Prospective ECG triggering has the potential of reducing radiation exposure while maintaining diagnostic accuracy of cardiac computed tomography (CT). The aim of this study is to review patient radiation doses associated with coronary artery calcium scoring (CACS) and CT coronary angiography (CTCA) and to compare results between prospective and retrospective acquisition schemes. Patient radiation doses from CACS and CTCA were extracted from 67 relevant studies. Mean effective dose for CACS and CTCA with prospective ECG triggering is significantly lower than retrospective acquisition, 0.9±0.4 vs. 3.1±1.4 mSv, p < 0.001, and 3.4±1.4 vs. 11.1±5.4 mSv, p < 0.001, respectively. In both cardiac CT examinations, application of dose modulation techniques result in significantly lower doses in retrospective schemes, however, even with dose modulation, retrospective acquisition is associated with significantly higher doses than prospective acquisition. The number of slices acquired per rotation and the number of X-ray sources of the CT scanner (single or dual source) do not have a significant effect on patient dose.