Objective To explore the application value of ECG tube current modulation technology of dual source CT in coronary angiography,compared with retrospectively ECG-gated technique.Methods 200 patients were randomly divided into ECG tube current modulation group (Group A)and retrospectively ECG-gated group(Group B).In Group A,the main parameters were the exposure time windows of full dose,which were set according to different heart rates.χ2 test was adopted in the subjective score,and t test was used in the objective score and radiation dose.Results There was no statistical significance in image quality between the two groups(χ2 =2.125,tnoise =-0.557,P >0.05 );The effective dose (ED)of Group A and Group B were (3.30±0.40)mSv and(6.90±1.76)mSv,respectively.The difference was statistically significant (t ED =-1 9.954,P <0.05).The radiation dosage of Group A was 52% lower than that of Group B.Conclu-sion Compared with retrospectively ECG-gated technique,the ECG tube current modulation technique ensures the image quality, and at the same time it can significantly reduce the radiation dose,therefore,it can be used as a routine examination technique of cor-onary angiography.