目的探讨低剂量CT(LDCT)与迭 代重建技术在健康体检筛查早期肺癌中 的可行性。方法 将600例健康体检者随机 分为常规剂量CT组和LDCT组，分别进行 常规剂量肺CT(120kV，150mAs)扫描和低 剂量肺CT(120kV，30mAs)扫描，采用迭代 重建技术对LDCT扫描图像进行重建，比 较两组主观图像质量，客观图像质量参 数（噪声、CT值、SNR)，辐射剂量参数 (CTDIvol、DLP、ED)及肺结节检出率。结 果 两组纵隔窗、肺窗主观图像质量均能 满足诊断要求，两组比较差异无统计学意 义(P>0.05)；LDCT组图像噪声略高于常规 剂量CT组，差异有统计学意义(P<0.05)； 但两组CT值、SNR比较，差异均无统计学 意义(P>0.05)。LDCT组CTDIvol、DLP、ED 均显著低于常规剂量CT组，差异均有统计 学意义(P<0.01)。两组受检者肺结节及早 期肺癌检出率比较，差异无统计学意义 (P>0.05)。结论 LDCT结合迭代重建技术 能获得较好的图像质量，且有效降低辐射 剂量，对早期肺癌的筛查具有重要的临床 应用潜力。

Objective To investigate the feasibility of low-dose CT (LDCT) imaging combined with iterative reconstruction technique for lung cancer early detection in healthy physical examination. Methods A total of 600 cases of healthy subjects were randomly divided into routine dose CT group and LDCT group, and the routine dose CT group was scanned with 120 kV and 150 mAs, LDCT group was scanned with 120 kV and 30 mAs. The LDCT scan image was reconstructed using iterative reconstruction techniques. The subjective image quality, objective image quality parameters (noise, CT value, SNR), radiation dose parameters (CTDIvol, DLP, ED) and lung nodule detection rate were compared between the two groups. Results The subjective image quality of the two groups of mediastinal window and lung window could meet the diagnostic requirements, the difference between the two groups was not statistically significant (P>0.05). The image noise of LDCT group was slightly higher than that of routine dose CT group, the difference was statistically significant (P<0.05), but the CT value and SNR between the two groups was not statistically significant (P>0.05). The CTDIvol, DLP and ED of LDCT group were significantly lower than those of routine dose CT group (P <0.01). The detection rate of lung nodules and early lung cancer in the two groups was not statistically significant (P>0.05). Conclusion LDCT combined with iterative reconstruction technique could obtain better image quality, and decrease X-ray radiation dose. It had important clinical potential for the early detection of lung cancer.