The article discusses the problem of carcinogenic risk assessment in the context of relationship with diagnostic radiation resulted from Computed Tomography (CT). The study aimed to evaluate the possible long-term carcinogenic effects after the exposure to a low dose of diagnostic radiation, appeared within a decade after the 1st CT scan. Information on patients examined using CT in the District Hospital of Kasli (KDH) has been derived from the CT archives since 2009 when the first CT examinations has been performed in the KDH. The data were linked to local Cancer registry, the Death registry, and the “CT Registry” database (CTDB) to obtain the information on vital status, the cause of death, cancer morbidity and CT examinations outside KDH, respectively. 275 CT examinations of 246 patients have been recorded to the data file (KDH cluster). To the end of the study, 46 cases of malignant tumours (MT) have been accumulated in the study group. The average observation time was 6.5 years (90% CI 6.2-6.8). The distribution of cancers among patients exposed to CT has been shown retrospectively through the date of birth of patient to December, 31, 2018. The cases of MT diagnosed prior to 1st CT examination have been excluded from the analyses. Cancer-related conditions stated before the date of 1stCT examination have been accounted. The cumulative cancer incidence after the exposure to CT, adjusted for predisposed conditions in the study group was 4.8%. The study results have been compared with the results of the LSS cohort study to assess the expected excess cancer morbidity. The data obtained in the study provide the information for a comprehensive epidemiological assessment of long-term effects related to diagnostic radiation exposure in the Ozyorsk Computed Tomography Cohort (OCTC study). Doi: 10.28991/SciMedJ-2021-0304-3 Full Text: PDF

Cancer morbidity among patients examined using computed tomography within 10 years follow-up period depending on various factors has been retrospectively analyzed. Information on Ozyorsk residents examined at the Kasli District Hospital was retrospectively collected. The data collection period started in 2009 when the first computed tomography examination has been performed in the X-ray department of Kasli District Hospital, and ended by December 31, 2018. The data obtained in the study were linked to the local Cancer registry, the Death registry, and the “CT Registry” database to receive information about the vital status, cancer morbidity and CT examinations performed outside the Kasli District Hospital. Cumulative incidence has been accounted in terms of predisposed conditions associated with cancer, cancer diagnoses stated before the date of the first CT examination and CT-confirmed malignancy cases. As a result of the study, information on 275 examinations of 246 residents of the Ozyorsk urban district has been derived. By the end of the observation period, 46 cases of malignant tumors were accumulated in the study group. The average time from 1st CT to the end of follow-up was 6.5 years. The distribution of carcinogenic effects among patients examined using CT has been shown retrospectively from the date of birth to the date of the end of follow-up. The cumulative cancer incidence adjusted for predisposing conditions has been compared with the LSS data. No epidemiological data were found on the relationship between the detected cases of malignant tumors and the diagnostic radiation from CT scans. The data obtained in the study provide information on the long-term oncological effects among Ozyorsk residents examined using CT as a source of additional information for a comprehensive assessment of the low dose effects associated with diagnostic exposure in the Ozyorsk Computed Tomography Cohort study.