Effective doses for coronary angiography.

A detailed study of dose data has been made for 100 coronary angiography examinations performed on a digital X-ray unit. Dose-area product (DAP) data have been analysed in terms of fluoroscopy and radiography for different projections. Projections patterns were similar for all cardiologists studied and the contribution to DAP from fluoroscopy was 32%. Data for 10 patients, selected because the percentage contributions to DAP from fluoroscopy and radiography were similar to the mean for the group, were used to derive conversion factors from DAP to effective dose. The mean DAP was 14 Gy cm2 and the effective dose 3.1 mSv. Conversion factors, based on the same protocol, were derived for a range of tube potentials and filtrations for use in estimation of effective doses with other units.