The radiation exposure of the medical team involved in 35 consecutive cardiac catheterisation procedures performed at the Istituto di Malattie dell'Apparato Cardiovascolare, University of Bologna, was calculated. A mapping of the iso-exposure lines and the values of radiation exposure of each component of the team were determined for each procedure. With these parameters the total amount of radiation for a normal diagnostic activity coul be calculated. The mean values obtained (150-250 mR/week) were in the range of the maximal values permitted to medical teams professionally exposed to the risk of radiation (3R/13 weeks). Rotation of the components of the team granted a continuing diagnostic activity within the limits of radiation exposure imposed by the law. An evaluation of the different procedures and techniques indicated coronary arteriography as the procedure with a higher risk of radiation (M = 50 mR/procedure) and pointed out the mechanism involved in order to obtain a considerable reduction of radiation exposure.