Abstract： Objective To investigate the value of low tube voltage (80 kV) for coronary computed tomography angiography (CCTA) in patients with normal body mass index (BMI) on 128-slice dual-source CT with novel high sensitive integrated circuit (IC) detector.Methods One hundred and three consecutive patients were scanned using prospectively ECG-triggered sequential CCTA protocol.All patients were randomly divided into group A and B.Group A was examined on a conventional 128-slice dual-source CT,while group B on a 128-slice dual-source CT with high sensitive integrated circuit detector.The tube voltage of group A was 100 kV and raw data was reconstructed with filtered back projection (FBP),while tube voltage of group B was 80 kV and raw data was reconstructed with both FBP (Subgroup B1) and sonogramaffirmed iterative reconstruction (SAFIRE) (Subgroup B2).The differences in background noise,signal-tonoise ratio (SNR),contrast-to-noise ratio (CNR),CT dose index volume (CTDIvol),effective dose (ED),and image quality between the groups were compared by using t test,ANOVA and x2 test.Results There were no significant differences in age,BMI or heart rate between the two groups (Group A,n =52 vs.Group B,n =51).Radiation exposure (CTDIvol and ED) of group B was significantly lower than that of group A [(8.93 ±2.55) vs.(13.87 ±4.62) mGy and (1.77 ±0.51)vs.(2.65 ±0.89) mSv,t =6.71,6.09,all P ＜ 0.01].SNR and CNR of proximal coronary arteries in group B2 were significantly higher than group A and B1,and there was no significant difference between the latter two.In group A,mean score of total 839 coronary artery segments was 1.29 ± 0.23,and the number of evaluable segments was 813 (96.9％).In group B1,mean score of total 820 coronary artery segments was 1.34 ± 0.29,and the number of evaluable segments was 789 (96.2％).In group B2,mean score of total 820 coronary artery segments was 1.33 ± 0.31,and the number of was 791 (96.5％).There were no significant differences in both mean score and percentage of evaluable segments between three groups (x2 =1.81,P ＞ 0.05).Conclusion Using 80 kV tube voltage on 128-slice dual-source CT equipped with novel integrated circuit detector and combining iterative reconstruction is feasible in patients with normal BMI,with the benefits of significantly reduced radiation dose and adequate image quality.