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

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.

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.

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.

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.

· 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..

· 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.