目的 探讨低kV大螺距联合IRIS 在降低胸部多层螺旋CT(MSCT)检查辐射剂 量中的临床应用价值。方法 70例行胸部 MSCT检查的患者随机分为常规组(n=35， 130kV，Pitch 0.8，FBP)、和低剂量组 (n=35，110kV，Pitch 2.0 IRIS)，对照 分析2组患者的图像质量与辐射剂量。 结果 2组患者的MSCT图像主观评分、客 观评分(SNR与CNR)比较差异均无统计学 意义(P>0.05)，低剂量组的CTDIvol、 DLP和ED均显著低于常规组和低剂量组(P ＜0.05)。结论 低kV大螺距联合IRIS能满 足胸部MSCT检查的诊断要求，并显著降低 患者的辐射剂量。

Objective To study the clinical evaluation of both low-kV high-pitch and IRIS on chest MSCT examination radiation dose reduction. Methods 70 patients undergone chest MSCT examination were randomly divided into routine group(n=35,130 kV, Pitch 0.8, FBP)and low dose group(n=35, 110 kV, Pitch 2.0, IRIS). Retrospectively,the quality of the images and the radiation dose of two groups were compared by two reviewers. Results The subjective image quality score and objective evaluation index (SNR and CNR)of two groups has no significant difference(P＞0.05). The radiation dose of low dose group (CTDIvol, DLP, and ED) was lower than that of routine group (P<0.05). Conclusion The image quality of both low-kV high-pitch and IRIS on chest MSCT examination can meet diagnostic requirement, and obviously reduce radiation dose.