5 0mA。更多还原

【Abstract】 Objective To study the optimal parameters of low-dose multi-slice CT (MSCT) scaning in lungs. Methods Thoracic MSCT scaning using diffent parameters was separately performed in each of 60 healthful volunteers and 47 cases of lung diseases. Tube current were adopted separately for repeat scans including low-dose of 10 mA,20 mA,30 mA,40 mA,50 mA,and standard-dose of 300 mA. Other four kinds of parameters were the same (including: 120 kV, 0.8 s/rotation scan time, 17.5 mm/rotation table feed,2.5～3.75 mm collimation). Focuses of the apexes, midzones and bases of lungs detected with different parameters were analysed statistically.Results On the images with 20 mA,the normal structures of the midzones and bases of lungs and the 3rd segmental bronchi were well seen , and the pulmonary focuses were all detected accurately , and there was no significant difference between 20 mA and standard dose (χ~2=0.3,P>0.05;χ~2=1.06,P>0.05). However, the focuses of the apexes of the lung could be detected accurately only with 30～50 mA . Conclusion In screening the early lung cancer the 20 mA tube current of low-dose MSCT scan can be used as the reference, but the scaning dose of the apexes of the lung should be increase to 30～50 mA.更多还原