This paper illustrates the annual trends in medical radiation exposure due to conventional radiography (CR), computed tomography (CT) and nuclear medicine (NM) procedures of the Emilia-Romagna population from 2001 to 2006. We gathered information about the type, number and mean doses of CR, CT, and NM examinations performed in 17 hospitals of the Emilia-Romagna region. In particular, numerical values of the following dosimetric parameters were requested: entrance skin dose for CR, CT dose index and dose-length product for CT and activity administered for NM. Lastly, the annual collective dose S and annual average per-caput dose were calculated. The 13 diagnostic imaging procedures that were the greatest contributors to the Emilia-Romagna population dose between 2001 and 2006 were identified and, for the year 2006, their percentage contribution to total procedures and population dose are indicated. CR, CT and NM accounted for 12%, 78% and 10% of the dose, and 83%, 15% and 2% of total procedures, respectively. The annual trends of S and average per capita dose are shown, and the theory underlying the use of these parameters is briefly discussed. This type of study relies heavily on the analysis of field data and as such, the growing attention paid in recent years to procedure optimisation should continue, and expand even for the justification of the procedures themselves as justification has a significant impact on the reduction of S and per-caput doses.