Abstract: Objective: To investigate the application of low tube voltage, low-volume contrast media and manual trigger scanfor coronary artery CT angiography with Flash scan modeon dual-source CT equipment about patients with low weight and low heart rate, through contrast with prospectively ECG-triggering sequentia and normal-volume contrast media. Methods: 48 patients were scanned with a prospectively ECG-triggering sequential or Flash CCTA protocol on DSCT. All patients were divided into two groups: the weight and heart ratein Group A was less then 65 kg and 65 beats per min, the injection rate and volume of contrast in Group A was 5.0 mL/s and 20 mL(350 mg I/m L), scanned with Flash scan mode, Tube voltage was 70 kV; the weight in Group B was less than 65 kg, the heart ratein in Group B was less than 65 beats per min, the injection rate and volume of contrastin in Group B was 5.0 mL/s and 50 mL(350 mg I/m L), scanned with a prospectively ECG-triggering sequential, Tube voltage was 100 kV. The raw data were reconstructed with sinogram affirmed iterative reconstruction(SAFIRE) technique. The differences of sex, age, HR,weight, BMI, CTDI_VOL, DLP and ED were compared. Besides, the CT value, noise, signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR) between the two Groups of the aortic root, left main coronary artery and the proximalsegment of each coronary arteries were compared. And Image quality(Ⅰ~Ⅳ) between the two Groups was compared. Results: There were no significant differences in sex, age, HR, weight and BMI between the two Groups(all P > 0.05), while there were no significant differences in the CT value, noise, SNR and CNR of the aortic root, left main coronary artery and the proximalsegment of each coronary arteries between the two groups(all P > 0.05). The CTDI_VOL, DLP and ED in Group B was higher than Group A(all P > 0.05). The scores of image quality showed no significant difference between the two Groups. They more than 96%. Conclusion: For patients with low weight and low heart rate, the use of tube voltage as 70 kV and low-volume contrast media in DSCT is feasible. The radiation dose and contrastdosage can be much lower.