PRELIMINARY ASSESSMENT OF STRUCTURE AND COLLECTIVE DOSE FROM CT EXAMINATIONS RELATED TO COVID-19 DIAGNOSTICS IN THE RUSSIAN FEDERATION IN MARCH -JUNE 2020

The use of computed tomography (CT) for the diagnostics of COVID-19 in the Russian Federation led to significant changes in the structure of X-ray diagnostics and levels of medical exposure of the patients. This study was aimed at the preliminary operative assessment of changes in the structure and collective dose from CT examinations in several representative hospitals, regions and on the level of the Russian Federation. The results of the study indicate that during the transformation of hospitals from general medical practice into dedicated COVID-19 facilities, the number of CT examinations increased up to 30%; the collective dose from CT exams increased up to a factor of 1.5. During a partial transformation of a medical facility into the hospital with separate COVID-19 departments, the increase in the number of CT examinations in the facility was more significant (up to a factor of 2 or more). These numbers correspond to 1.5 - 2.5 chest CT examinations (from 1 to 6) per patient admitted to hospital with COVID-19 diagnosis; and 1.2 chest CT examinations per patient in outpatient facilities, including a mandatory CT scan for the staging of COVID-19. The collective dose from CT examinations in the Russian Federation for March-June period of 2020 increased by the factor of 2 (from 16k man-Sv to 32k man-Sv); the collective dose of COVID-19 patients was about 12k man-Sv. For a more detailed and reliable assessment of the dynamics of changes in the structure of diagnostic radiology and levels of radiation exposure of patients in the Russian Federation, data collection in the regions of the Russian Federation and individual medical facilities will continue