Patients` cumulative doses during CT-examinations in Russian clinical practice

In modern clinical practice, multiple computed tomography examinations are increasingly common, which can lead to the accumulation of significant effective doses of patients. The aim of this study was to identify cases of high cumulative effective doses (more than 100 mSv) of adult patients undergoing computed tomography examinations in two departments of the Leningrad Regional Clinical Oncological Dispensary. Materials and Methods. The study is based on the analysis of patient effective dose data obtained from computed tomography examination logbooks for the periods 2020–2021 (Department No. 1) and 2019–2021 (Department No. 2). Effective doses were calculated based on dose-length product values using appropriate conversion coefficients in accordance with methodological guidelines MU 2.6.1.3584-19. Results. The study results showed that in Department No. 1, 1 % of patients (18 individuals) received cumulative doses exceeding 100 mSv, with a maximum value of 239 mSv. In Department No. 2, the corresponding figure was 0.3 % (9 individuals), with a maximum dose of 147 mSv. The dose accumulated over both extended periods (up to a year) and short intervals (less than a month). A comparison of the obtained results with international data showed that cumulative effective doses more than 100 mSv are often observed in non-oncological patients, including patients under the age of 40. In the study sample, most patients were over 40 years old. Justification and optimization of computed tomography examinations are the main tools for managing high cumulative effective doses in patients. It is important to emphasize the need to assess not only effective but also absorbed organ doses during multiple computed tomography examinations, especially when planning radiation therapy. Conclusions. Systematic monitoring of high cumulative effective doses in patients is necessary in the Russian Federation, particularly among younger patients.