低剂量双螺旋CT薄层扫描筛查早期肺癌初步研究

Low-Dose Radiation Thin-Section Dual Slices Helical CT of the Thorax for Mass Screening of Early Lung Cancer

目的 探讨低剂量双排探测器螺旋CT薄层扫描筛查早期肺癌的最佳扫描参数及其应用价值。方法 通过在不同扫描参数下对水模进行常规剂量及低剂量螺旋CT薄层扫描 ,评定不同扫描条件下采集图像的空间分辨力、密度分辨力、噪声水平和辐射剂量 ,选择最佳扫描参数。对 40名健康志愿者 (体重小于 75kg)的三个特定层面进行常规剂量及低剂量螺旋CT薄层扫描 ,评定对肺细微解剖结构、纵隔结构分辨能力和图像的伪影及噪声水平。对 15 0名无症状体检者进行胸部健康体检 ,评价胸部病变检出能力。结果 采用低剂量螺旋CT薄层扫描水模 ,在 3 0mAs ,床速 6.0mm / 9.0mm /rot条件下采集的图像可以清晰的分辨宽度为 1.0mm的线对 ,5 .0mm直径的圆形孔洞 ,单位面积辐射剂量为 1.5～ 1.6mGy。不同扫描条件对图像的空间分辨力、密度分辨力、图像噪声 ,对识别肺纹理级别、亚段支气管、次级肺小叶及纵隔结构是有显著影响的 ,0 .7s/rot 6.0HS 45mA与 1.0s/rot 9.0HS 3 0mA条件下采集的图像可满足临床需要 ,后者略优于前者。对15 0名无症状体检者进行筛查 ,共检出结节或肿块 46个 ,气管及亚段支气管管壁局限性增厚 2例 ,腔内隆起 3个。结论 选定 1.0s/rot 9.0HS 3 0mA ,AAR2为最佳扫描方案。低剂量螺旋CT薄层扫描具有辐射剂量小 ,?

Objective To probe into the optimal screening parameters for early lung cancer screening with low-dose radiation thin-section dual slices helical CT and to investigate the diagnostic and application value of the protocol.Methods On the phantom studies, the image quality obtained with the low-dose parameters and the standard-dose scanning technique were compared to evaluate spatial resolution, low-contrast resolution, noise level and radiation dose.And then select optimal screening parameters.On the 40 healthy volunteers, three images were obtained with selected low- and standard-dose scanning parameters:at the aortic arch, at the tracheal carina, and at the maximum transverse diameter of heart to assess anatomic clarity in the lung and mediastinum as well as the presence of artifacts and noise level.On the 150 symptom-free individuals for chest medical checkup, image quality or the detectability of pathologic findings in the lung and mediastinum using the optimal low-dose scanning parameters were evaluated.Results On the phantom studies,images quality acquired at low-dose parameters (30 mAs,6.0 mm/9.0 mm/rot table speed) was sufficient enough in detecting 1.0 mm-wire pair and 5mm-hole,furthermore,its radiation dose in unit area was only 1.5 mGy to 1.6 mGy.The image quality and anatomic clarity in the lung and mediastinum were affected significantly by different scanning parameters.The image quality obtained with 0.7 s/rot-6.0 HS-45 mA and 1.0 s/rot-9.0 HS-30 mA was adequate to clinical diagnosis,the later was superior to the former.On the 150 symptom-free individuals for chest medical checkup,46 focal lesions in nodules and masses,2 local thickening of bronchi or subsegmental bronchi and 3 intracavity hunches were detected.Conclusion According to preliminary experimental and clinical studies,scanning parameters (1.0 s/rot-9.0 HS-30 mA,AAR2) were picked out as optimal low-dose screening protocol.With the superior diagnostic accuracy,the lower radiation dose and the better price performance ratio,low-dose thin-section dual slices helical CT was considered to be an adequate and promising method for early lung-cancer screening.