【摘要】 目的 探讨低剂量螺旋CT扫描对肺结节检测的应用。方法 采用不同扫描参数对TM164A型性能模体和TM320D躯干CT剂量检测模体进行常规剂量及低剂量螺旋CT扫描,记录不同扫描条件下模体辐射剂量及采集图像的空间分辨力、密度分辨力、噪声水平和均匀度结果,对所有数据进行统计学处理,确定螺旋CT胸部低剂量扫描最佳参数;依据优化的低剂量扫描技术参数对肺结节检测进行图像视觉评价。结果(1)TM320D躯干模体CT剂量检测结果:160 mA常规剂量之CT剂量指数(CTDI)与低剂量各组(30 mA、50 mA、70 mA、90 mA)值比较有显著性差异,放射剂量随着管电流的增大而增加,尤其当管电流超过90 mA时,放射剂量增大的更为显著;(2)10 mA与30 mA、50 mA、70 mA、90 mA、160 mA各组之间图像噪声有显著性统计学差异,1 mm与3 mm、5 mm、7 mm、10 mm各组之间图像噪声也有显著性统计学差异;图像均匀性与管电流及层厚组间均无显著性差异。(3)空间分辨率和低对比分辨率随着管电流的增加而提高,当管电流降低至30 mA时,低对比分辨率显著降低。结论 通过对体模的研究,30～50 mA以及3～5 mm重建是低剂量CT肺部扫描的较佳参数组合,既可以有效地减少辐射剂量,又可以较好地保证图像的质量,较适合于早期肺癌筛查。更多还原

【Abstract】 Objective The probe the application of low-dose spiral CT scanning in evaluating pulmonary nodules.Methods The TM164A phantom and TM320D body phantom underwent low-dose and standard-dose spiral CT using different scanning parameters.The image spatial resolution,density resolution,noise level,field uniformity under different scanning conditions were record.All data were statistically analyzed to search out the optimum combination of scanning parameters and according to the optimized scanning parameters to evaluate the image vision of pulmonary nodes.Results(1) Results of TM320D body phantom CT scanning:there was of significant difference about the data of CT dose index(CTDI) between the 160 mA conventional-dose spiral CT and the lowdose groups(30 mA,50 mA,70 mA and 90 mA).(2) There was of significant difference about the image noise and tube current at 1mm slice and 10 mA with other groups.(3) The spatial resolution and low contrast resolution increased along with the increase of tube electricity,and 30 mA was an inflexion of low contrast resolution.Conclusion By analyzing the phantom,30～50 mA and 3～5 mm slice are the optimum scanning parameters in low-dose lung scanning and adapt to routine screening and early lung cancer screening.更多还原