In 159 consecutive patients, a total of 137 CCSs and 147 cCTAs were performed for evaluation of coronary artery disease with a 3rd gen DSCT. Anterior-posterior (AP) and lateral thoracic dimensions were measured from the CT data sets. Sum of AP and lateral dimensions, and effective diameters were calculated. Effective radiation dose was estimated by multiplying the dose-length product with a conversion factor of 0.014 mSv/mGy*cm. To account for differences in patient habitus, size-specific dose estimates (SSDEs) were calculated from volume CT dose indices based on conversion factors for effective patient diameters.