Introduction: Diagnostic reference levels are an important tool for monitoring and optimizing patient exposure to ionizing radiation. The development of intraoperative X-ray systems requires regular monitoring of dosimetric indicators and the establishment of typical values for individual procedures. Purpose: The purpose of this study was to determine typical dose-area product (DAP) values for selected intraoperative X-ray procedures at the University Medical Centre Ljubljana and to assess differences between the X-ray systems used. Methods: A retrospective study with secondary data analysis was conducted, including data from 495 patients collected between January and June 2025. Patient body weight, DAP, and fluoroscopy time were analysed for proximal femoral nail (PFN) insertion, partial hip arthroplasty (PEP), proximal humeral nail (PHN) insertion, tibial nail (ETN) insertion, spinal fixation, deep brain stimulation (DBS), and guided spinal fixation. Typical DAP values were determined using the median. Differences between X-ray systems were statistically analysed at a significance level of p < 0.05. Results: Typical DAP values were 67.33 µGym² for PFN, 11.33 µGym² for PEP, 16.00 µGym² for PHN, 17.88 µGym² for ETN, 314.51 µGym² for spinal fixation, 213.42 µGym² for DBS, and 186.69 µGym² for guided spinal fixation. No statistically significant differences in DAP between X-ray systems were observed for PFN (p = 0.965), ETN (p = 0.615), or spinal fixation (p = 0.605), whereas statistically significant differences were found for PEP (p < 0.001) and PHN (p < 0.001). Compared with a previous study conducted at the University Medical Centre Ljubljana in 2018, typical values for PFN, PEP, and PHN were 9.0%, 33.4%, and 54.3% lower, respectively, whereas the value for spinal fixation was 97.8% higher. Discussion and conclusion: The established typical values demonstrate substantial differences in patient exposure among different types of intraoperative X-ray procedures, highlighting the importance of procedure-specific monitoring for the optimization of radiation protection. For most procedures, no statistically significant differences in DAP were observed between X-ray systems, while the differences identified for PEP and PHN indicate the need for continued monitoring. The first systematically collected data for DBS and spinal fixation using the O-arm system provide a basis for further monitoring.
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