IRSA ASM 2024 Abstract

Purpose: Minimising proceduralist radiation exposure during CT intervention is important for proceduralist and patient safety.This study aimed to first retrospectively assess patient exposure and scanner parameters during CT interventions to subsequently inform prospective interventionalist exposure testing based on location and shielding.Materials and methods: A retrospective study reviewed 1019 CT interventions.Parameters including procedure type, exposure via DLP, tube current and voltage were evaluated.Those associated with minimised exposures were used to prospectively assess interventionalist exposure using a CT phantom.Exposures were measured at 10 positions in the scanner room, with/without shielding.Statistical analysis assessed differences in exposures between locations.Results: Factors most correlated with interventional DLP by multivariable logistic regression modelling include axial/helical scanning, number of interventional scans and scanner parameters optimised to tube voltage of 100 kV and current of 60 mA.Using these settings, exposures measured at 10 locations using phantom modelling demonstrate significantly lower exposures for interventionalists positioned outside the scanner room, and to the side of the gantry, with lower exposures further from the scanner.Scatter from multiple orthogonal directions was considered, rather than only direct exposure.Shielding significantly reduced exposure, especially when accounting for multidirectional scatter.Exposures are below ICRP occupational thresholds.Conclusion: Using optimised scanner parameters from a retrospective study to inform a prospective phantom model, the lowest exposures are observed outside the scanner room, or in the corner of the room in the shadow of the gantry, with full body shielding.Considering shielding form multidirectional scatter and dosimetric optimisation of position with different scanner setups can minimise interventionalist exposures.