During cardiac catheterization procedures, personnel receive relatively high radiation exposure. To evaluate what phases of the procedure produce the most exposure, a technique for calculating X-ray exposure to the eyes and thyroids of physicians performing such examinations was developed. This technique uses time-lapse photography to determine the position of the selected anatomical sites in time and space. A computer program is used to combine this spatial and temporal information with a model of exposure rates in space, enabling calculation, integration and accumulation of exposure per procedure during an entire procedure. For the primary cardiologist, the average exposures calculated by the developed technique were 29.2 mR for the eye and 25.1 mR for the thyroid, which is compared with the TLD [thermoluminescent dosimeter] measurements of 27.8 and 23.8 mR, respectively. For the assistant cardiologist, the average calculated values were 14.2 and 12.4 mR for eye and thyroid as compared to 9.3 and 6.5 mR, respectively, measured with TLD. Approximately 30-70% of eye and thyroid exposures were received during the cine portions of the procedures. These exposure values agree with previous studies.