CBCTs in a Swiss university dental clinic: a retrospective evaluation over 5 years with emphasis on radiation protection criteria

OBJECTIVES: To retrospectively evaluate all cone-beam computed tomography (CBCT) scans acquired from 2017 to 2022 in a Swiss university dental clinic with particular emphasis on radiation protection aspects. MATERIAL AND METHODS: Radiological databases at the dental clinic of the University of Bern, Switzerland, were explored using a self-developed search algorithm. Data of all acquired CBCT from 01.01.2017 to 27.06.2022 were screened. Exposure parameters (exposure time, exposure angle, milliampere (mA), kilovoltage (kV), field of view (FOV) size), dose area product (DAP), age, and sex of the patient were recorded anonymously. The collected data were analyzed mainly descriptively. Correlations measured the statistical relationships between the variables. RESULTS: A total of 10,348 CBCT datasets were analyzed. Patient age ranged from 5 to 96 years (mean: 49.4 years, SD: 21.6 years). The number of CBCTs in patients under 25 years was around 20% each year. In total, 10,313 (99.7%) CBCTs were acquired in small to medium FOV (FOV up to 10 cm of height), and 35 (0.3%) in large FOV (height > 10 cm). DAPs of small FOVs were 518.3 ± 233.2 mGycm(2) (mean ± SD), of medium FOV 1233 ± 502.2 mGycm(2), and of large FOV 2189 ± 368.7 mGycm(2). DAP (ρ = 0.4048, p < 0.0001) and kV (ρ = 0.0210, p = 0.0327) correlated positively with age. Reduced scan angle correlated with young age (r(pb) 0.2729, p < 0.001). mA did not correlate with age (p = 0.3685). CONCLUSIONS: This study demonstrates that certain well-known radiation protection aspects as the reduction of FOV, mA, kV, and scan angle were only partly considered. CLINICAL RELEVANCE: Known radiation protection aspects, especially in young patients, should be fully applied in regular clinical practice.