Beyond phantom testing: a dose-management-based approach for evaluation of AEC performance in interventional...

To develop and validate a method for assessing the performance and long-term constancy of Automatic Exposure Control (AEC) in interventional fluoroscopy using retrospectively collected clinical data from a Radiation Dose Management System (RDMS).

The method uses the system-reported Patient Equivalent Thickness (PET) as a surrogate for PMMA attenuation, enabling continuous evaluation of the air kerma rate-thickness response under clinical conditions. Three angiographic systems from two different manufacturers were monitored over two years (>135,000 fluoroscopic and acquisition events in the RDMS). Air kerma-rate data were grouped in 1-cm PET bins and analysed quarterly. Temporal deviations in the median air kerma rate and interquartile range (IQR) were computed relative to a reference quarter, and exponential air kerma rate-thickness fits were used to derive compensation coefficients (λ) as indicators of AEC stability.

PET was experimentally validated against PMMA and water thickness (R² > 0.98). One of the systems showed stable AEC behaviour, with quarterly median deviations within ± 5% and λ variations within a proposed ± 0.02 cm⁻¹ tolerance. In the other system, a 72% deviation was observed due to a detector failure; normal performance was restored after detector replacement and protocol updates. Outside this event, all systems remained within EFOMP ± 20% constancy limits.

RDMS-based PET analysis reliably reproduces phantom-derived ESAKR-thickness behaviour and enables continuous, clinically driven AEC surveillance. The method is sensitive to hardware faults and configuration changes, and provides a robust complement-not a replacement-to periodic phantom-based AEC testing.