Exposure rates during special procedures with C-arm type fluoroscopic systems

Area of Science:

• Medical Physics
• Radiological Sciences
• Biomedical Engineering

Background:

• Regulatory compliance for C-arm fluoroscopic equipment often relies on entrance air kerma rate (EAKR) measurements under specific, non-representative conditions.
• Standard measurement protocols may not reflect actual patient geometries, potentially leading to inaccurate radiation dose assessments.

Purpose of the Study:

• To evaluate the impact of typical patient geometries on EAKR measurements in C-arm fluoroscopic systems.
• To compare EAKRs measured under standard compliance conditions versus those under realistic clinical scenarios.

Main Methods:

• Observed and recorded typical patient geometries during 23 consecutive body vascular procedures.
• Measured EAKRs using five modern C-arm systems under both compliance and observed patient geometries.

Main Results:

• Typical source-to-image receptor distances (SIDs) of 1 m were observed, with patient entrance skin surface approximately 500 mm from the image receptor.
• Actual EAKRs were found to be up to 2.5 times higher than those measured under standard compliance geometry.

Conclusions:

• Standard compliance geometry measurements underestimate actual EAKRs in C-arm fluoroscopy.
• Accurate estimation of patient radiation doses necessitates utilizing actual patient geometries during EAKR measurements.