Evaluating the Long-Term Health Effects of Diagnostic Radiation Exposure: Opportunities and Future Directions

Purpose: To create a factual basis for conducting epidemiological studies on the long-term effects of low-dose diagnostic radiation exposure due to computed tomography examinations among the population living near the nuclear industrial complex enterprise. Material and methods: The primary source of information for the study was the archival registration logs of patients who underwent computed tomography at medical clinics of the Chelyabinsk region. Epidemiological surveillance of residents of Ozyorsk was carried out retrospectively using the cohort methodology. Information on main risk factors of radiation and non-radiation nature was collected for the study, and the cancer incidence was used as the outcome criteria. The information collected was stored in the “CT Register” database. Results: As of December 31, 2024, the database contains information on 34,264 records of 20,488 men and women aged 0 to 90 years. The follow-up period started on January 1, 1989 and ended on December 31, 2022. At the end of follow-up, 20 % of the individuals in the study cohort are alive, 38 % have died from various causes. The average effective dose for 1 CT study is 4.70±0.04 mSv. The number of malignant neoplasms in the cohort was 4,174 (20.4 %). The proportion of residents exposed to occupational radiation was 25 %. Discussion: Foreign analogues of the study indicate small risks at the individual level for those exposed during the CT examinations in childhood. The advantages of the «CT Registrer» database are: all ages of exposed, lifetime follow-up, accounting for several risk factors, and the possibility of reconstructing individual absorbed doses. Conclusions: For the first time in Russia, a medical and dosimetric registry of individuals living near the nuclear facility, and exposed to X-ray radiation during computed tomography has been created. The «CT Register» database provides the opportunity to conduct an epidemiological study to assess the long-term effects of exposure to low doses of diagnostic radiation, which is an important task for ensuring the radiation safety of the population.