【摘要】 目的 评价64层螺旋CT低剂量冠状动脉血管成像的价值。 方法 2009年1-6月157例患者随机分为3组，常规剂量组（A组）管电流量采用1 000 mAs，两个低剂量组（B、C组）分别采用800、600 mAs。对3组的图像质量、噪声、CT剂量指数（CTDI）、剂量长度乘积（DLP）和有效剂量（ED）进行评估。 结果 A、B、C组图像噪声分别为20.50±3.23、23.02±3.05和26.28±2.58，组间差异均无统计学意义（Pgt;0.05）；A、B、C组的CTDI分别为（58.7±0.23）、（46.98±2.27）、（35.28±3.56） mGy，DLP分别为（1 050.88±89.63）、（846.21±57.86）、（641.13±32.15） mGy?cm，ED分别为（14.78±2.56）、（11.85±1.87）、（8.98±1.15） mSv，B、C组的CTDI、DLP、ED均明显低于常规剂量A组（Plt;0.05），C组的CTDI、DLP、ED均为3组中最低值。 结论 64层螺旋CT冠状动脉血管检查，采用600 mAs管电流量获得的冠脉图像既可满足诊断需要，又可使患者接受的辐射剂量降低。【Abstract】 Objective To evaluate the best tube current for low-dose radiation CT in coronary artery imaging by 64-slices multi-detector CT. Methods From January to June 2009, a total of 157 consecutive patients were randomly divided into 3 groups: group A (conventional group): 1 000 mAs; group B: 800 mAs; group C: 600 mAs. The image quality, noise, CT dose index (CTDI), dose length product (DLP) and effective dose (ED) in each group were measured and compared respectively. Results The image noise scores in group A, B, and C were (20.50±3.23), (23.02±3.05) and (26.28±2.58), respectively. There was no statistically significant difference among the three groups in the two indexes (Pgt;0.05). The CTDI in group A, B and C were (58.7±0.23), (46.98±2.27), and (35.28±3.56) mGy, respectively; the DLP in each were (1 050.88±89.63), (846.21±57.86), and (641.13±32.15) mGy?cm, respectively; the Ed were (14.78±2.56), (11.85±1.87), and (8.98±1.15) mSv, respectively. All of the differences among the three groups in CTDI, DLP and ED were statistically significant (Plt;0.05). Conclusion The image with 600 mAs as tube current in the coronary artery imaging of 64-slices multi-detector CT could fulfill the need of the diagnosis, and the radiation dose is apparently lower than the conventional scan.