PATIENT DOSES IN COMPUTED TOMOGRAPHY EXAMINATIONS IN TWO REGIONS OF THE RUSSIAN FEDERATION.

Computed tomography (CT) is often a justified diagnostic tool, but is also associated with high exposure of the patients. Due to the rapid increase in the number of CT units and thus the availability of CT examinations in Russia, there is a growing need for optimisation within this field. In order to develop proper optimisation procedures for CT, the two regions St. Petersburg and Belgorod of Russia were chosen, representing an urban and a rural region, respectively. In 2014, a survey was conducted of the parameters applied in CT examinations in these regions, and the results show that the highest effective doses were observed for investigations of abdomen, reaching up to 137 mSv, and pelvic CT examinations, reaching up to 58 mSv, both with contrast agents. The dose distributions were approximately log-normal, and for the majority of the examinations, the 75th percentiles of the CT dose distributions in the Belgorod region were higher than observed in St. Petersburg. The aim of the current project is primarily to define and implement diagnostic reference levels as a part of the process of optimisation of CT examinations in Russia.