Objective To evaluate the image quality and radiation dose of third-generation dual-source CT with tin filtration for spectral shaping and iterative reconstructions.Methods Thirty-five patients underwent low-dose CT (LDCT) for lung cancer screening on second-generation dual-source CT and follow-ups on third-generation dual-source CT.Image quality and radiation dose were compared between the two examinations.Results The radiation dose of third-generation dual-source CT [dose-length product (DLP) (49.7 ± 18.2) mGy · cm, effective dose (ED) (0.73 ± 0.26) mSv] was lower than second-generation dual-source CT [DLP (86.37 ±13.44) mGy · cm, ED (1.20±0.42) mSv] (t=6.01, P=0.000;t =6.57, P=0.000).The objective image noise of second-generation dual-source CT [(25.7 ± 2.9) HU] was higher than that of third-generation dual-soure CT [(18.6 ±4.2) HU] (t =5.24, P =0.000).The subjective image noise of second-generation dual-source CT [(4.60 ± 0.49) scores] was significantly lower than that of third-generation dual-source CT [(4.80 ± 0.40) scores] (t =4.15, P =0.000).Conclusion Chest CT for the detection of pulmonary nodules can be performed with third-generation dual-source CT that produces high image quality and low radiation dose when using a stellar infinity detector with spectral shaping.%目的 探讨第3代双源CT扫描机全息光子探测器联合基于原始数据的迭代重建算法对胸部低剂量CT(LDCT)扫描剂量和图像质量的影响.方法 回顾性分析35例采用第2代双源CT扫描机行LDCT肺癌筛查并于半年至1年后应用第3代双源CT扫描机随诊的患者,比较第2代和第3代双源CT扫描机的扫描剂量和图像质量.结果 第2代双源CT的剂量长度乘积和有效剂量分别为(86.37 ±13.44) mGy·cm和(1.20±0.42) mSv,均明显高于第3代双源CT的(49.7±18.2) mGy·cm (t=6.01,P=0.000)和(0.73±0.26) mSv (t=6.57,P=0.000).第2代双源CT筛查时的图像噪声为(25.7±2.9) HU,明显高于第3代双源CT的(18.6±4.2) HU(=5.24,P=0.000).第3代双源CT的图像质量评分为(4.80 ±0.40)分,明显高于第2代双源CT的(4.60±0.49)分(t=4.15,P=0.000).结论 第3代双源CT扫描机通过全息光子探测器,可明显降低辐射剂量,有利于临床肺癌的早期筛查和病变的检出.
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