Inter- and intra-individual radiation dose variability in oncologic chest and abdominal computed tomography

Purpose: Computed tomography (CT) plays a central role in oncologic imaging, yet repeated examinations contribute substantially to cumulative radiation exposure. This study aimed to evaluate inter- and intra-individual radiation dose variability in chest and abdominal CT and the impact of CT device model and protocol standardization. Materials and Methods: In this retrospective single-center study, 42441 CT scans from 4986 adult oncologic patients were analyzed. Dose metrics (CTDIvol, DLP, SSDE, effective dose) were extracted using automated dose monitoring. Inter- and intra-individual radiation dose variability was assessed across four CT device models and various protocol subtypes. Intra-individual radiation dose variability was calculated relative to the lowest dose per patient and compared across CT devices and protocol subtypes. Results: Radiation dose varied substantially between devices, with CTDIvol differences of up to 2.4-fold in chest CT (2.98-7.26 mGy) and 1.7-fold in abdominal CT (5.26-8.77 mGy). The median intra-individual radiation dose variability was 93.7% (IQR 19.8-142.0%) in non-contrast chest CT, 66.3% (31.1-105.4%) in contrast-enhanced chest CT, 19.8% (11.8-32.3%) in non-contrast abdominal CT, and 28.2% (16.6-41.0%) in contrast-enhanced abdominal CT. When consecutive scans were performed on the same scanner, intra-individual radiation dose variability decreased to 14.7% (IQR 8.1-33.1%), 18.1% (9.5-31.3%), 11.7% (7.8-19.8%), and 15.3% (8.3-24.7%), respectively, indicating substantial device-specific effects. Conclusion: Significant radiation dose variability persists in oncologic CT, both between and within patients, despite the use of standardized protocols. Device-adapted dose management and consistent device use may improve dose consistency, support optimization in oncologic imaging, and reduce radiation exposure. Key Points: · Substantial radiation dose variability persists across CT devices despite protocol standardization.. · Intra-individual radiation dose variability is significant and highest in non-contrast chest CT.. · Consistent use of the same scanner reduces intra-individual radiation dose variability significantly.. · Internal diagnostic reference levels may improve radiation dose consistency and minimize exposure.. Citation Format: · Moradians AF, Rosok D, Serger R et al. Inter- and intra-individual radiation dose variability in oncologic chest and abdominal computed tomography. Rofo 2026; DOI 10.1055/a-2786-2534.