Dose optimization in cone-beam CT: impact of upper limb placement on patient and procedural exposure

Cone beam computed tomography (CBCT) is increasingly used during complex endovascular repair of aortic pathology, yet factors influencing CBCT radiation dose remain poorly understood. This study evaluates the impact of arm positioning and CBCT protocol type on radiation exposure.

Single-center, retrospective analysis of patients undergoing complex endovascular aortic repair with intraoperative CBCT between September 2021 and October 2023. Patients were stratified based on arm positioning (arms up vs. arms down) and CBCT protocol (4sDR 125 kVp Care Protocol vs. 4sDR Surgery Protocol). Primary outcomes included CBCT-specific radiation dose and total procedural radiation exposure.

A total of 96 patients were included, 30 (31.2%) positioned with arms-up and 66 (68.8%) with arms-down. No significant differences in CBCT radiation exposure were observed between arms-up and arms-down positioning. A strong correlation was found between BMI and CBCT effective dose (r=0.45, P<0.001). While the 4sDR 125 kVp Care Protocol resulted in lower CBCT-specific radiation (P=0.013), total procedural radiation exposure did not differ between protocols (P=0.20). Fluoroscopy and DSA were the main contributors to overall procedural radiation dose.

Patient arm positioning does not significantly affect CBCT radiation dose. BMI is a key determinant of radiation exposure, underscoring the need for size-specific imaging protocols. Despite differences in CBCT protocol radiation levels, total procedural radiation exposure remains similar due to the cumulative effect of fluoroscopy and DSA. Future research should focus on optimizing imaging strategies to minimize radiation exposure while maintaining procedural efficacy.